Deep rolling and roll straightening machines, types 7893R and 7895
The design of the transition curve radii on the main and pin bearings for crankshafts is a decisive factor for their service life. To increase the fatigue strength, a new technology developed by Hegenscheidt called deep rolling was successfully introduced to crankshaft production around the middle of the 1950s. Deep rolling the main and pin bearing radii enabled the introduction of higher motor outputs in the worldwide automotive industry. The deep rolling process introduced compressive residual stresses in the corner grooves of the crankshaft bearings, which lead to an increase in the fatigue strength and therefore to a significant increase in the service life. This technology was perfected innovatively by using angle-dependent deep rolling and, later on, roll-straightening processes. Roll straightening reduces the radial runout present in the crankshaft. Several patents were granted for the technologies and machine designs introduced between the early development and the levels achieved today. The progressive crankshaft machining technology applied nowadays in the automotive industry for compact motors was pivotal both in achieving material savings and in improving quality and service life.
Typ 7893R
| Typ 7893R-01 | Typ 7893R-02 | Typ 7893R-03 | Typ 7893R-03S | |
|---|---|---|---|---|
| Description of machines | Headstock and tailstock are manually adjustable. Ideally suited for machining a crankshaft type with varying strokes. | Headstock can be moved automatically. Tailstock is manually adjustable. Ideally suited for machining a crankshaft family with a varying number of bearings and varying strokes. | Headstock and tailstock can be moved automatically. Ideally suited for machining different crankshaft families | As in 7893R-03, however, the number of deep rolling units is less than the number of crankshaft bearings; machining several crankshaft bearings in sequence by means of moving the crankshaft (shifting) in front of the axially fixed deep rolling units. Ideally suited for machining different crankshaft families in small quantities. |
| Workpiece | ||||
| Distance between bearing centre lines for the outer main bearings, max.: | 920 mm | 920 mm | 920 mm | 920 mm on request > 920mm |
| Rolling arm length, max. (½ stroke + radius of counterweight): | 195 - 270 mm | 195 - 270 mm | 195 - 270 mm | 195 - 270 mm on request > 270 mm |
| Radius of counterweight for shift operation, max.: | - | - | - | Defined acc. to particular case |
| Max. number of machinable bearings: | 8 main bearings 6 pin bearings | 8 main bearings 6 pin bearings | 8 main bearings 6 pin bearings | defined acc. to particular case |
| Main bearing diameter, min / max.: | 30 / 88 mm on request > 88 mm | 30 / 88 mm on request > 88 mm | 30 / 88 mm on request > 88 mm | 30 / 88 mm on request > 88 mm |
| Pin bearing diameter, min / max.: | 30 / 84 mm on request > 84 mm | 30 / 84 mm on request > 84 mm | 30 / 84 mm on request > 84 mm | 30 / 84 mm on request > 84 mm |
| Bearing width, min.: | 18,5 mm | 18,5 mm | 18,5 mm | 18,5 mm |
| Stroke, max.: | 140 mm | 140 mm | 140 mm | 140 mm |
| Bearing spacing, min.: | 29,5 mm | 29,5 mm | 29,5 mm | 29,5 mm |
| Deep rolling units | ||||
| Max. deep rolling force: | 30.000 N optionally 40.000 N | 30.000 N optionally 40.000 N | 30.000 N optionally 40.000 N | 30.000 N optionally 40.000 N |
| Headstock | ||||
| Output of main drive motor: | 20 kW | 20 kW | 20 kW | 20 kW |
| Speed when deep rolling: | 120 rpm | 120 rpm | 120 rpm | 120 rpm |
| 60 rpm | 60 rpm | 60 rpm | 60 min-160 rpm | |
| Speed when roll straightening: | 30 rpm | 30 rpm | 30 rpm | 30 rpm |
| Machine | ||||
| Weight including auxiliaries: | approx. 13.800 kg | approx. 13.800 kg | approx. 13.800 kg | approx. 13.800 kg |
| Dimensions including integrated electrical cabinet and hydraulic system (L/W/H) approx.: | 4,5 x 2,5 x 2,2 m | 4,5 x 2,5 x 2,2 m | 4,5 x 2,5 x 2,2 m | 4,5 x 2,5 x 2,2 m |
| Max. machining height: | 1100 mm | 1100 mm | 1100 mm | 1100 mm |
Typ 7895
| Typ 7895 | |
|---|---|
| Maschinen- beschreibung | Spindelkasten und Reitstock manuell verstellbar zur Bearbeitung unterschiedlicher Kurbelwellenfamilien. Bearbeitung eines Kurbelwellentyps mit unterschiedlichen Hüben ohne Verstellung möglich. |
| Werkstück | |
| Lagermittenabstand der äußeren Hauptlager, max.: | 450 mm |
| Max. Durchmesser Gegengewicht: (abhängig von Hub und Lagerbreite) | 195 - 270 mm |
| Max. Anzahl bearbeitbarer Lager: | 5 Hauptlager 4 Hublager |
| Hauptlagerdurchm., min/max: | 30/88 mm |
| Pleuellagerdurchm., min/max: | 30/84 mm |
| Lagerbreite, min: | 18,5 mm |
| Hub, max.: | 120 mm |
| Lagerabstand, min: | 29,5 mm |
| Festwalzgeräte | |
| Max. Festwalzkraft: | 20000 N |
| Spindelkasten | |
| Leistung des Hauptantriebmotors: | 20 kW |
| Drehzahl beim Festwalzen: | 120 min-1 |
| Drehzahl beim Richtwalzen: | 60 min-1 |
| Drehzahl beim Messen: | 30 min-1 |
| Maschine | |
| Gewicht einschließlich Nebenaggregaten: | ca. 10.000 kg |
| Maße einschließlich integriertem Schaltschrank und Hydraulik (L/B/H) ca.: | 4,0 x 2,5 x 2,2 m |
| Bearbeitungshöhe: | 1100 mm |