Electric Throttle Valve Gear Support for Low-Friction Torque Transmission
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Solution Overview
Problem
Existing electric throttle valves face friction issues due to the inclination of the intermediate gear, which can lead to contact with the support member, causing reduced lifespan and decreased responsiveness of the deceleration mechanism.
Innovation Solution
A transmission mechanism with a hemispherical recessed portion on the intermediate gear and a matching projecting portion on the support member, allowing smooth sliding and reducing friction even when the intermediate gear is inclined, thereby supporting the gear and maintaining efficient drive force transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the intermediate gear is disposed with offset at mutually different positions in axial direction, then the deceleration mechanism can transmit drive force from motor to valve shaft, but the intermediate gear becomes inclined and contacts the support portion causing friction
Solution Approach 1:
The patent applies spheroidality by forming a hemispherical recessed portion in the intermediate gear and a corresponding hemispherical projecting portion in the support member. This curved surface configuration allows the intermediate gear to incline during operation without creating friction, as the spherical surfaces can accommodate angular deviations smoothly. The hemispherical geometry transforms the rigid contact problem into a compliant interface that maintains low friction even when the gear axis is not perfectly aligned.
2Power
If the intermediate gear rotates and transmits force, then the deceleration mechanism functions, but friction increases when the gear contacts the support portion
Solution Approach 1:
The hemispherical recessed portion and projecting portion create a curved contact interface that reduces friction during rotation. The spherical geometry allows the intermediate gear to rotate and transmit drive torque efficiently while minimizing energy loss to friction, as the curved surfaces distribute contact forces more evenly and reduce sliding resistance compared to flat or sharp-edged contacts.
3Ease of operation
If the intermediate gear is supported on the support member, then the gear can rotate, but the gear may contact the support portion causing reduced lifespan
Solution Approach 1:
The hemispherical recessed portion in the intermediate gear and the corresponding projecting portion in the support member create a compliant support interface. This curved geometry allows the intermediate gear to rotate freely while accommodating minor misalignments and inclinations without creating high-stress contact points. The spherical contact surfaces distribute loads more evenly, reducing wear and extending the lifespan of both the intermediate gear and support member.
Data Source
AI summary
A transmission mechanism includes: an intermediate shaft secured to a support portion provided in a valve body of an electric throttle valve and disposed in parallel to a motor shaft and a valve shaft; and an intermediate gear rotatably disposed at the intermediate shaft, in which the intermediate gear has a first intermediate gear engaged with a motor gear secured to the motor shaft and a second intermediate gear engaged with a valve gear secured to the valve shaft, the first intermediate gear and the second intermediate gear are integrally configured to be aligned in an axial direction of the intermediate shaft, a hemispherical recessed portion recessed upward around an axial center of the intermediate shaft is formed at a lower end portion of the intermediate gear, and a projecting portion projecting upward in a hemispherical shape around the axial center of the intermediate shaft and supporting the recessed portion is formed in a surface of the support portion facing the recessed portion of the intermediate gear.