CN115740347A - Combined core mold for freely forging large crank and using method - Google Patents

Abstract

The invention relates to a combined core mold for freely forging a large crank and a using method thereof. The die comprises a die body and a die handle, wherein the die handle and the die body are in a shovel shape, the front part of the die body is provided with a shovel head, the rear part of the die body is provided with a shovel tail, the thickness of the shovel tail is larger than that of the shovel head, two or more core dies with the thickness larger than that of the shovel head are arranged, the difference between the thickness of the shovel tail and that of the shovel head of each core die is different, the step forging is carried out on the crank cavity, the core dies are continuously replaced according to the sequence from large to small in the thickness difference of the die bodies, the crank cavity is gradually forged, the die cavities are further repeatedly forged by the core dies with different thicknesses without the thickness difference, the die cavities inside the cranks are closer to the design requirements, and the minimum metal processing allowance of the forged piece can be realized. Because the core die is replaced frequently, the temperature of the core die is not too high, die sticking is avoided, the forging is well formed, and the service life of the die is long.

Description

Combined core mold for freely forging large crank and using method

Technical Field

The invention relates to a forging die and a using method thereof, in particular to a combined core die for forging and forming an inner cavity of a large crank throw and a using method thereof, and belongs to the technical field of forging.

Background

The crank shaft is a key part for transmitting mechanical energy of an engine to the outside, the crank throw is an important part for converting reciprocating motion into rotary motion, and the crank throw of a large-scale crank shaft is large and complex in stress, so that the crank throw has enough rigidity, strength and capacity of bearing impact load, and in order to meet the performance requirements, a forged crank throw is usually selected. The process of forging the crank throw is very complicated, and the currently known advanced process is forging twice, wherein the first heat is as follows: drawing, upsetting, drawing to a preliminarily set size, upsetting to a proper size, further drawing to a set size, and forging the boss and the double wings in multiple processes; the second fire time: pressing the double wings to thin, drawing out and finishing to set size, forging the semi-cylindrical bent neck, bending the double wings around the bent neck, and finally pressing the double wings and finally forging. In the process, upsetting, drawing, rounding and bending are provided with a specific anvil, and during the double-fin pressing and final forging forming process, because the shape of the die and the design of the forging process are unscientific, the double-fin pressing is often not in place, and high-temperature heat conduction can cause die sticking to damage a pressing die and a forging piece.

Disclosure of Invention

The invention provides a combined core die for freely forging a large crank and a using method thereof.

The utility model provides a large-scale crank's of free forging combination mandrel, every mandrel includes die body and die shank, die body and die shank disjunctor, die shank and die body one-piece shovel shape, the die body front portion is shovel head, and the rear portion is shovel tail, its characterized in that:

the thickness of the shovel tail is larger than that of the shovel head, and the section from the shovel head to the shovel tail is an isosceles trapezoid;

the core moulds with the thickness of the shovel tail larger than that of the shovel head are arranged into two or more than two, and the included angle between the isosceles trapezoid waist and the isosceles trapezoid bottom on each core mould is different;

the thickness of the shovel head is the same as that of the shovel tail, and the section from the shovel head to the shovel tail is rectangular;

the number of the core moulds with the same shovel head thickness and shovel tail thickness is 1-3, and the width of the rectangle on each core mould is different.

Preferably, the front end of the shovel head is provided with an inward concave arc, and the curvature of the arc is the same as that of the crank neck of the crank forging.

Further, the left width and the right width of the die body are the same as the technological dimension of the forge piece.

Use method of combined core mold for freely forging large crank

Step 1, placing a herringbone bell crank forging piece between a large flat anvil and an upper anvil of a forging machine, inserting a core mold with the largest thickness difference between a shovel head and a shovel tail into an opening of the forging piece, inserting an inward-concave arc on a die body into the inner top of the herringbone forging piece, pressing the upper anvil downwards, pressing two sides of a herringbone, enabling two sides of the herringbone forging piece to be close to each other, turning up and down, forging and pressing, and enabling two sides of the forging piece to be close to the die body;

step 2, sequentially replacing the core moulds with the thickness difference of the shovel head and the shovel tail gradually reduced, and repeating the action of the step 1 to further attach the two sides of the herringbone forged piece;

step 3, replacing a core mold with the same thickness of the shovel head and the shovel tail and the largest thickness of the mold body, repeating the action of the step 1, attaching the core mold to two sides of the herringbone forge piece in parallel, and further forging the four-side turnover forge piece;

and 4, sequentially replacing core moulds with the same thickness of the shovel head and the shovel tail and the thickness of the mould bodies reduced one by one, and repeating the action of the step 3 to finish the finish forging of the mould cavity.

According to the invention, the core mold of the forged crank throw cavity is arranged in a gradient manner, the core mold is continuously replaced according to the sequence of the thickness difference of the mold body from large to small, the crank throw cavity is gradually forged to enable the cavity to be formed gradually, and finally the core molds with different thicknesses and without thickness difference are respectively and repeatedly forged to the cavity, so that the cavity in the crank throw is close to the design requirement, and the minimum machining allowance of the forged piece can be realized. The temperature rise of the die can be effectively controlled by replacing the core die and forging, and die sticking accidents are avoided. The forging piece is well formed, and the service life of the die is long.

Drawings

FIG. 1 is a schematic front view of the present invention,

figures 2 and 3 are cross-sectional views of the mold body with a thickness in the rear portion greater than the thickness in the front portion,

figure 4 is a cross-sectional view of the same thickness at the front and rear of the mold body,

figure 5 is a schematic view showing a forging state of the core mold in which the difference between the rear portion thickness and the front portion thickness of the mold body is the largest,

FIG. 6 is a schematic view showing a forging state of a core mold in which a difference between a rear thickness and a front thickness of a mold body is small,

fig. 7 is a schematic view showing a forging state of a core mold in which the front and rear portions of the mold body have the same thickness.

In the attached drawing, 1 is a die body, 2 is a die handle, 3 is an upper anvil, 4 and 7 are mechanical arms, 5 is a lower anvil, and 6 is a crank forging.

Detailed Description

The invention is further explained below with reference to the drawings:

the attached figures 1, 2, 3 and 4 show a combined core mold which is composed of two core molds 1 with different thicknesses and a core mold 1 with the same thickness, wherein the core mold shown in the attached figure 1 is in a shovel shape composed of a mold handle 2 and the mold body 1, the shovel head part of the shovel is provided with an inwards concave arc, and the mold body 1 is in a flat plate shape. Fig. 3 shows a section of the core mold in which the thickness of the mold body 1 at the shovel tail is greater than that of the shovel head, and the difference between the thicknesses of the shovel tail and the shovel head is smaller than that of the core mold shown in fig. 2, and fig. 4 shows a section of the core mold in which the thickness of the shovel tail of the mold body 1 is the same as that of the shovel head.

Fig. 5 shows a state that the core mold with the largest difference between the thickness of the shovel tail and the thickness of the shovel head forges two wings of the crank, the manipulator 4 clamps the crank forging 6 and stands between the upper anvil 3 and the lower anvil 5, the manipulator 7 clamps the core mold with the largest difference between the thickness of the shovel tail and the thickness of the shovel head and inserts the core mold into an inner cavity of the crank forging 6, a concave arc at the shovel head part faces to a crank neck inside the crank forging, and the upper anvil 3 and the lower anvil 5 extrude the crank forging 6 to enable the two wings to approach to the mold body 1.

Fig. 6 shows a state that the difference between the thickness of the shovel tail and the thickness of the shovel head is small, the core die forges the two wings of the crank, and the double wings of the crank forging 6 are further close to the die body 1 in the same way as fig. 4.

Fig. 7 shows a state that a core mold with the thickness of the shovel tail being the same as that of the shovel head forges two wings of a crank, a manipulator 4 clamps a crank forging 6 and stands between an upper anvil 3 and a lower anvil 5, the manipulator 7 clamps the core mold with the thickness of the shovel tail being the same as that of the shovel head and inserts the core mold into an inner cavity of the crank forging 6, a concave arc at the shovel head part faces a crank neck inside the crank forging, the upper anvil 3 and the lower anvil 5 extrude the crank forging 6 and synchronously rotate the crank forging 6 and the core mold, and a cavity inside the crank forging 6 and an outer side face are subjected to final forging.

Claims (2)

1. The utility model provides a large-scale crank's of free forging combination mandrel, every mandrel includes die body and die shank, die body and die shank disjunctor, die shank and die body one-tenth shovel shape, the die body front portion is shovel head, and the rear portion is shovel tail, its characterized in that:

the thickness of the shovel tail is larger than that of the shovel head, and the section from the shovel head to the shovel tail is an isosceles trapezoid;

the core moulds with the thickness of the shovel tail larger than that of the shovel head are arranged into two or more than two, and the included angle between the isosceles trapezoid waist and the isosceles trapezoid bottom on each core mould is different;

the thickness of the shovel head is the same as that of the shovel tail, and the section from the shovel head to the shovel tail is rectangular;

1-3 core moulds with the same thickness of the shovel head and the shovel tail are arranged, and the width of the rectangle on each core mould is different;

the front end of the shovel head is provided with an inward-concave arc, and the curvature of the arc is the same as that of the crank neck of the crank forging;

the left width and the right width of the die body are the same as the technological dimension of the forge piece.

2. The method of using a composite mandrel as claimed in claim 1 wherein:

step 1, placing a herringbone bell crank forging piece between a large flat anvil and an upper anvil of a forging machine, inserting a core mold with the largest thickness difference between a shovel head and a shovel tail into an opening of the forging piece, inserting an inward-concave arc on a die body into the inner top of the herringbone forging piece, pressing the upper anvil downwards, pressing two sides of a herringbone, enabling two sides of the herringbone forging piece to be close to each other, turning up and down, forging and pressing, and enabling two sides of the forging piece to be close to the die body;

step 2, sequentially replacing the core moulds with the thickness difference of the shovel head and the shovel tail gradually reduced, repeating the action of the step 1, and further attaching the two sides of the herringbone forged piece;

step 3, replacing a core mold with the same thickness of the shovel head and the shovel tail and the largest thickness of the mold body, repeating the action of the step 1, attaching the core mold to the two sides of the herringbone forge piece in parallel, and further forging the four-side turnover forge piece;

and 4, sequentially replacing core moulds with the same thickness of the shovel head and the shovel tail and the thickness of the mould bodies reduced one by one, and repeating the action of the step 3 to finish the finish forging of the mould cavity.

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