Movable Iron Core Linear Actuator Magnetic Spring Adjustment
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Solution Overview
Problem
Existing movable iron core linear actuators face challenges in adjusting magnetic spring characteristics, leading to increased mechanical spring costs, reduced mechanical spring life, and control accuracy issues due to fixed magnetic spring characteristics.
Innovation Solution
A movable iron core linear actuator design that includes a magnetic spring adjustment portion formed by removing a space portion from the stator core's facing portion, allowing for adjustable magnetic flux distribution and spring force, thereby enabling adjustment of the magnetic spring characteristic without increasing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the magnetic spring characteristic is fixed and not adjustable, then the manufacturing cost is reduced, but the mechanical spring life is shortened and control accuracy deteriorates
Solution Approach 1:
The invention applies local quality by creating a non-uniform magnetic flux distribution through the air gap between the stator core and permanent magnet. By controlling the air gap distance in specific regions, the magnetic spring characteristic is locally adjusted without changing the overall structure, thereby extending mechanical spring life while maintaining manufacturing simplicity.
Solution Approach 2:
The invention changes the air gap parameter between the stator core and permanent magnet to adjust the magnetic spring characteristic. By varying the air gap distance, the magnetic flux distribution changes, which directly controls the spring force characteristics without requiring additional adjustment mechanisms or increasing device complexity.
2Measurement precision
If the magnetic spring characteristic is fixed, then the device complexity is reduced, but the control accuracy and thrust efficiency deteriorate
Solution Approach 1:
The invention achieves local quality control by precisely controlling the air gap distance in different regions between the stator core and permanent magnet. This local adjustment of the air gap allows optimization of magnetic flux distribution in specific areas, improving control accuracy and thrust efficiency without adding complex control systems.
Solution Approach 2:
The invention applies dynamics by making the magnetic spring characteristic adjustable through air gap control. The air gap distance can be optimized for different operating conditions, allowing the magnetic spring characteristic to adapt to varying control requirements, thereby improving control accuracy without permanent structural complexity.
3Force
If the air gap between stator core and permanent magnet is reduced, then the magnetic spring force increases, but the magnetic flux distribution becomes less controllable
Solution Approach 1:
The invention changes the air gap parameter to optimize both magnetic spring force and flux distribution controllability. By carefully selecting and controlling the air gap distance, the design achieves sufficient magnetic spring force while maintaining manufacturable precision tolerances, avoiding the need for excessively tight gap controls that would be difficult to manufacture.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design prolongs mechanical spring life, reduces costs, and enhances control accuracy and efficiency by distributing load to the magnetic spring, allowing for novel spring characteristics such as reduced or eliminated spring constants, improving control precision and reducing thrust loss.
Implementation Method 1
When the coil is not energized, the pair of the permanent magnets forms a loop-shaped magnetic flux path which starts at one permanent magnet passes through the iron core, the other permanent magnet and the stator core and returns to the one permanent magnet
Implementation Method 2
the spring force of the magnetic spring which is changed by the magnetic flux produced by the permanent magnets in accordance with the relative position of the moving element with respect to the stator core
Implementation Method 3
A magnetic flux produced by energization of coil weakens a magnetic flux produced in a magnet situated in a necessary direction between the pair of permanent magnets, and strengthens a magnetic flux produced in the other magnet
Implementation Method 4
A space portion having low magnetic permeability compared with the stator core is formed to constitute a magnetic spring adjustment portion which changes magnetic flux distribution
Data Source
Figure 1
Figure 2
Figure 3(a)~3(c)
AI summary
To provide a movable iron core linear actuator which implements a novel aspect of a spring characteristic, including of capability of adjustment of the magnetic spring characteristic, without any increase in manufacturing cost. A movable iron core linear actuator includes a magnetic circuit (mc) which causes a moving element (2) to reciprocate. The magnetic circuit (mc) includes an iron core (20) constituting the moving element (2), a stator core (10) including a facing portion (10c) which faces the iron core (20), a pair of permanent magnets (12a, 12b) disposed in the facing portion (10c) along a reciprocating direction and having inverted magnetic poles at their surfaces which face the iron core, and a coil (11) wound around the stator core (10). Energization to coil (11) causes the moving element (2) to reciprocate. When the coil (11) is energized, the spring force of magnetic spring which changed in accordance with a relative position of the moving element (2) with respect to the stator core (10) is superimposed on the electromagnetic driving force (F1, F2) produced by the energization of the coil (11) and is applied to the moving element (2) by the magnetic flux produced by the permanent magnets (12a, 12b). A space portion (30) having low magnetic permeability compared with the stator core (10) is formed to constitute a magnetic spring adjustment portion (3) which changes magnetic flux distribution. The space portion (30) is formed in a state in which a part of the facing portion (10c) is removed in an area, which is the magnetic flux path, between a part of the facing portion (10c) of the stator core (10) and the permanent magnet (12b). By this magnetic spring adjustment portion (3), the magnetic spring characteristic which is the relationship the relative position of the moving element (2) with respect to the stator core (10) and the spring force of the magnetic spring is changed compared with a case in which no space portion (30) is formed.