Resolver Stator Fixation with Knock Pin Stop
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Solution Overview
Problem
The existing fixation structures for resolvers, such as those using knock pins, are prone to falling off due to vibrations, especially in vehicles, and can loosen due to thermal expansion differences between materials, leading to instability in the resolver stator's position.
Innovation Solution
A stop portion is provided to oppose the rear end of the knock pin, preventing its rearward movement and potential fall-off by engaging with the knock pin before it can completely dislodge from the knock hole, ensuring secure fixation even under thermal expansion and vibration conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a knock pin is used to position the resolver stator, then the resolver stator can be positioned with respect to the case, but the knock pin may fall off due to vibration or thermal expansion
Solution Approach 1:
The knock pin is divided into two functional segments: a positioning portion inserted into the knock hole for positioning, and a stop portion that extends beyond the knock hole to prevent complete dislodgement. This segmentation allows the knock pin to both position the resolver stator accurately and prevent itself from falling off during vibration or thermal expansion.
Solution Approach 2:
The stop portion is designed in advance to extend beyond the knock hole, creating a preliminary barrier that prevents the knock pin from falling off before vibration or thermal expansion can cause complete dislodgement. This preliminary protective structure ensures that even if the knock pin loosens, it cannot completely detach.
2Adaptability or versatility
If materials with different thermal expansion coefficients are used for the structure and knock pin, then thermal expansion differences occur, but this causes the knock pin to loosen
Solution Approach 1:
The stop portion acts as a cushioning barrier that compensates for the loosening effect of thermal expansion. When thermal expansion causes the knock pin to loosen, the stop portion prevents complete dislodgement by providing a physical barrier that absorbs the expansion-induced movement, maintaining the connection's stability.
3Ease of manufacture
If the knock pin is allowed to move freely, then installation is simple, but vibration causes the knock pin to fall off
Solution Approach 1:
The knock pin is segmented into a positioning portion for simple insertion and a stop portion for vibration resistance. The positioning portion maintains ease of installation by being inserted into the knock hole, while the stop portion extending beyond the knock hole prevents the pin from falling off during vibration, thus maintaining both installation simplicity and vibration resistance.
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 stop portion effectively prevents the knock pin from falling off, maintaining the resolver stator's position and stability, even in environments with significant thermal expansion and vibration, thereby ensuring accurate detection of the rotor's rotation position.
Implementation Method 1
in a case where a structure and a knock pin are formed, for example, from materials having different thermal expansion coefficients, the knock pin may be loosened due to a difference in thermal expansion
Implementation Method 2
a knock pin is easy to fall off due to vibration of the vehicle
Data Source
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AI summary
A knock pin (50) is inserted into a knock hole (54) of an electric motor case (18) to which a resolver stator (30) is fixed. The resolver stator (30) is positioned by engaging the knock pin (50) with an engagement groove (56). The resolver stator (30) includes a stop portion (58) at a position opposed to a rear end of the knock pin (50) in its insertion direction. When the knock pin (50) is about to fall off from the knock hole (54), the stop portion (58) prevents its movement, thereby preventing the falling off.