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Deep Rolling and Roll Straightening Machines

HEGENSCHEIDT 7895 - Deep rolling and roll straightening for economical crankshaft machining 

In powertrain applications, deep rolling is an attractive manufacturing technology for improving the operational stability of highly stressed crankshafts for automotive, commercial vehicle and industrial engines. The deep rolling process induces compressive residual stresses into the bearing fillets of crankshafts. HEGENSCHEIDT has had a decisive influence on this technology and has developed special machines for the economical machining of crankshafts with its deep rolling and  roll straightening machines.

Application and use

 

The 7895 is a universal deep rolling machine for the machining of crankshafts. Deep rolling is a process in which plastic deformation of the near-surface layer induces positive three-dimensional residual compressive stresses within the bearing fillet areas of the workpiece, which is subject to the highest stress. These counteract the tensile stresses that occur under load. The material is strengthened, the surface hardness increases, and the dynamic load capacity of the crankshaft is significantly increased.

With optimized deep rolling processes, incraeases in fatigue strength of over 200 % can be achieved. The HEGENSCHEIDT machine is equipped with its own high-performance tools to ensure maximum service life. The radial run-out on max. 3 main bearings is measured using precise measuring probes. The measured data serves as the basis for the roll straightening process.

 

Added value

  • Flexible machine concept for deep rolling and roll straightening crankshafts with different strokes, bearing spacing and number of bearings
  • Angle-dependent deep rolling to minimize axial runout, and prevent damage to the shoulders
  • Straightening of the crankshaft without loss of fatigue strength thanks to optional straightening rolling process
  • Measurement of radial runout on max. 3 main bearings
  • Self-learning straightening rolling program
  • Direct loading in machining position
  • Low loading height of 1,100 mm for manual loading; short distance to insertion position (500 mm)
  • Radial workpiece orientation
  • High process reliability thanks to monitoring of all processing parameters
  • Monitoring of the rolling depth (optional)
  • Tool breakage monitoring
  • New tool design without adjustment
  • Fixed rollers can be quickly adjusted to other bearing distances
  • Automatic stroke adjustment

Function

The deep rolling process induces residual compressive stresses into the fillet radii, increasing the fatigue limit and thus significantly increasing service life of the product. This technology was innovatively perfected through angle-dependent deep rolling and later roll straightening. Roll straightening reduces the existing radial runout of the crankshaft. From development to the present day, several patents have been granted for the technologies and machine designs. This advanced crankshaft machining technology used today in the automotive industry for compact engines achieves material savings and improves quality and service life. The headstock and tailstock of the machine are manually adjustable so that different crankshaft families can be machined. It is also possible to machine one type of crankshaft with different strokes without adjustment.

Highlights of the 7895

Machine specification

Machine data
Machine dimensions (L x W x H) 4,000 mm x 2,500 mm x 2,200 mm (incl. integrated control panel and hydraulic unit)
Machine weight 10 t (incl. auxiliary units)
Machine center height 1,100 mm
General specification
Power main drive  20 kW

Deep rolling speed 

120 min-1
Roll straightening speed 60 min-1
Measuring speed 30 min-1
Deep rolling force, max. 20 kN
Workpiece data  
Bearing center distance of the outer main bearings, max. 450 mm
Counterweight radius (depending on stroke and bearing width) 195 ... 270 mm
Number of machinable bearings, max. 5 main bearings, 4 pin bearings
Main bearing diameter, min. | max. 30 | 88 mm
Pin bearing diameter, min. | max. 30 | 84 mm
Bearing width, min. 18.5 mm
Stroke, max. 120 mm
Pitch between main and pin bearing, min. 29.5 mm

 

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Brochure

Here you will find all the contents of the 7895 as a download.

DOWNLOAD | PDF 1.11 MB

Our Services

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