Wastegate devices for internal combustion engines

Abstract

An exhaust gas valve device for an internal combustion engine is known, which has a flow housing (10), a valve body (14), a shaft (16), at least one radial bearing (26, 28), a sealing device (44), The flow housing defines a flow channel (12), the valve body (14) is fixed on the shaft, and the shaft (16) is connected to at least one of the flow housing (10) through the radial bearing. Mounted radially in bearing receptacles (22, 24), the sealing device has a ceramic disk (48) and a sleeve (50) fastened to the shaft (16). In order to reduce the coefficient of friction and wear between the axial bearing and the ceramic disk and to improve the tightness, it is proposed that the axial bearing (40) is fixed in the bore (34) and is made of sintered metal powder of an iron alloy with a high chromium content , and has an austenitic and ferritic composite structure with a carbide alloy composition and a uniformly distributed solid lubricant phase, and is axially loaded relative to a ceramic disk (48) which is free to rotate ground around the shaft (16).

Description

Technical field [0001] The invention relates to an exhaust gas valve device for an internal combustion engine, which has a flow housing, a valve body, a shaft, at least one radial bearing, and a sealing device. The flow housing defines a flow channel, and the valve body is fixed on the The sealing device has a ceramic disk and a sleeve fixed on the shaft. Background technique [0002] Such a wastegate arrangement can be produced, for example, in the form of a butterfly valve and used, for example, as an exhaust gas recirculation flap or an exhaust gas trap flap. [0003] When designing such a wastegate device, special attention must be paid to the seals and axial bearings used, which on the one hand must work as frictionlessly as possible and on the other hand must withstand increased thermal loads and Reliable sealing even in aggressive environments found in the exhaust gas range. The material pair used in the seal is particularly relevant here, since thermal expansion mu...

AI Technical Summary

Problems solved by technology

[0005] However, the problem with such a sealing device is that the sleeve made of steel and the ceramic disc are subject to significantly increased wear due to the pressure transmitted by the spring, although mainly a good sealing effect is achieved, which significantly limits this type of seal. Seal Persistence

In addition, ensuing wear also increases the necessary adjusting force, since the friction increases significantly

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