Rotary Feedthrough Bearing Layout for Low-Friction Media Transfer
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Solution Overview
Problem
Existing rotary feedthroughs are large and have high frictional torque due to numerous seals, leading to increased wear and susceptibility to errors, especially when multiple actuators are connected downstream, requiring multiple electrical and media lines which increase complexity and size.
Innovation Solution
The rotary feedthrough design transmits axial and radial forces primarily through the base part, minimizing the shaft section's diameter and using sealing rings with a smaller diameter than pivot bearings to reduce frictional torque, and incorporates a slip ring for electrical signal transmission with a specific radial distance configuration to minimize friction losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple seals are provided to seal multiple media lines for multiple actuators, then sealing reliability is improved, but device size increases and frictional torque increases
Solution Approach 1:
Multiple media lines are merged into a single common bore through which all lines pass. A single seal is provided that seals all media lines simultaneously at their entry points to the rotary part, eliminating the need for multiple separate seals while maintaining sealing reliability for multiple actuators
Solution Approach 2:
The single seal serves multiple functions by sealing all media lines at once. The common bore structure allows one seal to perform the sealing function for multiple actuators, reducing the overall number of sealing components while maintaining universal sealing capability
2Reliability
If multiple seals are provided to seal multiple media lines, then sealing reliability is improved, but frictional torque increases leading to increased wear
Solution Approach 1:
Multiple sealing functions are combined into a single seal component. By providing only one seal that seals all media lines simultaneously, the total frictional torque is reduced compared to having multiple separate seals, while maintaining adequate sealing reliability for all actuators
Solution Approach 2:
The potential harm of having multiple seals (increased friction and wear) is converted into a benefit by using a single seal design. The single seal creates less total friction than multiple seals would, reducing wear on the rotary bearing while still providing reliable sealing for all media lines
3Force
If axial and radial forces are transmitted via the shaft section, then force transmission is achieved, but the shaft section diameter must be large increasing device size
Solution Approach 1:
The function of transmitting axial and radial forces is extracted from the shaft section and assigned to the rotary bearing instead. This allows the shaft section to be designed with a smaller diameter since it only needs to transmit torque, not support axial and radial loads
Solution Approach 2:
The force transmission path is changed by using the rotary bearing's outer ring as a support surface. Axial and radial forces are transmitted through a different structural dimension (the bearing assembly) rather than through the shaft section, enabling a more compact design
4Adaptability or versatility
If a large number of electrical lines are provided for multiple actuators, then electrical signal transmission is achieved, but device complexity increases
Solution Approach 1:
Multiple electrical lines are bundled together as a single cable assembly that passes through the rotary feedthrough. The lines are routed together through the common bore structure, reducing the complexity of individual line management while maintaining the capability to transmit signals to multiple actuators
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
This design results in a compact, low-friction rotary feedthrough with reduced wear and lower drive torque, enhancing the stability and efficiency of force transmission while maintaining robustness for mechanical and electrical signal handling.
Implementation Method 1
The rolling elements are arranged between the inner ring and the outer ring of the drive bearing and the inner ring and the outer ring of the actuator bearing
Implementation Method 2
actuator bearing (42) and a drive bearing (40), each having an inner ring, an outer ring and rolling elements provided between the inner ring and the outer ring
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a rotary feedthrough (10) for arrangement on a handling unit between an actuator and a rotary drive, comprising a base part (12) and a rotary part (16) that can be rotated with respect to the base part (12) about a rotational axis (14), wherein the rotating part comprises an actuator flange, a drive flange and a shaft portion (18) arranged between the actuator flange and the drive flange, and further comprising base part-side media connections (28), rotating part-side media connections (30), media lines (32, 38) provided between the media connections (28, 30), and rotational bearings (40, 42) provided between the base part (12) and the rotary part (16). The invention is characterized in that an actuator rotational bearing (42) is arranged on the actuator flange (24) in such a way that forces acting in the axial and radial direction on the actuator flange (24) are introduced into the base part (12) via the actuator rotational bearing (42), and that a drive rotational bearing (40) is arranged on the drive flange (22) in such a way that the forces introduced by the actuator flange (24) into the base part (12) are guided via the drive rotational bearing (40) into the drive flange (22).