Shift Lever Base Rigidity via Segmented Bearing Bush
Solution Overview
Problem
The existing shift lever devices for automatic transmission vehicles face issues with reduced rigidity and dimensional accuracy due to large openings required for assembly, which can lead to warpage and make installation difficult.
Innovation Solution
A shift lever device with a base that uses a pivot shaft and bearing bushes with guide grooves and anti-rotation mechanisms to support the shift lever rotatably, eliminating the need for large openings and preventing warpage, while ensuring easy assembly and high accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a large opening is formed in the base to allow rotation of the shift lever during assembly, then the shift lever can be assembled rotatably, but the rigidity of the base is reduced
Solution Approach 1:
The bearing part is divided into two separate components: the base and the bearing bush. The bearing bush is a removable component that fits into the bearing part of the base. This segmentation allows the base to have a smaller opening while still accommodating the shift lever assembly, thereby maintaining base rigidity while enabling assembly functionality.
Solution Approach 2:
The bearing bush acts as an intermediary component between the pivot shaft and the bearing part. It mediates the connection by fitting into the bearing part and receiving the pivot shaft, allowing the shift lever to be assembled rotatably without requiring a large opening in the base itself.
2Weight of moving object
If the base is made of resinous material for lightweight construction, then weight is reduced, but the base becomes prone to warpage and dimensional accuracy deteriorates
Solution Approach 1:
The bearing part is segmented into the base and the removable bearing bush. This allows the bearing bush to be precisely manufactured and fitted into the base, compensating for the resinous base's susceptibility to warpage and maintaining high dimensional accuracy at the critical bearing interface.
Solution Approach 2:
The bearing bush is designed with specific dimensional parameters that allow it to fit precisely into the bearing part of the base. By controlling the dimensions and tolerances of the bearing bush, high positional accuracy is achieved despite the resinous base's tendency toward warpage.
3Ease of operation
If the opening in the base is enlarged for shift lever rotation, then assembly is enabled, but the positional accuracy of the bearing part deteriorates
Solution Approach 1:
The bearing part is divided into the base and the bearing bush. The bearing bush is a separate, precisely manufactured component that fits into the bearing part opening. This segmentation allows the opening to be adequately sized for assembly while the bearing bush itself maintains high positional accuracy through precise manufacturing.
Solution Approach 2:
The bearing bush serves as an intermediary that bridges the opening in the base and the pivot shaft. It maintains positional accuracy by providing a precisely fitted interface, decoupling the opening size requirements from the positional accuracy requirements.
4Ease of operation
If the shift lever is assembled in an inclined position to fit the pivot shaft into the bearing hole, then assembly is possible, but the assembly process becomes complex and time-consuming
Solution Approach 1:
The bearing bush is pre-assembled into the bearing part of the base before the shift lever is installed. This preliminary action prepares the assembly path and positioning features in advance, allowing the pivot shaft to be inserted directly into the bearing hole without requiring inclined assembly or complex maneuvers.
Data Source
AI summary
A shift lever device includes a shift lever having a pivot shaft formed at a base end of the shift lever integrally and a base having an opening formed to allow the shift lever to be inserted into the base and a pair of bearing parts formed so as to lie on opposing sides of the opening. The pivot shaft extends along a direction intersecting with a longitudinal direction of the shift lever. Each of the bearing parts has a bearing hole formed in the bearing part to adjoin the opening, a guide groove formed in the bearing part to communicate with the bearing hole, for introducing the pivot shaft into the bearing hole and a bearing bush which is to be inserted between the pivot shaft and the bearing hole. The bearing bush has a latch hook provided to engage with an interior of the bearing hole. The bearing bush is fitted to the bearing hole on condition that the pivot shaft is being inserting into the bearing hole through the guide groove, so that the shift lever is rotatably supported by the base through the bearing bush.