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Multisensor CMM Drives Dimensional Inspection of eDrive Housings

The increasingly integrated design of electric vehicle motors, power electronics and drivetrains is placing new demands on the quality inspectionof eDrive housings.

Many electric vehicle designs today integrate the electric motor, power electronics and drivetrain components within a single housing unit. This new kind of a combined electric axle drive, sometimes known as ‘eAxle’, reduces weight and axial installation space – ideal to accommodate the battery stacks of battery electric vehicles (BEVs) or the second engine and transmission in for hybrid electric vehicles (HEVs). But this design brings new challenges in the quality assurance process for such housings.

Challenges – Small sizes and high complexity

High Accuracy Leitz Reference HP Bridge CMM

As well as shaft and bearing quality, the thermal management of the system becomes an important issue to be verified. eDrive housings require an advanced cooling concept to manage the heat generated within the coils and hairpins of the electric motor, as well as by the power electronics. The integrated transmission and differential are key components for torque adaption and torque vectoring, and require high quality bearing arrangements in the housing.

Solution – Precision CMM with high flexibility

Such integrate system designs are leading to smaller and more complex housings being developed for electric vehicles, characterised by particular size, form and position specifications as well as lower wall thickness. As a result, dimensional tolerances for the housings are becoming tighter and certain features are harder to access during quality assurance processes. Housing inspections require standard geometries and profile feature measurement, with key features including sealing surfaces, flanges, boreholes, cooling holes or
coolant channels, wall thickness, bearing of the shaft and bearing arrangements that also provide support for an integrated drive including gears. Surface inspection and roughness measurement may also be required in some instances.

Advantages – Application-oriented sensor technology enables high adaptability

Because of the number and range of features found on a typical eDrive housing, a comprehensive yet flexible measurement solution is required to achieve the necessary accuracy without compromising on cycle times. Hexagon’s high and ultra-high accuracy coordinate measuring machines (CMMs) with multisensor capabilities offer such flexibility. By integrating a fixed tactile probe head, an indexing wrist and a roughness sensor on a single CMM, all of the important features of the eDrive housing can be captured quickly within a single program.

Offering fully-automatic sensor exchange within a part program, the Hexagon SENMATION universal sensor interface transforms a coordinate measuring machine (CMM) into a multisensor inspection device capable of completing the most intricate measurement challenges. The highly-accurate PRECITEC optical sensor uses focused white light to take roughness measurements on even the most complex surfaces.

SENMATION adds flexibility to the metrology setup, ensuring the most effective measurement method can be selected at all times to deliver the best possible results in the most efficient way – with no user intervention required.

CMM Roughness Sensor

SENMATION is a universal sensor interface system that enables easy exchange of sensing technology. With seamless shifts between inspection methods allows the measuring application to utilize both tactile and optical sensors within the same measurement program to ensure the right sensor is used for every feature of the workpiece.

Integrated directly into the CMM quill, SENMATION uses a sophisticated probe recognition system to quickly identify and check the status of the loaded sensor. With no need to recalibrate after exchange, the system delivers smooth changes and fast measurement operations. A universal sensor switch and intelligent sensor module mean that SENMATION can accept all common sensor types, while the scalable nature of the system means that additional sensors can be integrated in future.

With SENMATION, part measurement flexibility makes even the most complex measurement routine easy to program.

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