Gearbox Position Sensor Using Intermediary Coupling
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Solution Overview
Problem
Existing systems for identifying the engaged gear in motor-vehicle gearboxes are not compatible with rigid control cables, as they require direct mounting on flexible cables and suffer from sensitivity loss due to magnetization, and existing solutions with additional sensors are complex and costly.
Innovation Solution
A position sensor system that includes a movable reference element mechanically connected to a rigid end portion of the elongated mechanical transmission member, allowing for either linear or angular position detection, which can be installed on either the control lever or gearbox side, using contact or contactless sensors to provide a signal indicative of the engaged gear without direct mounting on the cable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a movable member is directly mounted on the control cable to detect gear position, then gear identification can be achieved, but the system cannot be installed on rigid rod-like control cables used in motor-vehicle gearboxes
Solution Approach 1:
The patent introduces an intermediary coupling mechanism that connects the position sensor to the control cable without requiring direct mounting. This coupling allows the sensor to follow the cable's movement while being mounted on stationary components, enabling compatibility with both flexible and rigid control cables through the same mounting structure.
2Measurement precision
If magnetic movable elements are mounted on steel control cables for position detection, then gear position can be detected, but the cable becomes magnetized causing sensor sensitivity loss
Solution Approach 1:
The patent extracts the magnetic movable element from direct contact with the steel control cable. By placing the magnetic element on a non-magnetic carrier that is coupled to the cable through non-magnetic components, the harmful magnetization effect on the cable is eliminated while preserving the position detection function.
Solution Approach 2:
Non-magnetic intermediary components are introduced between the magnetic movable element and the steel control cable to prevent direct magnetic interaction. This intermediary coupling allows mechanical force transmission while blocking the harmful magnetic field from affecting the cable.
3Measurement precision
If additional sensors are added to detect cable displacement for gear identification, then position detection is achieved, but the system becomes complex and costly
Solution Approach 1:
The patent combines the position detection function with the existing control cable mechanism by using the cable's own movement as the detection target. The single position sensor detects the displacement of the coupling mechanism that follows the cable's movement, eliminating the need for separate sensors on multiple components.
Solution Approach 2:
The coupling mechanism serves multiple functions: it transmits mechanical force from the cable to the control system while simultaneously acting as the detection target for the position sensor. This multi-functionality reduces the overall component count and system 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 simple, reliable, and cost-effective gear identification compatible with both rigid and flexible transmission members, avoiding sensitivity issues and additional sensor complexities, and can be integrated into existing motor-vehicle gearbox control devices without replacing parts.
Implementation Method 1
a position sensor arranged to detect the position of an elongated mechanical transmission member
Data Source
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AI summary
The control device comprises an elongated mechanical transmission member (10; 110) interposed between the gearbox and a control member (100) for transmitting to the gearbox the commands imparted through the control member, in such a manner that the gear engaged by means of the gearbox is linked to the linear position of the transmission member (10; 110). The device is provided with a position sensor (26; 126) comprising a movable reference element (28; 128), the movement of which is univocally determined by the movement of a rigid end portion (14; 114) of the transmission member (10; 110), and a stationary detection element (30) for detecting the position of the reference element (28; 128). The reference element (28; 128) is mechanically connected to the rigid end portion (14; 114) and spaced apart from it. Preferably, the position sensor is a linear position sensor (26) arranged to detect the linear position of the reference element (28), which is drivingly connected for translation with the rigid end portion (14) of the transmission member (10).