CN111720234B - Split composite piston and forming method - Google Patents

Split composite piston and forming method Download PDF

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Publication number
CN111720234B
CN111720234B CN201910218419.7A CN201910218419A CN111720234B CN 111720234 B CN111720234 B CN 111720234B CN 201910218419 A CN201910218419 A CN 201910218419A CN 111720234 B CN111720234 B CN 111720234B
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Prior art keywords
annular
piston
piston head
split
skirt
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CN111720234A (en
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强道前
强莉莉
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Priority to CN201910218419.7A priority Critical patent/CN111720234B/en
Priority to PCT/CN2020/079960 priority patent/WO2020187258A1/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F3/00—Pistons 
    • F02F3/0015—Multi-part pistons
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
    • B23P15/00—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F3/00—Pistons 
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F3/00—Pistons 
    • F02F3/0015—Multi-part pistons
    • F02F3/003—Multi-part pistons the parts being connected by casting, brazing, welding or clamping
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F3/00—Pistons 
    • F02F3/0015—Multi-part pistons
    • F02F3/003—Multi-part pistons the parts being connected by casting, brazing, welding or clamping
    • F02F2003/0061—Multi-part pistons the parts being connected by casting, brazing, welding or clamping by welding

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • General Engineering & Computer Science (AREA)
  • Pistons, Piston Rings, And Cylinders (AREA)

Abstract

The split surface of the piston head passes through the annular oil cavity, the split surface of the piston head is provided with an annular compensation opening, an annular compensation plate is arranged in the annular compensation opening, the bottom surface of the annular compensation plate and the split surfaces on the two sides form a weldable surface, and the piston head and the piston skirt are welded and connected along the weldable surface. The method comprises the following steps of S1: forming blanks of the piston head, the piston skirt and the annular compensation plate; s2: processing an annular compensation opening; s3: cleaning; s4: welding the annular compensation plate with the annular compensation port; s5: processing the split surface to form a continuous and complete weldable surface; s6: the split surfaces of the piston head and the piston skirt are attached and positioned; s7: the composite connection is realized along the split surfaces by welding; s8: carrying out postweld heat treatment; s9: and finishing and surface treatment are carried out. The invention has the advantages of stable and reliable structure, easy molding and strong technological adaptability.

Description

Split composite piston and forming method
Technical Field
The invention mainly relates to a forming technology of a steel piston of an internal combustion engine, in particular to a split composite piston and a forming method.
Background
The piston is arranged in the cylinder sleeve, when the internal combustion engine runs, the piston reciprocates at an upper dead point and a lower dead point, is a power conversion and output mechanism, has the main function of converting heat energy into mechanical work, and bears the inertia force generated by high-temperature, high-pressure and high-speed motion; simultaneously, with the internal-combustion engine intensive degree constantly improves, the heat load of piston head is higher, selects the better steel construction piston of performance for use to become the direction that promotes the piston performance, and prior art steel construction piston material mainly is the alloy steel that the heat resistance is good and the weldability is poor, if: 38MnVS6 or 42CrMoA, etc.
In order to strengthen the cooling of the piston head, the inner side of the ring groove part of the piston head, the lower part of the top of the piston and the outer side of the combustion chamber are provided with annular oil cavities which are formed by adopting a closed structure and adopting integral forging processing or are formed by welding through methods such as friction welding, high-energy beam welding, brazing and the like, the welding positions are arranged on the ring groove part, the top of the piston, the wall of the combustion chamber and the like, for example, a brazed steel piston is disclosed in the patent document with the reference number of CN201621416849.8, and a steel piston and a forming method thereof are disclosed in the patent document with the reference number of CN 201710243645.1.
In the prior art, 1, a steel piston formed by brazing is formed by connecting a main welding surface and an auxiliary welding surface between a piston head and a piston skirt through brazing to form an all-steel piston, wherein the main welding surface and the auxiliary welding surface are arranged on two sides of an annular oil cavity. The main face of weld is less than vice face of weld, and is parallel with the horizontal plane, and the main problem who exists is: because the two welding surfaces are not on the same plane, the welding gap is not consistent due to poor position precision in the machining process, the thickness of the brazing seam is different, the strength of the welding seam joint of the main welding surface and the auxiliary welding surface is poor, and the risk of failure of the welding seam is increased under the action of axial explosion pressure; the main welding surface is vertical to the auxiliary welding surface, the main welding surface is positioned in the combustion chamber, the molded surface of the combustion chamber is divided by a welding line, and the welding line is exposed in high-temperature and high-pressure gas of the combustion chamber, so that the failure risk in the working process of the combustion chamber is increased; the welding flux melts out at the edge of the welding seam in the annular oil cavity, and the welding flux at the edge of the welding seam on the inner side of the annular oil cavity melts out and has the risk of falling off in the reciprocating motion of the piston and the washing process of lubricating oil. 2. The steel piston formed by split welding is divided into an upper part and a lower part and is welded by electron beams at the position of a pin hole, and the main problems of the steel piston are as follows: the cross section of the pin hole position is wide, the welding seam is relatively deep, the welding process difficulty is high, especially, under the action of axial and radial alternating loads, the welding seam is easy to fail due to welding defects generated by welding, and the failure risk of the piston is increased.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a split composite piston and a forming method, wherein the split composite piston is stable and reliable in structure, easy to form and strong in technological adaptability.
In order to solve the technical problems, the invention adopts the following technical scheme:
the utility model provides a components of a whole that can function independently combined type piston, includes split type piston head and piston skirt portion, be equipped with combustion chamber, annular oil pocket, head annular and head inner chamber on the piston head, piston skirt portion is equipped with pinhole and skirt portion inner chamber, the components of a whole that can function independently face of piston head is through annular oil pocket, the components of a whole that can function independently face of piston head is seted up with the communicating annular compensation mouth in annular oil pocket bottom, the annular compensation board has been installed in the annular compensation mouth, the bottom surface of annular compensation board forms continuous complete face of welding jointly with the components of a whole that can function independently face of annular compensation mouth both sides of piston head, the face of welding is followed to piston head and piston skirt portion.
As a further improvement of the above technical solution:
the piston head and the piston skirt are provided with annular process half grooves at the same position of the respective split surfaces, and the two annular process half grooves form an annular process cavity together.
The annular structure formed by the annular process cavity is a circular ring.
The annular process cavity is positioned on the inner side of the annular compensation plate.
The annular process cavity is located on the outer side of the annular compensation plate.
And a bolt is connected between the piston skirt and the annular compensation plate.
A forming method based on the split composite piston comprises the following steps:
s1: respectively forming blanks of the piston head, the piston skirt and the annular compensation plate;
s2: processing an annular compensation plate and a piston head, and processing an annular oil cavity and an annular compensation port at the piston head;
s3: respectively cleaning the piston head and the annular compensation plate;
s4: installing the annular compensation plate into the annular compensation port, and welding the annular compensation plate and the annular compensation port by adopting diffusion welding;
s5: processing the split surface of the skirt part of the piston and the split surface of the head part of the piston with the annular compensation plate, so that the annular compensation plate and the split surfaces on the two sides of the annular compensation port form a continuous and complete weldable surface together;
s6: cleaning the piston head and the piston skirt, attaching the split surfaces of the piston head and the piston skirt, and positioning and mounting the attached piston head and the attached piston skirt;
s7: the compound connection is realized by adopting diffusion welding along the split surfaces attached to the head part and the skirt part of the piston;
s8: performing postweld heat treatment on the compounded piston;
s9: and (4) carrying out finish machining and surface treatment on the compounded piston by adopting mechanical machining.
A forming method based on the split composite piston comprises the following steps:
s1: respectively forming blanks of the piston head, the piston skirt and the annular compensation plate;
s2: processing an annular compensation plate and a piston head, and processing an annular oil cavity and an annular compensation port at the piston head;
s3: respectively cleaning the piston head and the annular compensation plate;
s4: installing the annular compensation plate into the annular compensation port, and welding the annular compensation plate and the annular compensation port by laser welding;
s5: processing the split surface of the piston skirt and the split surface of the piston head with the annular compensation plate to enable the annular compensation plate and the split surfaces on the two sides of the annular compensation port to jointly form a continuous and complete weldable surface, and forming a gap between the weldable surface and the split surface of the piston skirt, wherein the gap is positioned on the outer side of the annular process cavity, and the weldable surface is higher than the horizontal center line of the annular process cavity;
s6: cleaning the piston head and the piston skirt, fitting the split surfaces of the piston head and the piston skirt, placing brazing filler metal in an annular process cavity during fitting, and positioning and mounting the fitted piston head and the piston skirt;
s7: brazing is adopted to enable brazing filler metal to melt and flow outwards from the annular process cavity along the gap to achieve composite connection of the piston head and the piston skirt;
s8: performing postweld heat treatment on the compounded piston;
s9: and (4) carrying out finish machining and surface treatment on the compounded piston by adopting mechanical machining.
A forming method based on the split composite piston comprises the following steps:
s1: respectively forming blanks of the piston head, the piston skirt and the annular compensation plate;
s2: processing an annular compensation plate and a piston head, and processing an annular oil cavity and an annular compensation port at the piston head;
s3: respectively cleaning the piston head and the annular compensation plate;
s4: installing the annular compensation plate into the annular compensation port, and welding the annular compensation plate and the annular compensation port by laser welding;
s5: processing the split surface of the skirt part of the piston and the split surface of the head part of the piston with the annular compensation plate, so that the bottom surface of the annular compensation plate and the split surfaces on two sides of the annular compensation port of the head part of the piston form a continuous and complete weldable surface together; a gap is formed between the weldable surface and the split surface of the piston skirt part, the gap is positioned on the inner side of the annular process cavity, and the weldable surface is higher than the horizontal center line of the annular process cavity;
s6: cleaning the piston head and the piston skirt, fitting the split surfaces of the piston head and the piston skirt, placing brazing filler metal in an annular process cavity during fitting, and positioning and mounting the fitted piston head and the piston skirt;
s7: brazing is adopted to enable brazing filler metal to melt and flow inwards along the gap from the annular process cavity, and the composite connection of the piston head and the piston skirt is achieved;
s8: performing postweld heat treatment on the compounded piston;
s9: and (4) carrying out finish machining and surface treatment on the compounded piston by adopting mechanical machining.
A forming method based on the split composite piston comprises the following steps:
s1: respectively forming blanks of the piston head, the piston skirt and the annular compensation plate;
s2: processing an annular compensation plate and a piston head, and processing an annular oil cavity and an annular compensation port at the piston head;
s3: respectively cleaning the piston head and the annular compensation plate;
s4: installing the annular compensation plate into the annular compensation port, and welding the annular compensation plate and the annular compensation port by laser welding;
s5: processing the split surface of the piston skirt and the split surface of the piston head with the annular compensation plate, so that the bottom surface of the annular compensation plate and the split surfaces on two sides of the annular compensation port of the piston head jointly form a continuous and complete weldable surface, a gap is formed between the weldable surface and the split surface of the piston skirt, the gap is positioned on the inner side of the annular process cavity, and the weldable surface is higher than the horizontal center line of the annular process cavity;
s6: cleaning the piston head and the piston skirt, fitting the split surfaces of the piston head and the piston skirt, and positioning and mounting the fitted piston head and the piston skirt;
s7: the piston head and the piston skirt are compositely connected by adopting electron beam welding from outside to inside to the annular process cavity;
s8: performing postweld heat treatment on the compounded piston;
s9: and (4) carrying out finish machining and surface treatment on the compounded piston by adopting mechanical machining.
Compared with the prior art, the invention has the advantages that:
according to the split composite piston, the integral piston is provided with the split piston head and the split piston skirt, so that the processing difficulty of blank forging forming is reduced; the weldable surface is positioned at the bottom of the annular oil cavity, namely the welding seam is far away from the combustion chamber, so that the heat load borne by the welding seam is reduced; the annular compensation plate enables the area of the welding line to be relatively large, the mechanical stress level of the welding line is reduced, and the reliability of the welding line is improved; the annular compensation plate ensures the integrity of the body surface of the piston head part, forms a continuous and complete weldable surface, is beneficial to the implementation of welding processes such as brazing, diffusion welding, electron beam, laser welding and the like, has strong technological adaptability, and can meet the requirement of split connection of steel pistons; the annular compensation plate is located in the annular compensation opening and has a stable structure, the rigidity of the head annular groove is improved, and the failure risk caused by axial stress deformation of the head annular groove is reduced. The invention is based on the forming method of the split composite piston and has the corresponding technical effects of the split composite piston.
Drawings
Fig. 1 is a schematic front view of a split composite piston according to embodiment 1 of the present invention.
Fig. 2 is a schematic front view of a positioning state of the split composite piston according to embodiment 1 of the present invention.
FIG. 3 is a flow chart of the method for forming a split composite piston according to embodiment 1 of the present invention.
Fig. 4 is a schematic front view of a split composite piston according to embodiment 2 of the present invention.
FIG. 5 is a schematic view of the positioning state of the split composite piston of embodiment 2 of the present invention
Fig. 6 is a partially enlarged schematic structural view of the split composite piston according to embodiment 2 of the present invention.
FIG. 7 is a flow chart of the method for forming a split composite piston according to embodiment 2 of the present invention.
Fig. 8 is a schematic front view of a split composite piston according to embodiment 3 of the present invention.
FIG. 9 is a schematic view of the positioning state of the split composite piston of embodiment 3 of the present invention
Fig. 10 is a partially enlarged schematic structural view of a split composite piston according to embodiment 3 of the present invention.
Fig. 11 is a flowchart of a method for forming a split composite piston according to embodiment 3 of the present invention.
Fig. 12 is a schematic front view of a piston according to embodiment 4 of the method for forming a split composite piston of the present invention.
FIG. 13 is a schematic view of the piston positioning state in the embodiment 4 of the method for forming a split composite piston according to the present invention
Fig. 14 is a partially enlarged schematic structural diagram of a piston in embodiment 4 of the method for forming a split composite piston according to the present invention.
FIG. 15 is a flow chart of the method for forming a split composite piston according to embodiment 4 of the present invention.
The reference numerals in the figures denote:
1. a piston head; 11. a combustion chamber; 12. an annular oil chamber; 13. a head ring groove; 14. a head lumen; 15. an annular compensation port; 2. a piston skirt; 21. a pin hole; 22. a skirt inner cavity; 3. an annular compensation plate; 4. an annular process half-groove; 5. an annular process chamber; 6. and (4) bolts.
Detailed Description
The invention will be described in further detail below with reference to the drawings and specific examples.
Piston example 1:
fig. 1 to 2 show a first embodiment of the split composite piston of the invention, which includes a split piston head 1 and a split piston skirt 2, the piston head 1 is provided with a combustion chamber 11, an annular oil chamber 12, a head ring groove 13 and a head inner cavity 14, the piston skirt 2 is provided with a pin hole 21 and a skirt inner cavity 22, the split surface of the piston head 1 passes through the annular oil chamber 12, the split surface of the piston head 1 is provided with an annular compensation port 15 communicated with the bottom of the annular oil chamber 12, an annular compensation plate 3 is arranged in the annular compensation port 15, the bottom surface of the annular compensation plate 3 and the split surfaces on both sides of the annular compensation port 15 of the piston head 1 form a continuous and complete weldable surface together, and the piston head 1 and the piston skirt 2 are welded and connected along the weldable surface. The integral piston is provided with the split type piston head part 1 and the split type piston skirt part 2, so that the processing difficulty of blank forging forming is reduced; the weldable surface is positioned at the bottom of the annular oil cavity 12, namely the welding seam is far away from the combustion chamber, so that the heat load borne by the welding seam is reduced; the annular compensation plate 3 enables the area of a welding seam to be relatively large, reduces the mechanical stress level of the welding seam and improves the reliability of the welding seam; the annular compensating plate 3 ensures the integrity of the split surface of the piston head 1, forms a continuous and complete weldable surface, is beneficial to the implementation of welding processes such as brazing, diffusion welding, electron beam welding, laser welding and the like, has strong technological adaptability, and can meet the split connection of steel pistons; the annular compensation plate 3 is positioned in the annular compensation port 15, so that the structure is stable, the rigidity of the head annular groove 13 is improved, and the failure risk caused by axial stress deformation of the head annular groove 13 is reduced.
Piston example 2:
fig. 4 to 6 show a second embodiment of a split composite piston according to the invention, which is substantially identical to embodiment 1, except that: in the embodiment, the piston head 1 and the piston skirt 2 are provided with the annular process half grooves 4 at the same positions of the split surfaces, and the two annular process half grooves 4 form the annular process cavity 5 together. In the structure, the annular process cavity 5 is arranged to adapt to brazing and electron beam welding, and when in brazing, brazing filler metal can be placed in the annular process cavity 5 in advance, so that the brazing filler metal can enter a weldable surface to be welded conveniently; when electron beam welding is carried out, the annular process cavity 5 holds splashes generated during electron beam welding in the annular process cavity 5, and stable welding seam quality is facilitated.
In this embodiment, the annular structure formed by the annular process chamber 5 is a circular ring. In the structure, the annular structure is set to be a circular ring, so that the depth of the circumferential welding line is consistent, and the implementation of the welding process cannot be greatly influenced due to the difference of the depth of the welding line.
In this embodiment, the annular process chamber 5 is located inside the annular compensation plate 3. In the structure, the annular process cavity 5 is positioned on the inner side of the annular compensating plate 3 and is suitable for brazing and electron beam welding.
In this embodiment, bolts 6 are connected between the piston skirt 2 and the annular compensating plate 3. In this structure, four bolts 6 are connected at the relevant position between piston skirt portion 2 and annular compensating plate 3 after the welding, and the screw hole is on annular compensating plate 3, and four bolts 6 connect the connection structure of strengthening piston head 1 and piston skirt portion 2, reduce the inefficacy risk of brazing, and piston head 1 and piston skirt portion 2 adopt to braze, and the brazing filler metal flows from inside to outside when brazing.
In other embodiments, electron beam welding can also be adopted, wherein the electron beam welding is performed from outside to inside, and the welding seam strength is high.
Piston example 3:
fig. 8 to 10 show a third embodiment of a split composite piston according to the present invention, which is substantially the same as embodiment 2 except that: in this embodiment, the annular process chamber 5 is located outside the annular compensation plate 3. In the structure, the annular process cavity 5 is positioned outside the annular compensation plate 3 and is suitable for electron beam welding.
Method example 1:
fig. 1 to 3 show a first embodiment of a split composite piston molding method according to the present invention, which includes the steps of:
s1: respectively forming blanks of a piston head 1, a piston skirt 2 and an annular compensating plate 3;
s2: processing an annular compensation plate 3 and a piston head 1, and processing an annular oil cavity 12 and an annular compensation port 15 in the piston head 1;
s3: respectively cleaning the piston head 1 and the annular compensation plate 3;
s4: installing the annular compensation plate 3 into the annular compensation port 15, and welding the annular compensation plate 3 and the annular compensation port 15 by adopting diffusion welding;
s5: processing the split surface of the piston skirt 2 and the split surface of the piston head 1 with the annular compensation plate 3, so that the annular compensation plate 3 and the split surfaces on two sides of the annular compensation port 15 form a continuous and complete weldable surface together;
s6: cleaning the piston head 1 and the piston skirt 2, attaching the split surfaces of the piston head 1 and the piston skirt 2, and positioning and installing the attached piston head 1 and the attached piston skirt 2;
s7: the compound connection is realized by adopting diffusion welding along the split surfaces jointed with the piston head 1 and the piston skirt 2;
s8: performing postweld heat treatment on the compounded piston;
s9: and (4) carrying out finish machining and surface treatment on the compounded piston by adopting mechanical machining.
In the method, the piston head 1 and the piston skirt 2 are welded and connected by diffusion welding through high-temperature alloy, the welding seam extends to the whole weldable surface, the strength is close to that of a base metal, the defects of the welding seam are few, and the requirements of high heat-resistant temperature of the piston head and small piston size of a high-power-density engine can be met; the integral piston is provided with the split type piston head part 1 and the split type piston skirt part 2, so that the blank forming difficulty is reduced; the weldable surface is positioned at the bottom of the annular oil cavity 12, namely the welding seam is far away from the combustion chamber, so that the heat load borne by the welding seam is reduced; the annular compensation plate 3 enables the area of a welding seam to be relatively large, reduces the mechanical stress level of the welding seam and improves the reliability of the welding seam; the annular compensating plate 3 ensures the integrity of the split surface of the piston head 1, forms a continuous and complete weldable surface, is beneficial to the implementation of a diffusion welding process, has strong process adaptability, and can meet the split connection of a steel piston; the annular compensation plate 3 is positioned in the annular compensation port 15, so that the structure is stable, the rigidity of the head annular groove 13 is improved, and the failure risk caused by axial stress deformation of the head annular groove 13 is reduced.
In this embodiment, the periphery of piston skirt portion 2 sets up the location boss, combustion chamber 11 at piston head 1, head inner chamber 14 sets up supplementary clout, set up the central locating hole on the supplementary clout of combustion chamber 11, the periphery of piston skirt portion 2 and skirt portion inner chamber 22 set up supplementary clout equally, set up the pin hole on the supplementary clout of skirt portion inner chamber 22 and the supplementary clout of head inner chamber 14 respectively, when piston head 1 and piston skirt portion 2 fix a position, the pin hole is packed into to the locating pin, piston head 1 card is gone into between the location boss, utilize the tight central locating hole of instrument top, just so realized location to piston head 1 and piston skirt portion 2, after the welding, get rid of supplementary clout and location boss can.
Method example 2:
fig. 4 to 7 show a second embodiment of the split composite piston molding method according to the present invention, which includes the following steps:
s1: respectively forming blanks of a piston head 1, a piston skirt 2 and an annular compensating plate 3;
s2: processing an annular compensation plate 3 and a piston head 1, and processing an annular oil cavity 12 and an annular compensation port 15 in the piston head 1;
s3: respectively cleaning the piston head 1 and the annular compensation plate 3;
s4: the annular compensation plate 3 is arranged in the annular compensation port 15, and the annular compensation plate 3 is welded with the annular compensation port 15 by laser welding;
s5: processing the split surface of the piston skirt 2 and the split surface of the piston head 1 with the annular compensation plate 3, so that the annular compensation plate 3 and the split surfaces on two sides of the annular compensation port 15 jointly form a continuous and complete weldable surface, a gap is formed between the weldable surface and the split surface of the piston skirt 2, the gap is positioned on the outer side of the annular process cavity 5, and the weldable surface is higher than the horizontal center line of the annular process cavity 5;
s6: cleaning the piston head 1 and the piston skirt 2, fitting the split surfaces of the piston head 1 and the piston skirt 2, placing brazing filler metal in the annular process cavity 5 during fitting, and positioning and mounting the fitted piston head 1 and the piston skirt 2;
s7: brazing is adopted to enable brazing filler metal to melt and flow outwards from the annular process cavity 5 along the gap to achieve composite connection of the piston head 1 and the piston skirt 2;
s8: performing postweld heat treatment on the compounded piston;
s9: and (4) carrying out finish machining and surface treatment on the compounded piston by adopting mechanical machining.
In the method, a piston head 1 and a piston skirt 2 are connected by brazing welding, a welding seam is positioned on the outer ring of an annular process cavity 5, the skirt is on the upper part during brazing processing, the piston head 1 and the inner ring of the piston skirt 2 are in rigid butt joint, the piston head 1 and the outer ring of the piston skirt 2 are in clearance butt joint, and the weldable surface is higher than the horizontal center line of the annular process cavity 5; the outer ring is welded and connected, the axial compressive stress is relatively small, and the stress load of the butt welding seam is reduced; the piston head 1 and the piston skirt 2 are in direct rigid butt joint at the base material of the inner ring to bear axial compressive stress; the integral piston is provided with the split type piston head part 1 and the split type piston skirt part 2, so that the processing difficulty of blank forging forming is reduced; the weldable surface is positioned at the bottom of the annular oil cavity 12, namely the welding seam is far away from the combustion chamber, so that the heat load borne by the welding seam is reduced; the annular compensation plate 3 enables the area of a welding seam to be relatively large, reduces the mechanical stress level of the welding seam and improves the reliability of the welding seam; the annular compensating plate 3 ensures the integrity of the split surface of the piston head 1, forms a continuous and complete weldable surface, is beneficial to the implementation of a brazing welding process, has strong process adaptability, and can meet the split connection of steel pistons; the annular compensation plate 3 is located in the annular compensation opening 15 and has a stable structure, the rigidity of the head annular groove 13 is improved, and the failure risk caused by axial stress deformation of the head annular groove 13 is reduced.
In the embodiment, the periphery of the piston skirt portion 2 is provided with the positioning bosses, the combustion chamber 11 of the piston head portion 1 is provided with the auxiliary excess material, the auxiliary excess material of the head portion inner cavity 14 is provided with the central positioning hole, and the piston head portion 1 is clamped between the positioning bosses during positioning, so that the piston head portion 1 and the piston skirt portion 2 are compressed and positioned.
In this embodiment, the annular process chamber 5 is provided with an exhaust hole extending to the outside, which is beneficial to brazing.
In the embodiment, the outer ring clearance of the piston head 1 and the outer ring clearance of the piston skirt 2 are butted during positioning, the outer ring clearance is filled by solder during brazing, and the solder is used for brazing and connecting the outer rings.
In this embodiment, the piston and the center positioning hole correspond to the welding jig, which is beneficial for mass production
Method example 3:
fig. 8 to 11 show a third embodiment of the split composite piston molding method according to the present invention, which includes the steps of:
s1: respectively forming blanks of a piston head 1, a piston skirt 2 and an annular compensating plate 3;
s2: processing an annular compensation plate 3 and a piston head 1, and processing an annular oil cavity 12 and an annular compensation port 15 in the piston head 1;
s3: respectively cleaning the piston head 1 and the annular compensation plate 3;
s4: the annular compensation plate 3 is arranged in the annular compensation port 15, and the annular compensation plate 3 is welded with the annular compensation port 15 by laser welding;
s5: processing the split surface of the piston skirt 2 and the split surface of the piston head 1 with the annular compensation plate 3, so that the bottom surface of the annular compensation plate 3 and the split surfaces on two sides of the annular compensation port 15 of the piston head 1 form a continuous and complete weldable surface together; a gap is formed between the weldable surface and the split surface of the piston skirt 2, the gap is positioned on the inner side of the annular process cavity 5, and the weldable surface is higher than the horizontal center line of the annular process cavity 5;
s6: cleaning the piston head 1 and the piston skirt 2, fitting the split surfaces of the piston head 1 and the piston skirt 2, placing brazing filler metal in the annular process cavity 5 during fitting, and positioning and mounting the fitted piston head 1 and the piston skirt 2;
s7: brazing is adopted to enable brazing filler metal to melt and flow inwards from the annular process cavity 5 along the gap to achieve composite connection of the piston head 1 and the piston skirt 2;
s8: performing postweld heat treatment on the compounded piston;
s9: and (4) carrying out finish machining and surface treatment on the compounded piston by adopting mechanical machining.
In the method, a piston head 1 and a piston skirt 2 are connected by brazing welding, a welding seam is positioned on an inner ring of an annular process cavity 5, the skirt is on the upper part during brazing processing, the outer rings of the piston head 1 and the piston skirt 2 are in rigid butt joint, the piston head 1 and the inner ring of the piston skirt 2 are in clearance butt joint, and the weldable surface is higher than the horizontal center line of the annular process cavity 5; the inner rings are welded and connected, and the large welding seam area is beneficial to reducing the stress load of the butt welding seam; the integral piston is provided with the split type piston head part 1 and the split type piston skirt part 2, so that the processing difficulty of blank forging forming is reduced; the weldable surface is positioned at the bottom of the annular oil cavity 12, namely the welding seam is far away from the combustion chamber, so that the heat load borne by the welding seam is reduced; the annular compensation plate 3 enables the area of a welding seam to be relatively large, reduces the mechanical stress level of the welding seam and improves the reliability of the welding seam; the annular compensating plate 3 ensures the integrity of the split surface of the piston head 1, forms a continuous and complete weldable surface, is beneficial to the implementation of a brazing welding process, has strong process adaptability, and can meet the split connection of steel pistons; the annular compensation plate 3 is positioned in the annular compensation port 15, so that the structure is stable, the rigidity of the head annular groove 13 is improved, and the failure risk caused by axial stress deformation of the head annular groove 13 is reduced.
In the embodiment, the periphery of the piston skirt portion 2 is provided with the positioning bosses, the combustion chamber 11 of the piston head portion 1 is provided with the auxiliary excess material, the auxiliary excess material of the head portion inner cavity 14 is provided with the central positioning hole, and the piston head portion 1 is clamped between the positioning bosses during positioning, so that the piston head portion 1 and the piston skirt portion 2 are compressed and positioned.
In this embodiment, the annular process chamber 5 is provided with an exhaust hole extending to the outside, which is beneficial to brazing.
In the embodiment, the piston head 1 and the inner ring of the piston skirt 2 are in butt joint in a clearance mode during positioning, the clearance of the inner ring is filled with solder during brazing processing, and the inner ring is brazed and connected through the solder.
In this embodiment, the piston and the center positioning hole correspond to the welding jig, which is beneficial to mass production.
Method example 4:
fig. 12 to 15 show a fourth embodiment of the split composite piston molding method according to the present invention, which includes the steps of:
s1: respectively forming blanks of a piston head 1, a piston skirt 2 and an annular compensating plate 3;
s2: processing an annular compensation plate 3 and a piston head 1, and processing an annular oil cavity 12 and an annular compensation port 15 in the piston head 1;
s3: respectively cleaning the piston head 1 and the annular compensation plate 3;
s4: the annular compensation plate 3 is arranged in the annular compensation port 15, and the annular compensation plate 3 is welded with the annular compensation port 15 by laser welding;
s5: processing the split surface of the piston skirt 2 and the split surface of the piston head 1 with the annular compensation plate 3, so that the bottom surface of the annular compensation plate 3 and the split surfaces on two sides of the annular compensation port 15 of the piston head 1 form a continuous and complete weldable surface together, a gap is formed between the weldable surface and the split surface of the piston skirt 2, the gap is positioned on the inner side of the annular process cavity 5, and the weldable surface is higher than the horizontal center line of the annular process cavity 5;
s6: cleaning the piston head part 1 and the piston skirt part 2, attaching the split surfaces of the piston head part 1 and the piston skirt part 2, and positioning and installing the attached piston head part 1 and the attached piston skirt part 2;
s7: the piston head 1 and the piston skirt 2 are compositely connected by adopting electron beam welding from outside to inside to the annular process cavity 5;
s8: performing postweld heat treatment on the compounded piston;
s9: and (4) carrying out finish machining and surface treatment on the compounded piston by adopting mechanical machining.
In the method, a piston head 1 and a piston skirt 2 are welded and connected by adopting electron beam welding, a welding seam is positioned on the outer ring of an annular process cavity 5, the outer rings of the piston head 1 and the piston skirt 2 are rigidly butted before welding, the inner rings of the piston head 1 and the piston skirt 2 are in clearance butt joint, and the welding surface is higher than the horizontal center line of the annular process cavity 5; the outer ring is welded and connected, so that the axial tensile stress is borne, and the stress load of the butt weld is reduced; the piston head 1 and the piston skirt 2 are in direct rigid butt joint at the base material of the inner ring to bear axial compressive stress; the integral piston is provided with the split type piston head part 1 and the split type piston skirt part 2, so that the processing difficulty of blank forging forming is reduced; the weldable surface is positioned at the bottom of the annular oil cavity 12, namely the welding seam is far away from the combustion chamber, so that the heat load borne by the welding seam is reduced; the annular compensation plate 3 enables the area of a welding seam to be relatively large, reduces the mechanical stress level of the welding seam and improves the reliability of the welding seam; the annular compensating plate 3 ensures the integrity of the split surface of the piston head 1, forms a continuous and complete weldable surface, is beneficial to the implementation of an electron beam welding process, has strong process adaptability, and can meet the split connection of steel pistons; the annular compensation plate 3 is located in the annular compensation opening 15 and has a stable structure, the rigidity of the head annular groove 13 is improved, and the failure risk caused by axial stress deformation of the head annular groove 13 is reduced.
In the embodiment, the inner circle of the annular process half groove 4 of the piston head 1 is provided with a positioning bulge, the combustion chamber 11 of the piston head 1 is provided with auxiliary excess materials, the auxiliary excess materials are provided with central positioning holes, the positioning bulge enters the annular process half groove 4 of the piston skirt portion 2 during positioning, the central positioning holes are tightly pressed by a tool, and therefore the piston head 1 and the piston skirt portion 2 are positioned.
In the embodiment, the outer rings of the piston head 1 and the piston skirt 2 are just butted during positioning, the outer rings are processed by electron beam welding, the welding seams are longitudinally contracted, the piston head 1 and the piston skirt 2 are axially contracted, the gap between the inner rings is eliminated, and the inner rings are rigidly butted.
Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make numerous possible variations and modifications to the present invention, or modify equivalent embodiments to equivalent variations, without departing from the scope of the invention, using the teachings disclosed above. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical spirit of the present invention should fall within the protection scope of the technical scheme of the present invention, unless the technical spirit of the present invention departs from the content of the technical scheme of the present invention.

Claims (10)

1. The utility model provides a components of a whole that can function independently combined type piston, includes split type piston head (1) and skirt portion (2), be equipped with combustion chamber (11), annular oil chamber (12), head annular (13) and head inner chamber (14) on piston head (1), skirt portion (2) are equipped with pinhole (21) and skirt portion inner chamber (22), its characterized in that: the split surface of the piston head (1) passes through the annular oil cavity (12), the split surface of the piston head (1) is provided with an annular compensation port (15) communicated with the bottom of the annular oil cavity (12), an annular compensation plate (3) is arranged in the annular compensation port (15), the bottom surface of the annular compensation plate (3) and the split surfaces on two sides of the annular compensation port (15) of the piston head (1) form a continuous and complete weldable surface together, and the piston head (1) and the piston skirt (2) are connected by welding along the weldable surface.
2. The split composite piston of claim 1, wherein: the piston head (1) and the piston skirt (2) are provided with annular process half grooves (4) at the same positions of respective split surfaces, and the two annular process half grooves (4) form an annular process cavity (5) together.
3. The split composite piston of claim 2, wherein: the annular structure formed by the annular process cavity (5) is a circular ring.
4. The split composite piston of claim 3, wherein: the annular process cavity (5) is positioned on the inner side of the annular compensation plate (3).
5. The split composite piston of claim 3, wherein: the annular process cavity (5) is positioned outside the annular compensation plate (3).
6. The split composite piston of claim 4 or 5, wherein: and a bolt (6) is connected between the piston skirt part (2) and the annular compensating plate (3).
7. The molding method of the split composite piston according to claim 1, comprising the following steps:
s1: respectively forming blanks of a piston head (1), a piston skirt (2) and an annular compensating plate (3);
s2: processing an annular compensation plate (3) and a piston head (1), and processing an annular oil cavity (12) and an annular compensation port (15) on the piston head (1);
s3: respectively cleaning the piston head (1) and the annular compensation plate (3);
s4: installing the annular compensation plate (3) into the annular compensation port (15), and welding the annular compensation plate (3) and the annular compensation port (15) by adopting diffusion welding;
s5: processing the split surface of the piston skirt part (2) and the split surface of the piston head part (1) with the annular compensation plate (3) to ensure that the annular compensation plate (3) and the split surfaces on the two sides of the annular compensation port (15) form a continuous and complete weldable surface together;
s6: cleaning the piston head (1) and the piston skirt (2), attaching the split surfaces of the piston head (1) and the piston skirt (2) and positioning and installing the attached piston head (1) and the attached piston skirt (2);
s7: the composite connection is realized by adopting diffusion welding along the split surfaces attached to the piston head (1) and the piston skirt (2);
s8: performing postweld heat treatment on the compounded piston;
s9: and (4) carrying out finish machining and surface treatment on the compounded piston by adopting mechanical machining.
8. The molding method of the split composite piston according to claim 4, comprising the following steps:
s1: respectively forming blanks of a piston head (1), a piston skirt (2) and an annular compensating plate (3);
s2: processing an annular compensation plate (3) and a piston head (1), and processing an annular oil cavity (12) and an annular compensation port (15) on the piston head (1);
s3: respectively cleaning the piston head (1) and the annular compensation plate (3);
s4: the annular compensation plate (3) is arranged in the annular compensation port (15), and the annular compensation plate (3) is welded with the annular compensation port (15) by laser welding;
s5: processing the split surface of the piston skirt part (2) and the split surface of the piston head part (1) with the annular compensation plate (3), so that the annular compensation plate (3) and the split surfaces on the two sides of the annular compensation port (15) jointly form a continuous and complete weldable surface, a gap is formed between the weldable surface and the split surface of the piston skirt part (2), the gap is positioned on the outer side of the annular process cavity (5), and the weldable surface is higher than the horizontal center line of the annular process cavity (5);
s6: cleaning the piston head (1) and the piston skirt (2), bonding the split surfaces of the piston head (1) and the piston skirt (2), placing brazing filler metal in the annular process cavity (5) during bonding, and positioning and mounting the bonded piston head (1) and the bonded piston skirt (2);
s7: brazing is adopted to enable brazing filler metal to melt and flow outwards from the annular process cavity (5) along the gap to realize composite connection of the piston head (1) and the piston skirt (2);
s8: performing postweld heat treatment on the compounded piston;
s9: and (4) carrying out finish machining and surface treatment on the compounded piston by adopting mechanical machining.
9. The molding method of the split composite piston according to claim 5, comprising the following steps:
s1: respectively forming blanks of a piston head (1), a piston skirt (2) and an annular compensating plate (3);
s2: processing an annular compensation plate (3) and a piston head (1), and processing an annular oil cavity (12) and an annular compensation port (15) on the piston head (1);
s3: respectively cleaning the piston head (1) and the annular compensation plate (3);
s4: the annular compensation plate (3) is arranged in the annular compensation port (15), and the annular compensation plate (3) is welded with the annular compensation port (15) by laser welding;
s5: processing the split surface of the piston skirt (2) and the split surface of the piston head (1) with the annular compensation plate (3), so that the bottom surface of the annular compensation plate (3) and the split surfaces on two sides of the annular compensation port (15) of the piston head (1) form a continuous and complete weldable surface together; a gap is formed between the weldable surface and the split surface of the piston skirt (2), the gap is positioned on the inner side of the annular process cavity (5), and the weldable surface is higher than the horizontal center line of the annular process cavity (5);
s6: cleaning the piston head (1) and the piston skirt (2), bonding the split surfaces of the piston head (1) and the piston skirt (2), placing brazing filler metal in the annular process cavity (5) during bonding, and positioning and mounting the bonded piston head (1) and the bonded piston skirt (2);
s7: brazing is adopted to enable brazing filler metal to melt and flow inwards from the annular process cavity (5) along the gap to realize composite connection of the piston head (1) and the piston skirt (2);
s8: performing postweld heat treatment on the compounded piston;
s9: and (4) carrying out finish machining and surface treatment on the compounded piston by adopting mechanical machining.
10. The molding method of the split composite piston according to claim 4, comprising the following steps:
s1: respectively forming blanks of a piston head (1), a piston skirt (2) and an annular compensating plate (3);
s2: processing an annular compensation plate (3) and a piston head (1), and processing an annular oil cavity (12) and an annular compensation port (15) on the piston head (1);
s3: respectively cleaning the piston head (1) and the annular compensation plate (3);
s4: the annular compensation plate (3) is arranged in the annular compensation port (15), and the annular compensation plate (3) is welded with the annular compensation port (15) by laser welding;
s5: processing the split surface of the piston skirt part (2) and the split surface of the piston head part (1) with the annular compensation plate (3), so that the bottom surface of the annular compensation plate (3) and the split surfaces on two sides of the annular compensation port (15) of the piston head part (1) jointly form a continuous and complete weldable surface, a gap is formed between the weldable surface and the split surface of the piston skirt part (2), the gap is positioned on the inner side of the annular process cavity (5), and the weldable surface is higher than the horizontal center line of the annular process cavity (5);
s6: cleaning the piston head (1) and the piston skirt (2), attaching the split surfaces of the piston head (1) and the piston skirt (2), and positioning and installing the attached piston head (1) and the attached piston skirt (2);
s7: the piston head (1) and the piston skirt (2) are compositely connected by adopting electron beam welding from outside to inside to the annular process cavity (5);
s8: performing postweld heat treatment on the compounded piston;
s9: and (4) carrying out finish machining and surface treatment on the compounded piston by adopting mechanical machining.
CN201910218419.7A 2019-03-21 2019-03-21 Split composite piston and forming method Active CN111720234B (en)

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