CN109622856B

CN109622856B - Axial distance adjusting method for combined die in full-fiber crankshaft upsetting-extruding forming process

Info

Publication number: CN109622856B
Application number: CN201811524403.0A
Authority: CN
Inventors: 林军; 陈强; 康凤; 黄树海; 胡传凯; 夏祥生; 赵祖德
Original assignee: No 59 Research Institute of China Ordnance Industry
Current assignee: Southwest Institute of Technology and Engineering of China South Industries Group
Priority date: 2018-12-13
Filing date: 2018-12-13
Publication date: 2020-06-05
Anticipated expiration: 2038-12-13
Also published as: CN109622856A

Abstract

The invention discloses a method for adjusting the axial distance of a combined die in the upsetting-extruding forming process of an all-fiber crankshaft, which aims at solving the problem that the combined die structure adopted by the upsetting-extruding forming process inevitably generates axial plastic flow to cause the length of a main journal to be out of tolerance, the horizontal distance of the combined die is adjusted before forming according to the geometric parameters of a preformed blank, a crankshaft forging piece and the combined die, the axial length of a single main journal can be controlled within the range of +/-0.5 mm of a design value, the deviation value of the machining allowance of each crank arm of the crankshaft is less than or equal to 1mm, and the yield and the quality consistency of the all-fiber crankshaft forging piece can be effectively improved by the method.

Description

Axial distance adjusting method for combined die in full-fiber crankshaft upsetting-extruding forming process

Technical Field

The invention belongs to the field of precision plastic forming process and equipment, in particular to a forming process method of an all-fiber crankshaft forge piece, which can be used on various upsetting-extruding composite forming (or all-fiber forming) devices.

Background

The existing diesel engine greatly improves the power density and reduces the sizes of main parts of the existing diesel engine. The crankshaft is the most important part of the engine, and the fatigue performance of the crankshaft directly influences the reliability of the operation of the engine. The fatigue strength of the crankshaft prepared by the traditional free forging and other processes does not match the requirement of a high-power-density engine. The fatigue resistance of the crankshaft prepared by upsetting-extruding composite forming can be greatly improved, and the method is a preferred forming process of the high-performance crankshaft.

The upsetting-extruding forming process adopts a gradually-bent forming mode, and when the process is used for forming each bent, the angle of the current forming crank throw must be positioned, so that the angle between the bent throws is ensured. At present, in the upsetting-extruding forming process, the distance between the combined dies is generally calculated according to the design sizes of a step shaft blank drawing and a forging drawing. However, the problems that result directly from the design values of the two drawings are: firstly, the heated blank is difficult to put into a die; secondly, the axial length of the formed single crank throw is seriously out of tolerance.

In order to ensure that the axial dimension of the crankshaft meets the design requirements, it is important to calculate the internal spacing of the split molds and the spacing between the split molds.

Disclosure of Invention

Aiming at the requirement of the gap between the inside of the combined die and each combined die by feeding during the upsetting-extruding forming process of the crankshaft, the method for adjusting the axial distance between the combined dies during the upsetting-extruding forming process of the full-fiber crankshaft is improved, and the method comprises the following solving processes:

under the condition that original designs of a step shaft blank and a crankshaft forging are not changed, the size precision of the axial direction length of a main journal of the crankshaft forging is improved by adjusting the horizontal distance of the combined die.

The distance between a horizontal upsetting die and a horizontal thrust die of the upsetting-extruding forming die is P, and the axial lengths of a main journal, a connecting rod journal and a crank arm area of the step shaft blank are assumed to be P_Z、P_L、P_Q(ii) a The axial length of the single-throw main journal and the connecting rod journal of the crankshaft forge piece and the axial thickness of the crank arm are F_Z、F_L、F_Q(ii) a Thickness of upsetting die is T_D(ii) a The upsetting die is used for fixing the length Dz of the blank; the crankshaft has N crank throws; under the known conditions that all the cranks are formed from left to right in sequence, and the like, the distance of the die before forming each crank is determined in the horizontal direction according to the following method:

(1) before the 1 st crank throw is formed, the distances L1 between the horizontal upsetting dies on the left side and the horizontal upsetting dies on the right side and the staggered die are set to be PZ + PQ-FQ +5 mm-25 mm; the forming and thrust die clearance L2 in the right-side horizontal upsetting die was PL +0.5 × (PZ-DZ).

(2) When 2-N-1 crank throws are formed, the distances L1 between the horizontal upsetting dies on the left side and the horizontal upsetting dies on the right side and the middle staggered-turning dies on the middle side are set to be PQ-FQ +5 mm-25 mm; the distance L2 between the right horizontal upsetting die and the thrust die is PQ +1 mm-5 mm; the distance L0 between the left horizontal upsetting die and the thrust die is FQ +2 mm-10 mm, and L0+ DZ = FZ + FQ-1 mm-2 mm.

(3) When the Nth crank throw is formed, the distances between the horizontal upsetting dies on the left side and the horizontal upsetting dies on the right side and the middle staggered-crank die are set to be PQ-FQ +5 mm-25 mm; the distance L0 between the horizontal upsetting die and the thrust die on the left side is PQ +2 mm-5 mm, L0+ DZ = FZ + FQ-1 mm-2 mm, and L2 is equal to the designed size of the blank.

According to the invention, under the condition that the original design of the step shaft blank and the crankshaft forging is not changed, the dimensional accuracy of the axial length of the main journal of the crankshaft forging is improved by adjusting the horizontal distance of the combined die.

Drawings

FIG. 1 is a key dimension of a crankshaft forging;

FIG. 2 is an enlarged view of the left portion of FIG. 1;

FIG. 3 illustrates the combined mold position and parameter definition for the 1 st inflection mold;

FIG. 4 is an enlarged view of the left portion of FIG. 3;

FIG. 5 shows the relative positions of the combined mold from 2 nd corner to N-1 th corner;

FIG. 6 is an enlarged view of the middle of FIG. 5;

FIG. 7 shows the relative positions of the combined molds for the Nth turn forming;

fig. 8 is an enlarged view of the middle of fig. 7.

In the figure, 3-1 is a staggered-turning die, 3-2 is a right horizontal thrust die, 3-3 is a right horizontal upsetting die, 3-4 is a left horizontal upsetting die, and 3-5 is a left horizontal thrust die.

Detailed Description

The invention is further described with reference to the following figures and specific embodiments.

Example 1

The length Fz of a main journal of a single crank of a 6-crank crankshaft is =30mm, and the thickness of a crank armFQ =28mm, connecting rod neck length FL =60 mm; the length Pz of a main journal of a step shaft preform =32mm and the thickness P of a crank arm_Q=58mm, connecting rod neck length P_L=62 mm; t of upsetting die_D=20mm, Dz =28 mm. The horizontal spacing of the mold before the formation of each bell crank:

when the 1 st crutch is formed:

L₁=P_Z+P_Q-F_Q+5 mm-25 mm =32mm +58mm-28mm + 5-25 mm =62mm + 5-25 mm, considering the small size of the crankshaft, L₁The value is 70 mm.

L₂=P_L+0.5×(P_Z−D_Z)=62mm+0.5×(32mm−28)=64mm

And 2, when forming turning from 2 nd to 5 th:

L₁=P_Q-F_Q+5 mm-25 mm =58mm-28mm +5 mm-25 mm =30mm +5 mm-25 mm, considering the small size of the crankshaft, L₁The value is 38 mm.

L₂=P_Q+1 mm-5 mm =58mm +1 mm-5 mm, 60mm being taken

L₀=F_Q+2 mm-10 mm =28mm +2 mm-10 mm, due to L₀+28=30+28-1 mm-2 mm, 29mm being taken.

When the 6 th crutch is formed:

L₂Depending on the length of the stub bar,

example 2

In an 18-throw crankshaft, the length Fz of a main journal of a single throw =50mm and the thickness F of a crank arm_Q=72mm, connecting rod neck length F_L=96 mm; the length Pz of a main journal of a step shaft preform =60mm and the thickness P of a crank arm_Q=124mm, connecting rod neck length P_L=98 mm; t of upsetting die_D=112mm, Dz =48 mm. The horizontal spacing of the mold before the formation of each bell crank:

when the 1 st crutch is formed:

L₁=P_Z+P_Q-F_Q+5 mm-25 mm =60mm +124mm-72mm + 5-25 mm =112mm + 5-25 mm, considering the larger crankshaft size, L₁The value is 130 mm.

L₂=P_L+0.5×(P_Z−D_Z)=98mm+0.5×(60mm−48)=104mm

2 nd to 17 th in the forming process:

L₁=P_Q-F_Q+5 mm-25 mm =124mm-72mm +5 mm-25 mm =52mm +5 mm-25 mm, considering the larger crankshaft size, L₁The value is 70 mm.

L₂=P_Q+1 mm-5 mm =124+1 mm-5 mm, 130mm

L₀=F_Q+2 mm-10 mm =72mm +2 mm-10 mm, due to L₀+48=50+72+1 mm-2 mm, 73 mm.

When the 18 th crutch is formed

L₀=F_Q+2 mm-10 mm =72mm +2 mm-10 mm, due to L₀+48=50+72+1 mm-2 mm, 73 mm.

Aiming at the problem that the length of a main journal is out of tolerance because axial plastic flow is inevitably generated by a combined die structure adopted by an upsetting-extruding forming process, the method can control the axial length of a single main journal within the range of +/-0.5 mm of a design value by adjusting the horizontal spacing of the combined die before forming according to the geometric parameters of a preformed blank, a crankshaft forge piece and the combined die, and the deviation value of the processing allowance of each crank arm of a crankshaft is less than or equal to 1 mm.

Claims

1. The axial distance adjusting method of the combined die in the upsetting-extruding forming process of the full-fiber crankshaft is characterized in that the original design of a step shaft blank and a crankshaft forge piece is not changed, and the axial lengths of a main journal, a connecting rod journal and a crank arm area of the step shaft blank are respectively P_Z、P_L、P_Q(ii) a Single-throw main journal of crankshaft forging andthe axial length of the connecting rod neck and the axial thickness of the crank arm are F_Z、F_L、F_Q(ii) a Thickness of upsetting die is T_D(ii) a The upsetting die is used for fixing the length Dz of the blank; the crankshaft has N crank throws; the crank throws are sequentially formed from left to right, and the distance of the die in the horizontal direction before forming each crank throw is determined according to the following method:

(1) before the 1 st crank throw is formed, the distance L between the horizontal upsetting die and the staggered crank throw die on the left side and the right side₁Are all set as P_Z+P_Q-F_Q+5mm to 25 mm; distance L between right horizontal upsetting die and right horizontal thrust die₂Is P_L+0.5×(P_Z-D_Z)；

(2) When the 2 nd to N-1 th crank throws are formed, the distance L between the horizontal upsetting dies on the left side and the horizontal upsetting dies on the right side and the middle staggered die₁Are all set as P_Q-F_Q+5mm to 25 mm; distance L between right horizontal upsetting die and right horizontal thrust die₂Is P_Q+1mm to 5 mm; left horizontal upsetting die and left horizontal thrust die spacing L₀Is F_Q+2 mm-10 mm, and L₀+D_Z＝F_Z+F_Q-1mm～2mm；

(3) When the Nth crank throw is formed, the distances between the horizontal upsetting dies on the left side and the horizontal upsetting dies on the right side and the middle staggered die are set to be P_Q-F_Q+5mm to 25 mm; left horizontal upsetting die and left horizontal thrust die spacing L₀Is F_Q+2 mm-10 mm, and L₀+D_Z＝F_Z+F_Q-1mm～2mm，L₂Equal to the designed size of the blank.