CN115815508A - Forging die, piston forging method and piston - Google Patents

Abstract

The invention discloses a forging die, a piston forging method and a piston, which are used for processing a deep-cylinder thin-wall piston forging on a die forging hammer and comprise the following steps: the punch is provided with an impact end and a fixed end, and the shape structure of the impact end is matched with the shape structure of the inner wall of the piston forging; the upper module is provided with a fixing cavity matched with the fixing end and is provided with an axial positioning assembly for axially positioning the punch; the lower module is provided with a cavity which is used for placing the blank and is opposite to the fixed cavity; and the limiting piece is used for limiting the stroke of the die forging hammer. The die is used for forging the piston, the heated forging blank is placed in the cavity and then pre-forged through the limiting part under pressure, the limiting part is taken down afterwards to finish the precision forging and forming of the piston based on the size of the die, the one-fire forging and forming of the piston forging are realized, the piston forging meeting the processing requirements is produced with little allowance or no allowance, and the problems that multiple-fire forging processing procedures are multiple, machine transfer processing is needed, and the processing efficiency is low are solved.

Description

Forging die, piston forging method and piston

Technical Field

The invention relates to the field of piston forging, in particular to a forging die, a piston forging method and a piston.

Background

The piston is a very important part in an engine, mainly works under the conditions of high temperature, high pressure and high speed, is influenced by the working environment, and is required to have the characteristics of high strength, high precision, corrosion resistance and the like, the properties of high strength, corrosion resistance and the like are mostly material characteristics, and the requirement of high precision is mainly achieved through different processing technologies.

Generally, piston parts are mainly forged into a forged piece shape (the allowance is about 2 mm) by adopting a die forging hammer, then the forged piece is precisely pressed by a press (the allowance is about 1.5 mm), and finally, a machining process is adopted to meet the requirement that the parts have no allowance, but the method is time-consuming and labor-consuming, heating is needed before die forging, re-heating is needed before transferring and precisely pressing, the machining process is long, more machining stations are involved, dies are needed to be designed respectively for die forging and precise pressing, the size precision of the forged piece is further influenced by the size precision difference of the two dies, and the process controllability is poor.

Disclosure of Invention

The invention provides a forging die, a piston forging method and a piston, and aims to solve the technical problems of long processing procedure, low efficiency and poor dimensional accuracy controllability of a deep-cylinder thin-wall piston forging in the prior art.

The technical scheme adopted by the invention is as follows:

a forging die for deep-tube thin-walled piston forgings on a die hammer, comprising:

the punch comprises an impact end and a fixed end along the axial direction, and the shape and the structure of the impact end of the punch are matched with those of the inner wall of the piston forging;

the upper module is used for being fixed on an upper die frame of the die forging hammer, a fixing cavity matched with the fixed end of the punch is axially formed in the bottom of the upper module, and the upper module is provided with an axial positioning assembly used for axially positioning the fixed end of the punch in the fixing cavity and enabling a transition surface of the fixed end and an impact end of the punch to be flush with the end surface of the upper module;

the lower die block is used for fixing a lower die frame of the die forging hammer, a die cavity for placing blanks is formed in the top end face of the lower die block, and the die cavity is opposite to the fixed cavity;

the locating part can dismantle connect in go up the module or can dismantle connect in lower module is used for the restriction the stroke of die forging hammer and then makes the die forging hammer drives the drift is strikeed the stock is right the stock preforging makes the stock is full of the die cavity, the locating part still is used for removing after demolising right the stroke restriction of die forging hammer and then makes the die forging hammer drives the drift is strikeed the stock is right the stock carries out the finish forge.

As a further improvement of the above technical solution, the die includes a retaining structure for radially positioning and axially slidably guiding the upper die block and the lower die block, and further guiding the punch and preventing the blank from moving radially.

As a further improvement of the above technical solution, a mating hole communicated to the fixed cavity is formed in a side wall of the upper die block at a first set height position, the mating hole includes a mating section disposed close to the fixed cavity, and the punch is provided with a tapered hole at a second set height position; the axial positioning assembly comprises a tapered pin and a locking bolt, wherein the tapered pin is inserted into the matching hole from one end of the matching hole to the tapered hole and extends out of the matching hole, and then is in interference fit with the matching section and the tapered hole respectively so as to axially position the punch; the locking bolt is used for being in threaded connection with the insertion end of the matching hole so as to limit and fix the taper pin in the taper hole.

As a further improvement of the above technical solution, a vertical cross section of the tapered hole passing through the axis is a first trapezoid, a waist of the first trapezoid is parallel to the end surface of the upper module, a vertical cross section of the matching section passing through the axial direction is a second trapezoid, and a waist of one side of the second trapezoid corresponding to the first trapezoid is parallel to the end surface of the upper module.

As a further improvement of the above technical solution, the upper die block and the end of the fixed end of the punch are correspondingly provided with pin holes for arranging fastening pins for circumferential positioning.

As a further improvement of the above technical solution, the upper die block is axially provided with an impact hole communicating to the top of the upper die block and the fixing cavity, and the impact hole is used for impacting the punch and further detaching the punch after the punch is not positioned.

As a further improvement of the technical scheme, the lower module is provided with a piece unloading assembly used for separating the forging piece from the cavity after the blank is forged and formed.

As a further improvement of the above technical solution, the piece unloading assembly comprises an ejector rod and an unloading rod; the lower module is provided with an unloading hole for penetrating the unloading rod; the lower module is provided with an ejection hole used for mounting the ejection rod on the bottom surface of the cavity, so that when the ejection rod is placed in the ejection hole, the first end surface of the ejection rod is matched with the hole opening of the ejection hole and is flush with the bottom surface of the cavity; the ejection hole is communicated with the part unloading hole, and the second end of the ejection rod extends into the part unloading hole by placing the ejection rod in the ejection hole; the end part of the unloading rod is provided with an inclined surface structure which is used for contacting with the second end of the ejector rod and moving along the unloading hole direction, so that the axial position of the second end of the ejector rod is changed, and the forged piece is ejected.

According to another aspect of the present invention, there is also provided a piston forging method using the forging die described in any one of the above, the piston forging method including the steps of:

s1, mounting an upper module on an upper die frame of a die forging hammer, mounting a lower module on a lower die frame of the die forging hammer, and mounting a limiting piece;

s2, a punch is arranged in a fixing cavity of the upper module and is in interference fit with the fixing cavity, and the punch is axially positioned in the positioning cavity through an axial positioning assembly;

s3, lubricating the cavity;

s4, pre-forging, namely putting the heated blank into a cavity, and controlling a die forging hammer to drive a punch to impact the blank so that the cavity is filled with the blank;

s5, dismantling the limiting piece, performing precision forging forming, and controlling a die forging hammer to drive a punch to impact the blank to form the blank;

and S6, taking out the formed forged piece.

According to another aspect of the invention, a piston is also provided, and the forging die or the piston forging method is applied.

The invention has the following beneficial effects: the upper die block of the forging die is fixedly positioned on an upper die frame of a die forging hammer, namely, the upper die block is equivalent to a hammer head fixed on the die forging hammer to act along with the hammer head, a fixed cavity formed in the upper die block is used for being matched with a fixed end of a punch head, the fixed end of the punch head is axially positioned in the fixed cavity through an axial positioning assembly, so that the transition surfaces of the fixed end and an impact end of the punch head are flush with the end surface of the upper die block, namely, only the impact end part of the punch head is positioned outside the fixed cavity, the lower die block is fixedly positioned on a lower die frame of the die forging hammer, a cavity formed in the lower die block is used for placing a blank of a forged piece, the outer wall surface of the cavity is matched with the size of the outer wall of a target piston, and the shape structure and the size of the impact end of the punch head are matched with the shape structure and the size of the inner cavity of the target piston; during forging, the heated blank is placed in a cavity, a die forging hammer acts to drive a punch to impact the blank in the cavity for multiple times, a limiting part bears partial impact pressure to enable the blank to be basically filled in the cavity to finish pre-forging, after the limiting part is removed, the die forging hammer acts to drive the punch to impact the blank in the cavity again, the size of a die is matched with the size of a forged piece, and finish forging is carried out; the die is used for forging the piston, heated forging blank is placed in a cavity and then pre-forging is completed through the limiting part under pressure, then the limiting part is taken down to complete precision forging forming of the piston based on the size of the die, one-time forging forming of the piston forging is achieved, the piston forging meeting the processing requirements is produced, the problems that multiple-time forging processing procedures are multiple, machine transfer processing is needed, and processing efficiency is low are solved.

In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be described in further detail below with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a cross-sectional view of a preferred embodiment of the present invention;

FIG. 2 is a first schematic structural diagram of a preferred embodiment of the present invention;

FIG. 3 is a second schematic structural view of the preferred embodiment of the present invention;

FIG. 4 is a schematic view of a piston forging forming structure of the preferred embodiment of the invention;

FIG. 5 is a side view of the piston forging forming of the preferred embodiment of the present invention;

FIG. 6 is a top view of the piston forging formation of the preferred embodiment of the present invention;

1. the device comprises an upper module 11, a matching hole 12, a through hole 13, a fixing cavity 14, a matching protrusion 15, an impact hole 2, a lower module 21, a cavity 22, a part unloading hole 23, an ejection hole 24, a circular truncated cone protrusion 3, a part unloading rod 4, an ejection rod 5, a punch 51, a fixing end 52, an impact end 53, a tapered hole 6, a tapered pin 7, a fastening pin 8, a locking bolt 9, a nut 10 and a limiting piece.

Detailed Description

It should be noted that, in the present application, the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

FIG. 1 is a cross-sectional view of a preferred embodiment of the present invention; FIG. 2 is a first schematic structural diagram of a preferred embodiment of the present invention; FIG. 3 is a second schematic structural diagram of the preferred embodiment of the present invention; FIG. 4 is a schematic diagram of a piston forging forming structure of the preferred embodiment of the invention; FIG. 5 is a side view of the piston forging forming of the preferred embodiment of the present invention; FIG. 6 is a top view of a piston forging forming in accordance with a preferred embodiment of the present invention;

referring to fig. 1 to 6, a preferred embodiment of the present invention provides a forging die for processing a deep-cylinder thin-walled piston forging on a die hammer, the forging die including:

the punch 5 comprises an impact end 52 and a fixed end 51 along the axial direction, and the shape and the structure of the impact end 52 of the punch 5 are matched with the shape and the structure of the inner wall of the piston forging;

the upper die block 1 is used for being fixed on an upper die frame of the die forging hammer, a fixing cavity 13 matched with the fixing end 51 of the punch 5 is axially formed in the bottom of the upper die block 1, and the upper die block 1 is provided with an axial positioning assembly used for axially positioning the fixing end 51 of the punch 5 in the fixing cavity 13 and enabling transition surfaces of the fixing end 51 and an impact end 52 of the punch 5 to be flush with the end surface of the upper die block 1 so as to ensure the forging precision of the punch 5 on the inner cavity of the piston forging; the inner wall of the fixed cavity 13 is an inclined surface, the outer wall of the fixed end 51 of the punch 5 is an inclined surface (namely, the fixed end 51 of the punch 5 is in a circular truncated cone shape), and the fixed cavity 13 is in an open shape, so that the punch 5 can be more easily put in and has a guiding function;

the lower die block 2 is used for fixing a lower die frame of the die forging hammer, a die cavity 21 used for placing blanks is formed in the top end face of the lower die block 2, and the die cavity 21 is opposite to the fixing cavity 13;

the limiting part 10 is detachably connected to the upper module 1 or detachably connected to the lower module 2, and is used for limiting the stroke of the die forging hammer and further enabling the die forging hammer to drive the punch 5 to impact the blank to pre-forge the blank to enable the blank to be filled in the cavity 21, and the limiting part 10 is further used for removing the stroke limitation of the die forging hammer after being detached and further enabling the die forging hammer to drive the punch 5 to impact the blank to perform precision forging on the blank.

It can be understood that the upper die block 1 of the forging die is fixedly positioned on an upper die frame of a die forging hammer, namely, the upper die block is equivalent to a hammer head fixed on the die forging hammer to act along with the hammer head, a fixed cavity 13 formed in the upper die block 1 is used for being matched with a fixed end 51 of a punch 5, the fixed end 51 of the punch 5 is axially positioned in the fixed cavity 13 through an axial positioning assembly, so that a transition surface between the fixed end 51 and an impact end 52 of the punch 5 is flush with the end surface of the upper die block 1, namely, only the impact end 52 part of the punch 5 is positioned outside the fixed cavity 13, the lower die block 2 is fixedly positioned on a lower die frame of the die forging hammer, a die cavity 21 formed in the lower die block 2 is used for placing a forging blank, the outer wall surface of the die cavity 21 is matched with the outer wall size of a target piston, and the shape, structure and size of the impact end 52 of the punch 5 are matched with the shape, structure and size of an inner cavity of the target piston; during forging, a heated blank is placed in the cavity 21, the die forging hammer acts to drive the punch 5 to impact the blank in the cavity 21 for multiple times, the limiting part 10 bears partial impact pressure to enable the blank to be basically filled in the cavity 21 to complete pre-forging, after the limiting part 10 is taken down, the die forging hammer acts to drive the punch 5 to impact the blank in the cavity 21 again, the size of a die is matched with that of a forged piece, and finish forging forming is carried out; the die is used for forging the piston, heated forging piece blanks are placed in the cavity 21 and then are subjected to pressure bearing through the limiting piece 10 to complete pre-forging, the limiting piece 10 is taken down afterwards to complete piston precision forging forming based on the size of the die, one-time forging forming of the piston forging piece is achieved, the piston forging piece with little or no allowance meeting the processing requirements is produced, the problems that multiple-time forging processing procedures are multiple, machine transfer processing is needed, and the processing efficiency is low are solved.

In the embodiment, the die comprises a buckle stopping structure, the buckle stopping structure is used for radially positioning and axially sliding and guiding the upper die block 1 and the lower die block 2, and further guiding the punch 5 and preventing the blank from radially moving, specifically, the buckle stopping structure comprises a matching bulge 14 formed on the end surface of the upper die block 1 and a circular truncated cone bulge 24 formed on the lower die block 2, the height and the radial size of the inner wall surface of the matching bulge 14 are matched with the height and the radial size of the outer wall surface of the circular truncated cone bulge 24, and the matching bulge 14 is in an open shape by inclining a certain angle, in the action process of a die forging hammer, the circular truncated cone bulge 24 is embedded into the matching bulge 14, so that the upper die block 1 is radially positioned relative to the lower die block 2, and meanwhile, the buckle stopping structure guides the movement of the punch 5, and further avoids the blank from shifting; furthermore, the clearance between the matching bulge 14 and the circular truncated cone bulge 24 is controlled within the range of 0.05mm-0.1mm, the processing precision of the circumferential dimension of the forge piece is ensured, and the specific value is determined according to the processing precision requirements of different forge pieces;

further, the side wall of the upper module 1 is provided with a matching hole 11 communicated to the fixed cavity 13 at a first set height position, the matching hole 11 comprises a matching section arranged close to the fixed cavity 13, and the punch 5 is provided with a tapered hole 53 at a second set height position; the axial positioning assembly comprises a conical pin 6 and a locking bolt 8, the conical pin 6 is used for being inserted into the matching hole 11 from one end of the matching hole 11 to the conical hole 53 and extending out, and further is in interference fit with the matching section and the conical hole 53 respectively so as to axially position the punch 5, and only the impact end 52 of the punch 5 is located outside the fixing cavity 13, so that the precision of the piston forging is guaranteed; because the punch 5 works for a long time and bears large impact force, the punch is a vulnerable part, the upper module 1 is provided with the matching section through the matching hole 11, the punch 5 is provided with the tapered hole 53, the punch 5 is axially positioned through the tapered pin 6 and the tapered pin 6 in interference fit, the positioning accuracy is ensured, and meanwhile, the punch 5 is convenient to replace daily, the side wall of the upper module 1 is further provided with the through hole 12 opposite to the matching hole 11 at the first set height position so as to accommodate the tapered pin 6 extending out of the tapered pin hole, and the inlet end of the through hole 12 is used for extending into an external instrument or equipment to push out the tapered pin 6 by applying force so as to replace the punch 5 after being taken out;

the locking bolt 8 is used for being in threaded connection with the insertion end of the matching hole 11 so as to limit and fix the conical pin 6 in the conical hole 53, and further ensure that the conical pin 6 is matched and fastened with the punch 5, so that looseness in the using process is prevented, and therefore the axial positioning accuracy of the punch 5 is kept; it will be appreciated that the bore diameter of the internally threaded bore is greater than the bore diameter of the tapered pin 6;

it should be noted that the tapered hole 53 may be a conical hole or a truncated pyramid-shaped hole, which both ensure the accuracy of axial positioning of the punch 5 and facilitate disassembly and assembly;

in this embodiment, the vertical cross section of crossing the axis of bell mouth 53 is first trapezoidal, a waist of first trapezoidal is parallel with the terminal surface of last module 1, the axial vertical cross section of crossing of cooperation section is second trapezoidal, the waist that the second trapezoidal corresponds one side with first trapezoidal is parallel with the terminal surface of last module 1, the shape structure of taper pin 6 matches with bell mouth 53, it is concrete, the waist line that is located the downside of the vertical cross section of crossing the axis of bell mouth 53 is parallel with the terminal surface of last module 1, the cooperation section is the same, under bell mouth 6 and bell mouth 53 interference fit process state, the bottom side that keeps bell mouth 53 and cooperation section is located same horizontal plane, drift 5 and fixed cavity 13 interference fit, further improve the axial positioning precision to drift 5, thereby improve the machining dimension accuracy control to the piston coining.

In this embodiment, the end portions of the fixed ends 51 of the upper module 1 and the punch 5 are provided with corresponding pin holes for arranging the fastening pin 7 for circumferential positioning, the fastening pin 7 is a cylindrical pin, the pin holes are arranged at positions different from the punch 5, the punch 5 is embedded into the fixed cavity 13 through the fastening pin 7 in a contraposition manner and cannot rotate, and the tapered hole 53 is matched with the matching hole 11 at the moment, so that the tapered pin 6 can be conveniently installed.

Further, the upper die block 1 is provided with an impact hole 15 which is communicated with the top of the upper die block 1 and the fixed cavity 13 along the axial direction, and the upper die block is used for applying force to impact the punch 5 through the impact hole 15 by external instruments and equipment to detach the punch 5 from the fixed cavity 13 to detach the punch 5 after the punch 5 is not positioned (namely the tapered pin 6 is detached).

In this embodiment, the lower module 2 is provided with a unloading assembly for separating the forging from the cavity 21 after the blank is forged and formed;

specifically, the part unloading assembly comprises an ejector rod 4 and a part unloading rod 3; the lower module 2 is provided with a piece unloading hole 22 for the piece unloading rod 3 to penetrate through; the lower module 2 is provided with an ejection hole 23 used for mounting the ejection rod 4 on the bottom surface of the cavity 21, so that when the ejection rod 4 is placed in the ejection hole 23, the first end surface of the ejection rod 4 is matched with the orifice of the ejection hole 23 and is flush with the bottom surface of the cavity 21; the ejector hole 23 is communicated to the piece unloading hole 22, and the second end of the ejector rod 4 extends into the piece unloading hole 22 by placing the ejector rod 4 in the ejector hole 23; the end part of the unloading rod 3 is provided with an inclined surface structure which is used for contacting the second end of the ejector rod 4 and moving along the direction of the unloading hole 22 so as to change the axial position of the second end of the ejector rod 4 and eject the forged piece; the upper end of the ejection hole 23 is conical, the upper end of the ejection rod 4 is conical, when the ejection rod 4 is placed in the ejection hole 23, the conical section of the ejection rod 4 is matched with the conical section of the ejection hole 23, the ejection rod 4 is axially positioned, the outer diameter of the end part of the ejection rod 4 is matched with the aperture of the inlet end of the ejection hole 23, the end surfaces of the ejection rod 4 and the ejection hole 23 are flush and integrated when placed in the ejection hole 23, and the bottom surface of the forged and finely pressed piston forging is smooth and flawless; when the unloading rod 3 is inserted into the unloading hole 22, the inclined surface structure of the unloading rod faces upwards, the inclined surface structure is abutted to the bottom end of the ejection rod 4 after the unloading rod 3 extends into the unloading hole 22 by a certain depth, and the unloading rod 3 is further moved to eject the ejection rod 4 through inclined surface transformation so as to eject the piston forging formed by finish forging so as to take out the forging.

In practical application, based on the piston forging processed by the forging die, the allowance is less than 1.5mm, the actually tested forging exceeds twenty thousand pieces, and the qualification rate reaches more than 98%;

on the other hand, the embodiment also provides a piston forging method, which applies the forging die and comprises the following steps:

s1, mounting an upper module 1 on an upper die set of a die forging hammer, mounting a lower module 2 on a lower die set of the die forging hammer, and mounting a limiting piece 10; specifically, the upper module 1 and the lower module 2 are both provided with a connecting structure to be connected with the die forging hammer in a matching manner and ensure the connection precision, the installation and connection of the die and the die forging hammer belong to the mature prior art, and the embodiment is not described in more detail; the limiting piece 10 is an annular base plate and is sleeved on the circular truncated cone protrusion 24, so that the stroke of the matching protrusion 14 is limited, wherein the setting height of the limiting piece 10 can be controlled by setting the annular base plates with different inner diameters, so that different strokes of the punch 5 are limited;

s2, the punch 5 is arranged in a fixed cavity 13 of the upper module 1 and is in interference fit with the fixed cavity 13, and the punch 5 is axially positioned in the positioning cavity through an axial positioning assembly;

specifically, the fixed end 51 of the punch 5 is embedded into the fixed cavity 13, the fixed end and the fixed cavity are in interference fit and are relatively radially positioned at the same time, circumferential positioning is performed through the fastening pin 7, the tapered pin 6 is inserted into the matching hole 11 to the tapered hole 53 and extends out of the through hole 12, the tapered pin 6 and the tapered hole 53 are in interference fit through further locking of the locking bolt 8, and further locking is performed through the nut 9 to prevent looseness; in addition, the unloading rod 3 is moved out, so that the ejector rod 4 is ensured to fall into the ejector hole 23 completely, and the end surface of the ejector rod is ensured to be flush with the bottom surface of the cavity 21;

s3, lubricating the cavity 21 so as to put a blank;

s4, pre-forging, namely putting the heated blank into the cavity 21, and controlling a die forging hammer to drive the punch 5 to impact the blank so as to fill the cavity 21 with the blank;

specifically, after the blank is heated to a preset temperature, the blank is transferred into a lubricated cavity 21, and a control forging hammer is used for impacting inertia through a plurality of hammers and a die forging hammer to enable the blank to be basically filled in the cavity 21;

s5, precision forging forming, namely dismantling the limiting piece 10, and controlling a die forging hammer to drive the punch 5 to impact the blank to form the blank; specifically, the backing plate is moved out, and a die forging hammer is used for carrying out precision pressing on the pre-forged blank, and the precision pressing is carried out for two times of forming;

s6, taking out the formed forging;

specifically, the inclined surface structure of the unloading rod 3 is upwards extended into the unloading hole 22 and moved, so that the ejection rod 4 ejects out of the piston forging, and then the forging is taken out, and a forging process is completed.

According to the piston forging method, the piston is forged by using the forging die of the embodiment, the heated forging blank is placed in the cavity 21 and then is subjected to pressure bearing through the limiting part 10 to complete pre-forging, the limiting part 10 is taken down and piston finish forging forming is completed based on die size, one-time forging forming of the piston forging is realized, the piston forging with less allowance or no allowance meeting the processing requirements is produced, the problems that multiple-time forging processing procedures are multiple, machine transfer processing is needed and the processing efficiency is low are solved, the precision control is improved to realize the precision pressing effect of the press machine by using the die based on the operation method, the pre-forging forming of the die forging hammer and the precision pressing forming of the press machine are improved to be simultaneously carried out on the die forging hammer, the middle return heating procedure is cancelled, multiple times of disassembly and assembly are avoided, the production auxiliary time is reduced, the labor intensity is reduced, the production efficiency is improved, the size of the forging is ensured by using the die, the influence of the size precision difference between the precision pressing die and the forging die on the size of the forging is avoided, the forging size of the forging die is improved, the forging, the size consistency of the forging die is improved, the use of the precision pressing die and the pressure machine is reduced, and the manufacturing cost of the tooling is greatly reduced.

On the other hand, the embodiment also provides a piston, which is applied with the forging die or the piston forging method.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A forging die for deep barrel thin wall piston forgings on a die hammer, the forging die comprising:

the punch (5) comprises an impact end (52) and a fixed end (51) along the axial direction, and the shape and the structure of the impact end (52) of the punch (5) are matched with the shape and the structure of the inner wall of the piston forging;

the die forging hammer comprises an upper die block (1) and a lower die block (1), wherein the upper die block is used for being fixed on an upper die frame of the die forging hammer, a fixing cavity (13) matched with a fixing end (51) of a punch (5) is formed in the bottom of the upper die block (1) along the axial direction, an axial positioning assembly is arranged on the upper die block (1) and used for axially positioning the fixing end (51) of the punch (5) in the fixing cavity (13) and enabling a transition surface of the fixing end (51) and an impact end (52) of the punch (5) to be flush with the end surface of the upper die block (1);

the lower die block (2) is used for fixing a lower die frame of the die forging hammer, a die cavity (21) for placing blanks is formed in the top end face of the lower die block (2), and the die cavity (21) is opposite to the fixed cavity (13);

the limiting part (10) is detachably connected to the upper die block (1) or detachably connected to the lower die block (2) and used for limiting the stroke of the die forging hammer so that the die forging hammer drives the punch (5) to impact the blank to be pre-forged to enable the blank to be filled with the die cavity (21), and the limiting part (10) is further used for removing the stroke limitation of the die forging hammer after being detached so that the die forging hammer drives the punch (5) to impact the blank to perform precision forging on the blank.

2. Forging die according to claim 1, characterized in that it comprises a stop configuration for radially positioning and axially slidingly guiding the upper die block (1) and the lower die block (2), and thus the punch (5) and preventing the blank from moving radially.

3. The forging die as recited in claim 1, wherein the side wall of the upper die block (1) is provided with a fitting hole (11) communicating to the fixing cavity (13) at a first set height position, the fitting hole (11) includes a fitting section provided near the fixing cavity (13), and the punch (5) is provided with a tapered hole (53) at a second set height position; the axial positioning assembly comprises a conical pin (6) and a locking bolt (8), wherein the conical pin (6) is used for being inserted into the matching hole (11) from one end of the matching hole (11) to the conical hole (53) and extending out, and then is respectively in interference fit with the matching section and the conical hole (53) so as to axially position the punch (5); the locking bolt (8) is used for being in threaded connection with the insertion end of the matching hole (11) so as to limit and fix the taper pin (6) in the taper hole (53).

4. The forging die of claim 3, wherein the vertical cross section of the tapered hole (53) passing through the axis is a first trapezoid, a waist of the first trapezoid is parallel to the end face of the upper die block (1), and the vertical cross section of the engagement section passing through the axis is a second trapezoid, and a waist of the second trapezoid on the side corresponding to the first trapezoid is parallel to the end face of the upper die block (1).

5. The forging die of claim 1, wherein the fixed ends (51) of the upper die block (1) and the punch (5) are provided with corresponding pin holes for arranging fastening pins (7) for circumferential positioning.

6. The forging die of claim 1, wherein the upper die block (1) is axially provided with an impact hole (15) communicating with the top of the upper die block (1) and the fixing cavity (13) for impacting the punch (5) through the impact hole (15) to detach the punch (5) after canceling the positioning of the punch (5).

7. The forging die of claim 1, wherein the lower die block (2) is provided with a stripper assembly for removing a forging from the cavity (21) after the blank is forged.

8. The forging die of claim 7, wherein the stripper assembly comprises an ejector rod (4) and a stripper rod (3); the lower module (2) is provided with a piece unloading hole (22) for penetrating the piece unloading rod (3); the lower module (2) is provided with an ejection hole (23) used for mounting the ejection rod (4) on the bottom surface of the cavity (21), so that when the ejection rod (4) is placed in the ejection hole (23), the first end surface of the ejection rod (4) is matched with the hole opening of the ejection hole (23) and is flush with the bottom surface of the cavity (21); the ejector hole (23) is communicated to the part unloading hole (22), and the second end of the ejector rod (4) extends into the part unloading hole (22) by placing the ejector rod (4) in the ejector hole (23); the end part of the unloading rod (3) is provided with an inclined surface structure which is used for contacting with the second end of the ejector rod (4) and moving along the unloading hole (22) direction so as to change the axial position of the second end of the ejector rod (4) and eject the forge piece.

9. A piston forging method using the forging die according to any one of claims 1 to 8, comprising the steps of:

s1, mounting an upper module on an upper die frame of a die forging hammer, mounting a lower module on a lower die frame of the die forging hammer, and mounting a limiting piece;

s2, a punch is arranged in a fixing cavity of the upper module and is in interference fit with the fixing cavity, and the punch is axially positioned in the positioning cavity through an axial positioning assembly;

s3, lubricating the cavity;

s4, pre-forging, namely putting the heated blank into a cavity, and controlling a die forging hammer to drive a punch to impact the blank so as to fill the cavity with the blank;

s5, dismantling the limiting piece, performing precision forging forming, and controlling a die forging hammer to drive a punch to impact the blank to form the blank;

and S6, taking out the formed forged piece.

10. A piston, characterized in that the forging die according to any one of claims 1 to 8 or the piston forging method according to claim 9 is applied.

Images