Torque Limiting Mechanism for Reaction Force Output Device
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Solution Overview
Problem
The existing accelerator pedal devices apply excessive internal stress to motors and torque transmitting mechanisms due to the interlockable connection between the motor's rotating shaft and interlocking arm, which can lead to mechanical stress when a great force obstructs the motor's rotation.
Innovation Solution
A reaction force output device with a torque limiting mechanism is introduced between the reaction force output shaft and the interlocking arm, which limits torque transmission above a specified value, preventing excessive stress on the motor and torque transmitting parts by using a power spring to allow rotation when torque exceeds a predetermined value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor's rotating shaft and interlocking arm are always interlockably connected, then the reaction force is continuously transmitted to the operation pedal, but excessive internal stress is applied to the motor or torque transmitting mechanism when a great force obstructs the motor's rotation
Solution Approach 1:
A torque limiting mechanism is introduced as an intermediary component between the reaction force output shaft and the interlocking arm. This mechanism includes a torque limiting mechanism body, a limiting member with a limiting surface, and a resilient member. The limiting member can contact the limiting surface to slip when excessive torque is applied, thereby protecting the motor and torque transmitting mechanism from excessive internal stress while still allowing continuous reaction force transmission during normal operation
Solution Approach 2:
The torque limiting mechanism changes the torque transmission parameter dynamically. During normal operation, full torque is transmitted from the motor to the interlocking arm. When the torque exceeds a predetermined threshold value, the resilient member deforms and the limiting member contacts the limiting surface, causing the torque transmission to be limited to the threshold value, thus preventing excessive internal stress
2Reliability
If a torque limiting mechanism is added between the reaction force output shaft and interlocking arm, then excessive internal stress is inhibited, but the device complexity increases
Solution Approach 1:
The torque limiting mechanism is designed as a segmented structure with distinct functional components: a torque limiting mechanism body, a limiting member with a limiting surface, and a resilient member. This segmentation allows each component to perform its specific function independently while maintaining a relatively simple overall structure that can be integrated into the existing motor-driven reaction force output device
Solution Approach 2:
The torque limiting mechanism serves as a compact intermediary component that can be integrated between the reaction force output shaft and the interlocking arm. By using a resilient member and limiting surface configuration, the mechanism achieves torque limiting functionality without requiring complex additional structures, thus minimizing the increase in device complexity
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 torque limiting mechanism effectively inhibits excessive internal stress on the motor and torque transmitting parts, ensuring safe operation by controlling torque transmission and preventing excessive reaction forces during high pedaling forces or obstructive conditions.
Implementation Method 1
a spring member interposed between the action transmission lever and the rotary gear and elastically deformed to allow rotation of the rotary gear relative to the action transmission lever when torque acting on the rotary gear through the gear part is equal to or greater than a predetermined value
Data Source
AI summary
A reaction force output device includes: a motor that is a drive source that creates a reaction force; a reaction force output shaft that interlocks with an output shaft of the motor to rotate; and an interlocking arm that transmits output torque of the motor which is input to the reaction force output shaft to an operation pedal. A torque limiting mechanism, which limits the transmission of torque that is equal to or greater than a specified value between the reaction force output shaft and the interlocking arm, is interposed between the reaction force output shaft and the interlocking arm.