September 14, 2007
Development of “Oil Feeding-free Chain Tensioner” for Timing Chains
[ Oil feeding from engine is unnecessary ]
NTN Corporation (hereafter NTN) has developed an “Oil feeding-free chain tensioner”, which does not require oil feeding from the engine for chain tensioners integrated in a timing drive system that maintain proper tension of timing chain.
In recent years, hydraulic equipment such as variable valve timing systems is increasing and that has resulted in an increase in oil consumption in engines. To feed enough oil to the engine requires a larger oil pump, but this also makes the engine larger and increases the engine load that results in lowered fuel economy. NTN developed hydraulic chain tensioners utilizing oil fed from the engine as an oil damper and is currently mass-producing them, but NTN was requested from automakers to eliminate using oil fed from engine.
The newly developed oil feeding-free chain tensioner uses a spring damper as the damping mechanism and does not require oil feeding from the engine, but attains the same tension adjustment performance as that of a conventional hydraulic chain tensioner. Furthermore, it uses the same unique thread (buttress thread) as the conventional product that has a continuous no-back function* that enables a reduction in engine starting noise. Also, an advantage of making the tensioner oil feeding-free is that piping for oiling in engine becomes unnecessary.
NTN is presenting this new product to the global market as a necessary contribution to improved vehicle fuel economy.
| *Continuous no-back function : | Rod is kept at any (continuous) protrusion position. Without the function, there may be a case that plunger is pushed in when engine is stopped under the condition that the chain is tensioned. When the engine is re-started under this condition and the chain comes loose, noise generates at the mating position of camshaft and crankshaft. |
[Features]
| - | Oil feeding from engine is unnecessary |
| - | Piping for oiling in engine is unnecessary |
| - | Same tension adjustment function as conventional hydraulic chain tensioner |
| - | Continuous no-back function |
[Application]
| Auto-tensioners for timing chains of four wheel vehicle and motor cycle |
[Product Photo]
[Fitting position of chain tensioner]
