Thrust Characteristics of a Linear Oscillatory Actuator with Built-in Permanent Magnets

Abstract

This paper describes the thrust characteristics of a linear oscillatory actuator (LOA) with built-in permanent magnets for a pulsator in a milking machine. The LOA consists of a cylindrical rod with two slots and a stator with two built-in permanent ring magnets. A cylindrical rod in the LOA can reciprocate motion by the driving current. The design variables of the LOA-96 are established, and the relations between the design variables and thrust characteristics are considered in the light of an analysis using the finite element method (FEM). The newly designed LOA-96 is 60% smaller and lighter than the LOA-95. It has a maximum thrust of 7.3 N and a stable point at a displacement of x=2 mm when the exciting current is 1.3 A. The difference between the measured values and the values calculated by FEM is approximately ±10%. The stroke of the LOA-96 is a constant 4 mm, which means that it can be used in a pulsator.