Permanent magnets are used in many sensor applications as signal transmitters for Hall sensors and/or magnetoresistive sensors. The magnetic fields are relatively low, so external magnetic interference fields could lead to incorrect measurement results. In such cases, magnetic shielding is beneficial.
What is out Solution in this Case?
In this case, magnetic shielding helps. For example by joining the sensor magnet in a sleeve. By "joined in a sleeve", we mean the production process of a cost-efficient production since the entire assembly can be manufactured in a single step.
Which type of Magnetic Material do we use?
We use a plastic-bonded, pressed neodymium iron boron ring magnet. We can achieve minimum wall thicknesses of 1.5 mm. Narrow tolerances and precise magnetisations, for example multi-pole magnetisation at the inside diameter, are possible.
- Material designation NdFeB 72 / 70 pw | 65 / 70 pw | 65 / 85 pw
- Typical remanence of 700 mT
- Multi-pole magnetisation possible at the inside diameter
- Binding agent approx. 2 % epoxy
Advantages & Benefits
- Magnetic shielding
- No adhesive bonds
- Low use of magnetic material since wall thicknesses of up to 1.5 mm can be implemented
- Tight tolerances
- no adhesive gaps and therefore less imbalance
- Magnetic alloy without dysprosium
- Precise magnetisation
- efficient production
- can be produced in a single step
- Compact installation space due to the use of highly remanent magnetic material
- Speeds of more than 50,000 rpm are possible (burst protection)
- Design according to customer requirements
What are typical Applications?
Typical applications of magnetic field sensors include the contact-free detection of position, rotation and speed. Shielding is especially important in the e-mobility sector because of the interference fields that are prevalent there, for example in electro-hydraulic brake systems.
Depending on the version, the rotor position of a motor is transferred to the sensor element via the sensor magnet. With the help of the electrical system, the signals for functions such as the anti-lock braking system, tracking control system, electronic brake force distribution, adaptive cruise control or hill start assist and hill descent control can be made available.
In addition to electro-hydraulic brake systems, these types of sensor magnets are also used in many other safety-related applications or extras that increase the driving comfort. However, they are especially used where shielding is required to prevent opposing fields for safety reasons in order to prevent accidents and protect pedestrians, for example with electronic steering (including rear-axle steering), automatic gear selection or seatbelts.
In terms of the extras, these applications include seat adjustments, power windows or electric sunroofs, electric trunk lids or ventilation flaps for a pleasant interior temperature. Sensor applications are also used for engine management and exhaust gas recirculation (EGR).
Magnets in Vehicles
Applications with Magnet Sensors