7:24 main shaft / what knife handle connection is not even stress field is finite yuan of analysis

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Summary: ? Piao?:24 main shaft / the question with the big error of computation of Latin America formula that middling of design of knife handle connection uses, use finite yuan the law analysed 7:24 main shaft / the blame of knife handle connection is even stress field, studied connection interference is right main shaft / pressure of knife handle contact, knife handle is inside main shaft taper hole the influence of axial position, for main shaft / the design of knife handle connection and structure are optimized provided academic basis. 1 foreword because 7:24 main shaft / knife handle connection is had do not lock up oneself, easily the fast clamp of cutting tool, loose wait for an advantage, get applied extensively on numerical control machine tool and machining center consequently. In cutting treatment process, change to ensure the relative position of cutting tool and workpiece does not happen, certain interference needs between main shaft taper hole and knife handle cone, will in order to form stiffness of enough osculatory stress, contact satisfy treatment requirement. As a result of the tradition conic be filled with connection to devise a method too is it is a model in order to be based on the principle of large wall cylinder of Latin America formula, with material mechanical methodological computation is filled with the interference that connection place needs too, because this cannot mirror the actual structure of main shaft and knife handle accurately to be opposite,be out of shape and the influence of stress, cannot calculate accurately give the stress between connection face to distributing, affected the designs quality and application reliability of connection. In addition, when be being calculated with traditional method, with taper seat average diameter replaces combinative diameter, calculate not only complex, and the error is big. Tell from mechanical angle, 7:24 main shaft / knife handle connection attributes the complex problem with nonlinear height of attrib border condition, its characteristic is certain border the condition is being calculated impossibly can decide in the begining, area of computational result, contact and stress distributing is as outside of load change and change. In recent years, as nonlinear academic perfect the flying development with computer technology ceaselessly, use nonlinear finite yuan it is mature with each passing day already that the law solves this kind of complex problem. This research have the aid of at advanced finite yuan of commonly used 7:2 on technical analysis machine tool4 main shaft / the blame of knife handle connection is even stress field, in order to raise analytic efficiency and computational precision, for main shaft / the design of knife handle connection and optimize provide academic basis. Graph 1 main shaft / 2 7:2 of plan of structure of knife handle connection4 main shaft / the blame that knife handle connection is in is even stress field analysis because main shaft / the axial symmetry sex of structure of knife handle connection, for convenient analysis, use polar coordinates (R, θ ) show each weight. Among them, shearing stress =0 of τ R θ , radial stress and tangential the function that stress is R only, have nothing to do with θ , θ of the R(r) that it is σ , σ (R) . Manage together, heft of meet an emergency is θ of Epsilon;r(r) , Epsilon; (R) . As a result of axial symmetry sex, the direction of bulk edge radius of main shaft and knife handle expands equably or contract, produce radial deflection U(r) only namely, because this can press axial symmetry plane,stress problem seeks solution. The geometrical dimension between main shaft and knife handle connection and attrib border condition are shown 1 times like the graph. Balance equation is equation of geometry of =0drr of θ of σ of R- of σ of D σ R+ to be Epsilon;r=du, this compose equation is Epsilon; θ =udrr θ of σ of ν of Epsilon;r=1(σ R- ) θ of σ of Eepsilon; θ =1(- the attrib border condition of knife handle of ν σ R)E and main shaft is R2(r2=b)=0 of σ of R2(r2=a)=-p of σ of R1(r1=a)=-p{of σ of {σ R1(r1=0)=0 to establish afore-mentioned equation couplet respectively seek solution, because main shaft and knife handle all are steel simple stuff,the displacement weight that can gain knife handle and main shaft is 2)b2]E2(b2-a2)r2(2) of 2)r2+(1+ ν of ν of U1(r1)=-P[(1- ν 1)r1]E1(1)u2(r2)=-a2P[(1- , the model measures its flexibility and Poisson comparing is basic and identical, it is E and V respectively, criterion according to type (1) and type (2) , main shaft / the interference δ of knife handle connection can decide δ =2[u2(r2=a)-u1(r1=a)]=4ab2PE(b2-a2)(3) by next type by type (3) can get the osculatory pressure between main shaft and face of knife handle connection to be P=E δ (in B2-a2)4ab2P(4) type: A -- external diameter of sincere knife handle, b of main shaft internal diameter -- E of main shaft external diameter -- Yang model measures P -- osculatory pressure ν -- Poisson is compared from type (4) can see, below the circumstance that is fair value in interference, main shaft / the osculatory pressure that knife handle connection handles changes along with what cooperate a diameter and change, it is one is not even stress field, the osculatory pressure change that this and cylinder are filled with connection to be in too is apparently distinct. As a result of main shaft / the blame that place of knife handle connection exists is even stress field is brought about cannot use Latin America formula to study the analysis is filled with connection character too, the computation of principle of canister of assorted large wall that also cannot press average diameter contacts pressure. 3 7:24 main shaft / of knife handle connection finite yuan of analysis because main shaft / between face of knife handle connection cannot stickup meet an emergency piece, undertake determining to its stress condition hard, cannot undertake dogging study to the stress field between face of the connection in cutting process. Accordingly, pass advanced nonlinear finite yuan of software and circumstance of change of stress of visible technology imitate, can give priority to an axis / the design of knife handle connection and optimize provide academic basis. Because the structure of main shaft and knife handle is symmetrical, undertake finite yuan when the analysis, can use 2 dimension axial symmetry board unit imitate is three-dimensional and hypostatic unit. With ISO No.

50 main shaft / knife handle connection is exemple, main shaft / knife handle connection is finite yuan the model sees a picture 2, introduce board the stress between face of connection of osculatory unit analysis distributings circumstance, the axial pulling force that knife handle gets is 35, 000N. The attrition between connection face accords with coulomb law, coefficient of friction is 0.

12. E=2.

1 × 109Pa, ν =0.

3, ρ =7.

8 × 103Kg/m3 graph 2 main shaft / knife handle is conic connection is finite yuan of model attempt 3 main shaft / the blame between knife handle is even stress field pursues the ISO 7388/1 of relation international standard between 4 contacts pressure and interference, 83 set 7:2 with ISO/DIS 7290The cone angle public errand of 4 conic handles is AT4 class, next deviation are 0: 7:2The cone angle public errand of taper hole of 4 main shaft is AT4 class, deviation is on 0. According to afore-mentioned standard regulations, knowable ISO No.

The conic horn public errand of small end of 50 knife handle is 13"0, diametical public errand is 0-4.

3µm: The conic horn public errand of small end of main shaft taper hole is 0-13" , diametical public errand is 4.

30µm. The effect that analyses interference and couplet of axial pulling force to accept position to facilitate and the dependability that raise an analysis, assume the connection of main shaft and knife handle is in the poorest condition, namely knife handle is small upright diameter is next deviation and main shaft taper hole is small upright diameter is on deviation. Type (4) makes clear, main shaft / the osculatory pressure between face of knife handle connection is a blame even stress field, if the graph is shown 3 times,its change. Graph 3 when doing not have interference to be between main shaft and knife handle, the blame that after knife handle produces axial displacement to produce a contact with main shaft taper hole then below the action in pulling force of taut orgnaization axial, forms is even stress field. (1) 7:24 main shaft / the relation of pressure of contact of knife handle connection and interference from type (the size that 4) can see the connection on connection face contacts pressure depends on the size of interference, because this wants to ensure cutting process is medium, the connection condition between cutting tool and main shaft does not produce change, be in with respect to need main shaft / the initiative interference with bring to bear on certain between face of knife handle connection, stiffness of osculatory pressure, contact rises to machine pair of main shaft in order to satisfy cutting through playing plasticity to be out of shape below the action of axial pulling force / the requirement of condition of knife handle connection. Graph 4 medium curves make clear main shaft / the conic connection of knife handle contacts pressure as interference rise and rise. Accordingly, below the premise that has not produced invalidation in main shaft and knife handle material, contact stiffness of pressure, contact through raising initiative interference to rise to raising the connection dependability, whirl that raises cutting tool precision has active sense. By the graph 4 knowable, exceed 60µm when interference, osculatory pressure increases again scarcely, be opposite namely ISO No.

50 main shaft / knife handle connection, initiative interference is unfavorable exceed 60µm. Graph 4 in the curve still shows the two termination in connection to touch pressure the biggest, exceed 10µm when initiative interference especially when, the contacts pressure to compare other position contact pressure of small end is great a lot of. Normally the circumstance falls, it is according to the contact pressure designs interference, but main shaft / the inhomogenous sex that pressure contacts in knife handle connection gives main shaft / of knife handle it is difficult to was filled with connection design to bring too, if design interference according to contacting pressure,its reason depends on, so the interference that computation gives is not even change function namely, such connection is coming true on the project, because this must search new method,design main shaft / the connection of knife handle. As a result of standard 7:24 knife handle are longer, very difficult implementation does not have clearance to contact endlong, general requirement ensures before connection paragraph 70% above implementation is contacted and have enough osculatory pressure and osculatory stiffness. Graph the metabolic curve of 4 makes clear, in main shaft / on the osculatory length of knife handle 0 ～ 92.

The osculatory pressure between 5mm changes not very big, and the 90%(92 that this paragraph of distance already took whole contact length.

5mm/102.

8mm) . Accordingly, show actually from what the project applies besides set out, designing main shaft / when knife handle is filled with connection too, can study 0 ～ only 92.

5mm contacts the relation between the osculatory pressure on length and interference this paragraph. If should make,osculatory pressure is achieved 0.

8 × 108Pa is controlled, so in 0 ～ 92.

5mm contacts the interference on length to need to achieve 60µm, after that paragraph interference needs 30µm to be able to satisfy a requirement only, the structure of main shaft taper hole that designs by this is helpful for leveling contacting pressure already, after also be helpful for taper hole paragraph treatment. Graph the relation between position of axial of 5 knife handle and interference (2) 7:24 main shaft / the relation knife handle of the axial position of the knife handle in knife handle connection and interference wants as close together as the implementation between taper hole contact, must issue axial to move in the action of broach orgnaization, till both before paragraph complete contact. Be worth to decide in axial pulling force (35, below the circumstance of 000N) , the change that knife handle follows interference in the final axial position inside main shaft taper hole arrives in 18µm between ～ 153µm change, its change curve sees a picture 5. In cutting treatment process, need cutting tool is in X, Y, Z3 direction locates accurately. To same table machining center, the need in knife library is deployed a few use in order to offer to about a hundred cutting tool very, if differ knife handle and same an interference between main shaft differ bigger, can make different knife handle has bigger difference in the final axial position inside main shaft taper hole, the Z that brings about different cutting tool thereby differs to fixed position precision. Accordingly, if want to raise the Z of cutting tool to fixed position precision, must choose according to interference match knife handle, make same table the main shaft of machining center / the interference of knife handle connection changes inside a lesser limits, in order to raise Z to fixed position precision. 4 conclusion 7:24 main shaft / the osculatory pressure between face of knife handle connection is a blame even stress field, use finite yuan of law is OK study main shaft conveniently / of knife handle be filled with connection to measure pair of main shaft too / the influence of displacement of axial of pressure of knife handle contact, knife handle. The research of the article makes clear, main shaft / the conic connection of knife handle contacts pressure as interference rise and rise, the pressure of two upright contacts in connection is the greatest, when initiative interference exceeds 10µm, the contacts pressure to compare other position contact pressure of small end is great a lot of. Below the condition that is calm value in axial pulling force, knife handle follows the change of interference in the final axial position inside main shaft taper hole and change. CNC Milling