Hybrid Wheel Speed Sensor for Low-Speed Measurement
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Solution Overview
Problem
Existing brake systems struggle to reliably measure wheel speeds, especially at low speeds or when stationary, due to the need for complex adjustments and high installation costs, with passive sensors failing to induce measurable signals at low rotational speeds and active sensors requiring precise alignment.
Innovation Solution
A mixed system of active and passive sensors, where the active sensor, such as a Hall or GMR sensor, is used to measure wheel rotation with an auxiliary voltage, allowing for easy installation and reliable detection of low speeds without complex adjustments, and can be integrated with existing passive sensor systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a passive sensor is used for speed measurement, then the installation is simple and no auxiliary voltage is required, but the sensor cannot reliably measure low rotational speeds or standstill conditions
Solution Approach 1:
The patent combines passive and active sensor systems into a hybrid configuration. The passive sensor continues to provide speed measurement for normal operating conditions, while the active sensor with auxiliary voltage enables reliable measurement at low speeds and standstill. Both sensor types work together to resolve the contradiction between installation simplicity and low-speed measurement capability.
Solution Approach 2:
The sensor system is designed to perform multiple functions across different operating conditions. The passive sensor handles high-speed measurements, while the active sensor takes over for low-speed and standstill conditions. This multi-functional approach allows the system to maintain reliability across the entire speed range while preserving the installation advantages of passive sensors.
2Reliability
If an active sensor is used for speed measurement, then low speeds and standstill conditions can be reliably measured, but complex adjustment work and precise alignment are required during installation
Solution Approach 1:
The sensor system is segmented into distinct functional components: a passive sensor for normal speed measurement and an active sensor for low-speed measurement. This segmentation allows each sensor type to be optimized for its specific function while reducing the overall installation complexity. The passive sensor requires no auxiliary voltage and simpler installation, while the active sensor handles the demanding low-speed measurements.
Solution Approach 2:
The control unit acts as an intermediary that manages the transition between passive and active sensor operation. It processes signals from both sensor types and determines which sensor provides reliable measurements under current conditions. This intermediary function协调s the two sensor systems, allowing the active sensor to be used only when necessary for low-speed measurements, thereby reducing overall installation complexity.
3Device complexity
If a passive sensor is used, then no auxiliary voltage is needed and the system is simpler, but the AC voltage amplitude becomes insufficient at low rotational speeds for reliable measurement
Solution Approach 1:
The system changes the operational parameters of the sensor based on speed conditions. At normal speeds, the passive sensor operates without auxiliary voltage, maintaining system simplicity. At low speeds, the system activates the auxiliary voltage to the active sensor, changing its operational state to generate sufficient signal amplitude for reliable measurement. This parameter change allows the system to maintain simplicity when possible while ensuring measurement precision when needed.
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 reliable measurement of wheel speeds at low speeds and standstill conditions with simplified installation, reducing costs and eliminating the need for precise alignment, applicable to both commercial and passenger vehicles.
Implementation Method 1
The active sensor, such as a Hall or GMR sensor
Implementation Method 2
The active sensor, such as a Hall or GMR sensor
Implementation Method 3
passive speed measurement by means of induction
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a sensor device 38, 40 for measuring the rotational speed at a wheel 4, 6 of a vehicle 1. The sensor device 38, 40 has a sensor carrier 46, 50 with an active sensor 82, 84 for actively sensing the rotation of a pole wheel 58, 60, rotating along with the wheel 4, 6, in order to measure the rotational speed. The sensor carrier 46, 50 is arranged in such a way that it can be clamped in the region of the wheel, 4, 6. The invention permits an active sensor 82, 84 to be used without complex adjustment operations. Furthermore, the invention relates to a brake system 2 and to a vehicle 1 with the sensor device 38, 40 as well as to a measuring method 110 which can be carried out with the invention and to a braking method 102.