Rotary Electric Machine O-ring Sealing Cost Reduction
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Solution Overview
Problem
Conventional hybrid electric vehicle driving apparatuses face increased machining costs and material costs due to the need for O-ring housing grooves on two axial end portions of the motor casing, which also contribute to the weight of the motor casing.
Innovation Solution
A rotary electric machine design that omits at least one O-ring housing groove by using separate position regulating members to restrict the axial movement of O-rings, eliminating the need for machining grooves on the frame and allowing thinner wall thickness, thereby reducing machining and material costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If O-ring housing grooves are formed on two axial end portions of the motor casing, then the O-rings are properly held and coolant channels are formed, but machining costs increase and material costs increase due to thicker walls
Solution Approach 1:
The patent extracts the O-ring housing groove formation from the motor casing by introducing separate position regulating members. These members are mounted on the motor casing and directly regulate O-ring axial positions, eliminating the need for grooves to be formed in the motor casing itself. This resolves the contradiction by maintaining sealing reliability through proper O-ring positioning while eliminating the costly machining operations.
Solution Approach 2:
The patent introduces position regulating members as intermediary components between the motor casing and the O-rings. These members serve as mediators that perform the function of restricting O-ring axial movement without requiring the motor casing to have machined grooves. The position regulating members are simpler to manufacture and install, thereby reducing machining costs while maintaining the sealing function.
2Reliability
If O-ring housing grooves are formed on the motor casing, then the O-rings are properly held, but the small diameter portions become thicker increasing material costs and weight
Solution Approach 1:
The patent removes the requirement for deep grooves in the motor casing by extracting this function to separate position regulating members. This allows the motor casing walls to be made thinner since they no longer need to accommodate deep groove features, thereby reducing material usage and overall weight of the motor casing while maintaining proper O-ring positioning for sealing.
3Weight of stationary object
If the wall thickness of the small diameter portion is made thinner, then material costs and weight are reduced, but a machining process is required to make the wall thickness thinner increasing machining costs
Solution Approach 1:
The patent merges the functions of O-ring positioning and coolant channel formation into the position regulating members themselves, rather than requiring separate groove features in the motor casing. The position regulating members are designed to perform multiple functions: restricting O-ring axial movement and defining coolant channel geometry. This integration eliminates the need for additional machining to create thin walls with grooves, reducing both material costs and machining costs.
4Reliability
If two O-ring housing grooves are formed on the motor casing, then coolant channels are formed between the motor casing and intermediate housing, but the number of machining positions increases
Solution Approach 1:
The patent extracts the coolant channel definition function from the motor casing grooves and transfers it to the position regulating members. The position regulating members are mounted on the motor casing and directly define the coolant channel geometry through their outer circumferential surfaces. This eliminates the need for complex groove machining on the motor casing, reducing the number of machining positions and operations required while maintaining effective coolant channels.
Data Source
AI summary
In the rotary electric machine according to the present invention, a first O-ring 13a is mounted between a pair of position regulating members 12 that are press-fitted onto and held in a vicinity of a second axial end of an outer circumferential surface of a stator core housing portion 10a so as to be spaced apart in an axial direction, and is pressed and held between the stator core housing portion 10a and a cylindrical portion 16, and a second O-ring 13b is mounted into an O-ring housing groove 11 that is recessed into an outer circumferential surface of a frame mounting portion 10b, and is pressed and held between the frame mounting portion 10b and the cylindrical portion 16, such that a coolant channel 22 is formed between the frame 10 and the cylindrical portion 16.