Actuator pivot shaft rolling bearing with seal

Abstract

A variable turbine geometry turbocharger with an actuator pivot shaft with a rolling-element bearing having a rolling element between an inner race and outer race. Replacing a standard actuator shaft bushing with a rolling-element bearing may reduce friction and adverse movement in certain applications. Various seals may be feasible, such as a face seal attached to the inner or outer bearing race that could seal against the opposing race.

Description

BACKGROUND[0001]1. Field of the Disclosure[0002]This disclosure relates to turbochargers with variable turbine geometry with an actuator pivot shaft. Specifically, this disclosure relates to replacing a standard actuator shaft bushing with a rolling-element bearing.[0003]2. Description of Related Art[0004]Advantages of turbocharging include increased power output, lower fuel consumption and reduced pollutant emissions. The turbocharging of engines is no longer primarily seen from a high-power performance perspective, but is rather viewed as a means of reducing fuel consumption and environmental pollution on account of lower carbon dioxide (CO2) emissions. Currently, a primary reason for turbocharging is using exhaust gas energy to reduce fuel consumption and emissions. In turbocharged engines, combustion air is pre-compressed before being supplied to the engine. The engine aspirates the same volume of air-fuel mixture as a naturally aspirated engine, but due to the higher pressure, ...

AI Technical Summary

Benefits of technology

The text describes a special type of bearing that uses tiny rolling elements to carry heavy loads. These elements move smoothly and with very little friction. This type of bearing can be designed to have very little movement in the axial and radial directions, which makes it ideal for sealing applications. The text also explains that the position and surface finish of the bearing races can be carefully controlled to improve performance. Overall, the patent text describes a new technology that reduces friction and improves the performance of bearings.

Problems solved by technology

Other VTG actuator pivot shafts can experience significant wear in certain applications during operation, presumably from high pressure loading between the bushing and shaft near the fork end of the shaft (turbine side).

Lack of lubrication can cause high friction forces between the shaft and bearing components, reducing available VTG actuation torque.

Furthermore, in certain operations, it may be difficult to seal the shaft to the bearing housing because of clearance between the shaft and bushing and the associated misalignment of the shaft to the bushing / housing.

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