HEGENSCHEIDT 7893 crankshaft deep rolling and straightening machine

The HEGENSCHEIDT 7893 crankshaft deep rolling and straightening machine was built in 2001 by the German company HEGENSCHEIDT-MFD GmbH & Co. KG. The purpose of the machine is the fully automatic machining of crankshafts by roll recessing and straightening rolling, in order to significantly increase the fatigue strength of crankshafts. The design of the machine and the modern production technologies used guarantee excellent results of deep roling, high accuracy of straightening roll forming, and make it possible to achieve a long service life.

Deep rolling is a process during which three-dimensional compressive stresses are introduced by plastically deforming the subsurface layer. The material is strengthened with a simultaneous increase in surface hardness and the dynamic load capacity of the crankshaft is significantly increased. In the case of a combination of the roll-compression process and the straightening rolling process, the radial run-out of the crankshaft is minimised.

The design of the HEGENSCHEIDT 7893 allows up to 13 roller tools to be mounted, which are suspended by weight-compensated pneumatic cylinders. They are guided in a movable linear sled. Connections for the hydraulic system, rolling oil system, pneumatic system and measuring transducers for the force and position sensors are integrated into the gauges. The tools required for machining the crankshaft in use are mounted on the jigs.

The machine, equipped with a SIEMENS Sinumerik CNC control, operates at a working speed of 120 rpm and a straightening rolling speed of 30 rpm. When the machine is working with the working crimping force, 6 retractions occur and when increasing/decreasing the crimping force, 3 retractions occur. The maximum bearing diameter is 82 mm and the minimum bearing diameter is 30 mm. The total weight of the HEGENSCHEIDT 7893 is 13700 kg.

Technical data of the HEGENSCHEIDT 7893 machine

• crimping speed: 120 rpm
• straightening speed 30 rpm
• stroke of main bearing external crankshaft: max. 700 mm
• number of rollers kneading devices: 9 pieces
• number of rollers when increasing or decreasing the crushing force: 3
• number of crimping at working crushing force: 6
• maximum number of main bearings: 7
• maximum number of needle roller bearings: 6
• minimum distance between main and needle roller bearings: 29.5 mm
• minimum bearing diameter: 30 mm
• maximum bearing diameter: 82 mm
• minimum bearing width: 18 mm
• maximum stroke: 120 mm
• diameter of sled: 195 mm
• filling quantity of hydraulic system: 160 l
• working pressure of hydraulic system: 9/16 MPa
• cooling capacity of hydraulic system: 7 kW
• cooling water consumption in the hydraulic system: 3.8 m3/h
• filling quantity of the rolling oil aggregate: 30 l
• working pressure of oil aggregate for rolling: 1.5 MPa
• rolling oil consumption: 0.12 cm3/min
• filling quantity of rolling oil tank: 260 l
• working pressure of rolling oil tank: 0.5 MPa
• sound pressure level: 62 dB(A)
• peak value of acoustic pressure: 96.7 dB(C)
• capacity of return-circulation pump: approx. 25 l/min
• compressed air operating pressure: 0.4 MPa
• compressed air consumption: 10 m3/h
• maximum operating pressure of cooling water: 3 MPa
• cooling water consumption: 4.8 m3/h
• mains/connection voltage: 230/400 V
• voltage tolerance ± 15 %
• mains frequency: 50 Hz
• rated current: 50 A
• connection power: 35 kVa
• control voltage: 230 VAC
• valve voltage: 24 VDC
• PLC input and output voltage: 24 VDC
• weight of the HEGENSCHEIDT 7893 machine with all equipment: 13700 kg

Equipment of the 7893 machine

• CNC control: SIEMENS Sinumerik
• hydraulic aggregate: REXROTH
• rolling oil filtration system
• cleaning device for instruments and tools
• tool lubrication system
• safety housing and operator platform
• roller pinching device
• tailstock with spindle sleeve