DK28 diesel engine fittings plunger couple

The plunger couple of fuel injection pump is the precision couple of fuel injection pump. It reciprocates at high speed, pressurizes the fuel, and begins to press oil or drain oil within the specified time, is an important part of diesel engine.

Plunger couple parts (plunger sleeve and plunger) commonly used materials are tool steel (CrWMn) or rolling bearing steel (GCrl5). Plunger sleeve and plunger hardness requirements HRC62~65.

Marine diesel engine accessories plunger couple processing precision requirements, it has strict regulations on the performance of sealing, sliding, reliability and life, so that its processing technology is complex, process equipment precision requirements, precision measuring tools.

For medium and small fuel injection pumps, the radial clearance of the plunger couple is generally required to be 1.5~4um. Such high matching accuracy is difficult to achieve the requirement of complete exchange even through the strict tolerance of hole and outer circle size.

Therefore, the actual production is to use the amplification of the respective manufacturing tolerances of the couple. Then, according to the size of the production batch, single matching method or group matching method is selected to ensure the assembly requirements of even parts.