CN109128697A - A kind of production technology of crankshaft - Google Patents
A kind of production technology of crankshaft Download PDFInfo
- Publication number
- CN109128697A CN109128697A CN201810919436.9A CN201810919436A CN109128697A CN 109128697 A CN109128697 A CN 109128697A CN 201810919436 A CN201810919436 A CN 201810919436A CN 109128697 A CN109128697 A CN 109128697A
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- semi
- crankshaft
- parts
- smart base
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
- B23P15/00—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
- B23P2700/00—Indexing scheme relating to the articles being treated, e.g. manufactured, repaired, assembled, connected or other operations covered in the subgroups
- B23P2700/07—Crankshafts
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Shafts, Cranks, Connecting Bars, And Related Bearings (AREA)
- Forging (AREA)
Abstract
The invention discloses a kind of production technologies of crankshaft, the specific steps are as follows: step 1, selection forging obtain forging material；Step 2 slightly bores main oil-hole on forging material, obtains crude green body to the rough turn trunnion of forging material and connecting rod neck；Step 3 makes annealing treatment crude green body, then carries out half smart car to crude green body, obtains half smart base；Half smart base is carried out modifier treatment, smart car is then carried out on numerically-controlled machine tool, obtains smart base by step 4；Smart base surface is processed by shot blasting by step 5, then is cleaned with cleaning agent to the smart base after polishing, and semi-finished product are obtained；The surface of semi-finished product is coated dehydrated oil by step 6, is then rinsed surface of semi-finished with clear water and is collected flushing liquor；Step 7 smears antirust agent and low temperature drying, covers bag encasement to get finished product is arrived.Crankshaft produced by the invention has enough stiffness and strength, and the qualification rate of product is high, and product appearance is beautiful, has the good ability for absorbing impact load, wear-resistant and lubrication is good, long service life.
Description
Technical field
The present invention relates to Production of Crankshaft field, the production technology of specifically a kind of crankshaft.
Background technique
Crankshaft is most important component in engine.It bears the power that connecting rod transmits, and is transformed into torque and passes through
Crankshaft exports and other attachmentes on engine is driven to work.Crankshaft is used by centrifugal force, the gas of mechanical periodicity of gyrating mass
Property power and reciprocal inertia force collective effect, make crankshaft bear flexion torsion load effect.Therefore it is required that crankshaft have it is enough
Strength and stiffness have the good ability for absorbing impact load, and wear-resistant and lubrication is good, and uniformly, balance is good for work.
Existing crankshaft generallys use structural carbon steel or steel alloy production, and there are two significant points: trunnion and connecting rod
Neck.Trunnion is installed on cylinder body, and connecting rod neck is connect with crank pin end pore, and connecting rod small end hole is connect with steam-cylinder piston, is one
A typical slider-crank mechanism.
Existing crankshaft is opened in use for some time to be cracked, and leads to permeability even serious oil leak, so as to cause hair
The operating of motivation is impacted, brings inconvenience for the use of people.
Summary of the invention
The purpose of the present invention is to provide a kind of production technologies of crankshaft, to solve mentioned above in the background art ask
Topic.
To achieve the above object, the invention provides the following technical scheme:
A kind of production technology of crankshaft, the specific steps are as follows:
Step 1 selects 42CrMo metal bar to carry out sawing, bar is forged, forging temperature 1230-
1310 degrees Celsius, obtain forging material；
Step 2 slightly bores main oil-hole on forging material, obtains crude green body to the rough turn trunnion of forging material and connecting rod neck；
Step 3, by crude green body 420-530 degrees Celsius annealing 10-15 minutes, then with numerically-controlled machine tool to annealing after
Crude green body carry out half smart car, obtain half smart base；
Half smart base is carried out modifier treatment, smart car is then carried out on numerically-controlled machine tool, obtains smart base by step 4；
Smart base surface is processed by shot blasting by step 5, then is cleaned with cleaning agent to the smart base after polishing, obtain half at
Product；
The surfaces of semi-finished product is coated dehydrated oil and keeps 15-28 minutes under 23-35 degrees Celsius, then by step 6
Surface of semi-finished is rinsed with clear water and collects flushing liquor, and flushing liquor is centrifuged, dehydrated oil and water, dehydrated oil are obtained
Energy-saving and environment-friendly requirement can be met with recycling and reusing；
Dewatered semi-finished product are smeared antirust agent and low temperature drying by step 7, then cover bag encasement to get at
Product.
As a further solution of the present invention: nondestructive inspection being carried out to bar when selection bar, qualified material side of detecting a flaw
It can be used.
As a further solution of the present invention: modifier treatment includes high-frequency quenching and lonneal, and high-frequency quenching can mention
High workpiece hardness enhances the wearability of crankshaft, and tempering changes material internal stress, refines crystal grain, improves the toughness of crankshaft.
As a further solution of the present invention: the temperature of high-frequency quenching is 860-890 degrees Celsius, and the time is 6-12 minutes,
The temperature of lonneal is 490-550 degrees Celsius, and the time is 80-135 minutes.
As a further solution of the present invention: dehydrated oil includes the raw material of following parts by weight: 5.6-7.8 parts of vegetable oil, ring
3.3-4.7 parts of oxygen hexane, 1.7-2.8 parts of polyacrylamide, 7.9-10.8 parts of rice washing water, 2.6-3.7 parts of slag and lotus rhizome water mention
4.4-5.2 parts of liquid.
As a further solution of the present invention: the temperature of low temperature drying is 30-42 degrees Celsius.
Compared with prior art, the beneficial effects of the present invention are: the present invention has rational design, the crankshaft of production has enough
Stiffness and strength, the qualification rate of product is high, and product appearance is beautiful, has a good ability for absorbing impact load, it is wear-resistant and
Lubrication is good, and long service life can satisfy the use demand of people.
Specific embodiment
The technical solution of the patent is explained in further detail With reference to embodiment.
Embodiment 1
A kind of production technology of crankshaft, the specific steps are as follows:
Step 1 selects 42CrMo metal bar, carries out nondestructive inspection to bar, and qualified material of detecting a flaw can use,
Qualified bar is subjected to sawing, bar is forged, forging temperature is 1260 degrees Celsius, obtains forging material；
Step 2 slightly bores main oil-hole on forging material, obtains crude green body to the rough turn trunnion of forging material and connecting rod neck；
Step 3, by crude green body 480 degrees Celsius make annealing treatment 13 minutes, then with numerically-controlled machine tool to the crude green body after annealing into
Half smart car of row obtains half smart base；
Half smart base is carried out modifier treatment by step 4, and modifier treatment includes high-frequency quenching and lonneal, and high-frequency quenching can
To improve workpiece hardness, the wearability of crankshaft is enhanced, tempering changes material internal stress, and crystal grain is refined, the toughness of crankshaft is improved,
Then smart car is carried out on numerically-controlled machine tool, obtains smart base；
Smart base surface is processed by shot blasting by step 5, then is cleaned with cleaning agent to the smart base after polishing, obtain half at
Product；
The surface of semi-finished product is coated dehydrated oil and is kept for 22 minutes under 28 degrees Celsius, then uses clear water by step 6
It rinses surface of semi-finished and collects flushing liquor, flushing liquor is centrifuged, dehydrated oil and water are obtained, dehydrated oil can return
It receives and recycles, water can be used for the cooling water of machine tooling, meet energy-saving and environment-friendly requirement；
Dewatered semi-finished product are smeared antirust agent and low temperature drying by step 7, then cover bag encasement to get at
Product.
Embodiment 2
A kind of production technology of crankshaft, the specific steps are as follows:
Step 1 selects 42CrMo metal bar to carry out sawing, bar is forged, and forging temperature is taken the photograph for 1250
Family name's degree obtains forging material；
Step 2 slightly bores main oil-hole on forging material, obtains crude green body to the rough turn trunnion of forging material and connecting rod neck；
Step 3, by crude green body 475 degrees Celsius make annealing treatment 12 minutes, then with numerically-controlled machine tool to the crude green body after annealing into
Half smart car of row obtains half smart base；
Half smart base is carried out modifier treatment by step 4, and modifier treatment includes high-frequency quenching and lonneal, high-frequency quenching
Temperature is 880 degrees Celsius, and the time is 10 minutes, and workpiece hardness can be improved in high-frequency quenching, enhances the wearability of crankshaft, low temperature
The temperature of tempering is 530 degrees Celsius, and the time is 115 minutes, and tempering changes material internal stress, refines crystal grain, improves the tough of crankshaft
Property, smart car is then carried out on numerically-controlled machine tool, obtains smart base；
Smart base surface is processed by shot blasting by step 5, then is cleaned with cleaning agent to the smart base after polishing, obtain half at
Product；
The surface of semi-finished product is coated dehydrated oil and is kept for 22 minutes under 28 degrees Celsius, then uses clear water by step 6
It rinses surface of semi-finished and collects flushing liquor, flushing liquor is centrifuged, dehydrated oil and water are obtained, dehydrated oil can return
It receives and recycles, meet energy-saving and environment-friendly requirement；
Dewatered semi-finished product are smeared antirust agent and dried under 34 degrees Celsius, then cover bag encasement, i.e., by step 7
Obtain finished product.
Embodiment 3
A kind of production technology of crankshaft, the specific steps are as follows:
Step 1 selects 42CrMo metal bar, carries out nondestructive inspection to bar, and qualified material of detecting a flaw can use,
Sawing is carried out to the qualified bar of flaw detection, bar is forged, forging temperature is 1245 degrees Celsius, obtains forging material；
Step 2 slightly bores main oil-hole on forging material, obtains crude green body to the rough turn trunnion of forging material and connecting rod neck；
Step 3, by crude green body 490 degrees Celsius make annealing treatment 12 minutes, then with numerically-controlled machine tool to the crude green body after annealing into
Half smart car of row obtains half smart base；
Half smart base is carried out modifier treatment, smart car is then carried out on numerically-controlled machine tool, obtains smart base by step 4；
Smart base surface is processed by shot blasting by step 5, carries out rolling processing to axis hole after polishing, and rolling processing can letter
Chemical industry sequence, and can guarantee the processing request in each hole of crankshaft, make crankshaft that there is good lubricity, eliminates and go out in reaming procedure
Now because built-up edge or iron filings exclude it is unsmooth caused by inner hole plucking, pull phenomenon, then it is clear to the smart base after polishing with cleaning agent
It washes, obtains semi-finished product；
The surface of semi-finished product is coated dehydrated oil and is kept for 22 minutes under 28 degrees Celsius by step 6, and dehydrated oil includes
The raw material of following parts by weight: 5.6 parts of vegetable oil, 3.3 parts of oxepane, 1.7 parts of polyacrylamide, 7.9 parts of rice washing water, slag
2.6 parts and 4.4 parts of lotus rhizome Aqueous extracts, vegetable oil, oxepane, polyacrylamide, rice washing water, slag and lotus rhizome Aqueous extracts are mixed
It closes and uniformly obtains dehydrated oil, the dehydrating effect of the dehydrated oil is good, then rinses surface of semi-finished with clear water and collects flushing
Flushing liquor is centrifuged liquid, obtains dehydrated oil and water, and dehydrated oil can meet energy-saving and environment-friendly want with recycling and reusing
It asks；
Dewatered semi-finished product are smeared antirust agent and low temperature drying by step 7, then cover bag encasement to get at
Product.
Embodiment 4
A kind of production technology of crankshaft, the specific steps are as follows:
Step 1 selects 42CrMo metal bar, carries out nondestructive inspection to bar, and qualified material of detecting a flaw can use,
Sawing is carried out to the qualified bar of flaw detection, bar is forged, forging temperature is 1300 degrees Celsius, obtains forging material；
Step 2 slightly bores main oil-hole on forging material, obtains crude green body to the rough turn trunnion of forging material and connecting rod neck；
Step 3, by crude green body 510 degrees Celsius make annealing treatment 12 minutes, then with numerically-controlled machine tool to the crude green body after annealing into
Half smart car of row obtains half smart base；
Half smart base is carried out modifier treatment by step 4, and modifier treatment includes high-frequency quenching and lonneal, high-frequency quenching
Temperature is 870 degrees Celsius, and the time is 9 minutes, and workpiece hardness can be improved in high-frequency quenching, enhances the wearability of crankshaft, low temperature
The temperature of tempering is 520 degrees Celsius, and the time is 115 minutes, and tempering changes material internal stress, refines crystal grain, improves the tough of crankshaft
Property, smart car is then carried out on numerically-controlled machine tool, obtains smart base；
Smart base surface is processed by shot blasting by step 5, then is cleaned with cleaning agent to the smart base after polishing, obtain half at
Product；
The surface of semi-finished product is coated dehydrated oil and is kept for 20 minutes under 29 degrees Celsius by step 6, and dehydrated oil includes
The raw material of following parts by weight: 7.8 parts of vegetable oil, 4.7 parts of oxepane, 2.8 parts of polyacrylamide, 10.8 parts of rice washing water, slag
3.7 parts and 5.2 parts of lotus rhizome Aqueous extracts, vegetable oil, oxepane, polyacrylamide, rice washing water, slag and lotus rhizome Aqueous extracts are mixed
It closes and uniformly obtains dehydrated oil, the dehydrating effect of the dehydrated oil is good, then rinses surface of semi-finished with clear water and collects flushing
Flushing liquor is centrifuged liquid, obtains dehydrated oil and water, and dehydrated oil can meet energy-saving and environment-friendly want with recycling and reusing
It asks；
Dewatered semi-finished product are smeared antirust agent and dried under 36 degrees Celsius, then cover bag encasement, i.e., by step 7
Obtain finished product.
It is obvious to a person skilled in the art that invention is not limited to the details of the above exemplary embodiments, Er Qie
In the case where without departing substantially from spirit or essential attributes of the invention, the present invention can be realized in other specific forms.Therefore, no matter
From the point of view of which point, the present embodiments are to be considered as illustrative and not restrictive, and the scope of the present invention is by appended power
Benefit requires rather than above description limits, it is intended that all by what is fallen within the meaning and scope of the equivalent elements of the claims
Variation is included within the present invention.
In addition, it should be understood that although this specification is described in terms of embodiments, but not each embodiment is only wrapped
Containing an independent technical solution, this description of the specification is merely for the sake of clarity, and those skilled in the art should
It considers the specification as a whole, the technical solutions in the various embodiments may also be suitably combined, forms those skilled in the art
The other embodiments being understood that.
Claims (6)
1. a kind of production technology of crankshaft, which is characterized in that specific step is as follows:
Step 1 selects 42CrMo metal bar to carry out sawing, bar is forged, forging temperature 1230-1310
Degree Celsius, obtain forging material；
Step 2 slightly bores main oil-hole on forging material, obtains crude green body to the rough turn trunnion of forging material and connecting rod neck；
Step 3, by crude green body 420-530 degrees Celsius annealing 10-15 minutes, then with numerically-controlled machine tool to thick after annealing
Base carries out half smart car, obtains half smart base；
Half smart base is carried out modifier treatment, smart car is then carried out on numerically-controlled machine tool, obtains smart base by step 4；
Smart base surface is processed by shot blasting by step 5, then is cleaned with cleaning agent to the smart base after polishing, and semi-finished product are obtained；
The surface of semi-finished product is coated dehydrated oil and kept under 23-35 degrees Celsius 15-28 minutes, then with clear by step 6
Water rinses surface of semi-finished and collects flushing liquor, and flushing liquor is centrifuged, dehydrated oil and water are obtained；
Dewatered semi-finished product are smeared antirust agent and low temperature drying by step 7, cover bag encasement then to get finished product is arrived.
2. the production technology of crankshaft according to claim 1, which is characterized in that carry out nothing to bar when the selection bar
Damage flaw detection.
3. the production technology of crankshaft according to claim 1, which is characterized in that the modifier treatment include high-frequency quenching and
Lonneal.
4. the production technology of crankshaft according to claim 3, which is characterized in that the temperature of the high-frequency quenching is 860-
890 degrees Celsius, the time is 6-12 minutes, and the temperature of lonneal is 490-550 degrees Celsius, and the time is 80-135 minutes.
5. the production technology of crankshaft according to claim 1, which is characterized in that the dehydrated oil includes following parts by weight
Raw material: 5.6-7.8 parts of vegetable oil, 3.3-4.7 parts of oxepane, 1.7-2.8 parts of polyacrylamide, 7.9-10.8 parts of rice washing water,
2.6-3.7 parts and 4.4-5.2 parts of lotus rhizome Aqueous extracts of slag.
6. the production technology of crankshaft according to claim 1, which is characterized in that the temperature of the low temperature drying is 30-42
Degree Celsius.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109746649A (en) * | 2019-03-13 | 2019-05-14 | 芜湖肯昌机电有限公司 | A kind of processing technology of engine crankshaft |
| CN110438303A (en) * | 2019-08-07 | 2019-11-12 | 九江学院 | A kind of automobile-used 42CrMo crankshaft forged steel " three-step approach " heat treatment process of diesel oil |
| CN112207511A (en) * | 2020-09-17 | 2021-01-12 | 南京工程学院 | Short-flow manufacturing process for surface-hardened long-shaft forgings |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3911441A1 (en) * | 1988-04-07 | 1989-10-19 | Daido Metal Co Ltd | METHOD FOR PRODUCING A SEMI-DIVIDED BEARING |
| CN101954571A (en) * | 2010-09-16 | 2011-01-26 | 温州市龙湾沙城钢球厂 | Manufacturing process of 0.68 mm nonmagnetic alloy balls |
| CN103447778A (en) * | 2013-05-23 | 2013-12-18 | 浙江伟林机械零部件有限公司 | Machining process of engine crankshafts in heavy trucks |
| CN104384874A (en) * | 2014-09-27 | 2015-03-04 | 安徽金庆龙机械制造有限公司 | Processing process of automobile engine crank shaft |
| CN105196012A (en) * | 2015-09-23 | 2015-12-30 | 四川飞亚汽车零部件有限公司 | Novel process for processing crankshaft |
| CN106736313A (en) * | 2017-03-10 | 2017-05-31 | 湖南省卓尔轴瓦科技有限公司 | Go electroplating shaft bushing production technology |
-
2018
- 2018-08-10 CN CN201810919436.9A patent/CN109128697A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3911441A1 (en) * | 1988-04-07 | 1989-10-19 | Daido Metal Co Ltd | METHOD FOR PRODUCING A SEMI-DIVIDED BEARING |
| CN101954571A (en) * | 2010-09-16 | 2011-01-26 | 温州市龙湾沙城钢球厂 | Manufacturing process of 0.68 mm nonmagnetic alloy balls |
| CN103447778A (en) * | 2013-05-23 | 2013-12-18 | 浙江伟林机械零部件有限公司 | Machining process of engine crankshafts in heavy trucks |
| CN104384874A (en) * | 2014-09-27 | 2015-03-04 | 安徽金庆龙机械制造有限公司 | Processing process of automobile engine crank shaft |
| CN105196012A (en) * | 2015-09-23 | 2015-12-30 | 四川飞亚汽车零部件有限公司 | Novel process for processing crankshaft |
| CN106736313A (en) * | 2017-03-10 | 2017-05-31 | 湖南省卓尔轴瓦科技有限公司 | Go electroplating shaft bushing production technology |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109746649A (en) * | 2019-03-13 | 2019-05-14 | 芜湖肯昌机电有限公司 | A kind of processing technology of engine crankshaft |
| CN110438303A (en) * | 2019-08-07 | 2019-11-12 | 九江学院 | A kind of automobile-used 42CrMo crankshaft forged steel " three-step approach " heat treatment process of diesel oil |
| CN112207511A (en) * | 2020-09-17 | 2021-01-12 | 南京工程学院 | Short-flow manufacturing process for surface-hardened long-shaft forgings |
| CN112207511B (en) * | 2020-09-17 | 2021-10-26 | 南京工程学院 | Short-flow manufacturing process for surface-hardened long-shaft forgings |
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Application publication date: 20190104 |