CT Scanner Gantry Compliant Coupling and Electromagnetic Braking
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Solution Overview
Problem
Computed tomography (CT) scanners face issues with component stress and image quality due to rotational frame imbalances and deceleration challenges, particularly with high-speed scanners using low-friction bearings and contactless motion systems.
Innovation Solution
A compliant and rigid coupling system with a stator and bearing support, incorporating a braking component for controlled deceleration, and a contactless bearing to address stress and imbalance issues, ensuring accurate and efficient scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a friction brake is used on the motor to stop the rotating frame when power is lost, then the rotating frame can be stopped controllably, but the rotational friction is relatively high which increases energy loss and wear
Solution Approach 1:
The patent replaces the traditional friction-based mechanical brake with an electromagnetic braking system. The electromagnetic brake uses magnetic fields to generate braking force without physical contact, eliminating friction-related energy loss and wear while maintaining controllable stopping capability. The brake assembly includes electromagnetic coils that generate magnetic fields to interact with the rotating frame, providing contactless braking.
Solution Approach 2:
The patent introduces an electromagnetic field as an intermediary between the braking mechanism and the rotating frame. Instead of direct mechanical contact, the electromagnetic field serves as the medium to transfer braking force, enabling controlled deceleration without the harmful effects of friction. This intermediary approach allows for precise control while minimizing energy loss.
2Productivity
If low-friction bearings and contactless rotor motion systems are used to increase rotational speed, then productivity is improved, but deceleration time becomes excessively long when power is lost
Solution Approach 1:
The electromagnetic brake assembly acts as an intermediary braking mechanism that can be activated when power is lost. It uses electromagnetic fields to provide controlled deceleration force to the low-friction bearing system, enabling rapid stopping without the need for mechanical contact that would interfere with normal high-speed operation. The brake includes electromagnetic coils and a braking surface that interacts with the rotating frame.
Solution Approach 2:
The braking component is pre-positioned and ready for immediate activation in the event of power loss. The electromagnetic fields and braking surfaces are arranged so that braking force can be applied instantly when needed, reducing deceleration time without requiring any mechanical adjustments or interventions during the emergency stopping process.
3Ease of operation
If a relatively flexible bearing is coupled to relatively stiff rotating and tilting frames, then ease of operation is improved, but raceway distortion occurs which introduces raceway stress
Solution Approach 1:
The patent modifies the bearing support structure to provide controlled compliance through elastic deformation of support members. The support members are designed with specific elastic properties that allow them to deform under load, absorbing stress variations without transmitting them to the bearing raceways. This changes the stiffness parameter of the support structure to optimize both operational flexibility and stress distribution.
Solution Approach 2:
The patent applies different structural properties to different parts of the bearing support system. The bearing itself remains flexible for ease of operation, while the support members are designed with elastic characteristics to manage stress locally. This local differentiation of structural quality allows the system to achieve both operational flexibility and stress reduction without compromising either aspect.
4Adaptability or versatility
If the mounting surface accuracy varies from scanner to scanner, then adaptability is affected, but manufacturing precision becomes more difficult to maintain
Solution Approach 1:
The patent employs elastic support members that can deform to accommodate variations in mounting surface geometry. The elastic properties of these members allow them to conform to different surface accuracies, effectively compensating for manufacturing tolerances and variations between different scanner units. This parameter-based approach to compliance enables universal adaptability without requiring high-precision mounting surfaces.
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 enhances the lifespan of components, reduces stress on bearings, maintains image quality by minimizing wobble, and provides controlled braking during power loss, ensuring safe and efficient operation of CT scanners.
Implementation Method 1
The bearing support comprises at least two members spaced apart from each other by a corresponding highly compliant region. A first side of each member is coupled to the stator and a second side of each member is coupled to the first bearing portion.
Implementation Method 2
More recent scanner have increased rotational speeds, lower friction bearings and contactless rotor motion systems, which have led to increased deceleration times when power is lost.
Data Source
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AI summary
An imaging system (100) includes a rotating frame (106), a second frame (102, 104), and a support (108) that rotatably couples the rotating frame (106) to the second frame (102, 104). One of the rotating frame (106) or the second frame (102, 104) is compliantly coupled to the support (108) and the other of the rotating frame (106) or the second frame (102, 104) is rigidly coupled to the support (108). An imaging system includes a rotating frame (106), a tilt frame (104), and a stationary frame (102). A frame stiffener (110) provides structural support for the rotating and tilt frames (106, 104) along transverse axes. An imaging system (100) includes a rotating frame (106) and a second frame (102, 104) that rotatably supports the rotating frame (106). The rotating frame (106) is coupled to the second frame (102, 104) through a contactless bearing and controlled by a contactless mechanism. A braking component (112) selectively applies a brake to the rotating frame (106).