Hybrid Drive Ring Gear Fixing for Engine Reverse Travel
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Solution Overview
Problem
Hybrid vehicles equipped with internal combustion engines and electric motors cannot travel backward when the electric motor is disconnected, as power transmission from the engine is interrupted, preventing reverse travel by the engine alone.
Innovation Solution
A drive device with a power transmission mechanism featuring a sun gear, ring gear, and pinion gears, along with a ring gear fixing mechanism that allows non-rotatable fixation of the ring gear, enabling power input from the internal combustion engine for backward travel, even when the electric motor is disconnected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the electric motor is disconnected from the power transmission path, then the hybrid vehicle can generate electric power during vehicle stop time, but the vehicle cannot travel backward by the engine alone
Solution Approach 1:
The power transmission mechanism is segmented into multiple independent paths: one for forward travel (engine → sun gear → carrier → wheels) and one for backward travel (engine → sun gear → ring gear → carrier → wheels). The ring gear fixing mechanism acts as a switch to select between different power transmission paths, enabling the engine to independently provide both forward and backward travel capability without requiring the electric motor to be connected.
2Use of energy by moving object
If the electric motor is disconnected, then power generation during stop is enabled, but continuous mobility is compromised
Solution Approach 1:
The engine is designed to serve multiple functions: it can drive the vehicle forward through the sun gear and carrier, drive the vehicle backward through the ring gear and carrier, and allow the electric motor to generate power during vehicle stops. The ring gear fixing mechanism enables the engine to universally provide power for both forward and backward travel, ensuring continuous mobility even when the electric motor is disconnected.
3Adaptability or versatility
If a ring gear fixing mechanism is added to enable backward travel by engine alone, then backward travel capability is improved, but device complexity increases
Solution Approach 1:
The ring gear fixing mechanism is merged with the existing planetary gear mechanism structure. The fixing mechanism utilizes the ring gear that already exists in the planetary gear set for forward travel, and by adding a simple fixing capability (such as a brake or clutch), the same ring gear is used for backward travel. This merging approach enables backward travel functionality without adding completely separate transmission components, thereby limiting 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
Enables the hybrid vehicle to travel backward using the internal combustion engine alone, ensuring continuous mobility even if the electric motor is not functioning.
Implementation Method 1
a planetary gear mechanism including a sun gear (351) to which power input from an internal combustion engine (200) is transmitted, a ring gear (354) which meshes with the sun gear (351) via at least a one-step pinion gear (355)
Implementation Method 2
a brake mechanism (330) capable of non-rotatably fixing the ring gear (354) is provided between the ring gear (354) and the transmission case (357)
Data Source
AI summary
The object of the invention is to travel backward by an engine alone in a state where an electric motor is disconnected. Thus, external teeth are formed on the outer periphery of a ring gear which meshes with a first sun gear via a first pinion gear and a second pinion gear and to which power input from an electric motor is transmitted; a power transmission mechanism further includes a gear meshing with the external teeth of the ring gear; and a second clutch capable of non-rotatably fixing the ring gear at the time of causing a vehicle to travel backward with power input from an engine is provided between the ring gear and a transmission case.