The MAPAL tool programme for series production of scroll compressors.

Electrified auxiliary units

As a result of electrification in the automotive industry, more and more drive tasks
of the internal combustion engines are being performed by electrified components.
By electrifying the auxiliary units, these components can be used as required and
depending on the load, and thus contribute to reduced energy consumption. They
stand out thanks to their high reliability and low noise emissions as well as excellent
energy efficiency.

Auxiliary unit scroll compressor

An example of an electrified auxiliary unit is the scroll compressor, which is used as an electric refrigerant compressor in thermal management. Three specific machining operations on an aluminium scroll compressor for use in an electrified vehicle are presented as examples.
Sectional view of scroll compressor

FEATURES

  • Core pieces orbit and fixed scroll
  • Geometric accuracy and connection is paramount
  • Exact positioning of the spirals to each other

MACHINING REQUIREMENTS

  • High degree of shape accuracy of the spirals (≤ 20 μm)
  • High perpendicularity of flanks to base surface (≤ 20 μm)
  • Parallel alignment and flatness of ≤ 10 μm
  • Surface roughness (Rz) in the single-digit range
  • Perfect interaction between machine and tool

Processing steps on the auxiliary unit scroll compressor:

  • The combination tool finishes the recesses for the sealing grooves.

    Recesses for sealing elements

    • Pre-machining and finish machining of the recesses is carried out with double-edged PCD boring tools
    • Combination tool enables the machining of the connection bore
    • Distribution of the cut reduces cutting forces and ensures optimal chip formation

  • The boring tool with two stages machines the bearing bore of the scroll compressor.

    Precise bearing bore

    • Pre-machining is carried out by circular milling with a triple-fluted PCD milling cutter
    • Finish machining with double edge PCD boring tool with two stages and distribution of the cut to reduce the cutting forces

  • Machining of the high-precision spiral shapes with a milling cutter made of solid carbide.

    High precision spiral shapes

    • Pre-machining and finish machining with solid carbide milling cutters
    • Extremely sharp cutting edges ensure high dimensional accuracy

Other electrified components