Recoil Starter Torque Regulation Mechanism
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Solution Overview
Problem
Existing starters for small engines face challenges in consistently accumulating sufficient rotational torque due to unstable rotational resistance, leading to unreliable engine starting.
Innovation Solution
A starter system with a rotation regulating mechanism, including a regulating ratchet and a pressing unit, which accumulates torque in a torque-accumulation spring and releases it only when the accumulated torque exceeds the resilient pressing force, ensuring sufficient energy for engine startup regardless of rotational resistance variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rotational torque is accumulated in the torque-accumulation spiral spring to start the engine, then the engine can be started when the accumulated torque exceeds the rotational resistance, but when the rotational resistance is low, the accumulated energy may temporarily exceed the rotational resistance before sufficient torque is accumulated, causing the cam plate to rotate and preventing reliable engine starting
Solution Approach 1:
The pressing force of the pressing unit is set to a specific parameter range (larger than the starting rotational torque) to change the force parameter and prevent premature rotation of the cam plate. This parameter setting ensures that the cam plate only rotates when sufficient torque is accumulated, regardless of temporary fluctuations in rotational resistance.
Solution Approach 2:
The regulating ratchet and pressing unit are introduced as intermediary components between the torque-accumulation spiral spring and the cam plate. These intermediaries regulate the transmission of rotational torque, allowing the system to maintain reliable starting performance without requiring complex control mechanisms.
2Reliability
If the regulating ratchet is provided at a position shifted from the rotation center to regulate rotation, then the operation range of the ratchet can be regulated with a given resilient pressing force, but this may increase the device complexity and space requirement
Solution Approach 1:
The regulating ratchet is positioned at a location shifted from the rotation center, utilizing a different spatial dimension (radial offset) to achieve rotation regulation. This dimensional change allows the mechanism to function effectively with a compact design, as the offset position creates a lever arm that amplifies the pressing force without requiring additional space.
3Reliability
If the pressing unit is urged by a given resilient pressing force larger than the starting rotational torque, then the cam plate rotation can be prevented until sufficient torque is accumulated, but this requires precise force calibration and increases manufacturing complexity
Solution Approach 1:
The resilient pressing force is set to a specific parameter (larger than the starting rotational torque) to achieve reliable control of cam plate rotation. This parameter change simplifies the manufacturing process by providing a clear design criterion for the pressing force, eliminating the need for complex calibration procedures.
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 system effectively accumulates and releases rotational torque, ensuring reliable engine starting by regulating the operation range of the ratchet with a given resilient pressing force, minimizing deflection, and stabilizing rotation, even with varying engine resistance.
Implementation Method 1
a torque-accumulation spring (10) configured to accumulate the rotational torque applied from the rotation torque applying unit
Implementation Method 2
a pressing unit (40) provided on the starter case and urged by a given resilient pressing force to be engaged with the regulating ratchet
Implementation Method 3
when the rotational torque accumulated in the torque-accumulation spring exceeds the given resilient pressing force, the driving pulley or the rotating member urges back the pressing unit via the regulating ratchet so that the regulating ratchet is disengaged from the pressing unit
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
One of the embodiments provides a starter including: a starter case; a rotational torque applying unit; a torque-accumulation spring; a rotating member; a driving pulley; and a rotation regulating mechanism including: a regulating ratchet provided on the driving pulley or the rotating member at a position shifted from a rotation center thereof; and a pressing unit provided on the starter case and urged by a given resilient pressing force to be engaged with the regulating ratchet, wherein, when the rotational torque accumulated in the torque-accumulation spring exceeds the given resilient pressing force, the driving pulley or the rotating member urges back the pressing unit via the regulating ratchet so that the regulating ratchet is disengaged from the pressing unit, to thereby release the rotational torque.