# US 7,612,310 B2 · Manufacturing method of a molded gear > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,612,310 B2 - Document ID: US7612310B2 - Status: Granted - Kind: B2 - Application number: 11/386,823 - Filed: 2006-03-23 - Published: 2006-11-23 - Granted: 2009-11-03 - Earliest claimed: 2005-03-23 - Assignees: Enplas Corporation - Inventors: Masaaki Ojima; Yasutoshi Yoshida - Web page: https://patentgrep.com/patent/US7612310B2 ## CPC - B23P 15/14: gear parts, e.g. gear wheels - B23H 9/003: {Making screw-threads or gears} - B29C 45/26: Moulds - B29L 2015/003: {Gears} - F16H 55/0873: {for improving axial engagement, e.g. a chamfer at the end of the tooth flank} - B23P: METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS (arrangements for copying or controlling B23Q) - B23H: WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL (processes for the electrolytic or electrophoretic production of coatings, electroforming, or apparatus therefor C25D; processes for the electrolytic removal of material from objects C25F; manufacturing printed circuits using precipitation techniques to apply the conductive material to form the desired conductive pattern H05K3/18) - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES - F16H: GEARING ## Abstract A gear piece having a hollow portion of the same shape as a molded gear is formed by performing electrical discharge-machining with respect to a metal member that is smaller in thickness than a tooth width dimension of the molded gear, using a first discharging electrode; a chamfer-application piece having a recess portion of the same shape as the chamfered portions of the molded gear is formed by performing electrical discharge-machining by only a predetermined depth with respect to other metal member, using a second discharging electrode; a molding die is assembled by according the hollow portion of the gear piece with the recess portion of the chamfer-application piece; and the molded gear is manufactured by forming a gear member using the molding die. ## Claims ### Claim 1 A manufacturing method of a molded gear having a plurality of teeth, each being provided with a chamfered portion shaped by providing a slope in one end edges of the tooth, wherein the manufacturing method comprises: the steps of: performing electrical discharge-machining of a metal member having a thickness smaller than a dimension of a tooth width of the molded gear by moving a first discharging electrode that is formed to have the same shape as a cross-sectional shape taken perpendicularly to a rotation axis of the molded gear while penetrating the metal member in a direction of thickness thereof until a gear piece is formed to have a hollow portion the same in a shape thereof as the molded gear; performing electrical discharge-machining of a different metal member only a predetermined depth in a direction of thickness of the different metal member by moving a second discharging electrode that is formed to have a shape the same as a cross-sectional shape taken perpendicularly to the rotation axis of the molded gear and also to have a chamfered slope portion the same in a shape thereof as the chamfered portion of each tooth on a tip end of the second discharging electrode until a chamfer-application piece having a recess portion the same in a shape thereof as the chamfered portions of the molded gear; bringing the hollow portion of the gear piece and the recess portion of the chamfer-application piece to be in registration with each other and subsequently connecting the gear piece to the chamfering piece to thereby assemble a molding die; and manufacturing a molded gear by molding a gear forming material by using the assembled molding die. ### Claim 2 (depends on 1) The manufacturing method for the molded gear according to claim 1, wherein a combined value of thickness of said gear piece and processing depth of said chamfer-application piece is substantially equal to the tooth width of said gear. ### Claim 3 (depends on 2) The manufacturing method for the molded gear according to claim 2, wherein said gear forming material comprises resin. ### Claim 4 (depends on 1) The manufacturing method for the molded gear according to claim 1, wherein said gear forming material comprises resin. ### Claim 5 A manufacturing method of a molded gear having a plurality of teeth, each being provided with chamfered portion formed with slopes provided on one end edges of each tooth, wherein the manufacturing method comprises the steps of: performing electrical discharge-machining of a metal member having a thickness smaller than a dimension of a tooth width of the molded gear by moving a discharging electrode that is formed to have the same shape as a cross-sectional shape taken perpendicularly to a rotation axis of the molded gear and also to have a chamfered slope portion the same in a shape thereof as the chamfered portion of each tooth on a tip end of the discharging electrode while penetrating the metal member in a direction of thickness thereof until a gear piece is formed to have a hollow portion the same in a shape thereof as the molded gear; performing electrical discharge-machining of a different metal member only a predetermined depth in a direction of thickness of the different metal member by moving the discharging electrode until a chamfer-application piece having a recess portion the same in a shape thereof as the chamfered portions of the molded gear; bringing the hollow portion of the gear piece and the recess portion of the chamfer-application piece to be in registration with each other and subsequently connecting the gear piece to the chamfer-application piece to thereby assemble a molding die; and manufacturing the molded gear by molding a gear forming material by using the assembled molding die. ### Claim 6 (depends on 5) The manufacturing method for the molded gear according to claim 5, wherein a combined value of thickness of said gear piece and processing depth of said chamfer-application piece is substantially equal to the tooth width of said gear. ### Claim 7 (depends on 5) The manufacturing method for the molded gear according to claim 5, wherein said gear forming material comprises resin.