Solenoid Actuator Structure for Stable End-of-Stroke Thrust
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Solution Overview
Problem
Existing solenoid actuators face a decrease in thrust in the latter half of the stroke due to changes in the ratio of axial and radial components of magnetic force, which complicates the shapes of the mover and stator, increasing manufacturing costs.
Innovation Solution
A solenoid actuator design featuring a mover with an annular projection and a second stator with an annular recess, increasing the magnetism transfer area near the maximum stroke position, and using a second press part to form the annular recess, reducing manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the shapes of the mover and stator are changed to adjust the direction of magnetic force, then the thrust decrease in the latter half of the stroke is suppressed, but the manufacturing cost increases due to the complication of the shapes
Solution Approach 1:
The invention applies local quality by providing a protrusion on the mover and a corresponding recess on the stator that are localized to the peripheral edge portion. These local structural modifications change the magnetic force distribution only in the specific region where it is needed (peripheral area), without requiring complex changes to the entire mover and stator shapes. This maintains thrust in the latter half of the stroke while keeping manufacturing costs low.
2Reliability
If the axial length of magnetic transmission part is lengthened by fitting second stator core into hole in yoke, then the amount of axial overlap is ensured, but the device complexity increases
Solution Approach 1:
The invention extracts the magnetic transmission function from the traditional fitted stator core structure and relocates it to the peripheral edge portion through the protrusion-recess configuration. This separates the magnetic force generation function from the structural support function, allowing the main stator body to remain simple while the peripheral magnetic transmission elements are added only where needed.
3Reliability
If the magnetism transfer area is increased near maximum stroke position, then the thrust decrease is suppressed, but the manufacturing complexity increases
Solution Approach 1:
The invention increases the magnetism transfer area by utilizing the radial dimension through the peripheral edge protrusion and recess configuration. Instead of increasing the axial length of magnetic transmission parts (which would complicate the stator structure), the solution extends the magnetic interaction area radially at the peripheral edge, providing additional magnetic force where needed without increasing overall device complexity.
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
The design maintains thrust throughout the stroke range with minimal fluctuations and reduces manufacturing costs by simplifying the stator structure.
Implementation Method 1
a mover configured to be movable in the axial direction to a maximum stroke position from an original position on a radially inner side of the first stator toward the second stator by a magnetic force generated by energizing the coil
Implementation Method 2
a magnetism transfer area between the mover and the second stator increases in the vicinity of the maximum stroke position
Data Source
AI summary
A solenoid actuator 1 includes: a coil 3; a first stator 10 and a second stator 20 disposed with an air gap 11 therebetween in an axial direction so as to form a magnetic path 4 around the coil 3; and a mover 50 configured to be movable in the axial direction to a maximum stroke position (X=Xmax) from an original position (X=0) on a radially inner side of the first stator 10 toward the second stator 20 by a magnetic force generated by energizing the coil 3. The mover 50 has an annular projection 100 projecting in the axial direction from a peripheral edge portion of the mover 50. The second stator 20 includes: a second yoke 24; and a second press part 40 made of a magnetic material and disposed on an inner peripheral side of the second yoke 24 so as to at least partially form an annular recess 120 for receiving the annular projection 100 of the mover 50 at the maximum stroke position (X=Xmax).