CN116855701A - Method for processing large-modulus gear with early tooth surface resistance to micro-pitting - Google Patents
Method for processing large-modulus gear with early tooth surface resistance to micro-pitting Download PDFInfo
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- CN116855701A CN116855701A CN202310875593.5A CN202310875593A CN116855701A CN 116855701 A CN116855701 A CN 116855701A CN 202310875593 A CN202310875593 A CN 202310875593A CN 116855701 A CN116855701 A CN 116855701A
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- 238000000034 method Methods 0.000 title claims abstract description 44
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 147
- 239000010959 steel Substances 0.000 claims abstract description 147
- 238000005480 shot peening Methods 0.000 claims abstract description 81
- 238000005728 strengthening Methods 0.000 claims abstract description 53
- 238000005422 blasting Methods 0.000 claims abstract description 49
- 238000013178 mathematical model Methods 0.000 claims abstract description 33
- 238000010791 quenching Methods 0.000 claims abstract description 13
- 230000000171 quenching effect Effects 0.000 claims abstract description 13
- 238000005121 nitriding Methods 0.000 claims abstract description 10
- 238000005255 carburizing Methods 0.000 claims abstract description 8
- 239000003921 oil Substances 0.000 claims description 44
- 238000002347 injection Methods 0.000 claims description 23
- 239000007924 injection Substances 0.000 claims description 23
- 239000002245 particle Substances 0.000 claims description 19
- 239000012530 fluid Substances 0.000 claims description 17
- 238000005461 lubrication Methods 0.000 claims description 15
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 15
- 239000010687 lubricating oil Substances 0.000 claims description 14
- 239000004927 clay Substances 0.000 claims description 9
- 238000010438 heat treatment Methods 0.000 claims description 9
- 238000004140 cleaning Methods 0.000 claims description 6
- 238000005096 rolling process Methods 0.000 claims description 6
- 238000007789 sealing Methods 0.000 claims description 6
- 239000006061 abrasive grain Substances 0.000 claims description 5
- 101100129500 Caenorhabditis elegans max-2 gene Proteins 0.000 claims description 3
- 101100083446 Danio rerio plekhh1 gene Proteins 0.000 claims description 3
- 235000006679 Mentha X verticillata Nutrition 0.000 claims description 3
- 235000002899 Mentha suaveolens Nutrition 0.000 claims description 3
- 235000001636 Mentha x rotundifolia Nutrition 0.000 claims description 3
- 238000001035 drying Methods 0.000 claims description 3
- 238000005457 optimization Methods 0.000 claims description 3
- 238000005507 spraying Methods 0.000 claims description 3
- 239000013043 chemical agent Substances 0.000 claims description 2
- 238000005406 washing Methods 0.000 claims description 2
- 230000000694 effects Effects 0.000 abstract description 4
- 238000005452 bending Methods 0.000 abstract description 3
- 230000007797 corrosion Effects 0.000 abstract description 3
- 238000005260 corrosion Methods 0.000 abstract description 3
- 238000003672 processing method Methods 0.000 abstract 1
- 238000005256 carbonitriding Methods 0.000 description 9
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 239000007788 liquid Substances 0.000 description 4
- 239000013078 crystal Substances 0.000 description 3
- 239000010410 layer Substances 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 238000005482 strain hardening Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 239000002344 surface layer Substances 0.000 description 3
- 235000000621 Bidens tripartita Nutrition 0.000 description 2
- 240000004082 Bidens tripartita Species 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 206010006514 bruxism Diseases 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 208000006637 fused teeth Diseases 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 1
- 238000004026 adhesive bonding Methods 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D7/00—Modifying the physical properties of iron or steel by deformation
- C21D7/02—Modifying the physical properties of iron or steel by deformation by cold working
- C21D7/04—Modifying the physical properties of iron or steel by deformation by cold working of the surface
- C21D7/06—Modifying the physical properties of iron or steel by deformation by cold working of the surface by shot-peening or the like
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/04—Hardening by cooling below 0 degrees Celsius
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/32—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for gear wheels, worm wheels, or the like
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
- C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
- C23C8/24—Nitriding
- C23C8/26—Nitriding of ferrous surfaces
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Crystallography & Structural Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Gear Processing (AREA)
- Gears, Cams (AREA)
Abstract
The invention discloses an early tooth surface micro-pitting corrosion resistant processing method for a large-modulus gear, which comprises one or more of the following processes: firstly, carrying out a twice strengthening shot blasting process on a tooth surface; and after carburizing and quenching the gear, carrying out shot blasting and grinding on the large steel shot, carrying out shot blasting and strengthening on the small steel shot, and carrying out superfine grinding on the tooth surface. Secondly, carrying out a twice strengthening shot blasting process on the tooth surface; and after carburizing and quenching, carrying out shot peening strengthening on the large steel shot, grinding, carrying out cryogenic treatment after grinding, nitriding the tooth surface, carrying out micro grinding, carrying out shot peening strengthening on the small steel shot, and carrying out superfine grinding on the tooth surface. Thirdly, performing a primary strengthening shot blasting process on the tooth surface; and after carburizing and quenching the gear, carrying out shot peening strengthening on the large steel shot, then grinding, carrying out cryogenic treatment, nitriding the tooth surface, and then carrying out micro grinding. The steel shot peening strengthening effect is improved by establishing a mathematical model, the early micro-pitting resistance of the gear is improved, and the service life of the gear, the contact strength of the gear, the bending strength and the power density of the gear box are improved.
Description
Technical Field
The invention relates to the technical field of large-module gears, in particular to a method for processing a large-module gear to resist micro-pitting of an early tooth surface.
Background
For gear transmission with frequent start-stop and unstable operation, such as a wind power gear box, a large-scale marine gear box, an engineering marine gear box and the like, a tooth surface micro-pitting phenomenon often occurs in early operation, so that tooth surface damage is expanded, and the service life of the gear is influenced.
Hard tooth surface gears, namely carburized gears, are often subjected to shot peening, so that surface cold work hardening, crystal phase change, compact carburized surface layers and surface compressive stress are realized, and tooth roots and tooth surfaces are reinforced; the small-modulus gear is usually subjected to shot peening after grinding, the large-modulus gear is usually subjected to shot peening after grinding, but after grinding, the tooth surface can generate tensile stress, and early micro-pitting can occur in use.
The shot strength of shot peening is related to factors such as the hardness, the granularity, the striking force, the gear modulus, the depth of a hardened layer, the roughness of a tooth surface and the like of the shot, and certain balance is required. However, with large-module gears, it is difficult to achieve a certain advantageous balance with increasing module, which may lead to a decrease in the shot blasting effect.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a method for processing the large-modulus gear to resist early tooth surface micro-pitting, so as to improve the early micro-pitting resistance of the gear.
The technical scheme of the invention is as follows: the method for processing the large-modulus gear with early tooth surface micro-pitting resistance comprises one or more of the following processes:
firstly, carrying out a twice strengthening shot blasting process on a tooth surface; carrying out heat treatment carburization quenching on the gear, then carrying out shot blasting grinding on the gear with large steel shots, carrying out shot blasting strengthening on the gear with small steel shots after grinding, and then carrying out superfine grinding on the gear surface;
secondly, carrying out a twice strengthening shot blasting process on the tooth surface; carrying out heat treatment carburization quenching on a gear, then carrying out shot peening strengthening on the gear by using large steel shots, then grinding, then carrying out cryogenic treatment, nitriding the gear surface, then carrying out micro grinding, then carrying out shot peening strengthening on the gear by using small steel shots after grinding, and then carrying out superfine grinding on the gear surface; thirdly, performing a primary strengthening shot blasting process on the tooth surface; and carrying out heat treatment, carburizing and quenching on the gear, then carrying out shot peening strengthening on the large steel shot, then grinding, carrying out cryogenic treatment after grinding, nitriding the tooth surface, and then carrying out micro grinding.
The physical model for strengthening meshing fluid lubrication of the gear teeth by shot blasting of small steel shots is as follows: the gear teeth of the hardened gear 1 and the gear teeth of the hardened gear 2 are meshed, the meshing point is elastically deformed to generate a narrow band with the width of B, one or both of the hardened gear 1 and the hardened gear 2 are subjected to impact strong surface strengthening by small steel shots, the surfaces of the gears are full of spring pits, oil outlets of the meshing point and two end parts are provided with oil sealing protrusions except an oil inlet of the meshing point, and a high-pressure closed space is formed; the thickness of the oil film between gear teeth is h min The thickness of the oil film between the oil sealing protrusions is h mint When the gear runs, sliding is generated between gear teeth, a high-pressure oil film is generated, and the gear is a non-Newtonian fluid and can be regarded as a sliding long and narrow plane, and the depth of a micro pit on the upper surface and the lower surface becomes shallow to be K t The original depth is K, lubricating oil in the pit overflows the pit, so that a lubricating oil film is thickened, high pressure is generated by the lubricating oil in the pit, a rotating high-pressure oil mass is generated in the pit, the pit can be regarded as a rolling steel ball, a low-pressure area is arranged near an oil inlet end, a high-pressure area is arranged near an oil outlet, the gear meshing lubrication state is improved, the friction coefficient is reduced, and the surface strength of a tooth surface is increased.
For the small steel shot peening strengthening gear tooth axial engagement fluid lubrication physical model I (double-tooth peening), the hardened gear 1 is a tooth surface carburized small steel shot gear or a tooth surface carburized small steel shot gear, and the hardened gear 2 is a tooth surface carburized small steel shot gear or a tooth surface carburized small steel shot gear.
For the small steel shot peening strengthening gear tooth axial engagement fluid lubrication physical model II (single tooth peening), the hardened gear 1 is a tooth surface carburized small steel shot gear or a tooth surface carburized small steel shot gear, and the hardened gear 2 is a carburized nitrogen grinding gear.
Establishing a mathematical model I for strengthening the shot blasting of the large steel shot to obtain equivalent shot blasting strength and coverage rate of the shot blasting of the large steel shot, wherein the mathematical model is as follows:
p (Dm) is an Almen arc height function and is related to the size of the gear module;
d, the diameter of the large steel shot is related to the modulus m, and a is a coefficient;
y, the hardness of the large steel shot is related to the modulus m;
s big steel shot speed, the big steel shot speed is related to the modulus m;
h, the flow of the large steel shots is related to the model number and the shot strength Almen arc height and the modulus m of the gear shot peening strengthening machine;
the theta injection angle is related to the model and the modulus m of the gear shot peening machine;
the spraying distance is related to the model of the gear shot peening machine, the Almen arc height of shot peening intensity and the modulus m;
t jet time is related to the model of the gear shot peening machine, the Almen arc height of shot peening intensity and the modulus m;
λ D for large steel shot coverage, f 1 f 2 …f 7 Is a shot blasting strength influence function;
f 1 (D) Is the optimal influence value of the diameter of the large steel shot, f 2 (y) is the optimal influence value of the hardness of the large steel shot, f 3 (s) is the optimal influence value of the speed of the large steel shot, f 4 (H) Is the optimal influence value of the flow of the large steel shot, f 5 (theta) is the optimal influence value of the injection angle of the large steel shot, f 6 (l) F is the optimal influence value of the injection distance of the large steel shot 7 And (t) is the optimal influence value of the injection time of the large steel shot.
Establishing a mathematical model II for strengthening the shot blasting of the small steel shot to obtain numerical values such as the shot blasting strength, the coverage rate and the like of the shot blasting, wherein the mathematical model is as follows:
the diameter of the small steel shot is related to the modulus m, and z is a coefficient; y, the hardness of the small steel shot, wherein the hardness of the small steel shot is related to the modulus m;
s small shot speed, the small shot speed is related to the modulus m;
h small steel shot flow is related to the model of the gear shot peening machine, the Almen arc height of shot peening intensity of 0.20-0.37 (mm) A and the modulus m;
the theta injection angle is related to the model and the modulus m of the gear shot peening machine;
the injection distance is related to the model number of the gear shot peening machine and the Almen arc height of shot peening intensity of 0.20-0.37 (mm) A and the modulus m;
t jet time is related to the model number of the gear shot peening machine and the Almen arc height of shot peening intensity of 0.20-0.37 (mm) A and the modulus m;
λ x coverage rate, related to process mode; lambda (lambda) x ＝150％-200％；
Two basic parameters of shot peening quality: shot strength P x And coverage lambda x ；
f 1 (D) Is the optimal influence value of the diameter of the steel shot, f 2 (y) is the optimal influence value of the hardness of the steel shot, f 3 (s) is the optimal influence value of the speed of the steel shot, f 4 (H) Is the optimal influence value of the flow of the steel shot, f 5 (theta) is the optimal influence value of the injection angle of the steel shot, f 6 (l) F is the optimal influence value of the shot jet distance 7 (t) is the optimal influence value of the shot injection time;
steel shot diameter: d, a step of performing the process;
coverage rate: lambda (lambda) x ；
Pit diameter: d, a step of;
pit height before loading: k, performing K;
pit height after loading: k (K) t ；
Pit volume before loading: v (V) k ；
Post-load pit volume: v'. K ；
The amount of lubricating oil spilled after loading (total increase in oil film volume): q (Q) Δ ；
Total increase in total oil film volume of engagement surface after loading: q is a group;
number of engagement face pits after loading: n.
The tooth surface superfinishing adopts two grinding grits, the first is to grind the upper natural high-mesh whetstones into nearly circular grits; the second is that the fine clay with high purity is sintered into round particles as abrasive particles, the fine clay is filtered, beaten and stirred for a long time, calcined for 15 days at high temperature of 900 ℃ to 1100 ℃ at the highest temperature by small fire, medium fire and big fire, and finally cooled by water to prepare the cyan round particles.
Establishing a mathematical model of abrasive particle vibration, wherein in the first step, the tooth surface time after the shot blasting is cleaned by corrosive chemical agent is T 1 Then quickly washing with water; step two, the gear and the grinding gravel are added with continuous running water and put into a vibration device to vibrate V max1 Angular velocity omega 1 Vibrating for a period of time T 2 Then cleaning with water; third, the gear and the baked clay particles are put into a vibration device to vibrate V max2 Angular velocity omega 2 Vibrating for a period of time T 3 And cleaning with water, and drying to obtain the antirust oil.
The mathematical model of the abrasive grain vibration is as follows:
D m for the equivalent diameter of the abrasive particles, a 1 ，a 2 ，a 3 ，a 4 ，a 5 And the proportion weight coefficient is determined by experimental iterative optimization.
According to the invention, a large steel shot peening mathematical model I, a small steel shot peening mathematical model II and a vibration grinding mathematical model IV are established, a small steel shot carbonitriding peening mathematical model III is established, steel shot peening and vibration grinding effects are improved, a sliding parallel liquid film mixed lattice rolling liquid film group composite physical model and a pit density optimal mathematical model for meshing working movement of a gear with a pit are established, early micro-pitting resistance of the gear is improved, and the service life of the gear is prolonged. The contact strength and the bending strength of the gears can be improved by 50% or even higher, and the meshing efficiency of the gears is improved; the power density of the gear box is greatly improved, and the utilization rate of resources is improved.
Drawings
FIG. 1 is a block flow diagram of the step (basic type) of the tooth face carburized small steel shot strengthening process;
FIG. 2 is a block diagram of the step of strengthening the small steel shot of tooth face carbonitriding (adding nitrogen);
FIG. 3 is a block flow diagram of a tooth face carbonitriding process step (nitrogen addition type simplified);
FIG. 4 is a graph of the anti-micropitting gear collocation relationship;
FIG. 5 is a schematic illustration of a shot peening layer;
FIG. 6 is a schematic view of a carbonitriding gear shot blast;
FIG. 7 is a schematic illustration of tooth engagement fluid lubrication (physical model I) (straight tooth for example);
FIG. 8 is a schematic illustration of axial meshing fluid lubrication of gear teeth (physical model I) (straight teeth for example);
FIG. 9 is a schematic illustration of tooth meshing fluid lubrication (single gear shot) (physical model II) (straight tooth for example);
FIG. 10 is a schematic illustration of gear tooth axial engagement fluid lubrication (single gear shot) (physical model II) (straight tooth for example);
fig. 11 is a schematic view of vibratory grinding (ultra-fine grinding teeth) of abrasive grains;
fig. 12 is a schematic view of vibratory grinding (ultra-fine grinding teeth) of abrasive grains;
fig. 13 is a shot peening cloud point diagram.
Detailed Description
The invention is further described below with reference to the accompanying drawings.
As shown in fig. 1, 2 and 3, the method for solving the problem of early micro-pitting of the tooth surface of the large-modulus gear comprises the following steps: 1. carrying out a twice strengthening shot blasting process on the tooth surface; the gear is subjected to heat treatment carburization quenching, then is subjected to large steel shot blasting and grinding, then is subjected to optimized small steel shot blasting strengthening after grinding, and then is subjected to optimized tooth surface superfinishing grinding, namely so-called vibration grinding. 2. Carrying out a twice strengthening shot blasting process on the tooth surface; the gear is subjected to heat treatment carburization quenching, then is subjected to large steel shot peening and grinding, is subjected to cryogenic treatment after grinding, is subjected to nitriding of the tooth surface, is subjected to micro grinding, is subjected to optimized small steel shot peening after grinding, and is subjected to optimized superfine grinding, namely the so-called vibration grinding. 3. Carrying out a primary strengthening shot blasting process on the tooth surface; and carrying out heat treatment, carburizing and quenching on the gear, then carrying out shot peening strengthening on the large steel shot, then grinding, carrying out cryogenic treatment after grinding, nitriding the tooth surface, and then carrying out micro grinding. Thus, the tooth surface has higher strength and hardness, and early micro-pitting is not easy to generate.
As shown in fig. 4, the gears produced by these three methods may be paired together or may be paired in combination. And simultaneously establishing a large steel shot peening mathematical model I, a small steel shot peening mathematical model II and a tooth surface superfinishing mathematical model IV, and a small steel shot carbonitriding peening mathematical model III.
Carrying out shot peening strengthening on tooth surface tooth root large steel shot after carburizing the gear according to design requirements and standard technical regulations, and generating surface cold work hardening with a certain depth, crystal phase change, compact carburized surface layer and surface compressive stress; grinding the gear according to a standard technical specification; because grinding tensile stress is generated after grinding, tooth surface small steel shot peening is performed after grinding, so that surface cold work hardening with smaller layer depth, crystal phase change, compact carburized surface layer and surface compressive stress are generated; and performing superfine grinding on the tooth surface, and removing peaks generated by the tooth surface after shot blasting, namely performing chemical corrosion and grit vibration grinding. Because the surface of the gear has the optimal diameter and depth of the pits, a high-pressure oil storage point is generated when the gear operates, and the gear teeth are meshed with a fluid lubrication schematic diagram. As shown in fig. 5 and 6. The tooth surface is spread with a tiny pit due to strong shot blasting, the meshing surface deforms when the tooth surface is meshed to form a long and narrow plane with the width of B, the depth of the tiny pit becomes shallow, lubricating oil in the pit can overflow the pit, high pressure is generated by the lubricating oil in the pit, sliding is generated among the tooth surfaces during gear operation, a high pressure oil film is generated, the tooth surface is a non-Newtonian fluid and can be regarded as a sliding long and narrow plane, and a rotating high pressure oil mass can be generated in the pit and can be regarded as a rolling steel ball, so that the gluing resistance and the pitting resistance of the tooth surface are improved, and particularly, the friction coefficient between the tooth surfaces is reduced when the gear is at a low speed, and the gear transmission efficiency is improved.
Physical model i of small shot peening strengthening gear tooth meshing fluid lubrication (double tooth peening): as shown in fig. 7 and 8, the gear teeth of the hardened gear 1 and the hardened gear 2 are meshed, the hardened gear 1 is a tooth surface carburized small steel shot gear or a tooth surface carburized small steel shot gear, the hardened gear 2 is a tooth surface carburized small steel shot gear or a tooth surface carburized small steel shot gear, and the meshing point is elastically deformed to generate a narrow band with the width of B. The gear 1 and the gear 2 are subjected to impact strong surface strengthening of small steel shots after being subjected to tooth grinding, the surfaces of the gears are full of pits, oil outlets of meshing points and two ends generate oil sealing protrusions except for oil inlets of the meshing points, and a high-pressure closed space is formed; the thickness of the oil film between gear teeth is h min The thickness of the oil film between the oil sealing protrusions is h mint When the gear runs, sliding is generated between gear teeth, a high-pressure oil film is generated, and the gear is a non-Newtonian fluid and can be regarded as a sliding long and narrow plane, and the depth of a micro pit on the upper surface and the lower surface becomes shallow to be K t The original depth is K, and the lubricating oil in the pits overflows the pits, so that the lubricating oil film becomes thicker. The lubricating oil in the pit generates high pressure, and the pit generates rotating high-pressure oil clusters, which can be regarded as a rolling steel ball, and the oil near the oil inlet end is a low-pressure area, and the oil near the oil outlet is a high-pressure area. Thus, the meshing lubrication state becomes good, the friction coefficient becomes small, and the tooth surface strength becomes large.
Physical model II (single tooth shot) for axially meshing fluid lubrication of small steel shot peening strengthening gear teeth: as shown in fig. 9 and 10, the gear teeth of the hardened gear 1 and the hardened gear 2 are meshed, the hardened gear 1 is a tooth surface small steel shot reinforced gear, and the gear 2 is a carbonitriding grinding gear, namely, a single tooth shot reinforced gear is meshed.
The method is characterized in that after carburizing and quenching according to the drawing requirements, the carburized gear is subjected to strengthening shot blasting and then gear grinding, the precision of the carburized gear meets the drawing requirements (the same as the first process of a physical model I), then the gear is subjected to deep cooling at 190 ℃ below zero, then the gear surface nitriding is performed at 400 ℃ to 600 ℃, then the gear grinding is performed, and the precision of the gear is up to the drawing requirements.
The physical model II is similar to the physical model I, the difference is that the hardened gear 2 is a carbonitriding grinding gear, and is a non-tooth surface small steel shot reinforced gear, and the lubricity is slightly poorer than that of the physical model I.
Establishing a mathematical model I for carrying out shot peening strengthening on large-diameter steel shots before grinding of carburized gears:
1. providing better original surface quality, and the surface roughness Ra is less than or equal to 1.6 mu m;2. selecting reasonable steel shot hardness and diameter and shot blasting pressure; 3. shot blasting with large-diameter steel shots before tooth grinding, and then tooth grinding; 4. the steel shot blasting selects reasonable coverage rate, which is generally between 200% and 300%.
Expressed mathematically as:
p (Dm) is an Almen arc height function, and is related to the size of the gear module.
λ D Large steel shot coverage rate, f, which is a conventional process means 1 f 2 …f 7 Is a shot blasting strength influence function; d, the diameter of the large steel shot is related to the modulus m, and a is a coefficient;
y, the hardness of the large steel shot is related to the modulus m;
s big steel shot speed, the big steel shot speed is related to the modulus m;
h, the flow of the large steel shots is related to the model number and the shot strength Almen arc height and the modulus m of the gear shot peening strengthening machine;
the theta injection angle is related to the model and the modulus m of the gear shot peening machine;
the spraying distance is related to the model of the gear shot peening machine, the Almen arc height of shot peening intensity and the modulus m;
t jet time is related to the model of the gear shot peening machine, the Almen arc height of shot peening intensity and the modulus m;
lambda large shot coverage.
f 1 (D) Is the optimal influence value of the diameter of the steel shot, f 2 (y) is the optimal influence value of the hardness of the steel shot, f 3 (s) is the optimal influence value of the speed of the steel shot, f 4 (H) Is the optimal influence value of the flow of the steel shot, f 5 (theta) is the optimal influence value of the injection angle of the steel shot, f 6 (l) F is the optimal influence value of the shot jet distance 7 And (t) is the optimal influence value of the shot injection time.
Establishing a small-diameter steel shot peening strengthening mathematical model II after carburized gear grinding:
shot peening strengthening process parameters of small steel shots: obtaining optimal parameters related to the modulus of the gear, and expressing the optimal parameters in a mathematical manner;
the diameter of the small steel shot is related to the modulus m, and z is a coefficient; y, the hardness of the small steel shot, wherein the hardness of the steel shot is related to the modulus m;
s small shot speed, the shot speed is related to the modulus m;
h small steel shot flow is related to the model of the gear shot peening machine, the Almen arc height of shot peening intensity of 0.20-0.37 (mm) A and the modulus m;
the theta injection angle is related to the model and the modulus m of the gear shot peening machine;
the injection distance is related to the model number of the gear shot peening machine and the Almen arc height of shot peening intensity of 0.20-0.37 (mm) A and the modulus m;
t jet time is related to the model number of the gear shot peening machine and the Almen arc height of shot peening intensity of 0.20-0.37 (mm) A and the modulus m;
λ x coverage rate, related to process mode; lambda (lambda) x ＝150％-200％；
Two basic parameters of shot peening quality: shot strength P x And coverage lambda x 。
f 1 (D) Is the optimal influence value of the diameter of the steel shot, f 2 (y) is the optimal influence value of the hardness of the steel shot, f 3 (s) is the optimal influence value of the speed of the steel shot, f 4 (H) Is the optimal influence value of the flow of the steel shot, f 5 (theta) is the optimal influence value of the injection angle of the steel shot, f 6 (l) F is the optimal influence value of the shot jet distance 7 (t) is the optimal influence value of the shot injection time;
steel shot diameter: d, a step of performing the process;
coverage rate: lambda (lambda) x ；
Pit diameter: d, a step of;
pit height before loading: k, performing K;
pit height after loading: k (K) t ；
Pit volume before loading: v (V) k ；
Post-load pit volume: v'. K ；
The amount of lubricating oil spilled after loading (total increase in oil film volume): q (Q) Δ ；
Total increase in total oil film volume of engagement surface after loading: q is a group;
number of engagement face pits after loading: n.
Establishing a small-diameter steel shot peening strengthening mathematical model III of the carbonitriding gear (the cryogenic nitriding after the grinding of the carbonitriding gear): the model is similar to mathematical model ii.
Tooth surface superfinishing (so-called vibratory grinding):
vibration grinding mathematical model (mathematical model iv): after the gear shot peening, the tooth surface has obvious peak-valley characteristics, has influence on the bearing capacity of the gear, and is easy to cause micro pitting. The ultra-fine grinding of the tooth surface can be carried out, and the peak generated by the tooth surface after shot blasting is eliminated, namely, chemical corrosion and gravel vibration grinding are carried out. The specific method comprises the following steps: two kinds of materials were preparedGrinding grits, the first is to grind the grits into nearly round grits (sized according to the gear modulus) with an equal natural high-mesh knife stone, and the diameter D of the grits m Five of m/3, m/4, m/5, m/6 and m/7 are series; the equivalent diameter of the abrasive particles is D m . The second is that the high-purity fine clay is sintered into round particles as abrasive particles, the fine clay is filtered, beaten and stirred for a long time, the diameter is determined according to the size of the modulus of the gear, and the round particles are sintered for 15 days at the high temperature of 900 ℃ to 1100 ℃ at the highest by small fire, medium fire and large fire, and finally are cooled by water to prepare the cyan round particles. Diameter D of abrasive grain m Five of m/3, m/4, m/5, m/6 and m/7 are series.
As shown in FIGS. 11 and 12, in the first step, the tooth surface time after the shot blasting is washed with a corrosive chemical (such as dilute hydrochloric acid) is T 1 Then quickly rinsed with water (this step may be omitted); step two, the gear and the grinding gravel are added with continuous running water and put into a vibration device to vibrate V max1 Angular velocity omega 1 Vibrating for a period of time T 2 Then cleaning with water; third, the gear and the baked clay particles are put into a vibration device to vibrate V max2 Angular velocity omega 2 Vibrating for a period of time T 3 And cleaning with water, and drying to obtain the antirust oil. The vibration direction is left and right direction and up and down direction, see the attached drawings.
D m For the equivalent diameter of the abrasive particles, a 1 ，a 2 ，a 3 ，a 4 ，a 5 And the proportion weight coefficient is determined by experimental iterative optimization.
The invention establishes a large steel shot peening mathematical model I, a small steel shot peening mathematical model II and a vibration grinding mathematical model IV, improves steel shot peening and vibration grinding effects, establishes a sliding parallel liquid film mixed lattice rolling liquid film group composite physical model (physical models I and II) and a pit density optimal mathematical model (mathematical models I, II and III) for meshing working movement of a gear with a pit, improves early micro-pitting resistance of the gear and prolongs the service life of the gear. The contact strength and the bending strength of the gears can be improved by 50% or even higher, and the meshing efficiency of the gears is improved; the power density of the gear box is greatly improved, and the utilization rate of resources is improved.
Claims (9)
1. A method for processing a large-modulus gear with early tooth surface micro-pitting resistance is characterized by comprising the following steps: comprises one or more of the following processes:
firstly, carrying out a twice strengthening shot blasting process on a tooth surface; carrying out heat treatment carburization quenching on the gear, then carrying out shot blasting grinding on the gear with large steel shots, carrying out shot blasting strengthening on the gear with small steel shots after grinding, and then carrying out superfine grinding on the gear surface;
secondly, carrying out a twice strengthening shot blasting process on the tooth surface; carrying out heat treatment carburization quenching on a gear, then carrying out shot peening strengthening on the gear by using large steel shots, then grinding, then carrying out cryogenic treatment, nitriding the gear surface, then carrying out micro grinding, then carrying out shot peening strengthening on the gear by using small steel shots after grinding, and then carrying out superfine grinding on the gear surface;
thirdly, performing a primary strengthening shot blasting process on the tooth surface; and carrying out heat treatment, carburizing and quenching on the gear, then carrying out shot peening strengthening on the large steel shot, then grinding, carrying out cryogenic treatment after grinding, nitriding the tooth surface, and then carrying out micro grinding.
2. The method for processing the early tooth surface micro-pitting resistance of the large-modulus gear according to claim 1, which is characterized by comprising the following steps: the physical model for strengthening meshing fluid lubrication of the gear teeth by shot blasting of small steel shots is as follows: the gear teeth of the hardened gear 1 and the gear teeth of the hardened gear 2 are meshed, the meshing point is elastically deformed to generate a narrow band with the width of B, one or both of the hardened gear 1 and the hardened gear 2 are subjected to impact strong surface strengthening by small steel shots, the surfaces of the gears are full of spring pits, oil outlets of the meshing point and two end parts are provided with oil sealing protrusions except an oil inlet of the meshing point, and a high-pressure closed space is formed; the thickness of the oil film between gear teeth is h min The thickness of the oil film between the oil sealing protrusions is h mint When the gear runs, sliding is generated between gear teeth, a high-pressure oil film is generated, and the gear is a non-Newtonian fluid and can be regarded as a long and narrow sliding planeThe depth of the tiny pits on the lower two sides becomes shallow to K t The original depth is K, lubricating oil in the pit overflows the pit, so that a lubricating oil film is thickened, high pressure is generated by the lubricating oil in the pit, and a rotating high-pressure oil mass is generated in the pit and can be regarded as a rolling steel ball, a low-pressure area is arranged near an oil inlet end, and a high-pressure area is arranged near an oil outlet.
3. The method for processing the early tooth surface micro-pitting resistance of the large-modulus gear according to claim 2, which is characterized in that: the physical model I for strengthening meshing fluid lubrication of the gear teeth by shot blasting of small steel shots is as follows: the hardened gear 1 is a tooth surface carburized small steel shot gear or a tooth surface carburized small steel shot gear, and the hardened gear 2 is a tooth surface carburized small steel shot gear or a tooth surface carburized small steel shot gear.
4. The method for processing the early tooth surface micro-pitting resistance of the large-modulus gear according to claim 2, which is characterized in that: the physical model II of the axial meshing fluid lubrication of the small steel shot peening strengthening gear teeth is as follows: the hardened gear 1 is a tooth surface carburized small steel shot gear or a tooth surface carburized small steel shot gear, and the hardened gear 2 is a tooth surface carburized grinding gear.
5. The method for processing the early tooth surface micro-pitting resistance of the large-modulus gear according to claim 1, which is characterized by comprising the following steps: establishing a mathematical model for strengthening the shot blasting of the large steel shot to obtain numerical values such as shot blasting strength, coverage rate and the like of the shot blasting of the large steel shot, wherein the mathematical model is as follows:
p (Dm) is an Almen arc height function and is related to the size of the gear module;
d, the diameter of the large steel shot is related to the modulus m, and a is a coefficient;
y, the hardness of the large steel shot is related to the modulus m;
s big steel shot speed, the big steel shot speed is related to the modulus m;
h, the flow of the large steel shots is related to the model number and the shot strength Almen arc height and the modulus m of the gear shot peening strengthening machine;
the theta injection angle is related to the model and the modulus m of the gear shot peening machine;
the spraying distance is related to the model of the gear shot peening machine, the Almen arc height of shot peening intensity and the modulus m;
t jet time is related to the model of the gear shot peening machine, the Almen arc height of shot peening intensity and the modulus m;
λ D for large steel shot coverage, f 1 f 2 …f 7 Is a shot blasting strength influence function;
f 1 (D) Is the optimal influence value of the diameter of the large steel shot, f 2 (y) is the optimal influence value of the hardness of the large steel shot, f 3 (s) is the optimal influence value of the speed of the large steel shot, f 4 (H) Is the optimal influence value of the flow of the large steel shot, f 5 (theta) is the optimal influence value of the injection angle of the large steel shot, f 6 (l) F is the optimal influence value of the injection distance of the large steel shot 7 And (t) is the optimal influence value of the injection time of the large steel shot.
6. The method for processing the early tooth surface micro-pitting resistance of the large-modulus gear according to claim 1, which is characterized by comprising the following steps: establishing a mathematical model for strengthening the shot blasting of the small steel shot to obtain numerical values such as the shot blasting strength, the coverage rate and the like of the shot blasting, wherein the mathematical model is as follows:
the diameter of the small steel shot is related to the modulus m, and z is a coefficient;
y, the hardness of the small steel shot, wherein the hardness of the small steel shot is related to the modulus m;
s small shot speed, the small shot speed is related to the modulus m;
h small steel shot flow is related to the model of the gear shot peening machine, the Almen arc height of shot peening intensity of 0.20-0.37 (mm) A and the modulus m;
the theta injection angle is related to the model and the modulus m of the gear shot peening machine;
the injection distance is related to the model number of the gear shot peening machine and the Almen arc height of shot peening intensity of 0.20-0.37 (mm) A and the modulus m;
t jet time is related to the model number of the gear shot peening machine and the Almen arc height of shot peening intensity of 0.20-0.37 (mm) A and the modulus m;
λ x coverage rate, related to process mode; lambda (lambda) x ＝150％-200％；
Two basic parameters of shot peening quality: shot strength P x And coverage lambda x ；
f 1 (D) Is the optimal influence value of the diameter of the steel shot, f 2 (y) is the optimal influence value of the hardness of the steel shot, f 3 (s) is the optimal influence value of the hardness of the steel shot, f 4 (H) Is the optimal influence value of the flow of the steel shot, f 5 (theta) is the optimal influence value of the injection angle of the steel shot, f 6 (l) F is the optimal influence value of the shot jet distance 7 (t) is the optimal influence value of the shot injection time;
steel shot diameter: d, a step of performing the process;
coverage rate: lambda (lambda) x ；
Pit diameter: d, a step of;
pit height before loading: k, performing K;
pit height after loading: k (K) t ；
Pit volume before loading: v (V) k ；
Post-load pit volume: v (V) ,K ；
The amount of lubricating oil spilled after loading (total increase in oil film volume): q (Q) Δ ；
Total increase in total oil film volume of engagement surface after loading: q is a group;
number of engagement face pits after loading: n.
7. The method for processing the early tooth surface micro-pitting resistance of the large-modulus gear according to claim 1, which is characterized by comprising the following steps: the tooth surface superfinishing adopts two grinding grits, the first is to grind the upper natural high-mesh whetstones into nearly circular grits; the second is that the fine clay with high purity is sintered into round particles as abrasive particles, the fine clay is filtered, beaten and stirred for a long time, calcined for 15 days at high temperature of 900 ℃ to 1100 ℃ at the highest temperature by small fire, medium fire and big fire, and finally cooled by water to prepare the cyan round particles.
8. The method for processing the early tooth surface micro-pitting resistance of the large-modulus gear according to claim 1, which is characterized by comprising the following steps: establishing a mathematical model of abrasive particle vibration, wherein in the first step, the tooth surface time after the shot blasting is cleaned by corrosive chemical agent is T 1 Then quickly washing with water; step two, the gear and the grinding gravel are added with continuous running water and put into a vibration device to vibrate V max1 Angular velocity omega 1 Vibrating for a period of time T 2 Then cleaning with water; third, the gear and the baked clay particles are put into a vibration device to vibrate V max2 Angular velocity omega 2 Vibrating for a period of time T 3 And cleaning with water, and drying to obtain the antirust oil.
9. The method for processing the early tooth surface micro-pitting resistance of the large-modulus gear according to claim 8, which is characterized in that: the mathematical model of the abrasive grain vibration is as follows:
D m for the equivalent diameter of the abrasive particles, a 1 ，a 2 ，a 3 ，a 4 ，a 5 And the proportion weight coefficient is determined by experimental iterative optimization.
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| CN202310875593.5A CN116855701A (en) | 2023-07-17 | 2023-07-17 | Method for processing large-modulus gear with early tooth surface resistance to micro-pitting |
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