Sealed Shift Position Sensing for Contamination-Prone Transmissions
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Solution Overview
Problem
Existing sensor devices for detecting shift positions in vehicle transmissions are prone to contamination by chips and ferritic particles, leading to inaccurate detection and reduced longevity due to their exposure within the transmission space.
Innovation Solution
A sealed and encapsulated sensor device design where the transmitter element is separated from the transmission chamber, using a rod element with a non-magnetic material and a sealing element to prevent contamination, and a guide element to maintain the movement axis constant, ensuring accurate and long-lasting detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor element is positioned separately from the transmission housing for non-contact detection, then the detection precision is improved, but the sensor element becomes vulnerable to contamination by metal shavings and ferritic particles in the transmission chamber
Solution Approach 1:
The patent divides the transmission system into two separate compartments: a transmission chamber containing the lubricant and transmission components, and a sealed auxiliary chamber housing the sensor element. This segmentation allows the sensor to detect transmission position non-contactly through the housing wall while being protected from contamination by metal shavings and ferritic particles in the transmission chamber.
Solution Approach 2:
The housing wall acts as an intermediary barrier between the sensor element and the transmission chamber. The magnetic field generated by the encoder element can penetrate this non-magnetic housing wall, enabling detection while the physical barrier prevents contamination particles from reaching the sensor element.
2Device complexity
If the sensor element is placed within the transmission chamber for direct detection, then the device complexity is reduced, but the reliability decreases due to attraction of ferritic particles and contamination
Solution Approach 1:
The sensor element is extracted from the transmission chamber and relocated to a sealed auxiliary chamber. This extraction eliminates the harmful interaction where the magnetic encoder element would attract ferritic particles from the transmission components, thereby preventing contamination-related failures and extending sensor device lifespan.
Solution Approach 2:
The auxiliary chamber is sealed to create a protected environment for the sensor element. This sealed space acts as an inert barrier that prevents transmission contaminants (metal shavings, ferritic particles) from reaching the sensor, ensuring reliable operation without requiring the sensor to be directly exposed to the harsh transmission chamber environment.
3Reliability
If a sealed auxiliary chamber is used to protect the sensor element, then the reliability is improved, but the device complexity increases due to additional sealing and structural components
Solution Approach 1:
The housing wall serves multiple functions simultaneously: it provides the structural boundary of the transmission system, acts as a magnetic field transmission medium for non-contact detection, and functions as a contamination barrier separating the transmission chamber from the sealed auxiliary chamber. This multi-functionality reduces the need for additional separate components.
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
This solution effectively prevents contamination, maintains detection accuracy, and extends the sensor device's lifespan by keeping the transmitter element isolated from contaminants, ensuring reliable shift position detection.
Implementation Method 1
The sensor element (124) is designed to detect a position of the encoder element (124), which corresponds to the switching position or a movement dependent on a change in the switching position
Implementation Method 2
The rod element (130) is made of a non-magnetic material
Data Source
Figure 1~2
AI summary
The invention relates to a sensor device (120) for detecting a shifting position of a vehicle transmission (100). The vehicle transmission (100) comprises a transmission chamber (102), in which transmission elements (106, 108, 110, 112) are arranged. The sensor device (120) comprises a bar element (130), which extends from the transmission chamber (102) into a secondary chamber (122) sealed off from the transmission chamber (102) and is arranged in such a way that the bar element can be moved in dependence on the shifting position. The bar element (130) has an interface (132) arranged in the transmission chamber (102) for coupling the bar element (130) to a transmission element (108) positioned in dependence on the shifting position and an accommodating segment (134) arranged in the secondary chamber (122). The sensor device (120) also has an indicating element (124), which is attached to the accommodating segment (134) of the bar element (130). The sensor device (120) also has a detecting device (126) for detecting a position of the indicating element (124) depending on the shifting position or a motion of the indicating element (124) depending on a change in the shifting position.