Servovalve Torque Motor Pole Piece Segmentation for Air Gap Calibration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for adjusting air gaps in servovalve torque motors are inefficient, leading to high costs, time consumption, and potential damage to magnetic domains, requiring complex and costly calibration processes such as magnetic heat treatment and wire electrical discharge machining, which can result in reduced performance and contamination issues.
Innovation Solution
The design features detachable and attachable perpendicularly extending portions on C-shaped pole pieces that can be easily adjusted and reattached to a ring-shaped section, allowing for precise calibration of air gaps without disassembling the entire servovalve, reducing the need for expensive and time-consuming processes like grinding or WEDM.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If Magnetic Heat Treatment and wire cutting are used to adjust air gaps, then air gap precision is improved, but magnetic domain performance is damaged and contamination occurs
Solution Approach 1:
The pole piece is divided into a main body and a detachable adjustment portion. This segmentation allows the adjustment portion to be removed, modified, and reattached without subjecting the main magnetic pole to damaging machining processes, thereby preserving magnetic domain integrity while achieving precise air gap adjustment.
Solution Approach 2:
The adjustment function is extracted from the main pole piece structure and placed in a separate detachable adjustment portion. This extracted component can be precisely machined independently and then attached to the pole piece, avoiding contamination and magnetic domain damage to the main magnetic structure.
2Manufacturing precision
If grinding or WEDM is used to adjust poles, then air gap accuracy is improved, but material is damaged and surface quality deteriorates
Solution Approach 1:
By segmenting the pole piece into a main body and a detachable adjustment portion, the harmful machining operations are confined to the adjustment portion only. The main pole piece surface remains undamaged, preserving its magnetic properties and surface quality.
Solution Approach 2:
The adjustment portion acts as a sacrificial component that can be precisely machined and replaced if needed. This disposable-like approach allows aggressive machining of the adjustment portion without concern for damaging the main magnetic pole structure.
3Manufacturing precision
If traditional calibration methods are used, then air gap adjustment is achieved, but assembly disassembly is required and time consumption increases
Solution Approach 1:
The adjustment portion is designed to be dynamically removable and reattachable from the pole piece. This dynamic configuration allows calibration to be performed on the assembled valve without complete disassembly, significantly reducing calibration time while maintaining adjustment precision.
Solution Approach 2:
The adjustment portion can be pre-adjusted and pre-calibrated before final assembly with the pole piece. This preliminary action allows the main assembly process to proceed faster, with minimal on-site adjustment time required.
4Manufacturing precision
If wire cutting process is used, then air gap precision is improved, but contamination occurs and cleaning costs increase
Solution Approach 1:
The wire cutting operation is extracted from the main assembly process and applied only to the separate adjustment portion. This isolation prevents metal chips and contamination from entering the main valve internal passages, eliminating the need for extensive cleaning operations.
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 method simplifies the calibration process, reduces material damage, and lowers costs by allowing for accurate adjustment of air gaps without altering the material properties, thus improving the efficiency and precision of servovalve torque motor assembly.
Implementation Method 1
first and second permanent magnets held between said pole pieces
Implementation Method 2
first and second magnetic coils coupled to said armature
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
An improved torque motor (100) for use in a servovalve is described herein, comprising: first and second pole pieces (20', 20"), having a C-shaped cross-section comprising a ring shaped section (20a, 20b) extending in a first plane with first (20c, 20e) and second portions (20d, 20f) extending perpendicularly away from said plane and inwards towards an armature plate (50). The perpendicularly extending portions (20c-20f) are detachable from and attachable to the ring-shaped section (20a, 20b) of the pole pieces (20', 20") to allow for easier calibration and adjustment of the air gaps between the pole pieces and the armature plate positioned there between. An improved method for calibrating the air gaps in a torque motor (100) of a servovalve is also described herein comprising: assembling the torque motor (100) and after assembly, measuring the air gaps e1 - e4 between the perpendicularly extending portions (20c-20f) of the pole pieces and the armature plate (50), then detaching and removing these perpendicularly extending portions (20c-20f) of the pole pieces; altering their dimensions and re-attaching the perpendicularly extending portions (2c-2f) to said ring-shaped section (20a, 20b) to produce the correct air gap sizes.