CN117340686A - Preparation method of friction-resistant nodular cast iron crankshaft and crankshaft - Google Patents
Preparation method of friction-resistant nodular cast iron crankshaft and crankshaft Download PDFInfo
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- CN117340686A CN117340686A CN202311108911.1A CN202311108911A CN117340686A CN 117340686 A CN117340686 A CN 117340686A CN 202311108911 A CN202311108911 A CN 202311108911A CN 117340686 A CN117340686 A CN 117340686A
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- cast iron
- nodular cast
- crankshaft
- iron crankshaft
- friction
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- 229910001141 Ductile iron Inorganic materials 0.000 title claims abstract description 140
- 238000002360 preparation method Methods 0.000 title claims abstract description 13
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 28
- 229910002804 graphite Inorganic materials 0.000 claims abstract description 28
- 239000010439 graphite Substances 0.000 claims abstract description 28
- 238000000227 grinding Methods 0.000 claims abstract description 27
- 239000002245 particle Substances 0.000 claims abstract description 24
- 230000003647 oxidation Effects 0.000 claims abstract description 17
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 17
- 229910001018 Cast iron Inorganic materials 0.000 claims abstract description 15
- 238000000034 method Methods 0.000 claims description 45
- 238000005498 polishing Methods 0.000 claims description 19
- 238000001816 cooling Methods 0.000 claims description 13
- 238000010438 heat treatment Methods 0.000 claims description 12
- 244000137852 Petrea volubilis Species 0.000 claims description 10
- 238000004519 manufacturing process Methods 0.000 claims description 10
- 238000004140 cleaning Methods 0.000 claims description 8
- 239000006004 Quartz sand Substances 0.000 claims description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 6
- 239000010431 corundum Substances 0.000 claims description 6
- 229910052593 corundum Inorganic materials 0.000 claims description 6
- 239000010432 diamond Substances 0.000 claims description 6
- 229910003460 diamond Inorganic materials 0.000 claims description 6
- 238000001125 extrusion Methods 0.000 claims description 5
- 239000000314 lubricant Substances 0.000 claims description 4
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 2
- 229910010271 silicon carbide Inorganic materials 0.000 claims description 2
- 238000004321 preservation Methods 0.000 claims 1
- 230000033001 locomotion Effects 0.000 abstract description 8
- 230000008859 change Effects 0.000 abstract description 7
- 230000008569 process Effects 0.000 description 27
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 12
- 238000005299 abrasion Methods 0.000 description 12
- 239000000843 powder Substances 0.000 description 12
- 238000012545 processing Methods 0.000 description 5
- 230000001376 precipitating effect Effects 0.000 description 4
- 230000009471 action Effects 0.000 description 3
- 239000000853 adhesive Substances 0.000 description 3
- 230000001070 adhesive effect Effects 0.000 description 3
- 238000005520 cutting process Methods 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- 238000004506 ultrasonic cleaning Methods 0.000 description 3
- 239000010687 lubricating oil Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000010301 surface-oxidation reaction Methods 0.000 description 2
- 230000006978 adaptation Effects 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000000498 ball milling Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 230000001050 lubricating effect Effects 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000008439 repair process Effects 0.000 description 1
- 238000003892 spreading Methods 0.000 description 1
- 230000007480 spreading Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B1/00—Processes of grinding or polishing; Use of auxiliary equipment in connection with such processes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B5/00—Machines or devices designed for grinding surfaces of revolution on work, including those which also grind adjacent plane surfaces; Accessories therefor
- B24B5/36—Single-purpose machines or devices
- B24B5/42—Single-purpose machines or devices for grinding crankshafts or crankpins
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C3/00—Shafts; Axles; Cranks; Eccentrics
- F16C3/04—Crankshafts, eccentric-shafts; Cranks, eccentrics
- F16C3/06—Crankshafts
- F16C3/14—Features relating to lubrication
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Ocean & Marine Engineering (AREA)
- Shafts, Cranks, Connecting Bars, And Related Bearings (AREA)
Abstract
The invention provides a preparation method of an antifriction nodular cast iron crankshaft and the crankshaft, comprising the following steps: s1, removing an oxidation medium on the surface of a nodular cast iron crankshaft to obtain a first nodular cast iron crankshaft; s2, separating graphite particles out of the nodular cast iron crankshaft to obtain a second nodular cast iron crankshaft; s3, extruding and grinding the second nodular cast iron crankshaft to enable precipitated graphite particles to be separated from cast iron to correspondingly form a plurality of pits, and obtaining the friction-resistant nodular cast iron crankshaft with changed surface texture. According to the invention, the pits distributed on the surface of the crankshaft change the surface texture, so that on one hand, the fluctuation of friction coefficient can be reduced, the occurrence of stick-slip motion is avoided, and on the other hand, the wear rate can be reduced, and the end face is protected from being scratched. In addition, for the crankshaft structure, the arrangement of the pits can also reduce the contact area between the crank pin and the large end of the connecting rod, thereby further reducing friction damage between the crank pin and the large end of the connecting rod and greatly prolonging the service life of the crank pin.
Description
Technical Field
The invention relates to the technical field of crankshafts, in particular to a preparation method of an antifriction nodular cast iron crankshaft and the crankshaft.
Background
In industrial production, wear between the crank pin and the connecting rod big end is one of the common problems in engine repair and maintenance. The big end of the connecting rod is sleeved on the crank pin, and the big end of the connecting rod is rotationally connected with elements such as a piston and the connecting rod through a main shaft, so that corresponding motion impact and force transmission are borne, the contact part of the big end of the connecting rod and the crank pin is extremely easy to wear due to high pressure and high temperature and Gao Maca force in a motion state, the phenomenon of dent, deformation, even formation of wear particles and the like can occur on the surface of the crank pin along with the increase of working time, and the problems of loose adaptation and incapability of normal working between the crank pin and the big end of the connecting rod further occur, so that the reduction of friction force between the crank pin and the big end of the connecting rod is always a core problem focused in the field.
In the present stage, for the manner of reducing the friction force between the crank pin and the large end of the connecting rod, including surface lubrication, control working condition and the like, but the lubricant is difficult to keep on the surface of the crank pin for a long time, needs to be added regularly, and adds a small burden to the actual use process, in the actual working condition, because the main shaft is usually required to be arranged into an elliptic structure capable of limiting the rotation angle, the friction force generated by the large end of the connecting rod around the crank pin is not uniform, the common working angle of the large end of the connecting rod is found to be rotation with the expansion central angle of 30 degrees around the surface of the crank pin along the arc length of the large end of the connecting rod, namely, the large end of the connecting rod swings back and forth within 15 degrees relative to the vertical direction, so that the abrasion of the upper surface of the crank pin is the opposite, the abrasion degree of the upper surface of the crank pin is reduced in the direction of diffusing to two sides, and therefore the omnibearing protection of the crank pin and the excellent abrasion-resistant effect cannot be achieved only by controlling the working condition.
Disclosure of Invention
Therefore, the invention aims to solve the technical problems of serious abrasion between a crank pin and the large end of a connecting rod and influence on the service life in the prior art, and provides a preparation method of an antifriction nodular cast iron crankshaft and the crankshaft.
In order to solve the technical problems, the invention provides a preparation method of an antifriction nodular cast iron crankshaft, which comprises the following steps:
s1, removing an oxidation medium on the surface of the nodular cast iron crankshaft to obtain a first nodular cast iron crankshaft;
s2, separating graphite particles out of the nodular cast iron crankshaft to obtain a second nodular cast iron crankshaft;
s3, extruding and grinding the second nodular cast iron crankshaft to enable the precipitated graphite particles to be separated from cast iron to correspondingly form a plurality of pits, so as to obtain the friction-resistant nodular cast iron crankshaft with the surface texture changed.
In one embodiment of the invention, the pits are filled with a lubricant.
In one embodiment of the present invention, in step S3, the second ductile iron crank pin surface includes a first friction region and a second friction region, wherein the pit density in the first friction region is 20% -25%, and the pit density in the second friction region is 10% -15%.
In one embodiment of the present invention, in step S3, the extrusion grinding is performed by using abrasive particles, where the abrasive particles are one or more of white corundum, quartz sand, silicon carbide, and diamond, and the abrasive particles have a diameter of 12.5 μm to 18.0 μm.
In one embodiment of the invention, after the step S3 is finished, the friction-resistant nodular cast iron crankshaft is subjected to post-treatment, so that the friction-resistant nodular cast iron crankshaft with a clean surface is obtained.
In one embodiment of the present invention, step S2 specifically includes:
s21, heating and preserving heat of the first nodular cast iron crankshaft to obtain a first nodular cast iron crankshaft which is expanded by heating; and S22, cooling the heated and expanded first nodular cast iron crankshaft to obtain a second nodular cast iron crankshaft in which graphite is precipitated due to different thermal expansion coefficients.
In one embodiment of the present invention, in step S21, the heating temperature is not lower than 360 ℃, the holding time is not less than 1 hour, and in step S22, the cooling rate is not lower than 3.3 ℃/S.
In one embodiment of the present invention, step S1 specifically includes: s11, polishing the surface of the nodular cast iron crankshaft for the first time by adopting sand paper with the particle size not less than 200 meshes to obtain a nodular cast iron crankshaft after rough grinding; s12, carrying out secondary grinding on the surface of the roughly ground nodular cast iron crankshaft by adopting sand paper with more than 800 meshes to obtain a finely ground nodular cast iron crankshaft; and S13, polishing and cleaning the refined nodular cast iron crankshaft to obtain a first nodular cast iron crankshaft from which the oxidation medium on the surface of the nodular cast iron crankshaft is removed.
In order to solve the technical problems, the invention provides a crankshaft, which is prepared by adopting the preparation method of the friction-resistant nodular cast iron crankshaft, comprising the following steps: a crank pin, the crank pin surface forming a plurality of dimples; the two balance weights are axially arranged on two sides of the crank pin along the crank pin, and are movably connected with the crank pin; and the two main shafts are respectively connected with the two balance weights.
In one embodiment of the invention, the crank pin surface is provided with a first friction area and two second friction areas which are respectively arranged at two sides of the first friction area, wherein the density of the pits in the first friction area is 20% -25%, and the density of the pits in the second friction area is 10% -15%.
Compared with the prior art, the technical scheme of the invention has the following advantages:
according to the preparation method of the friction-resistant nodular cast iron crankshaft and the crankshaft, the pits distributed on the surface of the crank pin change the surface texture, so that on one hand, fluctuation of friction coefficient can be reduced, further stability of a friction process is guaranteed, stick-slip movement is effectively avoided, on the other hand, abrasion rate and friction temperature rise can be reduced, severe adhesive abrasion in the friction process is improved, and the end face is protected from being scratched. In addition, for the crankshaft structure, the arrangement of the pits can also reduce the contact area between the crank pin and the large end of the connecting rod, thereby further reducing friction damage between the crank pin and the large end of the connecting rod and greatly prolonging the service life of the crank pin.
Drawings
In order that the invention may be more readily understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof that are illustrated in the appended drawings.
FIG. 1 is a schematic perspective view of a crankshaft in accordance with a preferred embodiment of the present invention;
fig. 2 is a schematic perspective view of the crankshaft of fig. 1 from another perspective.
Description of the specification reference numerals: 100. a crank pin; 110. a first friction region; 120. a second friction region; 200. a balance weight; 300. a main shaft.
Detailed Description
The present invention will be further described with reference to the accompanying drawings and specific examples, which are not intended to be limiting, so that those skilled in the art will better understand the invention and practice it.
Example 1
The embodiment provides a preparation method of an antifriction nodular cast iron crankshaft, which comprises the following steps:
s1, removing oxidation medium on the surface of a nodular cast iron crankshaft to obtain a first nodular cast iron crankshaft, wherein in the actual production and processing process, substances such as water, oxygen and the like in air are adsorbed on the surface of the nodular cast iron crankshaft, so that a layer of compact oxidation medium is formed on the surface of the nodular cast iron crankshaft, the oxidation medium layer is required to be removed preferentially before the formal texture change of the nodular cast iron crankshaft is carried out, and further, the oxidation medium removal process in the embodiment is specifically as follows:
s11, polishing the surface of the nodular cast iron crankshaft for the first time by adopting 200-mesh sand paper to obtain a nodular cast iron crankshaft after rough grinding, wherein the process can primarily remove uneven textures and obvious scratches on the surface of the crankshaft after cutting;
s12, carrying out secondary grinding on the surface of the roughly ground nodular cast iron crankshaft by adopting 800-mesh sand paper to obtain a finely ground nodular cast iron crankshaft, wherein scratches, burrs, scraps and the like on the surface of the crankshaft can be further removed in the process;
and S13, polishing and cleaning the spheroidal graphite cast iron crankshaft subjected to fine grinding to obtain a first spheroidal graphite cast iron crankshaft with the oxidation medium on the surface of the spheroidal graphite cast iron crankshaft removed, specifically, polishing the spheroidal graphite cast iron crankshaft by adopting a polishing machine in the embodiment to completely remove the oxidation medium on the surface of the crankshaft, and cleaning the spheroidal graphite cast iron crankshaft with an acetone solution for 15 minutes after polishing, so as to obtain the first spheroidal graphite cast iron crankshaft with a clean surface, wherein after the process is finished, the roughness of the surface of the crankshaft can reach Ra=0.1, and the subsequent requirements on the surface processing of the crankshaft can be met.
S2, precipitating graphite particles from the nodular cast iron crankshaft to obtain a second nodular cast iron crankshaft. Based on the special physicochemical properties of the nodular cast iron crankshaft, the graphite component and the cast iron component can be influenced by temperature change to correspondingly change the microstructure structure, and particularly, when the temperature is changed, on one hand, the thermal expansion coefficient of graphite in the ball-milling cast iron is different from that of cast iron, so that the binding force between graphite and cast iron is weakened when the temperature is changed, and the graphite is more easily separated from the cast iron, and on the other hand, the nucleation capability of the cast iron is reduced due to the change of the temperature, so that an environment which is easier for precipitating the graphite is provided. The method comprises the following specific steps:
and S21, heating and preserving heat of the first nodular cast iron crankshaft to obtain the first nodular cast iron crankshaft which is heated and expanded, wherein the heating temperature in the embodiment is 360 ℃, and the preserving heat time is 1 hour.
S22, cooling the heated and expanded first nodular cast iron crankshaft to obtain a second nodular cast iron crankshaft with graphite precipitated due to different thermal expansion coefficients, wherein in the embodiment, the cooling speed is 3.3 ℃/S, so that the surface temperature of the first nodular cast iron crankshaft can be reduced from 360 ℃ to room temperature in about ten seconds, and graphite can be sufficiently precipitated by rapid cooling so as to facilitate the follow-up grinding separation.
S3, extruding and grinding the second nodular cast iron crankshaft to enable precipitated graphite particles to be separated from cast iron to correspondingly form a plurality of pits, and obtaining the friction-resistant nodular cast iron crankshaft with changed surface texture. In the embodiment, the friction between the crank pin and the large end of the connecting rod is reduced through three aspects, the first small pits and the second small pits can change the surface texture of the crank pin, fluctuation of friction coefficient, abrasion rate and friction temperature rise are reduced, and further occurrence of severe adhesive abrasion in the friction process is improved. Second, the multiple dimple design can reduce the contact area between the crank pin and the connecting rod large end, thereby further reducing frictional damage between the two. Thirdly, the pits in the embodiment are filled with the lubricant, and the texture can form tiny grooves in a lubricating oil film to prevent the lubricating film from being damaged and stripped, so that the oil film bearing capacity of the crank pin surface and the holding capacity of the lubricating oil are effectively improved, and further, moving parts of the crankshaft are lubricated better. Further, since the main shaft is generally required to be provided in an elliptic cylindrical structure capable of restricting the rotation angle, the friction force generated by the large end of the connecting rod around the crank pin is not uniform, and during the use of the conventional crankshaft, the abrasion of the upper surface of the crank pin is most serious, and the abrasion degree decreases in the direction of spreading to both sides along the upper surface thereof, so in this embodiment, the upper surface of the crank pin is a first friction region which receives a larger friction force, and thus the required pit density is larger, and two second friction regions which receive a smaller friction force are symmetrically provided on both sides of the first friction region, and thus the required pit density is smaller, specifically, in this embodiment, the pit density in the first friction region of the crank pin is 25%, and the pit density in the second friction region of the crank pin is 15%, and the friction force received by the crank pin in the first friction region is larger than the friction force received by the crank pin in the second friction region. In the embodiment, white corundum is adopted for extrusion grinding, the diameter of white corundum particles is 12.5 mu m, specifically, the embodiment places white corundum powder in a powder pool, then the crank pin and the large end of the connecting rod perform forward and reverse rotation reciprocating motion in the powder pool, and in the process, graphite balls are extruded and rubbed by the white corundum powder under the action of multidimensional pressure so as to separate from cast iron, so that a distributed texture is formed on the surface of the crank pin. After the processing process is finished, in the embodiment, the friction-resistant nodular cast iron crankshaft is further subjected to post-treatment, so that the friction-resistant nodular cast iron crankshaft with a clean surface is obtained, and the post-treatment process specifically comprises the following steps: ultrasonic cleaning was performed in an acetone solution for 15 minutes.
In summary, according to the preparation method of the friction-resistant nodular cast iron crankshaft in the embodiment, the surface texture of the friction-resistant nodular cast iron crankshaft is changed through pits distributed on the surface of the crank pin, so that on one hand, fluctuation of friction coefficient can be reduced, and further stability of a friction process is guaranteed, stick-slip movement is effectively avoided, on the other hand, abrasion rate and friction temperature rise can be reduced, occurrence of severe adhesive abrasion in the friction process is improved, and the end face is protected from being scratched. In addition, for the crankshaft structure, the arrangement of the pits can also reduce the contact area between the crank pin and the large end of the connecting rod, thereby further reducing friction damage between the crank pin and the large end of the connecting rod and greatly prolonging the service life of the crank pin.
Example two
The preparation method of the friction-resistant nodular cast iron crankshaft in the embodiment comprises the following steps:
s1, removing oxidation medium on the surface of a nodular cast iron crankshaft to obtain a first nodular cast iron crankshaft, wherein the process of removing the oxidation medium in the embodiment is specifically as follows:
s11, polishing the surface of the nodular cast iron crankshaft for the first time by adopting 400-mesh sand paper to obtain a nodular cast iron crankshaft after rough grinding, wherein the process can primarily remove uneven textures and obvious scratches on the surface of the crankshaft after cutting;
s12, carrying out secondary grinding on the surface of the roughly ground nodular cast iron crankshaft by adopting 1200-mesh sand paper to obtain a finely ground nodular cast iron crankshaft, wherein scratches, burrs, scraps and the like on the surface of the crankshaft can be further removed in the process;
and S13, polishing and cleaning the spheroidal graphite cast iron crankshaft subjected to fine grinding to obtain a first spheroidal graphite cast iron crankshaft with the surface oxidation medium removed, specifically, polishing the spheroidal graphite cast iron crankshaft by adopting a polishing machine in the embodiment to completely remove the oxidation medium on the surface of the crankshaft, and cleaning the spheroidal graphite cast iron crankshaft for 20 minutes by adopting an acetone solution after polishing, thereby obtaining the first spheroidal graphite cast iron crankshaft with the clean surface.
S2, precipitating graphite particles from the nodular cast iron crankshaft to obtain a second nodular cast iron crankshaft. The method comprises the following specific steps:
and S21, heating and preserving heat of the first nodular cast iron crankshaft to obtain the first nodular cast iron crankshaft which is heated and expanded, wherein the heating temperature in the embodiment is 400 ℃, and the preserving heat time is 1.2 hours.
S22, cooling the heated and expanded first nodular cast iron crankshaft to obtain a second nodular cast iron crankshaft with graphite precipitated due to different thermal expansion coefficients, wherein in the embodiment, the cooling speed is 4.0 ℃/S, so that the surface temperature of the first nodular cast iron crankshaft can be reduced from 400 ℃ to room temperature in about ten seconds, and graphite can be sufficiently precipitated by rapid cooling so as to facilitate the follow-up grinding separation.
S3, extruding and grinding the second nodular cast iron crankshaft to enable precipitated graphite particles to be separated from cast iron to correspondingly form a plurality of pits, and obtaining the friction-resistant nodular cast iron crankshaft with changed surface texture. In this embodiment, the upper surface of the crank pin is a first friction area, which bears a larger friction force, so that the required pit density is larger, two second friction areas are symmetrically arranged on two sides of the first friction area, which bear a smaller friction force, so that the required pit density is smaller, specifically, in this embodiment, the pit density in the first friction area of the crank pin is 20%, the pit density in the second friction area of the crank pin is 10%, and the friction force borne by the crank pin in the first friction area is larger than that borne by the crank pin in the second friction area. In this embodiment, quartz sand is used for extrusion grinding, the diameter of the quartz sand particles is 18.0 μm, specifically, the embodiment places quartz sand powder in a powder pool, and then makes the crank pin and the large end of the connecting rod perform forward and reverse rotation reciprocating motion in the powder pool, and in the process, graphite balls are extruded and rubbed by the quartz sand powder under the action of multidimensional pressure to separate from cast iron, so that a distributed texture is formed on the surface of the crank pin. After the processing process is finished, in the embodiment, the friction-resistant nodular cast iron crankshaft is further subjected to post-treatment, so that the friction-resistant nodular cast iron crankshaft with a clean surface is obtained, and the post-treatment process specifically comprises the following steps: ultrasonic cleaning was performed in an acetone solution for 20 minutes.
Example III
The preparation method of the friction-resistant nodular cast iron crankshaft in the embodiment comprises the following steps:
s1, removing oxidation medium on the surface of a nodular cast iron crankshaft to obtain a first nodular cast iron crankshaft, wherein the process of removing the oxidation medium in the embodiment is specifically as follows:
s11, polishing the surface of the nodular cast iron crankshaft for the first time by adopting 600-mesh sand paper to obtain a nodular cast iron crankshaft after rough grinding, wherein the process can primarily remove uneven textures and obvious scratches on the surface of the crankshaft after cutting;
s12, carrying out secondary grinding on the surface of the roughly ground nodular cast iron crankshaft by adopting 1000-mesh sand paper to obtain a finely ground nodular cast iron crankshaft, wherein scratches, burrs, scraps and the like on the surface of the crankshaft can be further removed in the process;
and S13, polishing and cleaning the spheroidal graphite cast iron crankshaft subjected to fine grinding to obtain a first spheroidal graphite cast iron crankshaft with the surface oxidation medium removed, specifically, polishing the spheroidal graphite cast iron crankshaft by adopting a polishing machine in the embodiment to completely remove the oxidation medium on the surface of the crankshaft, and cleaning the spheroidal graphite cast iron crankshaft for 18 minutes by adopting an acetone solution after polishing, thereby obtaining the first spheroidal graphite cast iron crankshaft with the clean surface.
S2, precipitating graphite particles from the nodular cast iron crankshaft to obtain a second nodular cast iron crankshaft. The method comprises the following specific steps:
and S21, heating and preserving heat of the first nodular cast iron crankshaft to obtain the first nodular cast iron crankshaft which is heated and expanded, wherein the heating temperature in the embodiment is 380 ℃, and the preserving heat time is 1.5 hours.
S22, cooling the heated and expanded first nodular cast iron crankshaft to obtain a second nodular cast iron crankshaft with graphite precipitated due to different thermal expansion coefficients, wherein in the embodiment, the cooling speed is 3.8 ℃/S, so that the surface temperature of the first nodular cast iron crankshaft can be reduced from 380 ℃ to room temperature in about ten seconds, and graphite can be sufficiently precipitated by rapid cooling so as to facilitate the follow-up grinding separation.
S3, extruding and grinding the second nodular cast iron crankshaft to enable precipitated graphite particles to be separated from cast iron to correspondingly form a plurality of pits, and obtaining the friction-resistant nodular cast iron crankshaft with changed surface texture. In this embodiment, the upper surface of the crank pin is a first friction area, the required pit density is larger, two second friction areas are symmetrically arranged on two sides of the first friction area, the required pit density is smaller, specifically, in this embodiment, the pit density in the first friction area of the crank pin is 22.5%, the pit density in the second friction area of the crank pin is 12.5%, and the friction force born by the crank pin in the first friction area is greater than that born by the crank pin in the second friction area. In this example, diamond is used for extrusion grinding, the diameter of diamond particles is 15.0 μm, specifically, in this example, diamond powder is placed in a powder pool, and then when the crank pin and the large end of the connecting rod perform forward and reverse rotation reciprocating motion in the powder pool, in this process, graphite balls are extruded and rubbed by the diamond powder under the action of multidimensional pressure so as to be separated from cast iron, thereby forming a distributed texture on the surface of the crank pin. After the processing process is finished, in the embodiment, the friction-resistant nodular cast iron crankshaft is further subjected to post-treatment, so that the friction-resistant nodular cast iron crankshaft with a clean surface is obtained, and the post-treatment process specifically comprises the following steps: ultrasonic cleaning was performed in an acetone solution for 18 minutes.
Example IV
The embodiment provides a crankshaft, which is manufactured by the manufacturing method of the friction-resistant ductile iron crankshaft in the first embodiment, and the specific structure comprises the following steps: a crank pin 100, a plurality of pits being formed on a surface of the crank pin 100; the two balance weights 200 are respectively arranged at two sides of the crank pin 100 along the axial direction of the crank pin 100, and are movably connected with the crank pin, in particular rotate around the crank pin 100; two main shafts 300, any main shaft 300 is an elliptic cylindrical shaft body, which is correspondingly penetrated and connected with two balance weights 200, and synchronously swings corresponding to the balance weights 200 and the main shaft 300.
Referring to fig. 1 and 2, in this embodiment, two balance weights 200 are correspondingly sleeved on the periphery of the crank pin 100 and can reciprocally rotate around the crank pin 100, the crank pin shown in fig. 1 is taken as a reference, in this embodiment, the center of the balance weight 200 is located below the crank pin 100, the two balance weights 200 are shaped, sized and shaped elements with the same mass, in the actual use process, the balance weight 200 rotates around the crank pin 100, the large end of the connecting rod rotates around the crank pin 100, wherein the common working angle of the large end of the connecting rod rotates around the surface of the crank pin 100 along the arc length of the surface of the crank pin by within 30 °, so that the friction force born by the surface area of the crank pin is the largest, the area is defined as a first friction area 110 in this embodiment, correspondingly, two areas bearing smaller friction forces are symmetrically arranged on the front side and the rear side of the first friction area 110, in this embodiment, the area is defined as a second friction area 120, and further, the friction area 120 is defined as a second friction area 120, compared with the first friction area 120, and the friction area 120 is a pit density area is 25% compared with the first pit density area 110, and the pit density is 15%. The specific principle of the present embodiment for reducing the friction damage of the crankshaft is the same as that of the first embodiment, so that redundant description is omitted here.
Example five
The present embodiment provides another crankshaft, which has the same main structure and connection as the fourth embodiment, in which the pit density in the first friction area 110 is 20% and the pit density in the second friction area 120 is 10%.
It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations and modifications of the present invention will be apparent to those of ordinary skill in the art in light of the foregoing description. It is not necessary here nor is it exhaustive of all embodiments. And obvious variations or modifications thereof are contemplated as falling within the scope of the present invention.
Claims (10)
1. A preparation method of an antifriction nodular cast iron crankshaft is characterized by comprising the following steps of: the method comprises the following steps:
s1, removing an oxidation medium on the surface of the nodular cast iron crankshaft to obtain a first nodular cast iron crankshaft;
s2, separating graphite particles out of the nodular cast iron crankshaft to obtain a second nodular cast iron crankshaft;
s3, extruding and grinding the second nodular cast iron crankshaft to enable the precipitated graphite particles to be separated from cast iron to correspondingly form a plurality of pits, so as to obtain the friction-resistant nodular cast iron crankshaft with the surface texture changed.
2. The method for manufacturing the friction-resistant nodular cast iron crankshaft according to claim 1, wherein the method comprises the following steps: and the pits are filled with lubricant.
3. The method for manufacturing the friction-resistant nodular cast iron crankshaft according to claim 1, wherein the method comprises the following steps: in step S3, the second spheroidal graphite cast iron crankshaft surface includes a first friction area and a second friction area, the pit density in the first friction area is 20% -25%, and the pit density in the second friction area is 10% -15%.
4. The method for manufacturing the friction-resistant nodular cast iron crankshaft according to claim 1, wherein the method comprises the following steps: in the step S3, abrasive particles are adopted for extrusion grinding, wherein the abrasive particles are one or more of white corundum, quartz sand, silicon carbide and diamond, and the diameter of the abrasive particles is 12.5-18.0 mu m.
5. The method for manufacturing the friction-resistant nodular cast iron crankshaft according to claim 1, wherein the method comprises the following steps: and (3) after the step (S3) is finished, carrying out post-treatment on the friction-resistant nodular cast iron crankshaft to obtain the friction-resistant nodular cast iron crankshaft with clean surface.
6. The method for manufacturing the friction-resistant nodular cast iron crankshaft according to claim 1, wherein the method comprises the following steps: the step S2 specifically comprises the following steps:
s21, heating and preserving heat of the first nodular cast iron crankshaft to obtain a first nodular cast iron crankshaft which is expanded by heating;
and S22, cooling the heated and expanded first nodular cast iron crankshaft to obtain a second nodular cast iron crankshaft in which graphite is precipitated due to different thermal expansion coefficients.
7. The method for manufacturing the friction-resistant nodular cast iron crankshaft according to claim 6, wherein the method comprises the following steps: in the step S21, the heating temperature is not lower than 360 ℃, the heat preservation time is not less than 1 hour, and in the step S22, the cooling speed is not lower than 3.3 ℃/S.
8. The method for manufacturing the friction-resistant nodular cast iron crankshaft according to claim 1, wherein the method comprises the following steps: the step S1 specifically comprises the following steps:
s11, polishing the surface of the nodular cast iron crankshaft for the first time by adopting sand paper with the particle size not less than 200 meshes to obtain a nodular cast iron crankshaft after rough grinding;
s12, carrying out secondary grinding on the surface of the roughly ground nodular cast iron crankshaft by adopting sand paper with more than 800 meshes to obtain a finely ground nodular cast iron crankshaft;
and S13, polishing and cleaning the refined nodular cast iron crankshaft to obtain a first nodular cast iron crankshaft from which the oxidation medium on the surface of the nodular cast iron crankshaft is removed.
9. A crankshaft, characterized in that: a method of making a friction resistant ductile iron crankshaft according to any one of claims 1 to 8 comprising:
a crank pin, the crank pin surface forming a plurality of dimples;
the two balance weights are axially arranged on two sides of the crank pin along the crank pin, and are movably connected with the crank pin;
and the two main shafts are respectively connected with the two balance weights.
10. A crankshaft as claimed in claim 9, wherein: the crank pin surface is provided with a first friction area and two second friction areas which are respectively arranged on two sides of the first friction area, the pit density in the first friction area is 20% -25%, and the pit density in the second friction area is 10% -15%.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311108911.1A CN117340686A (en) | 2023-08-30 | 2023-08-30 | Preparation method of friction-resistant nodular cast iron crankshaft and crankshaft |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311108911.1A CN117340686A (en) | 2023-08-30 | 2023-08-30 | Preparation method of friction-resistant nodular cast iron crankshaft and crankshaft |
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| CN117340686A true CN117340686A (en) | 2024-01-05 |
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|---|---|---|---|
| CN202311108911.1A Pending CN117340686A (en) | 2023-08-30 | 2023-08-30 | Preparation method of friction-resistant nodular cast iron crankshaft and crankshaft |
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| CN (1) | CN117340686A (en) |
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- 2023-08-30 CN CN202311108911.1A patent/CN117340686A/en active Pending
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