Vacuum Pump Coupling Disc Assembly for Shaft Eccentricity Compensation
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Solution Overview
Problem
Vacuum pumps experience material fatigue due to radial misalignment between the output shaft of the electric motor and the drive shaft of the pumping system, caused by assembly tolerances, especially at high operating speeds.
Innovation Solution
A clutch arrangement with a wobbling clutch disc that compensates for radial offset between the two shafts through a relative movement defined by two perpendicular linear guides, preventing twisting and subjecting the clutch disc to compressive forces rather than shear stresses, thus avoiding material fatigue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the output shaft of the electric motor is directly coupled to the drive shaft of the pump system, then the connection is torsionally rigid, but assembly tolerances cause radial misalignment that leads to material fatigue at high speeds
Solution Approach 1:
A clutch arrangement with a clutch disk acts as an intermediary between the motor output shaft and the pump drive shaft. The clutch disk compensates for radial misalignment through relative movement along two perpendicular linear guides, eliminating forced stresses while maintaining torque transmission. This mediator allows the two shafts to remain slightly misaligned without causing material fatigue.
Solution Approach 2:
The clutch arrangement introduces dynamic capability to the connection, allowing the clutch disk to move relative to the shafts during operation. This dynamic adjustment compensates for radial offsets that would be problematic in a static rigid connection, enabling the system to adapt to assembly tolerances while maintaining reliability at high speeds.
2Reliability
If a clutch arrangement is introduced to compensate for radial offset, then material fatigue is prevented, but the device complexity increases
Solution Approach 1:
The clutch arrangement is segmented into three main components: a first clutch hub connected to the motor shaft, a second clutch hub connected to the pump drive shaft, and a clutch disk connecting the two hubs. This segmentation allows each component to perform a specific function while keeping the overall structure manageable and maintainable.
Solution Approach 2:
The clutch disk serves as a simple intermediary component that absorbs the complexity of compensation. Rather than making the shafts or bearings complex, the design introduces a single intermediate element that handles the radial offset compensation through its ability to move along the linear guides.
3Power
If the clutch disc is designed to be torsionally rigid for torque transmission, then torque is transmitted effectively, but the clutch disc is subjected to forced stresses that cause material fatigue
Solution Approach 1:
The clutch disk is designed to be dynamically adaptable rather than statically rigid. It maintains sufficient torsional stiffness for torque transmission but allows relative movement along the linear guides to compensate for radial offsets. This dynamic capability prevents forced stresses while maintaining effective power transmission between the shafts.
Solution Approach 2:
The system changes the operational parameters of the clutch disk from a fixed rigid connection to a movable connection with defined degrees of freedom. The clutch disk can move along the linear guides while maintaining torsional connection, effectively changing its mechanical parameters to simultaneously achieve torque transmission and stress avoidance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively compensates for radial offsets without inducing material fatigue, ensuring smooth torque transmission and reducing the risk of deformation and wear, allowing the clutch disc to be designed more delicately with reduced shear stress.
Implementation Method 1
The two linear guides are sliding joints, which allow a linear movement of the clutch disk in the radial direction of the pump shafts, but prevent twisting between the respective clutch partners in the form of the clutch hubs and the clutch disk. However, since the potential directions of movement of the two linear guides are oriented perpendicularly to one another
Implementation Method 2
If a rotation of the output shaft of the electric motor is transmitted to the drive shaft of the pump system via the clutch arrangement and there is a radial offset between the two shafts, this radial offset is compensated for by a relative movement of the clutch disk. In particular, a kind of wobbling movement of the clutch disc occurs here, which compensates for any radial offset between the two shafts.
Data Source
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AI summary
The present disclosure relates to a coupling arrangement and a vacuum pump with a pumping system driven by an electric motor, wherein the electric motor has an output shaft which is effectively connected to a drive shaft of the pumping system by means of the coupling arrangement. The coupling arrangement comprises a first coupling hub rigidly connected to the output shaft, a second coupling hub rigidly connected to the drive shaft, and a coupling disc in the power flow path between the output shaft and the drive shaft, which is rigidly connected to the first coupling hub by means of a first linear guide and is rigidly connected to the second coupling hub by means of a second linear guide, wherein the second linear guide is oriented perpendicular to the first linear guide.