Starter Electromagnetic Switch Radial Dimension Reduction
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Solution Overview
Problem
Conventional starters for engines face challenges in minimizing the radial dimension of the electromagnetic switch due to the need for sufficient insulation distance and space between terminal bolts, which limits the close disposition of these components.
Innovation Solution
The starter design incorporates a cup-shaped contacts cover with a single terminal bolt for connecting the battery and a conductive metal member extending through the side wall to connect the motor, eliminating the need for a second terminal bolt and ensuring a sufficient insulation distance, thereby minimizing the electromagnetic switch's radial dimension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If two terminal bolts are arranged to extend in the axial direction of the motor and align with each other in the radial direction, then the electromagnetic switch can be assembled, but the radial dimension of the electromagnetic switch increases due to the required insulation distance between the terminal bolts
Solution Approach 1:
The invention extracts one of the two terminal bolts from the conventional configuration. Instead of having two terminal bolts extending axially and aligning radially, only one terminal bolt extends in the axial direction. The second electrical connection is achieved through a conductive member extending through the side wall of the contacts cover, thereby eliminating the need for a second axial terminal bolt and reducing the radial dimension.
Solution Approach 2:
The invention changes the dimensional orientation of the second electrical connection from axial to radial. Instead of having both terminal bolts extend in the axial direction, the second connection is achieved through a conductive member that extends through the side wall in the radial direction. This dimensional change allows the connections to be made without requiring radial alignment of two axial terminal bolts, thus minimizing the radial dimension.
2Reliability
If sufficient insulation distance is secured between terminal bolts, then electrical insulation is ensured, but the terminal bolts cannot be closely disposed in the radial direction
Solution Approach 1:
The invention changes the orientation of the second electrical connection from axial to radial by using a conductive member that extends through the side wall. This allows the first terminal bolt to extend axially while the second connection is made radially, ensuring sufficient insulation distance between the axial terminal bolt and the radially extending conductive member, thereby maintaining electrical insulation while minimizing the radial dimension.
Solution Approach 2:
The invention employs asymmetric arrangement of the electrical connections. Instead of symmetric axial alignment of two terminal bolts, one terminal bolt extends axially while the second connection is made through a conductive member extending radially through the side wall. This asymmetric configuration ensures adequate insulation distance while reducing the radial dimension.
3Reliability
If distance between terminal bolts is increased to prevent insulator interference, then reliable contact is achieved, but the electromagnetic switch radial dimension increases
Solution Approach 1:
The invention extracts the second axial terminal bolt from the configuration. Instead of having two axial terminal bolts that require radial spacing to prevent insulator interference, only one axial terminal bolt remains. The second electrical connection is achieved through a conductive member extending radially through the side wall, eliminating the need for radial spacing between two axial terminal bolts and thus reducing the radial dimension while maintaining contact reliability.
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 configuration allows for a reduced diameter of the contacts cover and the entire electromagnetic switch in the radial direction, facilitating easier assembly and minimizing stress concentrations while maintaining effective electrical connections.
Implementation Method 1
When the electromagnetic coil is energized, the plunger is attracted by a magnetic attraction to move the movable contact
Implementation Method 2
The first end portion is inserted in the contacts cover through the side wall of the contacts cover. The second end portion is located outside the contacts cover and electrically connected to the motor
Data Source
AI summary
A starter includes a motor and an electromagnetic switch disposed close to and radially outward of the motor. The switch includes a contacts cover, a terminal bolt, and a conductive metal member. The contacts cover is cup-shaped. The terminal bolt is secured in the contacts cover so as to extend in the axial direction of the motor through an end wall of the contacts cover. The metal member has a first and a second end portion. The first end portion is inserted in the contacts cover through a side wall of the contacts cover. The second end portion is located outside the contacts cover and electrically connected to the motor. The switch further includes a movable contact, a first fixed contact that is electrically connected to a power source via the terminal bolt, and a second fixed contact made up of the first end portion of the metal member.