CN108857283B - Step-by-step cold extrusion process for tappet body of engine fuel injection system - Google Patents
Step-by-step cold extrusion process for tappet body of engine fuel injection system Download PDFInfo
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- CN108857283B CN108857283B CN201810794188.XA CN201810794188A CN108857283B CN 108857283 B CN108857283 B CN 108857283B CN 201810794188 A CN201810794188 A CN 201810794188A CN 108857283 B CN108857283 B CN 108857283B
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- extrusion process
- tappet body
- cold extrusion
- injection system
- fuel injection
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- 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
Abstract
The invention discloses a tappet body step-by-step cold extrusion process of an engine fuel injection system, which comprises the following steps of: blanking; reversely extruding and stretching the square hole; and (4) backward extruding and stretching the round hole. According to the tappet body prepared by the step-by-step cold extrusion process, the metal streamline in the part is consistent with the shape of the part and is distributed in a uniform fiber streamline shape, the mechanical property of the part is improved, and reasonable compressive stress is formed on the inner surface and the outer surface of the part, so that the integral fatigue strength of the part is improved; meanwhile, the tappet body is prepared by adopting a step-by-step cold extrusion process, and an internal cavity does not need to be processed, so that raw materials are saved, and the production cost is reduced.
Description
Technical Field
The invention relates to the technical field of extrusion forming, in particular to a tappet body step-by-step cold extrusion process of an engine fuel injection system.
Background
The engine is a machine capable of converting other forms of energy into mechanical energy, and comprises an internal combustion engine (gasoline engine and the like), an external combustion engine (stirling engine, steam engine and the like), an electric motor and the like, wherein the internal combustion engine converts chemical energy into mechanical energy; the engine is suitable for a power generation device, and can also refer to a whole machine comprising a power device, such as a gasoline engine, an aircraft engine and the like. The engine fuel injection system is a fuel supply device which directly injects a certain amount of fuel into a cylinder or an air inlet channel by using an injector under a certain pressure. The fuel injection system comprises a pump nozzle injection system, the pump nozzle injection system is a diesel engine fuel injection system which combines and installs a plunger matching part and a fuel injector matching part in a shell, and a special camshaft is required to be arranged on a cylinder cover to directly drive a tappet to control the oil pumping process of a plunger pump. The function of the tappet body is to transmit the thrust of the camshaft to the push rod and bear the lateral force applied when the camshaft rotates.
The existing tappet body processing technology is as follows: selecting a diameter of
The 20CrMnTi round rough bar stock is cut into 65mm long and 642g by a common sawing machine, and is subjected to end face flattening, rough turning of an excircle, drilling at two ends, rough boring, rough machining of a square hole at the center and a round hole at the other end, finish turning and continuous finish machining to obtain a finished product. The whole machining process is complex and complicated, rough turning, punching, boring, machining center rough machining, finish machining and the like are needed, the production efficiency is low, and the surface roughness of the inner hole of the part can hardly meet the requirement; the material weight needs 642g, so that great material waste exists, and the production cost of parts is greatly increased; analyzing the metal flow line of the processed part, wherein the metal flow line at the inner step is brokenThe on state reduces the overall strength of the part, which in turn results in a shortened engine life.
Therefore, how to change the current situations of high production cost and low part strength caused by the processing technology of the tappet body of the fuel injection system of the engine in the prior art is an urgent problem to be solved by the technical personnel in the field.
Disclosure of Invention
The invention aims to provide a tappet body step-by-step cold extrusion process of an engine fuel injection system, which aims to solve the problems in the prior art, improve the structural strength of the formed tappet body and reduce the production cost.
In order to achieve the purpose, the invention provides the following scheme: the invention provides a tappet body step-by-step cold extrusion process of an engine fuel injection system, which comprises the following steps of:
step one, sawing and blanking to obtain a cylindrical blank, performing spheroidizing annealing on the blank, performing sand blasting on the surface of the blank, and finally performing phosphorization and saponification on the blank;
step two, reversely extruding and stretching the square hole, and controlling the depth, the bottom thickness and the symmetry degree with the excircle of the square hole by utilizing equal-height blocks on the die;
and step three, reversely extruding and stretching the round hole, and controlling the thickness between the round hole and the square hole to meet the requirement of the part.
Preferably, in the first step, the blank is made of 20CrMnTi carburizing steel.
Preferably, in the step one, when the blank is spheroidized, an annealing furnace which is vacuumized and protected by nitrogen gas is adopted, the temperature is raised for 4 hours after charging, the temperature is raised to 780 ℃ and then kept for 5 hours, the furnace is cooled to 680 ℃ and then kept for 5 hours, and the blank is taken out of the furnace and cooled in air after being cooled to 350 ℃.
Preferably, in the second step, after the square holes are subjected to backward extrusion and stretching, the roughness of the inner walls of the square holes is ensured to reach Ra0.6 μm.
Preferably, in the third step, the circumferential eccentricity of the stretching punch rod is adjusted to ensure the thickness between the round hole and the square hole, and the standard detection steel ball is used for measurement.
Preferably, in the third step, the thickness deviation between the round hole and the square hole is +/-0.03 mm.
Compared with the prior art, the invention has the following technical effects: the invention relates to a tappet body step-by-step cold extrusion process of an engine fuel injection system, which comprises the following steps of: blanking; reversely extruding and stretching the square hole; and (4) backward extruding and stretching the round hole. According to the tappet body prepared by the step-by-step cold extrusion process, the metal streamline in the part is consistent with the shape of the part and is distributed in a uniform fiber streamline shape, the mechanical property of the part is improved, and reasonable compressive stress is formed on the inner surface and the outer surface of the part, so that the integral fatigue strength of the part is improved; meanwhile, the tappet body is prepared by adopting a step-by-step cold extrusion process, and an internal cavity does not need to be processed, so that raw materials are saved, and the production cost is reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.
FIG. 1 is a schematic structural diagram of a blank in a first step of a tappet body step-by-step cold extrusion process of an engine fuel injection system according to the present invention;
FIG. 2 is a sectional view of the sectional structure of the tappet body of the fuel injection system of the engine in the main view direction of the backward extrusion stretching square hole in the step two of the step-by-step cold extrusion process;
FIG. 3 is a schematic top view of a backward extrusion stretching square hole in step two of the step-by-step cold extrusion process for the tappet of the fuel injection system of the engine of the present invention;
FIG. 4 is a schematic structural diagram of a backward extrusion stretching circular hole in step three of the step-by-step cold extrusion process of the tappet body of the engine fuel injection system of the present invention;
FIG. 5 is a metal flow line analysis of a tappet body prepared by the step-by-step cold extrusion process of the tappet body of the engine fuel injection system of the present invention;
FIG. 6 is a metal flow line analysis diagram of a tappet body obtained by machining;
wherein, 1 is a square hole, and 2 is a round hole.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention aims to provide a tappet body step-by-step cold extrusion process of an engine fuel injection system, which aims to solve the problems in the prior art, improve the structural strength of the formed tappet body and reduce the production cost.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
Referring to fig. 1-6, wherein fig. 1 is a schematic structural diagram of a blank in a step one of a step cold extrusion process of a tappet of an engine fuel injection system according to the present invention, FIG. 2 is a sectional view of the stretching square hole in the backward extrusion direction in the second step of the step-by-step cold extrusion process for the tappet of the fuel injection system of the engine of the present invention, FIG. 3 is a schematic top view of a backward extrusion drawing square hole in step two of the step-by-step cold extrusion process for the tappet of the fuel injection system of the engine of the present invention, FIG. 4 is a schematic structural diagram of a backward extrusion stretching circular hole in the third step of the step-by-step cold extrusion process of the tappet body of the fuel injection system of the engine of the present invention, fig. 5 is a metal flow line analysis diagram of a tappet body prepared by the tappet body step-by-step cold extrusion process of the engine fuel injection system of the invention, and fig. 6 is a metal flow line analysis diagram of the tappet body obtained by adopting a machining mode.
The invention provides a tappet body step-by-step cold extrusion process of an engine fuel injection system, which comprises the following steps of:
step one, sawing and blanking to obtain a cylindrical blank, performing spheroidizing annealing on the blank, performing sand blasting on the surface of the blank, and finally performing phosphorization and saponification on the blank;
step two, reversely extruding and stretching the square hole 1, and controlling the depth, the bottom thickness and the symmetry degree with the excircle of the square hole 1 by utilizing equal-height blocks on a die;
and step three, reversely extruding and stretching the round hole 2, and controlling the thickness between the round hole 2 and the square hole 1 to meet the requirement of the part.
According to the tappet body prepared by the step-by-step cold extrusion process, the metal streamline in the part is consistent with the shape of the part and is distributed in a uniform fiber streamline shape, please refer to fig. 4 and fig. 5, the mechanical property of the part is improved, and reasonable compressive stress is formed on the inner surface and the outer surface of the part, so that the integral fatigue strength of the part is improved; meanwhile, the tappet body is prepared by adopting a step-by-step cold extrusion process, and an internal cavity does not need to be processed, so that raw materials are saved, and the production cost is reduced.
Specifically, in the first step, the blank is made of 20CrMnTi carburizing steel, the diameter of the blank is 38mm, and during blanking, a high-speed circular saw is adopted to saw and cut the blank, so that the blanking weight is accurate, and the production efficiency is improved. Meanwhile, the uniform consistency of blanking avoids the damage of the die caused by the inconsistent blank.
In addition, in the first step, when the blank is spheroidized, an annealing furnace which is vacuumized and protected by nitrogen gas is adopted, the temperature is raised for 4 hours after charging, the temperature is kept for 5 hours after the temperature is raised to 780 ℃, the temperature is kept for 5 hours after the furnace is cooled to 680 ℃, and the furnace is taken out of the furnace for air cooling after the furnace is cooled to 350 ℃, so that the surface oxidation decarburization of the blank is reduced, and the final carburization quality of a product is ensured. After spheroidizing annealing, performing sand blasting treatment on the surface of the blank on a shot blasting machine to remove surface impurities to obtain a sand pit surface with uniform surface, and preparing for subsequent phosphorization and saponification; the phosponification treatment is carried out in preparation for cold extrusion.
More specifically, in the second step, after the square hole 1 is subjected to backward extrusion and stretching, the roughness of the inner wall of the square hole 1 is ensured to reach Ra0.6 μm. The tappet body square hole 1 and the circular hole 2 are complex in shape, need circular arc transition and are difficult to process and obtain by a cutting method, the step-by-step cold extrusion process can obtain a complex inner hole shape and good surface roughness, the surface roughness can reach Ra0.3-0.6 mu m, the inner cavity does not need to be machined, the processing period is shortened, and the production efficiency is improved.
Furthermore, in the third step, in order to offset the resilience amount of the material after cold extrusion, the circumferential eccentric amount of the stretching punch rod is adjusted to ensure the thickness between the round hole 2 and the square hole 1, and the standard detection steel ball of S phi 16 is used for measuring to ensure that the thickness reaches 220 -0.01。
Furthermore, in the third step, a 450T high-precision hydraulic press is adopted, a 22kW servo motor is adopted to drive, a high-precision plunger pump is adopted, and an electronic ruler is matched, so that the thickness deviation between the round hole 2 and the square hole 1 is +/-0.03 mm.
The tappet body is prepared by the step-by-step cold extrusion process, the metal streamline inside the part is consistent with the shape of the part and is distributed in a uniform fiber streamline shape, the square mechanical property of the part is improved, and reasonable pressure stress is formed on the inner surface and the outer surface of the part by the reasonable cold extrusion process, so that the integral fatigue strength of the part is improved. The step-by-step cold extrusion process can obtain a complex inner hole shape and good surface roughness, and the cavity in the part does not need to be lathed, so that the processing period is greatly shortened, and the production efficiency is improved.
The principle and the implementation mode of the invention are explained by applying a specific example, and the description of the embodiment is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.
Claims (5)
1. A step-by-step cold extrusion process for a tappet body of an engine fuel injection system is characterized by comprising the following steps of:
step one, sawing and blanking to obtain a cylindrical blank, performing spheroidizing annealing on the blank, adopting an annealing furnace with vacuumizing and nitrogen gas filling protection, heating for 4 hours after charging, heating to 780 ℃, keeping the temperature for 5 hours, cooling to 680 ℃, keeping the temperature for 5 hours, cooling to 350 ℃, discharging from the furnace, air cooling, performing sand blasting on the surface of the blank, and finally performing phosphorus saponification on the blank;
step two, reversely extruding and stretching the square hole, and controlling the depth, the bottom thickness and the symmetry degree with the excircle of the square hole by utilizing equal-height blocks on the die;
and step three, reversely extruding and stretching the round hole, and controlling the thickness between the round hole and the square hole to meet the requirement of the part.
2. The engine fuel injection system tappet body step-by-step cold extrusion process according to claim 1, characterized in that: in the first step, the blank is made of 20CrMnTi carburizing steel.
3. The engine fuel injection system tappet body step-by-step cold extrusion process according to claim 1, characterized in that: and in the second step, after the square hole is subjected to backward extrusion and stretching, ensuring that the roughness of the inner wall of the square hole reaches Ra0.6 mu m.
4. The engine fuel injection system tappet body step-by-step cold extrusion process according to claim 1, characterized in that: in the third step, the circumferential eccentricity of the stretching punch rod is adjusted to ensure the thickness between the round hole and the square hole, and a standard detection steel ball is used for measurement.
5. The engine fuel injection system tappet body step-by-step cold extrusion process according to claim 1, characterized in that: in the third step, the thickness deviation between the round hole and the square hole is +/-0.03 mm.
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| CN201810794188.XA CN108857283B (en) | 2018-07-19 | 2018-07-19 | Step-by-step cold extrusion process for tappet body of engine fuel injection system |
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| CN201810794188.XA CN108857283B (en) | 2018-07-19 | 2018-07-19 | Step-by-step cold extrusion process for tappet body of engine fuel injection system |
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| CN108857283B true CN108857283B (en) | 2020-09-15 |
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| CN101259490B (en) * | 2008-04-16 | 2010-10-06 | 项龙江 | Processing method of marble for marble lockset and its special-purpose mold |
| CN102240689B (en) * | 2011-05-30 | 2013-02-20 | 陈怡� | Processing method of lighter electrical cap |
| CN103624205A (en) * | 2013-12-04 | 2014-03-12 | 江苏威鹰机械有限公司 | Cold-forging plastic molding technology of precisely-forged brake threaded pipe component |
| CN103862237B (en) * | 2014-03-11 | 2016-08-17 | 宁波固远管件有限公司 | A kind of little four square set multiple step format cold-extrusion technologies |
| CN203817080U (en) * | 2014-05-13 | 2014-09-10 | 四川中邦模具有限公司 | Cold extrusion die for automobile tappet |
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