External Gear Position Sensor Layout for Multi-Position Transmissions
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Solution Overview
Problem
Existing gear position detecting systems in multi-position transmissions require multiple sensors arranged inside and outside the transmission case, leading to reduced maintainability and increased complexity due to space constraints and the need for protective measures and wiring.
Innovation Solution
A gear position detecting sensor arrangement featuring a first sensor on the elongated shaft and a second sensor outside the transmission case, with the elongated shaft integrated into the shift drum, allowing for easier access and maintenance, and utilizing a switch sensor to detect turn positions with high accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensors are arranged inside and outside the transmission case to detect gear position, then detection accuracy is improved, but maintainability deteriorates due to reduced access space and increased complexity
Solution Approach 1:
The patent transitions sensor arrangement from a two-dimensional planar layout (inside/outside transmission case) to a three-dimensional radial distribution around the elongated shaft. Sensors are positioned at different radial distances from the shaft center, enabling multiple sensors to be arranged in a compact cylindrical space without interfering with transmission case access, thereby maintaining both detection accuracy and serviceability.
Solution Approach 2:
The elongated shaft serves multiple functions: it acts as the rotational element for gear shifting, provides the central axis for sensor arrangement, and serves as a mounting structure for sensor targets. This multi-functional design eliminates the need for separate sensor mounting brackets or housings, simplifying the overall structure and improving maintainability while supporting multiple sensors for accurate gear position detection.
2Measurement precision
If sensors are arranged inside the transmission case to detect gear position, then detection accuracy is improved, but device complexity increases due to protective parts and wiring requirements
Solution Approach 1:
The patent extracts sensors from the traditional enclosed transmission case environment and repositions them in the radial space around the elongated shaft. This extraction eliminates the need for complex protective housings, sealed cable penetrations, and intricate wiring arrangements that would be required to protect sensors located inside the transmission case, while still enabling accurate gear position detection through radial magnetic field sensing.
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 solution enhances maintainability and detection accuracy by allowing external access and protection of sensors, simplifies the shift drum structure, and reduces installation space while maintaining high detection precision.
Implementation Method 1
a first sensor (85) which is fitted to other end portion of the elongated shaft (84) and which detects a turn position of the elongated shaft (84)
Implementation Method 2
a second sensor (83) which is located outside in a radial direction of the elongated shaft (84) between the one end portion and the other end portion of the elongated shaft (84) and which detects that the elongated shaft (84) is located at a specified turn position
Data Source
AI summary
A gear position of a multi-position transmission, which shifts and drives a vehicle according to a turn motion of a shift drum, is detected by a plurality of sensors. An end portion of the shift drum is fitted with an end portion of an elongated shaft rotated coaxially with the shift drum. A first sensor which is fitted to other end portion of the elongated shaft detects a turn position of the elongated shaft. A second sensor which is located outside in a radial direction of the elongated shaft between the one end portion and the other end portion of the elongated shaft detects that the elongated shaft is located at a specified turn position. The first sensor and the second sensor are fitted from the outside of a transmission case of the multi-position transmission and are exposed to the outside of the transmission case.