CN101560593B - 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 reinforcing process of engine for automobile bent axle.

Background technology

Spheroidal graphite cast iron is widely used in the manufacturing of automobile engine crankshaft owing to having 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 along with the raising that Engine Exhaust Emission is required, supercharging technology has obtained increasing application in motor car engine in recent years.The supercharging inter-cooling engine even higher to explosion pressure 12-14MPa, 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 supercharging 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, it is characterized in that, described technique is, utilizes rolling wheel to carry out direct roll extrusion to the fillet of bent axle, during roll extrusion, the roll extrusion angle [alpha] is 30-45 °, roll extrusion power P is 8000-15000N, and the roll extrusion radius R is 1.5-2.5mm, and the roll extrusion degree of depth is 0.1-0.2mm.The technical scheme that adopts is: a kind of fillet rolling and reinforcing technology of normalized nodular cast iron crankshaft, the fillet rolling and reinforcing technology of described normalized nodular cast iron crankshaft is, fillet to bent axle utilizes rolling wheel to carry out direct roll extrusion, during roll extrusion, satisfy following condition, bearing shell edge load phenomenon can not occur:

1) maximum roll extrusion projection is apart from bent axle shelves lateral distance: $L\≈R+\sqrt{R^2-{(R-h)}^2};$

2)L≤[(B ₁-B ₂)/2+1.25]；

3) bearing shell edge (B ₁-B ₂The projection τ of place)/2 _bBe no more than 0.003mm;

Wherein, R is the roll extrusion radius, and h is the roll extrusion degree of depth, B ₁Be the distance between two bent axle shelves sides, B ₂Be the bearing shell width, getting the roll extrusion angle [alpha] is 30-45 °, and roll extrusion power P is 8000-15000N, and 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 on 73.25%, adapted to the service requirements of the supercharging inter-cooling engine of high explosion pressure, make ductile iron crankshaft also can be used for the even higher supercharging inter-cooling engine of explosion pressure 12-14MPa, thus decrease the manufacturing cost of bent axle.By the optimum combination to each parameter of fillet rolling, the bearing shell edge load phenomenon of having avoided causing because of the roll extrusion projection.

Description of drawings

Accompanying drawing 1 is the schematic diagram of fillet rolling.

Accompanying drawing 2 is the schematic diagram at the crankshaft fillet place after roll extrusion.

Accompanying drawing 3 is schematic diagram that bent axle coordinates with bearing shell.

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

Embodiment

The below further illustrates the present invention.

As shown in Figure 1, when carrying out fillet rolling, can be according to the design of concrete automobile engine crankshaft, and the parameter such as tired bending value, bearing shell tolerance clearance, explosion pressure is determined the roll extrusion parameters such as roller pressure 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 roll extrusion.Obviously, described fillet is bullnose.

The present invention's rolling device used is identical with existing rolling device, and above it during by roll extrusion bull wheel 2, rolling wheel 1 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 roller pressure 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 is:

$L\≈R+\sqrt{R^2-{(R-h)}^2}$

As shown in Figure 2, make L≤[(B by choosing the 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 can not occur.

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 technique 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 the roll extrusion degree of depth is 0.15mm.Roll extrusion projection τ _b≤ 0.003mm.

Effect after roll extrusion is: the tired moment M after 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 of boosting type engine and relates to service condition: M _-1〉=1800N.m.

Claims (1)

1. the fillet rolling and reinforcing technology of a normalized nodular cast iron crankshaft, it is characterized in that, the fillet rolling and reinforcing technology of described normalized nodular cast iron crankshaft is, fillet to bent axle utilizes rolling wheel to carry out direct roll extrusion, during roll extrusion, satisfy following condition, bearing shell edge load phenomenon can not occur:

1) maximum roll extrusion projection is apart from bent axle shelves lateral distance:

2)L≤[(B ₁-B ₂)/2+1.25]；

3) bearing shell edge (B ₁-B ₂The projection τ of place)/2 _bBe no more than 0.003mm;

Wherein, R is the roll extrusion radius, and h is the roll extrusion degree of depth, B ₁Be the distance between two bent axle shelves sides, B ₂Be the bearing shell width, getting the roll extrusion angle [alpha] is 30-45 °, and roll extrusion power P is 8000-15000N, and 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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