NIPPON PISTON RING CO., LTD.
239Patents
50Active
239Granted
45Portfolio score
Filing activity: Dec 5, 1973 → Jul 15, 2022 · 14 expiring within 5 years
Most-cited patents
| Patent | Title | Area | Cited by | Status |
|---|---|---|---|---|
| US4570316A | Method for manufacturing a rotor for a rotary fluid pump | Emerging Cross-Sectional Technologies | 75 | Expired |
| US6139599A | Abrasion resistant iron base sintered alloy material for valve seat and valve seat made of iron base sintered alloy | Chemistry; Metallurgy | 43 | Expired |
| US5272930A | Mechanical element having a shaft pressure-fitted into an engaging member and its manufacturing method | Emerging Cross-Sectional Technologies | 40 | Expired |
| US4644912A | Cam shaft and method of manufacture | Emerging Cross-Sectional Technologies | 39 | Expired |
| US4222575A | Shaft seal device | Mechanical Engineering; Lighting; Heating | 38 | Expired |
| US5273570A | Secondary hardening type high temperature wear-resistant sintered alloy | Chemistry; Metallurgy | 36 | Expired |
| US4419413A | Powder molding method and powder compression molded composite article having a rest-curve like boundary | Emerging Cross-Sectional Technologies | 35 | Expired |
| US6553957B1 | Combination of cylinder liner and piston ring of internal combustion engine | Mechanical Engineering; Lighting; Heating | 30 | Expired |
| US4185842A | Seal ring | Emerging Cross-Sectional Technologies | 29 | Expired |
| US8733313B2 | Iron-based sintered alloy for valve seat, and valve seat for internal combustion engine | Mechanical Engineering; Lighting; Heating | 29 | Active |
| US5895517A | Sintered Fe alloy for valve seat | Chemistry; Metallurgy | 28 | Expired |
| US5419217A | Machine element with at least a fitting member pressure-fitted on a shaft and method of making the same | Emerging Cross-Sectional Technologies | 27 | Expired |
| US10605374B2 | Valve seat insert excellent in wear resistance made of iron-base sintered alloy for internal combustion engines, and assembly of valve seat insert and valve | Chemistry; Metallurgy | 25 | Active |
| US4198195A | Rotary fluid pump or compressor | Mechanical Engineering; Lighting; Heating | 23 | Expired |
| US4093239A | Piston rod sealing arrangement for a stirling engine | Emerging Cross-Sectional Technologies | 23 | Expired |
| US4632074A | Wear-resistant member for use in internal combustion engine and method for producing the same | Emerging Cross-Sectional Technologies | 22 | Expired |
| US4708029A | Camshaft | Emerging Cross-Sectional Technologies | 22 | Expired |
| US4969262A | Method of making camshaft | Emerging Cross-Sectional Technologies | 22 | Expired |
| US4595556A | Method for manufacturing camshaft | Emerging Cross-Sectional Technologies | 22 | Expired |
| US4904302A | Roller in rotary compressor and method for producing the same | Mechanical Engineering; Lighting; Heating | 19 | Expired |
| US4472350A | Method of making a compound valve seat | Emerging Cross-Sectional Technologies | 19 | Expired |
| US5092361A | Inline type check valve | Emerging Cross-Sectional Technologies | 19 | Expired |
| US4612695A | Method of manufacturing a hollow cam shaft | Emerging Cross-Sectional Technologies | 19 | Expired |
| US4345943A | Abrasion resistant sintered alloy for internal combustion engines | Chemistry; Metallurgy | 18 | Expired |
| US5466276A | Valve seat made of secondary hardening-type high temperature wear-resistant sintered alloy | Chemistry; Metallurgy | 18 | Expired |
Source: USPTO / EPO open patent data. Counts and citation impact are objective bibliographic measures.