Trust screw selection method:
1. Knowing conditions: UPH, workbench quality M1, itinerary length LS, maximum speed VMAX, acceleration time T1 and T3, positioning accuracy+-0.3mm/1000mm, reciprocating exercise cycle, gap 0.15mm
Second, select items: screw diameter, guide, nut model, accuracy, axial gap, screw support method, motor
Third, calculation:
1. accuracy and type.
(Tour gap, axial gap) 0.15mm, select the screw with a gap below 0.15, check the table with a screw with a diameter of less than 32mm. The 32mm clearance is 0.14mm.
In order to meet+-0.3mm/1000mm,+-0.3mm/1000 = x/300
X =+-0.09mm. You must choose a guide accuracy of ± 0.090mm/300mm or more. See the accuracy level of the scioner, select the C7 screw. Type of Aflery: According to the agency, the type of screws is: rolling or grinding screws, positioning or transmission
2. Guide. (Determine the rolling beads and rotation speed at a straight line speed and rotation speed)
The maximum speed of the guide and the motor pH> = 60*1000*v/(n/a)
(1.) pH: screw rod guide mm
(2.) V: The highest feed speed M/s is predetermined
() N: Motor use speed RPM
() A: deceleration ratio
3. Diameter. (Determine diameter of the load) dynamic load and static load; calculate thrust, generally only look at the dynamic load
Calculation of axial load: U friction coefficient; a = vmax/t acceleration; T to accelerate the deceleration time;
Horizontal time: Undertaking the maximum axial load during acceleration, to withstand the minimum load during the deceleration; when vertical: to bear the maximum axial load when rising, the minimum load when decreases; the minimum load;
1. At the time of acceleration (ascending) n: FMAX = u*m*g+f-m*A
2. During the deceleration (decrease) n: fmin = u*m*m*g+f-m*A
3. In a constant speed, n: f even = u*m*g+fu
Due to the thinner the diameter of the screw shaft, the smaller the axial load of the screw shaft
4. length. (Total length = work stroke+nut length+safety balance+installation length+connection length+balance). If the protection is increased, such as the protective cover, the telescopic ratio of the protective cover (usually 1: 8. The maximum extension of the protective cover is divided into 8).
5. Support method. Fixed-fixed fixation-support support-support fixation-freedom
6. Choice of nut:
7. Use speed calculation: screw shaft diameter 20mm, guide pH = 20mm maximum speed vmax = 1m/s
Then: the highest speed NMAX = vmax60/pH. Motoring speed (critical speed) n1 = r (d1/)*
The coefficient determined by R installation method; D1 = silk grooved groove trail; L = installation spacing so: maximum speed
8. Selection of stiffness
9. Select motor verification: stiffness verification, accuracy level verification, life selection, driving torque selection
The roller screw is pre -tightened:
1. Method: Double nut washer, pre -tightening, pre -tightening of single nut, and pre -tightening of the diameter of the single nut to increase the diameter;
2. Objective: Eliminate the axial gap of the drum screw side, increase the rigidity and DN value of the drum screw tribe: D: the nominal diameter of the drill screw side, and the diameter (mm) at the center of the ball; Extreme speed (RPM) guidance accuracy, positioning accuracy, repeated positioning accuracy
Guideline accuracy:
1. Average itinerary deviation E (um) in the effective itinerary LU, EP = 2*(lu/300)*v300 <= c;
2. Any 300mm stroke Virgin V300 (UM), V300 <=
positioning accuracy:
(1.) Direct accuracy
(2.) Axial gap
(3.) The axial rigidity of the transmission system
(4.) Heat deformation
(5.) The movement posture of the screw
Repeat positioning accuracy: The repetitive positioning accuracy tends to be zero.
