US4772340A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making iron-base articles having a remelted layer
Assignee: Honda Motor Co Ltd
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Filing: 1988-01-15
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Granted: 1988-09-20
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Expires: 2008-01-15
Abstract
Abstract An iron-base article such as a camshaft has a remelted layer of high wear resistance on a cam surface, for example. To make such an iron-base article, molten metal is poured into a mold with a chill set therein to cast an iron-base article having a chilled region formed in contact with said chill. Then, metal powder which provides wear resistance upon being mixed is added to at least a portion of said chilled region. A high level of energy is applied to the portion of the chilled region to heat and remelt the same, and the remelted portion is thereafter cooled to form a remelted layer therein.
Inventors
- 👤 Masatoshi Kawaguchi
- 👤 Hiroshi Yoshinaga
- 👤 Fusao Nakajima
- 👤 Toshihiko Matsubara
- 👤 Hisao Hirono
- 👤 Masayoshi Higashi
- 👤 Tetsuo Iwahashi
- 👤 Norio Tajima
- 👤 Toshihiko Saga
- 👤 Shohei Hayakawa
- 👤 Akitaka Inou
- 👤 Kunio Kishino
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 23:14
CPC Classifications
B; B23; B23K; B23K9/00; B23K9/04; B23K9/044; Y; Y10; Y10S; Y10S148/00; Y10S148/902; Y10S148/903
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
209 words
A method for remelting and hardening the cam surface of a camshaft the steps comprising: applying a high level of energy from a plasma arc generated by a plasma torch to the cam surface of the camshaft to be remelted and hardened continually at a predetermined obtuse angle to said cam surface to be remelted, the angle said high level of energy is applied to said cam surface varying as said camshaft is rotated so as to maintain said high level of energy continually at said predetermined obtuse angle to said cam surface as said cam shaft and said torch are rotated relative to each other; while applying said high level of plasma arc energy to said cam surface, rotating said plasma torch generating said plasma arc and said cam surface being remelted and hardened with respect to each other and, during said rotating, maintaining said plasma torch applying said energy continually at said predetermined obtuse angle to a line tangential to the cam surface undergoing remelting so that said surface undergoing remelting is slightly lower than the immediately preceding surface remelted while said preceding remelted surface hardens; and continuing said rotating, remelting and hardening until all of said cam surface to be hardened has been remelted and hardened.
Claim 2
Independent Claim
209 words
A method for remelting and hardening the cam surface of a camshaft the steps comprising: applying a high level of energy from a plasma arc generated by a plasma torch to the cam surface of the camshaft to be remelted and hardened continually at a predetermined obtuse angle to said cam surface to be remelted, the angle said high level of energy is applied to said cam surface varying as said camshaft is rotated so as to maintain said high level of energy continually at said predetermined obtuse angle to said cam surface as said cam shaft and said torch are rotated relative to each other; while applying said high level of plasma arc energy to said cam surface, rotating said plasma torch generating said plasma arc and said cam surface being remelted and hardened with respect to each other and, during said rotating, maintaining said plasma torch applying said energy continually at said predetermined obtuse angle to a line tangential to the cam surface undergoing remelting so that said surface undergoing remelting is slightly lower than the immediately preceding surface remelted while said preceding remelted surface hardens; and continuing said rotating, remelting and hardening until all of said cam surface to be hardened has been remelted and hardened.
Claim 3
Dependent Claim
54 words
A method, as recited in claim 1, in which said angle of said plasma torch applying said energy is adjusted as said camshaft and said cam surface are rotated to continually maintain said angle obtuse and said surface undergoing remelting slightly lower than said immediately preceding surface remelting while said preceding remelted surface hardens.
Claim 4
Independent Claim
24 words
A method, as recited in any one of claims 1 to 2, in which said plasma arc is generated by a pulsating arc current.
Claim 5
Dependent Claim
25 words
A method, as recited in claim 3, in which said pulsating arc current comprises a DC arc current with a pulse arc current added thereto.
Claim 6
Dependent Claim
33 words
A method, as recited in claim 4, in which said DC arc current is of a constant magnitude and said pulse arc current is added to said constant DC arc current in pulses.
Claim 7
Dependent Claim
31 words
A method, as recited in claim 5, in which the frequency of said pulse arc current is not substantially less than 2H z and not substantially more than 30H z .
Claim 8
Dependent Claim
31 words
A method, as recited in claim 5, in which the frequency of said pulse arc current is not substantially less than 5H z and not substantially more than 30H z .
Claim 9
Dependent Claim
34 words
A method, as recited in claim 6, in which said pulse arc current is added to and disconnected from said DC arc current of constant magnitude in repeating pulses of substantially equal time duration.
Claim 10
Dependent Claim
49 words
A method, as recited in claim 6, in which the proportion of said equal time duration in which said pulse arc current is added to said DC arc current of constant magnitude is not substantially less than 5% and not substantially more than 95% of the total time duration.
Claim 11
Dependent Claim
49 words
A method, as recited in claim 6 in which the proportion of said equal time duration in which said pulse arc current is added to said DC arc current of constant magnitude is not substantially less than 20% and not substantially more than 80% of the total time duration.
Claim 12
Dependent Claim
49 words
A method, as recited in claim 7, in which the proportion of said equal time duration in which said pulse arc current is added to said DC arc current of constant magnitude is not substantially less than 5% and not substantially more than 95% of the total time duration.
Claim 13
Dependent Claim
49 words
A method, as recited in claim 7, in which the proportion of said equal time duration in which said pulse arc current is added to said DC arc current of constant magnitude is not substantially less than 20% and not substantially more than 80% of the total time duration.
Claim 14
Dependent Claim
49 words
A method, as recited in claim 11, in which said high level plasma arc energy applied to said cam surface forms a shallow pool of molten metal on said cam surface and said repeating pulses of substantially equal time duration vibrate and stir said molten metal in said pool.
Claim 15
Dependent Claim
49 words
A method, as recited in claim 12, in which said high level plasma arc energy applied to said cam surface forms a shallow pool of molten metal on said cam surface and said repeating pulses of substantially equal time duration vibrate and stir said molten metal in said pool.
Claim 16
Dependent Claim
65 words
A method, as recited in claim 13, in which said cam surface to be remelted and hardened is molded with a chill set therein at the region to be remelted and hardened and said chilled region has added thereto a metal powder which provides wear resistance to said surface when said surface is remelted, said metal powder is mixed therein and said surface is hardened.
Claim 17
Dependent Claim
65 words
A method, as recited in claim 14, in which said cam surface to be remelted and hardened is molded with a chill set therein at the region to be remelted and hardened and said chilled region has added thereto a metal powder which provides wear resistance to said surface when said surface is remelted, said metal powder is mixed therein and said surface is hardened.
Claim 18
Dependent Claim
37 words
A method, as recited in claim 10, in which the ratio between the peak value and the base value of said pulse arc current applied to said plasma torch is in a range from 1.5 to 15.
Claim 19
Dependent Claim
37 words
A method, as recited in claim 10, in which the ratio between the peak value and the base value of said pulse arc current applied to said plasma torch is in a range from 2 to 15.
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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) | 1991-09-20 | 1992-03-21 | 1992-09-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-20 | 1996-03-21 | 1996-09-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-20 | 2000-03-21 | 2000-09-20 | $7700.00 | Window Closed / Lapsed |