Gear

Abstract

A gear in which forged chamfered portions are formed on the respective ridge line portions at intersections between tooth bottom lands, tooth flanks, and a tooth tip land of the gear and end faces in the axial direction of the gear, and which does not need machining such as cutting to remove burrs caused by hobbing in the conventional techniques.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing the main portion of the gear according to the first embodiment of the present invention;

FIG. 2 is a perspective view showing the main portion of the gear according to the second embodiment of the present invention;

FIGS. 3A-3C are perspective views and edge view wholly showing the gear according to the second embodiment of the present invention;

FIG. 4 is a partially cutaway perspective view of the gear according to the second embodiment of the present invention;

FIG. 5 is an enlarged perspective view of the section surrounded by the circle D (shown in FIG. 3C) in the gear according to the second embodiment of the present invention;

FIGS. 6A-6D are enlarged partially cut away perspective views of the section B of FIG. 4 and sectional views respectively along the H-H line, along the G-G line, and along the F-F line in FIG. 6A in the gear according to the second embodiment of the present invention;

FIG. 7 is a perspective view wholly showing a die for shaping the gear according to the second embodiment of the present invention by forging;

FIG. 8 is a development of an upper die, a lower die and the forged work gear according to the second embodiment of the present invention;

FIG. 9 is an enlarged perspective view of the portion E of the die in the FIG. 7;

FIG. 10 is an enlarged partially cut away perspective view of the die along with A-A in FIG. 8 according to the second embodiment of the present invention;

FIGS. 11A-11D are enlarged perspective views of the portion B of the die in FIG. 10 according to the second embodiment of the present invention;

FIG. 12 is a process chart showing hot forging process in the manufacturing method according to the second embodiment of the present invention;

FIG. 13 is a process chart showing cold forging process in the manufacturing method according to the second embodiment of the present invention;

FIG. 14 is a partially enlarged perspective view of the gear according to the third embodiment of the present invention;

FIG. 15 is a partially enlarged perspective view of the die according to the third embodiment of the present invention;

FIG. 16 is a sectional view explaining uniform impregnation of the material in the die according to the third embodiment of the present invention;

FIGS. 17A-17C are explanatory drawings explaining fiber flows and density of the texture according to the third embodiment of the present invention;

FIG. 18 is a perspective view showing the main portion of the gear according to the fourth embodiment of the present invention; and

FIG. 19 is a perspective view showing the main portion of the gear according to the fifth embodiment of the present invention.

Claims

1. A gear, wherein forged chamfered portions are formed on the respective ridge line portions at intersections between tooth bottom lands, tooth flanks, and a tooth tip land of the gear and end faces in the axial direction of the gear.

2. The gear according to claim 1, wherein forged chamfered portions are further formed on straight ridge line portions between the tooth bottom lands and the tooth flanks of the gear.

3. The gear according to claim 2, wherein forged chamfered portions are further formed on straight ridge line portions between the tooth flanks and the tooth tip land of the gear.

4. The gear according to claim 2, wherein forged chamfered portions are further formed on ridge line portions at intersections between said forged chamfered portions between the tooth bottom lands and the tooth flanks of the gear and end faces in the axial direction of the gear.

5. The gear according to claim 3, wherein forged chamfered portions are further formed on ridge line portions at intersections between said forged chamfered portions between the tooth flanks and the tooth tip land of the gear and end faces in the axial direction of the gear.

6. The gear according to claim 5, wherein said forged chamfered portions formed on ridge line portions at intersections between the tooth bottom lands, the tooth flanks, and the tooth tip land of the gear and the end faces in the axial direction of the gear are respectively formed by round chamfering.

7. The gear according to claim 6, wherein the curvatures of said round chamfering are different from each other.

8. The gear according to claim 7, wherein joint portions between forged chamfered portions adjacent to each other formed on ridge line portions at intersections between the tooth bottom lands, the tooth flanks, and the tooth tip land of the gear and the end faces in the axial direction of the gear are formed at a curvature that is gradually changed.

9. The gear according to claim 8, wherein the gear is formed by forging a material shaped so as to increase a tooth width of the gear toward the tooth tip, and inserted into a die having chamfered portions for forge-shaping chamfered portions on the respective ridge line portions at intersections between the tooth bottom lands, the tooth flanks, and the tooth tip land and end faces in the axial direction of the gear.

10. A gear, wherein round forged chamfered portions are formed on the respective ridge line portions at intersections between tooth bottom lands, tooth flanks, and a tooth tip land of the gear to be shaped by forging and end faces in the axial direction of the gear.

11. The gear according to claim 5, wherein the respective chamfered portions formed on the respective ridge line portions at intersections between the tooth bottom lands, the tooth flanks, and the tooth tip land of the gear and end faces in the axial direction of the gear are formed by round chamfering at a predetermined constant curvature.

12. The gear according to claim 7, wherein joint portions between chamfered portions adjacent to each other formed on the respective ridge line portions at intersections between the tooth bottom lands, the tooth flanks, and the tooth tip land of the gear and end faces in the axial direction of the gear are formed by round chamfering at a predetermined constant curvature.