Boring of essence of internal-combustion engine aluminous piston sells aperture craft to analyse

The article introduced internal-combustion engine aluminium the technical requirement of piston pin aperture, sell the treatment characteristic of opening working procedure according to boring of essence of life, analysed the cause that affects the precision that sell aperture from the respect such as system of equipment, cutting tool, put forward corresponding improvement, assure measure, produce the effectiveness that these measure identified in practice in large quantities of quantities. As engine function rise ceaselessly, the structure of the piston changes subsequently, taller and taller also to the precision requirement of piston pin aperture. Internal-combustion engine aluminous piston (see a picture 1) sell aperture, precision of its appearance, dimension and exterior demand are very high, press the regulation of GB1148-93, the cylinder that sells aperture is spent should be 5 class, requirement 2 ～ 3mm; Dimension public errand is IT5, it is 4 ～ 8mm commonly; Surface roughness is Ra0 commonly.

4mm. In batch manufacturing condition falls, boring of essence of life sells opening working procedure to want to achieve such requirement, a series of severe measure ability must be adopted to satisfy treatment to ask on craft. Graph aluminous piston of 1 internal-combustion engine my factory is home the biggest piston processes a business, for home almost all leader plant form a complete set, in the piston treatment respect accumulated rich experience. In producing practice, we used the following measure to make sure each technology that sells aperture asks. When the vibration that reduces boring machine bores hole, as a result of the vibration of machine tool oneself and ab extra oscillatory metropolis apparent ground affects the circularity that sells aperture to place boring, for this, we take the following step: 1.

In lathe bed and installation of place of ground surface contact 4 are decreased brace up mat, can make the circularity that sell aperture is able to improve. My factory passes a test, the circularity that sell aperture can rise 0.

3 ～ 0.

4mm. 2.

Consolidate puts the foundation of the machine tool. Dig foundation greatly, deepen the concrete layer ply of foundation, use decrease brace up material separates boring machine foundation and week exclosure side, prevent all round the vibration of the machine tool sends boring machine. The improvement of cutting tool system falls in the condition with equipment precision, proper configuration, want to raise requirement of the precision that sells aperture, contented treatment, cutting tool system is crucial. For this, we basically undertake analytic improvement from the following respects: 1.

The improvement of boring lever (1) because boring of essence of life sells aperture,the design of boring lever is made is treatment of high speed cutting, slight vibration will affect the exterior surface roughness of piston pin aperture directly, accordingly, the coaxial that designs lever of boring of the requirement when making and main shaft in boring lever is spent be less than 0.

01mm, and whole boring lever is departmental outside the circle should undertake grinding is machined. In making sure boring lever turns in high speed so, can poise, reduce vibration, removed the influencing factor of boring lever itself. The position of tool bore affects the treatment angle of the cutting tool after holding clip directly, because this is when boring lever design (see a picture 2) , center of requirement tool bore passes boring lever center or center of lever of boring of deviate of tool bore center is apart from certainly, and tool bore center is perpendicular at boring lever axes, assure to hold the treatment point of view of the cutting tool after clip; In the meantime, give corresponding and departmental look tolerancepublic errand, because boring lever replaces the change that causes surface roughness of surface of the treatment that sell aperture,decrease. The boring staff of the treatment that sell aperture is general cantilever is longer, because this boring lever must undertake stabilizing aggrandizement heat treatment, the strength that can increase boring staff so, rigid, reduce boring staff suffer force to be out of shape, raise level of surface roughness of surface of piston pin aperture. Graph the design construction of 2 boring lever (2) the flutter that one of keys that the material of boring lever sells aperture quality issue depend on selling pole of aperture essence boring cutter. Kong Shi is sold in boring, the long way of boring lever is compared be more than commonly 5, achieve even individually 10. Boring lever is in treatment process, suffer bend, the assorted effect that turn round and reduces load, meeting generation is oscillatory, when the piston that sells aperture to be less than φ 15mm in treatment especially, because the diameter of boring lever is lesser, its circumstance especially apparent. We are in when for Japan small pine machines some piston, its sell aperture diameter to be φ 8mm only, and the diameter of boring lever is smaller, because the flutter of boring lever makes,sell what aperture short of stipulates surface roughness, cylinder is spent to occupy 1/3. By material mechanical and knowable: K ∝ EI/L3, namely I of K of boring lever static stiffness and E of quantity of its data stretch standard, inertial quadrature becomes direct ratio, just become inverse ratio with 3 when hang the L that extend a capacity. Because get,hang the L that extend a capacity the limitation of piston diameter size, its value cannot change commonly too much, this asks we choose material of stretch model generous. Our current boring lever data is 45# steel, its flexibility model measures E=196 ～ 216GPa, bigger to selling aperture diameter (＞ φ 15mm) piston, its are mechanical function can satisfy the treatment that sells aperture basically still to ask; To selling the piston with aperture lesser diameter, we are about to seek data of stretch model generous. Hard alloy (the 610GPa of ～ of E=600 of stretch model quantity of YG8) , apparent, stiffness of lever of hard alloy boring is ambitious lever of boring of Yu Gang qualitative alloy, but its defect is not easy treatment. Our attempt solders in the front of boring lever steel of on one paragraph of 45# , so that machine the via of outfit clip cutting tool and screw. We will machine φ 8mm to sold the result of aperture to undertake contrast with two kinds of cutting tool, the BHT-20 that in me the factory abstains machined 10 pistons respectively on boring machine, actually test data sees a table. The result makes clear: In same treatment the condition falls, the treatment effect of lever of hard alloy boring is close friends more than lever of 45# steel boring. The treatment data that the watch uses lever of two kinds of boring to get (3) when the structural boring lever of boring lever works, get not only the action of static force, still have qualitative hardness of interrupted cutting, material at the same time oneself of lever of inhomogenous, boring is lopsided the wallop that causes with the place such as the self excited vibration in cutting process or hand in change the interference of force, because this asks boring lever has certain static tigidity not only, have enough inhibition even all sorts of perturbed force cause oscillatory ability, fight namely brace up quality. When the comparison when cutting force and weight of boring lever oneself is big, very easy in cutting process self excited vibration, machine what the diameter is less than φ 15mm to sell Kong Shi especially, this kind of condition is very serious. Because hard alloy is not easy treatment and cost are high, we still can be below the case that does not use rod of hard alloy boring, deserve to weigh through increasing to lever of 45# steel boring, increase oneself weight, decrease from brace up. Its are specific the method is: The plumbic bar with larger proportion is held in boring lever extreme (see a picture 3) , hold bottom clearance 0.

05 ～ 0.

1mm; Block up with silk after outfit is good had blocked up, hold axial clearance 0.

1 ～ 0.

2mm, assure plumbic club to turn in freedom of boring lever internal energy, make boring lever rotates in high speed process middleman and guarantor holds dynamic balancing. Test result makes clear, this kind of measure enhanced boring lever greatly fight brace up quality. Graph the basic structure of lever of 3 small boring 2.

The improvement of cutting tool and cutting parameter (1) the material of cutting tool and point of view are current, boring of essence of life sold the cutting tool of aperture to change diamond cutting tool by hard alloy cutting tool mostly, bore hole quality had clear improvement. Because hardness of making synthetic diamond is tall, treatment difficulty is great, the design that passes for many times experiments, our make choice of the main technique parameter of cutting tool: R0 of arc of point of a knife.

5 ～ 1, the horn before cutting tool is 5 ° , the horn after cutting tool, deputy hind horn is mixed for 12 ° respectively 8 ° , cutting tool ligament is wide 0.

2mm, ra0 of surface roughness of face of knife of cutting tool around.

1mm. Observation falls in 30 times magnifier, edge does not have breach crackle. Use the cutting tool boring that has machined by this geometry angle to sell aperture, the circularity that sell aperture is measured to be less than after treatment 0.

003mm, exterior surface roughness is less than Ra0.

4mm. Below same condition, use treatment of PCD cutting tool to sell Kong Shi, cutting tool life can achieve 20 000, be hard alloy cutting tool 50 multiple. The exterior surface roughness of treatment by original Ra0.

4 ～ Ra0.

8mm reduces Ra0.

2 ～ Ra0.

4mm. Every can decrease assemble and unassemble cutting tool, blade grinds a knife to reach adjust the auxiliary time 30min such as cutting tool. This shows, use PCD cutting tool not only quality had apparent promotion, and manufacturing efficiency also rises greatly. (2) cutting parameter is spent to assure to sell the cylinder of aperture, dimension public errand, surface roughness, the craft parameter when boring sells aperture is very important also. The course experiments for many times, we sum up the cutting parameter that went out to suit him equipment, boring of essence of life sells Kong Bi must be high speed cutting, main shaft revolution is controlled in 3 000r/min; Take a knife cannot too fast, feed is in 0.

05 ～ 0.

Between 07mm/r; The cutting deepness control of knife of essence of life is in 0.

02 ～ 0.

Between 05mm, can do cutting. Press above parameter treatment, each to selling aperture requirement in can achieving a product basically to set. The place on last word put together is narrated, the factor that affects precision of piston pin aperture and exterior surface roughness is omnibus. In producing a course, we notice existence is worn above the element of a few respects, and the measure with relevant to was being adopted hereat needle, made sure my factory is in the manufacturing process of large quantities of quantities thereby, boring of essence of life sells the boring in opening working procedure to give the cylinder that sells aperture to spend, the requirement that the project such as dimension public errand, surface roughness can reach a clientele completely. CNC Milling