Decoupler Assembly Torque Equaliser Roller Clutch
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Solution Overview
Problem
Existing decoupler assemblies for combustion engines, particularly those using wrap springs, face issues with reliability due to heat generation, wear, and potential fire risks from lubricant, and are susceptible to breakage under high torque conditions, leading to reduced long-term reliability and increased noise and vibration.
Innovation Solution
A decoupler assembly incorporating a torque equaliser with a one-way clutch bearing and arcuate spring elements, which provides improved reliability, reduced noise, and increased load capacity by using a spring sealing arrangement and a compact design that dampens high torque pulsations without reaching end positions, thereby reducing noise and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wrap spring is used in the torque equaliser, then torque transmission is achieved, but heat generation and wear occur due to sliding contact with the lubricant, creating fire risk and reducing reliability
Solution Approach 1:
The patent replaces the wrap spring mechanism with a roller clutch mechanism. The roller clutch uses rolling elements (rollers) instead of a sliding wrap spring, fundamentally changing the mechanical interaction from sliding friction to rolling friction. This substitution eliminates the sliding contact between the spring and clutch surface that generated heat and fire risk, while maintaining torque transmission capability through the rolling elements engaged with the inner and outer clutch surfaces.
Solution Approach 2:
The patent removes the lubricant from the system by eliminating the wrap spring that required lubrication. The roller clutch mechanism operates without lubricant, extracting the harmful element (lubricant) that combined with heat to create fire risk. The rollers transmit torque through direct mechanical engagement without requiring a lubricating film, thereby eliminating the fire hazard entirely.
2Reliability
If a wrap spring is used in the torque equaliser, then torque transmission is achieved, but wear occurs due to sliding contact, reducing long-term reliability
Solution Approach 1:
The patent replaces the sliding contact mechanism of the wrap spring with a rolling contact mechanism using rollers. The rollers rotate on their axes as they transmit torque between the inner and outer clutch surfaces, converting high-wear sliding friction into low-wear rolling friction. This mechanical substitution dramatically reduces wear on the contact surfaces, enabling long-term reliable operation without degradation.
3Power
If the decoupler assembly is located on the output shaft of a diesel combustion engine, then high torque levels are transmitted, but the wrap spring is susceptible to breakage under these conditions
Solution Approach 1:
The patent replaces the fragile wrap spring with a robust roller clutch mechanism designed to withstand high torque loads. The rollers are engaged with tapered surfaces on the inner and outer clutch members, creating a mechanically strong connection that can transmit the high torque levels produced by diesel engines without breaking. The rolling contact mechanism distributes the load across the roller surfaces and engagement faces, preventing stress concentration and failure.
4Reliability
If arcuate spring elements are used instead of wrap spring, then load capacity and reliability are improved, but device complexity increases
Solution Approach 1:
The patent segments the torque transmission function into discrete roller elements rather than using a continuous wrap spring. Each roller is an independent element that can be individually engaged and disengaged, providing modular functionality. This segmentation allows the system to achieve high reliability through redundant load paths while keeping each individual component simple in structure.
Solution Approach 2:
Instead of using a flexible wrap spring that conforms to the clutch surface, the patent uses rigid rollers that maintain their shape and transmit force through point contact. This inversion from flexible to rigid elements, combined with the tapered engagement surfaces, creates a simpler, more reliable structure that is easier to manufacture and maintain.
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 reliability and safety of the decoupler assembly by reducing wear, heat generation, and the risk of fire, while maintaining high torque transmission capabilities and compact packaging, thus addressing the limitations of traditional wrap spring designs.
Implementation Method 1
one or two arcuate spring elements arranged to transmit torque between the inner member and outer member
Implementation Method 2
one-way clutch bearing having plurality of individual wedging locking elements that are disposed between the inner and outer race
Data Source
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AI summary
The disclosure concerns a decoupler assembly (1) comprising a torque equaliser (10) and a one-way clutch bearing (11). The torque equaliser (10) comprises an inner member (12) having a rotational axis (A), an outer member (15a, 15b) disposed concentrically and surrounding the inner member (12), and two arcuate spring elements (16) arranged between the inner member (12) and outer member (15a, 15b) and configured to transmit torque between the inner member (12) and outer member (15a, 15b). The inner member (12) is rotationally displaceable relative to the outer member (15a, 15b) at least 30 degrees upon compression of the two arcuate spring elements (16). The one-way clutch bearing (11) is located in the same radial plane as torque equaliser (10) and rotationally connected to the inner or outer member (12, 15a, 15b). The one-way clutch bearing (11) comprises an outer race (28), an inner race (29), and a plurality of individual wedging locking elements (23) that are disposed between the inner and outer race (28, 29). The disclosure also concerns decoupler assemblies with a torque equaliser comprising a single spiral spring element or a rubber-based spring element.