No.000209 Transfer and Press Mechanism

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30

Application Overview

Purpose

• Purpose: To transfer and press-fit washers.
  Operation: A washer is suctioned by vacuum, rotated by 180°, transferred to the press fitting part, and press-fit onto the shaft by the cylinder. The head rotates by -180° to return to the suction part to pick up the next workpiece.

Target workpiece

• Workpiece: washer
  Size: φ20, t0.5

Design Specifications

Operating Conditions or Design Requirements

• Outer dimensions: W230 x D263 x H598mm
  Rotating angle:±180°
  Press fit stroke:8mm
  Suction head positioning time(when rotated by 180°)1Sec

Required Performance

• Press fitting force: 40N or higher

Selection Criteria for Main Components

• As the press fitting force is 40N or higher, a φ20 cylinder is selected.
  To achieve 180° rotation time of 1 second, a 100W motor is selected.

Design Evaluation

Verification of main components

• Verify if the motor selected can satisfy the load inertia and load torque requirements.
• Calculation of shaft-converted load inertia
  • Conditional value: inertia of reducer JMG = 0.051kg·cm², inertia of shaft JS = 4.705kg·m², inertia of coupling JC = 6.300kg·cm², inertia of rotary table JK = 198.4kg·cm², reduction ratio 1/nm = 1/21.
  • From shaft-converted load inertia JL = JMG + (JC + JK + JS) x (1/nm)², JL = 0.051 + (6.3 + 198.375 + 4.705) x (1/21)² = 0.526kg·cm².
    From inertia ratio m = JL/JM, m = 0.526/0.078 = 6.8 < 17 times (motor specification recommended value).
• Calculation of torque during acceleration
  • Conditional value: efficiency of drive section η = 0.980, motor rotation speed N0 = 832.233r/min, acceleration time Tsa = 0.200s, motor shaft-converted load torque TL = 0.000N·m.
  • From torque during ascending acceleration TMa = ((((JL/η) + JM) x N0) / (9.55 x 104 x Tsa)) + TL, TMa = ((((0.526 / 0.987) + 0.078) x 832.233) / (9.55 x 104 x 0.2)) + 0.000 = 0.027N·m.
  • The maximum torque is reached during acceleration, and as peak load rate Rp is obtained by Rp = (Tma / Ttyp) x 100, where rated torque Ttyp = 0.32N·m,
    Rp = (0.027/0.32) x 100 = 8.438%
  • If the actual load torque is calculated by calculating the torque during each operation pattern, 0.014N·m < 0.32N·m (rated torque).

Other Design Consideration

• As the index table for feeding workpieces is arranged at a lower position, the mounting bracket for the motor is placed at the top of the mechanism.
  In addition, a servo motor is employed to address high speed requirements and the acceleration/deceleration.