Nut of guide screw of scroll of cutting machine tool deputy

92-0.

96) than slip guide screw (η = 0.

20-0.

40) tall 3-4 times. Nut of ball guide screw is moved deputily (static) coefficient of friction is basic and equal, match with scroll slideway, the moment of force that start is very small, motion is extremely acute, crawl won't appear when low speed. Nut of ball guide screw deputy can eliminate gap completely and can tighten beforehand, reason has taller axial stiffness, and do not have dead band of light locomotive trip reversely, precision of retrorse fixed position is tall. Coefficient of friction of nut of ball guide screw is small, without from the lock, can realize reversible drive. Nut of ball guide screw general one's duty mixes deputy ball loop means circularly outer circulation two kinds. 2, the nominal diameter D0 of the guide screw of ball of D0 of diameter of name of main technique parameter of ball guide screw is the diameter that points to ball center circle. D0 value is greater, the carrying capacity of guide screw and stiffness are bigger. With the ball guide screw in drive of feed of numerical control machine tool, take D0 = 20mm-100mm. Choice D0 value should be more than the 1/35-1/30 of L0 of guide screw length. Ph of lead of basic lead Ph should dictate according to the pulse of the machine tool requirement and laden case will choose. After nominal diameter D0 is affirmatory, ph value is great, can make the β promoting role of whorl greatens. General β > 2 ° , take β normally > 3.

5 ° . Ball diameter D0 takes D0 = 0 commonly.

6Ph. The job of ball encircles several J and N of working ball gross, j of working group number is taken commonly 2.

5-3.

5, and N of working ball gross with not be more than 150 advisable. The K that list number asks working group counts more circumstance, can use biserial or the configuration of the much nut that list type. 3, deputy design calculates nut of ball guide screw rated and dynamic carry on one's shoulder and rated dead load are rated and dynamic carry on one's shoulder is the nut of ball guide screw that points to a batch of identical parameter deputy, after N ﹥ runs 6 times of 10 to just turn below the same job requirement of =10r/min, the helix of 90% deputy (point to whorl raceway and scroll body) do not produce the fatigue loss that nod corrode can susceptive is the biggest axial load, the definition is rated and dynamic Ca of carry on one's shoulder. Rated dead load is to point to a ball guide screw deputy in static state or low rotate speed (N<=10r/min) below the condition, the plasticity deflection the sum that accepts the generation between the ball with osculatory the greatest stress and raceway interface achieves ball diameter 0.

The load of 0001 times the biggest axial when, the definition is Ca0 of rated dead load. Guide screw of ball of computation of intensity of deputy exhaustion of ball guide screw should according to its rated and dynamic carry on one's shoulder is chosen. The equivalent of ball guide screw moves the Fm in type of L (N) of √ of load Cm = Fm * 3---Axial work load (N) , when load rule of the mode that press sheet changes, when all sorts of rotate speed use opportunity photograph to be the same as, fm =(2Fmax+Fmin)/3; Fmax, fmin---Guide screw is the biggest, load of the smallest axial (N) ; L---Working life, it is 1 unit with just turning 6 times of 10, l = 60nT/1000000n---Guide screw rotate speed (R/min) ; T---Service life (H) , desirable to numerical control machine tool T = 15000h. The ball guide screw when the Jing Zaijiang of ball guide screw spends computational low speed to run deputy, should press load of work of the biggest axial, press computation namely dead load Cj is choice basis. Its computation formula is: The Fmax in type of Cj = Kp * Kr * Fmax---Load of work of the biggest axial (N) ; Kp---Load property coefficient, numeric and Alexandrine; Kr---Hardness affects coefficient, HRC>=58 takes Kr = 2.

0-1.

2. 4, nut of ball guide screw chooses measure deputily (1) the numerical value that computational action changes load Cm in the equivalent on ball guide screw; L * Kp * Kr * F of √ of Cm = 3 (2) find out from inside trade catalogue of ball guide screw what move load Cm close with equivalent is rated and dynamic carry on one's shoulder is worth Ca, make Cm<=Ca, preliminary the model that chooses a few guide screw and concerned structural parameter; (3) ask according to specific work, to structural dimension, circular means, move the respect such as unoccupied place method and transmission efficiency to have primary election, single out more appropriate nominal diameter D0 from inside a few model of primary election, pitch Ph, ball job encircles several J, ball lists several K to wait, determine some type again; (4) the model that the basis is singled out, listed the numerical value of each parameter, and whether do its stiffness and stability safety factor satisfy checking computations requirement. If do not satisfy a requirement, need to choose other model additionally, make afore-mentioned checking computation again, till satisfy a requirement till; (5) when N<10r/min low speed runs, ball guide screw needs to undertake Jing Jiang spends operation. CNC Milling