US5722295A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Injection-molded gear for engine and manufacturing method therefor
Assignee: Subaru Corp
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Filing: 1996-09-25
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Granted: 1998-03-03
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Expires: 2016-09-25
Abstract
Abstract An injection-molded gear for an utility engine has a high reliability, tenacity, and accuracy, capable of being manufactured at low cost without requiring cutting, and ensuring a substantial reduction in noise. An inner part of a cam crankshaft gear is formed of an insert ring of a sintered iron alloy. An outside portion and a toothed crest portion of the gear are formed by injection-molding a polyamide resin such as nylon 66 and heat-treating the resulting molded product so that its relative viscosity is equal to or larger than 3.5. The relative viscosity is defined as η/η 0 where η 0 is a viscosity of sulfuric acid of 98% concentration and η is a viscosity of a solution of the 98% sulfuric acid in which the polyamide resin is dissolved at a concentration of 1.0%.
Inventors
- 👤 Mitsugu Sakai
- 👤 Yoshimitsu Tateno
- 👤 Kiyoshi Arai
- 👤 Katsuharu Morioka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 13:29
CPC Classifications
F; F16; F16H; F16H55/00; F16H55/02; F16H55/06; Y; Y10; Y10S; Y10S74/00; Y10S74/10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49462; Y10T29/49467; Y10T29/4948; Y10T74/00; Y10T74/19; Y10T74/1987; Y10T74/19893; Y10T74/19907
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
93 words
An injection-molded gear for an engine, comprising: an inside portion; and a toothed outside portion formed around said inside portion, at least said toothed outside portion being molded from a polyamide resin, said portion of the polyamide resin having a relative viscosity equal to or larger than 3.5, said relative viscosity being defined as η/η 0 where η 0 is a viscosity of sulfuric acid of 98% concentration and η is a viscosity of a solution of the 98% sulfuric acid in which the polyamide resin is dissolved at a concentration of 1.0%.
Claim 2
Dependent Claim
93 words
An injection-molded gear for an engine, comprising: an inside portion; and a toothed outside portion formed around said inside portion, at least said toothed outside portion being molded from a polyamide resin, said portion of the polyamide resin having a relative viscosity equal to or larger than 3.5, said relative viscosity being defined as η/η 0 where η 0 is a viscosity of sulfuric acid of 98% concentration and η is a viscosity of a solution of the 98% sulfuric acid in which the polyamide resin is dissolved at a concentration of 1.0%.
Claim 3
Dependent Claim
18 words
The injection-molded gear according to claim 1, wherein: said polyamide resin is a sole constituent of the gear.
Claim 4
Dependent Claim
32 words
The injection-molded gear according to claim 1, wherein: said inside portion comprises an insert ring separate from said toothed outside portion, said toothed outside portion being integrally molded around said insert ring.
Claim 5
Dependent Claim
20 words
The injection-molded gear according to claim 3, wherein: said polyamide resin is a sole constituent of the toothed outside portion.
Claim 6
Dependent Claim
16 words
The injection-molded gear according to claim 3, wherein: said insert ring is made of a metal.
Claim 7
Dependent Claim
15 words
The injection-molded gear according to claim 5, wherein: said metal is a sintered iron alloy.
Claim 8
Independent Claim
90 words
A method for manufacturing an injection-molded gear for an engine, comprising the steps of: molding a polyamide resin to form a toothed gear configuration to obtain a molded product; and processing the molded product to have a relative viscosity equal to or larger than 3.5, said relative viscosity being defined as η/η 0 where η 0 is a viscosity of sulfuric acid of 98% concentration and η is a viscosity of a solution of the 98% sulfuric acid in which said polyamide resin is dissolved at a concentration of 1.0%.
Claim 9
Independent Claim
90 words
A method for manufacturing an injection-molded gear for an engine, comprising the steps of: molding a polyamide resin to form a toothed gear configuration to obtain a molded product; and processing the molded product to have a relative viscosity equal to or larger than 3.5, said relative viscosity being defined as η/η 0 where η 0 is a viscosity of sulfuric acid of 98% concentration and η is a viscosity of a solution of the 98% sulfuric acid in which said polyamide resin is dissolved at a concentration of 1.0%.
Claim 10
Dependent Claim
30 words
The method according to claim 5, further comprising the steps of: providing an insert ring of a metal; and thereafter carrying out said step of molding around said insert ring.
Claim 11
Dependent Claim
17 words
The method according to claim 7, wherein: said step of processing is carried out in a vacuum.
Claim 12
Dependent Claim
17 words
The method according to claim 9, wherein: said vacuum is equal to or smaller than -500 mmHg.
Claim 13
Dependent Claim
18 words
The method according to claim 7, wherein: said step of processing is carried out in an inert gas.
Claim 14
Dependent Claim
12 words
The method according to claim 11, wherein: said inert gas is nitrogen.
Claim 15
Dependent Claim
12 words
The method according to claim 11 wherein: said inert gas is helium.
Claim 16
Dependent Claim
36 words
The method according to claim 7, wherein said step of processing is carried out at a temperature higher than half a melting point of the polyamide resin and lower than the melting point by 10° C.
Claim 17
Dependent Claim
41 words
The method according to claim 7, wherein: said viscosities are determined by measuring times needed for a predetermined amount of said sulfuric acid and the same amount of said solution to flow down a pipe by a predetermined vertical distance, respectively.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-03-02 | 2001-09-01 | 2002-03-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-03-02 | 2005-09-01 | 2006-03-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-03-02 | 2009-09-01 | 2010-03-03 | $7700.00 | Window Closed / Lapsed |