CN108637612B - Machining process of piston for aero-engine - Google Patents
Machining process of piston for aero-engine Download PDFInfo
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- CN108637612B CN108637612B CN201810469056.XA CN201810469056A CN108637612B CN 108637612 B CN108637612 B CN 108637612B CN 201810469056 A CN201810469056 A CN 201810469056A CN 108637612 B CN108637612 B CN 108637612B
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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
- B23P15/10—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass pistons
Abstract
The scheme discloses a machining process of a piston for an aero-engine in the pistons for the aero-engine, which comprises an earlier stage treatment step, an inner hole machining step, an inner hole preliminary machining step and a step of drilling a hole inwards from a large end center shaft; firstly, drilling a bottom hole, namely drilling a phi 11 multiplied by 200 lengthened hole with the depth of the bottom hole being 50-10 mm; then the first hole expansion is carried out, the hole is expanded to the depth of 173mm by using an elongated drill with the diameter of 12 multiplied by 200, and then the second hole expansion is carried out: secondary reaming is carried out by using a lengthened drill with the diameter of 14.2 multiplied by 200, the reaming depth is 154mm, and primary reaming is carried out: carrying out primary reaming by using a special internal cooling cutter to ensure that the aperture size is phi 14.4, the depth is 155mm, and the surface finish is Ra3.2um; fine reaming: replacing the second internal cooling reamer for fine reaming to ensure that the aperture size is phi 14.48 and the surface finish is Ra1.6um; then, the conical surface is turned, the rod part is ground and the post-processing is carried out. After trial production, the process scheme can well ensure the processing of the inner hole of the piston and ensure various technical requirements.
Description
Technical Field
The invention relates to the field of pistons for aero-engines, in particular to a machining process of a piston for an aero-engine.
Background
In an aircraft engine, a piston part is used, the part belongs to a long-shaft deep-hole part, and the part parameter is (default unit in mechanical parts: millimeter)<mm>General omission of unwritten): maximum outer diameter of phi 54.5, length of 232, minimum wall thickness of 3.06, and hole diameter of phi 14.50 +0.05Depth 155, bottom hole phi 120 +0.12And a depth of 173.
From the machining parameters, the most difficult machining of pistons has three aspects: 1. the depth of the hole reaches 155, 2, the surface finish requirement is higher, the surface finish requirement is Ra0.8um, 3, the wall thickness difference between the inner hole and the excircle cannot be more than 0.1.
When an inner hole is machined, the hole is deep, the surface finish requirement is Ra0.8um, the size precision requirement and the surface finish requirement of the hole are difficult to guarantee when the hole is machined by adopting the traditional drilling machining, so that the machining scheme of reaming is preliminarily determined when the hole is machined, but the surface quality and the size precision of a machined part are difficult to control because a working part of a reamer cannot be cooled by cooling liquid when a common reamer is used for machining a deep hole.
Because the minimum wall thickness is required to be 3.06, the thickness difference between the outer circle and the inner hole wall is less than 0.1, the requirements on the size precision and the surface quality of the outer circle of the piston are high, the turning process scheme of a general numerical control lathe is difficult to guarantee, the outer circle needs to be guaranteed by grinding, the outer circle can be ground only by taking the inner hole as a reference during grinding, the outer circle can be ground only by tightly jacking the jacking hole by matching with a tailstock, and the jumping of the jacking hole and the inner hole cannot be more than 0.02.
If the index requirement of the piston for the aeroengine is met, the piston can be completed by perfect and reasonable steps, and the manufacturing quality of the piston is still poor after being tried for many times by people in the field, so that the parameter requirement is met, the reasonable steps need to be researched, and the better matching of all processing steps is also needed.
Disclosure of Invention
The invention aims to provide a processing technology of a piston for an aero-engine, and aims to solve the problem that the parameter requirements are difficult to meet in the existing process of manufacturing the piston for the aero-engine.
The machining process of the piston for the aero-engine comprises the following steps:
the method comprises the following steps: cutting a rod piece steel material with the length of 232mm to be used as a rod body for processing the piston;
the piston is initially processed, the large-end of the piston is turned, and the large-end of the piston is manufactured in a turning mode through a lathe according to the size of the large-end of the piston;
step three, performing heat treatment on the piston which is initially processed;
step four, machining the rod body of the piston, and turning to manufacture the outer diameter of the rod body according to the size of the outer circle of the rod body
Fifthly, initially processing an inner hole, and drilling a hole inwards from a central shaft of the large end; firstly, drilling a bottom hole, namely drilling a phi 11 multiplied by 200 lengthened hole with the depth of the bottom hole being 50-10 mm; then the first hole expansion is carried out, the hole is expanded to the depth of 173mm by using an elongated drill with the diameter of 12 multiplied by 200, and then the second hole expansion is carried out: and then the second reaming is carried out by using a lengthened drill with the diameter of 14.2 multiplied by 200, the reaming depth is 154mm,
step six, primary reaming: using a special internal cooling cutter to carry out primary reaming to ensure that the aperture size is
The depth is 155mm, and the surface finish is Ra3.2um;
step seven, finely reaming the hole: replacing the second internal cooling reamer for fine reaming to ensure the aperture size to be
The surface finish is Ra1.6um;
step eight, turning a conical surface: processing an inner conical surface with the angle of 60 degrees multiplied by 0.80+0.2 at an inner orifice;
step nine, drilling a center hole: mandrel tensioning part utilizing lathe fixture
The surface of the inner hole, the mandrel and the inner hole are tightly matched through conicity; drilling a central hole with phi 4-phi 8.5 on the end surface of one side of the rod body;
step ten, turning the outer circle: the piston is fixed on a lathe through an inner hole and a tip hole, and the excircle of the big end of the piston is processed, wherein the diameter of the excircle is
Turning the shape of the rod body, and reserving 0.2 grinding allowance on the rod body;
step eleven, grinding the rod part: positioning and clamping
The outer circle of the rod body is tightly propped against the central hole through the clamp, and the outer molded surface of the rod body is ground, so that the surface finish requirement is Ra0.8um.
And step twelve, post-treatment, namely removing burrs on the surface of the piston, cleaning, nitriding, performing thread machining on the inner hole, and polishing the surface again to finish the manufacturing of the piston.
The working principle and the advantages of the scheme are as follows: when processing the hole, because the hole is darker, has reached 155mm, adopt traditional drilling processing to process this hole and hardly guarantee its size precision requirement and surface finish requirement, consequently adopt internal cooling formula reamer when processing the hole, make the coolant liquid can the direct action in the blade part of cutter, and then guarantee that the cutter obtains the cooling to guarantee turning bits in time to clear up, through boring the bottom hole: adopting a phi 11 multiplied by 200 lengthened drill bit and using a phi 12 multiplied by 200 lengthened drill bit for the first time expansionAfter the hole is drilled to 173mm deep, the hole is reamed for the second time by using a lengthened drill with the diameter of 14.2 multiplied by 200 and the depth is ensured to be 154, then the inner cooling reamer is replaced to ream the inner hole, and the aperture size of the inner hole is ensured to be
The depth is 155mm, the surface finish is Ra3.2um, a special internal cooling cutter is used for fine reaming, and the aperture size is ensured to be
The surface finish degree is Ra1.6um, through reaming twice and reaming twice, and the aperture of each hole is strictly controlled, after trial production, the technological scheme can well guarantee each technology required by the piston.
The thickness difference between the outer circle and the inner hole wall of the piston is not more than 0.1mm, and the piston is manufactured by tightly abutting the center hole, so that the bending resistance of the wall thickness is ensured. After the support is tightly carried out, the bounce of the center hole and the inner hole is not more than 0.02, and the part is tightly supported by a mandrel of the vehicle clamp when the center hole is drilled
The surface of the inner hole, a mandrel of the clamp and the inner hole are in tight fit through taper, a central hole is machined under the condition of no other external force, a clamping mode of simultaneously jacking in two aspects is adopted, the outer circle is machined, the purpose is to correct the jumping of the center hole and the outer circle, through the combination of the steps, the wall thickness difference of the inner hole and the outer circle of the machined piston is 0.05-0.08 mm, and the technical requirement that the wall thickness difference of the inner hole and the outer circle is not more than 0.1mm is met.
The first optimization scheme is based on the basic scheme: the steel used in the first step is high-grade nitrided steel of 38 crmol, and has the characteristics of high wear resistance, high fatigue strength and high strength. Has the characteristics of small impact load and high wear resistance.
And the second optimization scheme is based on the first optimization scheme: the heat treatment mode in the second step is as follows: heating the piston to 880-890 ℃, preserving heat for 10-15 min, and then soaking the piston into a sodium chloride aqueous solution for cooling; and cooling to the normal temperature, heating the piston to 500-550 ℃, preserving the heat for 20-30 min, and then air-cooling to the normal temperature. The hardness of the piston is improved through heat treatment, and the impact toughness of the piston is further improved.
And the optimization scheme III is based on the optimization scheme I or the optimization scheme II: the internal cooling cutter comprises a cutter handle and a cutting rod detachably connected with the cutter handle, cooling liquid channel holes are formed in the cutter handle and the cutting rod, and shunt channel holes are formed in the cutting rod and are evenly distributed on the cutting rod and communicated with the cooling liquid channel holes. The special internal cooling cutter is used for reaming and punching, and when cutters with different sizes are used, the cutting rod can be directly detached and replaced, so that the cutter is more flexible to use.
And the optimization scheme IV is based on the optimization scheme III: step twelve, in the post-treatment, after the surface is ground and polished again,
the surface of the piston is treated by chromium plating, and the oxidation of the piston can be slowed down after the chromium plating, so that the service life of the piston is ensured.
Drawings
FIG. 1 is a schematic diagram of a piston structure for an aircraft engine;
fig. 2 is a flow chart of a machining process of a piston for an aircraft engine.
Detailed Description
The following is further detailed by the specific embodiments:
reference numerals: the piston big end 1, the body of rod 2, hole 32, bottom outlet 31, apex hole 4.
As shown in figure 1, the piston for the aeroengine structurally comprises a piston big end 1 and a rod body 2, an inner hole 32 with the diameter phi of 14.5mm and the depth of 155mm is manufactured inwards from the center of the piston big end 1, a bottom hole 31 coaxial with the inner hole is also manufactured, the diameter of the bottom hole 31 is phi 12mm, the depth of the bottom hole is 173mm, the whole surface finish is required to be Ra0.8um, and the wall thickness difference between the inner hole 32 and the outer circle cannot be larger than 0.1 mm.
As shown in fig. 2, in order to manufacture a piston for an aircraft engine, the embodiment provides the following specific method: the method comprises the following steps: cutting a rod piece steel material with the length of 232mm to be used as a rod body for processing the piston;
the piston is initially processed, the large-end of the piston is turned, and the large-end of the piston is manufactured in a turning mode through a lathe according to the size of the large-end of the piston;
step three, performing heat treatment on the piston which is initially processed;
step four, machining the rod body of the piston, and turning to manufacture the outer diameter of the rod body according to the size of the outer circle of the rod body
Fifthly, initially processing an inner hole, and drilling a hole inwards from a central shaft of the large end; firstly, drilling a bottom hole, namely drilling a phi 11 multiplied by 200 lengthened hole with the depth of the bottom hole being 50-10 mm; then the first hole expansion is carried out, the hole is expanded to the depth of 173mm by using an elongated drill with the diameter of 12 multiplied by 200, and then the second hole expansion is carried out: and then the second reaming is carried out by using a lengthened drill with the diameter of 14.2 multiplied by 200, the reaming depth is 154mm,
step six, primary reaming: using a special internal cooling cutter to carry out primary reaming to ensure that the aperture size is
The depth is 155mm, and the surface finish is Ra3.2um;
step seven, finely reaming the hole: replacing the second internal cooling reamer for fine reaming to ensure the aperture size to be
The surface finish is Ra1.6um;
step eight, turning a conical surface: processing an inner conical surface with the angle of 60 degrees multiplied by 0.80+0.2 at an inner orifice;
step nine, drilling a center hole: mandrel tensioning part utilizing lathe fixture
The surface of the inner hole, the mandrel and the inner hole are tightly matched through conicity; drilling a central hole with phi 4-phi 8.5 on the end surface of one side of the rod body;
step ten, turning the outer circle: the piston is fixed on a lathe through an inner hole and a tip hole, and the excircle of the big end of the piston is processed, wherein the diameter of the excircle is
Turning the shape of the rod body, and reserving 0.2 grinding allowance on the rod body;
step eleven, grinding the rod part: positioning and clamping
The outer circle of the rod body is tightly propped against the central hole through the clamp, and the outer molded surface of the rod body is ground, so that the surface finish requirement is Ra0.8um.
And step twelve, post-treatment, namely removing burrs on the surface of the piston, cleaning, nitriding, performing thread machining on the inner hole, and polishing the surface again to finish the manufacturing of the piston.
The steel used in the first step is high-grade nitrided steel of 38 crmol, and has the characteristics of high wear resistance, high fatigue strength and high strength. Has the characteristics of small impact load and high wear resistance.
The heat treatment mode in the second step is as follows: heating the piston to 880-890 ℃, preserving heat for 10-15 min, and then soaking the piston into a sodium chloride aqueous solution for cooling; and cooling to the normal temperature, heating the piston to 500-550 ℃, preserving the heat for 20-30 min, and then air-cooling to the normal temperature. The hardness of the piston is improved through heat treatment, and the impact toughness of the piston is further improved.
The internal cooling cutter comprises a cutter handle and a cutting rod detachably connected with the cutter handle, cooling liquid channel holes are formed in the cutter handle and the cutting rod, and shunt channel holes are formed in the cutting rod and are evenly distributed on the cutting rod and communicated with the cooling liquid channel holes. The special internal cooling cutter is used for reaming and punching, and when cutters with different sizes are used, the cutting rod can be directly detached and replaced, so that the cutter is more flexible to use.
And step twelve, in the post-treatment, after the surface is ground and polished again, the surface of the piston is treated to be plated with chromium, and the oxidation of the piston can be slowed down after the chromium plating, so that the service life of the piston is ensured.
The foregoing is merely an example of the present invention and common general knowledge of known specific structures and features of the embodiments is not described herein in any greater detail. It should be noted that, for those skilled in the art, without departing from the structure of the present invention, several changes and modifications can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicability of the patent. The scope of the claims of the present application shall be determined by the contents of the claims, and the description of the embodiments and the like in the specification shall be used to explain the contents of the claims.
Claims (5)
1. A processing technology of a piston for an aeroengine is characterized in that: comprises the following steps of (a) carrying out,
firstly, intercepting a rod piece steel with the length of 232mm as a rod body for processing a piston;
the piston is initially processed, the large-end of the piston is turned, and the large-end of the piston is manufactured in a turning mode through a lathe according to the size of the large-end of the piston;
step three, performing heat treatment on the piston which is initially processed;
step four, machining a rod body of the piston, and turning to manufacture the outer diameter of the rod body according to the size of the outer circle of the rod body;
fifthly, initially processing an inner hole, and drilling a hole inwards from a central shaft of the large end; firstly, drilling a bottom hole, namely drilling a lengthened hole with the diameter of 11 mm multiplied by 200mm, wherein the depth of the lengthened hole is 50-10 mm; then the first hole expansion is carried out, the hole is expanded to the depth of 173mm by using an elongated drill with the diameter of 12mm multiplied by 200mm, and then the second hole expansion is carried out: using a lengthened drill with the diameter of 14.2 multiplied by 200mm to perform secondary hole expansion, wherein the hole expansion depth is 154 mm;
step six, primary reaming: carrying out primary reaming by using an internal cooling cutter, and ensuring that the aperture size is phi 14.4+ 0.050 mm, the depth is 155mm, and the surface finish is Ra3.2um;
step seven, finely reaming the hole: replacing the second internal cooling cutter to carry out fine reaming, and ensuring that the aperture size is phi 14.48+ 0.050 mm and the surface finish is Ra1.6um;
step eight, turning a conical surface: machining at 60 degrees multiplied by 0.8 at inner orifice0 +0.2A mm inner conical surface;
step nine, drilling a center hole: the surface of an inner hole with the diameter of phi 14.5+0.05mm of a part is tightly supported by a mandrel of a lathe fixture, the mandrel is tightly matched with the inner hole through taper, and a central hole with the diameter of phi 4-phi 8.5mm is drilled on the end face of one side of a rod body;
step ten, turning the outer circle: fixing the piston on a lathe through an inner hole and a tip hole, and processing the excircle of the large-end of the piston, wherein the diameter of the excircle is phi 54.500.05 mm; turning the shape of the rod body, and reserving a grinding allowance of 0.2mm on the rod body;
step eleven, grinding the rod part: positioning and clamping an outer circle with phi 54.500.05 mm, tightly jacking a central hole through a clamp, and grinding the outer molded surface of the rod body to ensure that the surface finish requirement is Ra0.8um;
and step twelve, post-treatment, namely removing burrs on the surface of the piston, cleaning, nitriding, performing thread machining on the inner hole, and polishing the surface again to finish the manufacturing of the piston.
2. The process for machining a piston for an aircraft engine according to claim 1, wherein: the steel used in the first step is 38 crmol high-grade nitrided steel.
3. The process for machining a piston for an aircraft engine according to claim 2, wherein: the heat treatment mode in the third step is as follows: heating the piston to 880-890 ℃, preserving heat for 10-15 min, and then soaking the piston into a sodium chloride aqueous solution for cooling; and cooling to the normal temperature, heating the piston to 500-550 ℃, preserving the heat for 20-30 min, and then air-cooling to the normal temperature.
4. A process for manufacturing a piston for an aircraft engine according to claim 2 or 3, wherein: the internal cooling cutter comprises a cutter handle and a cutting rod detachably connected with the cutter handle, cooling liquid channel holes are formed in the cutter handle and the cutting rod, and shunt channel holes are evenly distributed in the cutting rod and communicated with the cooling liquid channel holes.
5. The process for machining a piston for an aircraft engine according to claim 4, wherein: and step twelve, in the post-treatment, after the surface is ground and polished again, the surface of the piston is treated to carry out chromium plating.
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| CN109488655B (en) * | 2018-12-10 | 2020-08-11 | 中国航发贵州黎阳航空动力有限公司 | Piston assembly and design method thereof |
| CN110369971B (en) * | 2019-08-19 | 2021-04-20 | 四川航天烽火伺服控制技术有限公司 | Grinding rod machining process with externally threaded taper shank for grinding machine |
| CN110961863A (en) * | 2019-11-18 | 2020-04-07 | 常州时进精密机械有限公司 | Taper hole mirror surface machining process |
| CN112318066A (en) * | 2020-09-22 | 2021-02-05 | 成都银河动力有限公司 | Sample sampling method for aluminum piston with inner cooling oil cavity |
| CN114571191A (en) * | 2022-03-21 | 2022-06-03 | 苏州冠钻精密工具有限公司 | Machining process of workpiece |
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| CN1152488A (en) * | 1995-12-22 | 1997-06-25 | 德州机床厂 | Machining method for deep taper hole |
| JP2004337997A (en) * | 2003-05-13 | 2004-12-02 | Mitsubishi Materials Corp | Stepped deep hole machining method and stepped drill |
| CN102079045A (en) * | 2009-12-01 | 2011-06-01 | 贵州航天控制技术有限公司 | Processing method of parts with long shaft and thin wall and processing clamp thereof |
| CN104209714A (en) * | 2014-08-20 | 2014-12-17 | 安庆市天润工程机械有限责任公司 | Processing technique for piston rod of steering cylinder |
| CN106425286A (en) * | 2015-11-24 | 2017-02-22 | 沈阳黎明航空发动机(集团)有限责任公司 | Machining method for deformation control of high-precision thin-wall cylinder shaft |
| CN206009871U (en) * | 2016-08-10 | 2017-03-15 | 台州华达工量具制造有限公司 | A kind of integral type cutter |
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Effective date of registration: 20230712 Address after: Right side of Yangfan Avenue, Donggongsi Town, Huichuan District, Zunyi City, Guizhou Province 563000 Patentee after: ZUNYI SOUTHWEST MACHINERY EQUIPMENT Co.,Ltd. Address before: Jiaotong village, Donggongsi Town, Huichuan District, Zunyi City, Guizhou Province Patentee before: ZUNYI ZUNYUN REFRIGERATION FITTINGS Co.,Ltd. |
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