Justification of dynamic parameters of a crescent-shaped cutter blade for a vine shoot trimming machine

Abstract

Тhe article addresses the problem of drive dynamic instability in a vine shoot trimming machine, which occurs when cutting green grape shoots due to cyclic impact loads. Traditional stabilization methods – installing an additional flywheel or phase misalignment of the blades – complicate the design and increase metal consumption. As an alternative solution, a method of rotation stabilization is proposed that uses the crescent-shaped cutter blade itself as an inertial stabilizer (integrated flywheel) on the drive shaft to smooth the torque, thereby eliminating the need for a separate inertial element. The cutting force for a vine shoot with a diameter of 14 mm was experimentally determined to be 171.3 N. For a blade with a diameter of 215 mm and a minimum technological thickness of 6 mm, rotating at a frequency of 52.33 s⁻¹, the moment of inertia was calculated. Energy balance calculations showed that with a blade mass of 0.86 kg, the rotation irregularity coefficient of the drive shaft is δ=0.180, which significantly exceeds the permissible limits. When the mass is increased to 3,8 kg, δ decreases to 0.0300, which corresponds to the industry-recommended range of 0.02–0.04. The obtained results confirm that targeted selection of the working element's mass and moment of inertia makes it possible to smooth effectively the impulse technological loads, simplifying the design, reducing its metal consumption and cost without deteriorating the drive's dynamic characteristics. The proposed approach eliminates the need for a separate flywheel, simplifying the kinematic scheme and reducing the design cost without compromising the drive's dynamic performance. The practical significance of the work lies in developing a methodology for parametric calculation of the cutting elements of vine shoot trimming machines that perform the combined function of a flywheel.