Hybrid Guide Assembly Thermal Clearance Modulation
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Solution Overview
Problem
Existing solutions for guiding a crankshaft in a heat engine face challenges in balancing the longevity of plain bearings with the low friction benefits of rolling bearings, often requiring complex and costly actuators to control the engagement of angular contact rolling bearings.
Innovation Solution
A hybrid guide assembly combining a rolling bearing and a sliding bearing, where the sleeve has a thermal radial expansion coefficient that modulates the operational clearances as a function of temperature, allowing the rolling bearing to dominate at low temperatures and the sliding bearing to take over at higher temperatures without an external actuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If rolling bearings are used to guide the crankshaft, then friction is reduced, but service life becomes insufficient compared to other engine components
Solution Approach 1:
The patent combines a rolling bearing and a plain bearing into a hybrid guide assembly where both bearings share the load-carrying function. The rolling bearing provides low-friction operation while the plain bearing provides longevity, and their coordinated operation allows the system to achieve both reduced friction and extended service life compared to using either bearing type alone.
2Reliability
If an actuator is introduced to control the engagement of angular contact rolling bearing, then both longevity and low friction characteristics are achieved, but device complexity and cost increase significantly
Solution Approach 1:
The hybrid guide assembly automatically adjusts the load distribution between the rolling bearing and plain bearing based on operating conditions without requiring external control. The bearings self-regulate their engagement through elastic deformation and clearance variations, eliminating the need for actuators, sensors, or control systems while maintaining both longevity and low-friction performance.
Solution Approach 2:
The patent utilizes changes in operating parameters such as temperature, load, and speed to automatically modulate the functional clearance and load distribution between the two bearings. As operating conditions vary, the elastic deformation and thermal expansion of bearing components naturally adjust the engagement level, allowing the system to adapt without external control mechanisms.
3Duration of action of stationary object
If plain bearings are used to guide the crankshaft, then service life is extended, but friction increases compared to rolling bearings
Solution Approach 1:
The patent combines a rolling bearing and a plain bearing into a hybrid guide assembly where both bearings share the load-carrying function. The rolling bearing provides low-friction operation while the plain bearing provides longevity, and their coordinated operation allows the system to achieve both reduced friction and extended service life compared to using either bearing type alone.
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 solution enables efficient temperature-dependent modulation of bearing intervention, optimizing the use of both rolling and sliding bearings to extend lifespan and reduce friction, thereby enhancing the overall performance and cost-effectiveness of the guide assembly.
Implementation Method 1
the sleeve has a thermal radial expansion coefficient such that the algebraic difference between the residual operating clearance of the rolling bearing and the operating clearance increases by passing from negative values to positive values when the operating temperature increases
Data Source
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AI summary
The hybrid guide assembly has at least one rolling bearing (20) and at least one plain bearing (18) defining a common axis of revolution (100), the rolling bearing (20) having at least one internal raceway (24, 24A, 24B) that faces radially outwards, at least one external raceway (26, 26A, 26B) that faces radially inwards opposite the internal raceway (24, 24A, 24B) and rolling bodies (22, 22A, 22B) that circulate on the internal raceway (24, 24A, 24B) and the external raceway (26, 26A, 26B), the rolling bearing (20) having an operating residual clearance (JR) depending on an operating temperature in a predetermined range of temperatures, the plain bearing (18) having at least one sliding track (36, 36A, 36B) and at least one sleeve (32, 32A, 32B) situated radially opposite and at a distance from the sliding track (36, 36A, 36B) so as to form an operating clearance (JL) between the sliding track (36, 36A, 36B) and the sleeve (32, 32A, 32B) depending on the operating temperature in the predetermined range of temperatures, the sliding track (36, 36A, 36B) being fixed with respect to one of the internal raceway (24, 24A, 24B) or external raceway (26, 26A, 26B), the sleeve (32, 32A, 32B) being fixed with respect to another of the internal raceway (24, 24A, 24B) or external raceway (26, 26A, 26B). The sleeve (32, 32A, 32B) has a coefficient of radial thermal expansion such that the algebraic difference between the operating residual clearance (JR) of the rolling bearing (20) and the operating clearance (JL) increases, passing from negative values to positive values when the operating temperature increases in the predetermined range of temperatures.