Starter Electromagnetic Switch Coil Winding for Magnetic Force Reduction
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Solution Overview
Problem
Existing starting devices for internal combustion engines face challenges in providing sufficient torque while minimizing the risk of damage to components due to intense magnetic field interactions, which can lead to excessive adjustment forces on the piston and pinion.
Innovation Solution
The electromagnetic switch design incorporates coil windings wound in opposite directions within the gap between the piston and core, reducing the magnetic field locally and maintaining structural integrity without altering the overall geometry, allowing for efficient torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the electrical current supplied to the drive motor is increased to provide sufficient torque for starting the internal combustion engine, then the torque is improved, but the magnetic field strength increases leading to excessive adjustment force and potential damage to the pinion and ring gear
Solution Approach 1:
The patent applies local quality by creating a non-uniform magnetic field distribution through the groove structure on the piston. The groove is positioned specifically in the region where the magnetic field acts on the piston, locally reducing the magnetic field strength in that area. This allows the overall magnetic field to remain strong for sufficient torque while the local field strength at the piston surface is reduced to prevent excessive adjustment force and component damage.
Solution Approach 2:
The groove on the piston acts as an intermediary structure that modifies the interaction between the magnetic field and the piston. By introducing this geometric feature, the patent creates a buffer zone that reduces the direct impact of the strong magnetic field on the piston surface, thereby mediating between the need for strong magnetic field (for torque) and the need to limit magnetic field effects (to prevent damage).
2Object-affected harmful factors
If a ferromagnetic bypass body is provided on the coil carrier to weaken the magnetic field, then the magnetic field strength is reduced, but the structural space available for coil winding decreases
Solution Approach 1:
Instead of adding a bypass body that occupies radial or axial space, the patent uses a groove feature that utilizes the surface geometry of the piston. This dimensional approach allows magnetic field modification without compromising the volume available for coil winding, as the groove is formed on the existing piston surface rather than requiring additional structural elements.
Solution Approach 2:
The patent extracts the magnetic field modification function from a separate bypass body component and integrates it directly into the piston structure through the groove. This eliminates the need for an additional bypass body that would occupy space, while still achieving the desired magnetic field weakening effect through the groove geometry alone.
3Object-affected harmful factors
If the piston is equipped with an encircling groove to reduce the influence of the magnetic field, then the magnetic field influence is reduced, but the non-uniform profile leads to non-uniform sliding of the piston within the coil carrier
Solution Approach 1:
The groove is designed as a localized feature rather than a complete encircling groove. By positioning the groove specifically in the region where magnetic field reduction is needed and making it axially limited in extent, the patent achieves magnetic field reduction while maintaining a relatively uniform piston profile in other areas, thereby preserving more uniform sliding characteristics.
Solution Approach 2:
Instead of using a complete encircling groove that would significantly disrupt the piston profile, the patent uses a partial groove that is axially limited. This partial action provides sufficient magnetic field reduction in the critical region while minimizing the overall impact on the piston's sliding uniformity within the coil carrier.
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 approach effectively reduces the magnetic force on the piston, preventing damage to the pinion and ring gear while maintaining or increasing torque, ensuring reliable engine starting without structural compromise.
Implementation Method 1
the coil winding 13 generates a magnetic field within the cavity 18, which magnetic field adjusts the piston 12 axially in the direction of a core 22
Implementation Method 2
During operation, the coils generate a magnetic field within the coil carrier, which magnetic field adjusts a ferromagnetic piston within the coil carrier in the direction of a core
Data Source
Figure 1~3
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Figure 7~8
AI summary
The present invention relates to an electromagnetic switch (1) for a starting device (2) of an internal combustion engine (3), which electromagnetic switch has a coil wire (30) wound to form a coil winding (13), wherein the coil wire (30) is wound in a first winding direction (28) and partially in a second winding direction (29) which is opposite to the first winding direction (28), and wherein at least one winding of the coil wire (30) wound in the second winding direction (29) axially overlaps an axial gap (32) which, in a passive position (27) of a piston (12) of the switch (1), is formed between the piston (12) and a core (22). The invention furthermore relates to a starting device (2) for an internal combustion engine (3), which starting device has an electromagnetic switch (1) of said type.