Power Transmission Device with Selective Differential Element Fixing
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Solution Overview
Problem
In power transmission devices, when a rotational element of a differential is fixed, power from two connected power sources cannot be effectively transmitted to an output shaft due to identical configuration of rotational elements.
Innovation Solution
A power transmission device with a differential having three rotational elements and a connection switching device that selectively fixes one rotational element, allowing the second power source to be connected to other rotational elements, enabling power transmission in multiple modes, including a mode where one rotational element is fixed and another is coupled to the input shaft or output shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If one rotational element is fixed to transmit power from the first power source, then power transmission efficiency is improved, but the second power source cannot be connected to transmit power
Solution Approach 1:
The patent divides the three rotational elements into distinct functional groups: one element (sun gear) is dedicated to the first power source connection, another element (ring gear) is dedicated to the second power source connection, and the third element (carrier) serves as the output. This segmentation allows independent connection and disconnection of each power source without interfering with the other, resolving the contradiction between efficient power transmission and connection flexibility.
Solution Approach 2:
The patent employs a connection switching device that dynamically reconfigures the connection relationships among the three rotational elements and two power sources based on operational requirements. The switching device can fix one element while connecting another to either power source, enabling the system to adapt between single-power-source and dual-power-source modes, thus maintaining both transmission efficiency and versatility.
2Ease of manufacture
If rotational elements are configured identically for simplicity, then manufacturing cost is reduced, but power transmission capability is limited
Solution Approach 1:
The patent deliberately introduces asymmetry by assigning different functional roles to the three rotational elements of the planetary gear device: the sun gear (first rotational element) connects to the first power source, the ring gear (second rotational element) connects to the second power source, and the carrier (third rotational element) serves as the output shaft. This asymmetric configuration enables diverse power transmission modes while maintaining the inherent structural simplicity of the planetary gear mechanism.
Solution Approach 2:
The planetary gear device's three rotational elements are designed to serve multiple functions: each element can act as an input, output, or fixed element depending on the connection configuration. This multi-functionality allows the same basic structure to support various power transmission modes (single power source, dual power source, different output selections) without requiring additional components, thus achieving versatility without compromising manufacturing simplicity.
Data Source
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AI summary
Power of one power source is transmitted to drive wheels in a state in which one rotational element (R) among three rotational elements (S, C, R) included in a differential (24) is fixed to a fixing member (29). A power transmission device in which any one of three rotational elements (S, C, R) included in a differential (24) is selectively fixed to a fixing member (29), wherein a second power source (MG) is coupled to rotational elements other than the rotational element (R) fixed by a connection switching device (40) to the fixing member (29) among the three rotational elements, (S, C, R) and the differential is switched, by the connection switching device (40), between a first mode in which any one of the three rotational elements (S, C, R) is fixed to an input shaft (21), one of the remaining rotational elements (S, C) is fixed to the fixing member (29), and the other (S) is coupled to a first output shaft (22), and a second mode in which the three rotational elements (S, C, R) are respectively coupled to the second power source (MG), the first output shaft (22), and a second output shaft (23).