CN101560593A - Fillet rolling and reinforcing technology of normalized nodular cast iron crankshaft - Google Patents

Abstract

The invention provides a fillet rolling and reinforcing technology of a normalized nodular cast iron crankshaft, belonging to the processing technology of an engine crankshaft. The technology comprises the following steps: a rolling wheel is utilized to directly roll the fillet of the crankshaft; during rolling, the rolling angle alpha is from 30 degrees to 45 degrees, the rolling pressure P is from 8000N to 15000N, the rolling radius R is from 1.5mm to 2.5mm, and the rolling depth h is from 0.1mm to 0.2mm. The technology can effectively improve the fatigue bending moment of the crankshaft by more than 73.2 percent and satisfies the use requirements of a supercharged mid-cooling engine with high explosion pressure so that the nodular cast iron crankshaft can also be used in the supercharged mid-cooling engine with the explosion pressure of 12MPa to 14MPa or even higher, and the manufacture cost of the crankshaft is greatly decreased. The invention optimizes and combines various fillet rolling parameters and avoids the bearing edge load phenomenon caused by rolling protrusions.

Description

A kind of fillet rolling and reinforcing technology of normalized nodular cast iron crankshaft

Technical field

The present invention relates to a kind of complete processing of engine crankshaft, especially a kind of engine for automobile Strengthen Techniques of Crankshaft.

Background technology

Spheroidal graphite cast iron has obtained using widely in the manufacturing of automobile engine crankshaft owing to have high strength, high-ductility, high-wearing feature, high damping property and good processing characteristics and lower production cost.Particularly in being the natural aspiration type automobile engine crankshaft of 7-9MPa, explosion pressure is in absolute predominance.Yet in recent years along with the raising to the motor car engine emission request, supercharging technology has obtained increasing application in motor car engine.To explosion pressure 12-14MPa even higher charge inter cooling engine, the performances such as tired moment of flexure of the engine ductile iron crankshaft that existing complete processing is produced, can not satisfy the requirement of service condition, must adopt other material, thereby improve production cost.

Summary of the invention

Technical problem to be solved by this invention is, a kind of fillet rolling and reinforcing technology of normalized nodular cast iron crankshaft is provided, and it can effectively improve the tired moment of flexure of bent axle, with the service requirements of the charge inter cooling engine that adapts to high explosion pressure.

The present invention realizes like this, a kind of fillet rolling and reinforcing technology of normalized nodular cast iron crankshaft, described technology is, fillet to bent axle utilizes rolling wheel to carry out direct roll extrusion, during roll extrusion, the roll extrusion angle [alpha] is 30-45 °, and roll extrusion power P is 8000-15000N, the roll extrusion radius R is 1.5-2.5mm, and roll extrusion degree of depth h is 0.1-0.2mm.

This normalizing attitude fillet rolling and reinforcing technology can effectively improve the tired moment of flexure of bent axle, tired moment of flexure can improve more than 73.2%, adapted to the service requirements of the charge inter cooling engine of high explosion pressure, make ductile iron crankshaft also can be used for explosion pressure 12-14MPa even higher charge inter cooling engine, thereby reduced the manufacturing cost of bent axle significantly.By to each Parameter Optimization combination of fillet rolling, avoided the bearing shell edge load phenomenon that causes because of the roll extrusion projection.

Description of drawings

Fig. 1 is the synoptic diagram of fillet rolling.

Fig. 2 is the synoptic diagram at the crankshaft fillet place after the roll extrusion.

Fig. 3 is the synoptic diagram that bent axle cooperates with bearing shell.

Among the figure, the 1-rolling wheel, 2-roll extrusion bull wheel, 3-treats rolling crankshafts, the 4-bearing shell.

Embodiment

Further specify the present invention below.

As shown in Figure 1, when carrying out fillet rolling, can be according to the design of concrete automobile engine crankshaft, and parameter such as tired moment of flexure value, bearing shell tolerance clearance, explosion pressure is determined roll extrusion parameters such as roll extrusion power P, roll extrusion angle [alpha], roll extrusion degree of depth h, roll extrusion radius R.

Described roll extrusion is to carry out after other mechanical workouts of ductile iron crankshaft.Make the bent axle finished product through after the roll extrusion.Obviously, described fillet is a bullnose.

The used rolling device of the present invention is identical with existing rolling device, and roll extrusion bull wheel 2, rolling wheel 1 are arranged above it.During roll extrusion, rolling wheel is at the roll extrusion bull wheel and treat between the fillet of rolling crankshafts 3.

Maximum roll extrusion projection τ is the function of roll extrusion power P, roll extrusion fillet R, bent axle matrix hardness H.

Calculating maximum roll extrusion projection apart from the formula of bent axle shelves lateral distance L is:

$L\≈R+\sqrt{R^2-{(R-h)}^2}$

As shown in Figure 2, make L≤[(B by choosing parameters such as P, α, R, h ₁-B ₂)/2+1.25], and make bearing shell 4 edge (B ₁-B ₂The projection τ of place)/2 _bBe no more than 0.003mm, bearing shell edge load phenomenon then can not take place.

Embodiment 1

To be strengthened is that model is the ductile iron crankshaft of Y4102, and material is QT800-3.

A kind of fillet rolling and reinforcing technology of normalized nodular cast iron crankshaft, described technology be, utilizes rolling wheel to carry out direct roll extrusion to the fillet of bent axle, during roll extrusion, the roll extrusion angle [alpha] is 40 °, and roll extrusion power P is 9800N, the roll extrusion radius R is 2.0mm, and roll extrusion degree of depth h is 0.15mm.Roll extrusion projection τ _b≤ 0.003mm.

Strengthening effect after the roll extrusion is: the tired moment M behind the normalizing attitude fillet rolling _-1=1985N.m, and the normalizing attitude tired moment M of rolling crankshafts not _-1=1146N.m, tired moment of flexure increase rate is 73.2%.

The technique effect of above-mentioned processing satisfies the tired moment of flexure design of boosting type engine service condition: M _-1〉=1800N.m.

Claims (1)

1, a kind of fillet rolling and reinforcing technology of normalized nodular cast iron crankshaft, it is characterized in that, described technology is, fillet to bent axle utilizes rolling wheel to carry out direct roll extrusion, during roll extrusion, the roll extrusion angle [alpha] is 30-45 °, and roll extrusion power P is 8000-15000N, the roll extrusion radius R is 1.5-2.5mm, and roll extrusion degree of depth h is 0.1-0.2mm.

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