Over-Running Decoupler Torque Limiter for Spring Resonance Control
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Solution Overview
Problem
Over-running decouplers in drive systems experience resonance due to torsional loads, leading to reduced operating life, as the torsionally resilient coupling vibrates at a natural frequency, especially under load conditions involving driven accessories and torsional vibrations from a source of rotary power.
Innovation Solution
An over-running decoupler with a one-way clutch and helical wrap spring is designed to inhibit resonance by controlling the maximum deflection of the spring, ensuring it remains within a predetermined design deflection that does not reduce the fatigue life, and includes a resonance-inhibiting clutch that disengages when deflection exceeds a predetermined amount.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a torsionally resilient coupling is used in an over-running decoupler to permit decoupling and reduce torsional loads, then the decoupler can protect driven components during deceleration, but the coupling may resonate at natural frequency under load conditions, significantly reducing operating life
Solution Approach 1:
The patent introduces a movable clamp assembly that can dynamically adjust the tension on the torsionally resilient coupling. The clamp assembly moves along the coupling to change its effective length and stiffness characteristics, allowing the system to adapt to varying load conditions and avoid resonant frequencies that would reduce operating life.
Solution Approach 2:
The patent changes the physical parameters of the torsionally resilient coupling by adjusting the clamp position, which modifies the coupling's length, stiffness, and natural frequency. This parameter adjustment allows the system to operate away from resonant conditions while maintaining the protective decoupling function.
2Adaptability or versatility
If the torsionally resilient coupling is allowed to deflect freely under load, then the decoupler can accommodate torsional vibrations from the source of rotary power, but the coupling may deflect beyond design limits and reduce fatigue life
Solution Approach 1:
The patent employs a feedback mechanism where the movable clamp assembly responds to the deflection of the torsionally resilient coupling. When the coupling deflects beyond predetermined limits, the clamp assembly is actuated to increase tension and restrain further deflection, preventing excessive stress that would reduce fatigue life while still allowing normal operational vibrations.
Solution Approach 2:
The patent provides protective action in advance by positioning the clamp assembly to prevent excessive deflection before it occurs. The clamp acts as a preventive measure that limits the maximum deflection of the coupling under load, protecting the spring from fatigue damage before it can accumulate.
3Ease of manufacture
If the clamp assembly is fixed in position, then the manufacturing and assembly process is simpler, but the system cannot adapt to varying load conditions and may resonate under certain operating conditions
Solution Approach 1:
The patent transforms the static clamp assembly into a dynamic one that can move along the torsionally resilient coupling. This movement capability allows the clamp to adjust the coupling's effective length and stiffness to match varying operational requirements, preventing resonance while maintaining reasonable manufacturing complexity through the use of simple guide structures and springs.
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 prevents resonance in the over-running decoupler, thereby extending its operational life and ensuring reliable torque transmission without reducing the fatigue life of the springs, as demonstrated by reduced angular displacement and improved operational characteristics compared to prior art systems.
Implementation Method 1
a helical wrap spring (44) having a first end (66), a second end (68) and a plurality of coils (70) between the first and second ends. The first end (66) of the helical wrap spring (44) is drivingly engaged to the rotary member (32)... one or more springs disposed between the carrier and the hub
Implementation Method 2
at least one spring that resiliently couples the carrier to the hub
Implementation Method 3
a one-way clutch having a clutch spring (44), a carrier (42) that is coupled to the clutch spring (44) and at least one spring that resiliently couples the carrier (42) to the hub (34)
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A method for producing an over-running decoupler that is configured to transmit rotary power between a rotary member and a hub. The over-running decoupler includes a one-way clutch having a clutch spring, a carrier that is coupled to the clutch spring and at least one spring that resiliently couples the carrier to the hub. The method includes: establishing a desired fatigue life of the at least one spring; establishing a design deflection of the at least one spring during resonance, wherein deflection of the at least one spring at the design deflection during resonance does not reduce a fatigue life of the at least one spring below the desired fatigue life; and preventing resonance in the over-running decoupler by controlling a maximum deflection of the at least one spring such that the maximum deflection is less than or equal to the design deflection