Integrated EV Drive Motor Bracket Sealing
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Solution Overview
Problem
Existing electric vehicle drive devices face challenges in size, cost, weight, and reliability due to a double case structure and difficulty in pre-assembly inspection of motor and speed reducer components, leading to reduced productivity.
Innovation Solution
An integrated motor and speed reducer configuration with a motor bracket having outer through holes and a tubular surrounding portion that seals with the speed reducer case, allowing for single-body attachment and inspection, reducing material costs and weight, and simplifying assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a motor and speed reducer are individually manufactured and combined with sealed cases, then sealing against the outside is ensured, but the device cannot be reduced in size, cost, and weight due to the double case structure
Solution Approach 1:
The patent merges the motor case and speed reducer case into a single integrated case structure. The motor is positioned within the speed reducer housing, eliminating the need for separate sealed cases for each component. This integration maintains sealing performance while removing the double case structure, thereby reducing size, cost, and weight.
Solution Approach 2:
The speed reducer housing serves multiple functions: it acts as the outer protective case, provides sealing against the outside environment, and serves as the mounting structure for the motor. This multi-functional design eliminates redundant structural elements while maintaining all necessary sealing and protective functions.
2Device complexity
If the motor and speed reducer are integrated without a double case structure, then size, cost, and weight are reduced, but inspection for the motor as a single body cannot be performed
Solution Approach 1:
The patent segments the assembly process into distinct phases: first assembling and inspecting the motor as a complete unit with both bearings, then integrating it with the speed reducer. This segmentation allows for thorough motor inspection before final integration, ensuring reliability while maintaining the simplified single-case structure.
Solution Approach 2:
The motor is fully assembled and inspected before being integrated with the speed reducer. This preliminary action ensures that the motor meets all performance criteria independently, allowing for proper quality control and reliability verification while maintaining the space-saving integrated design.
3Device complexity
If one rotor bearing is provided to the speed reducer case, then the motor and speed reducer can be integrated, but precise attachment work becomes difficult and productivity is lowered
Solution Approach 1:
The patent introduces a motor support as an intermediary component that facilitates precise attachment. The motor support provides standardized mounting interfaces and positioning features, making the integration of the motor with the speed reducer more precise and efficient, thereby improving productivity while maintaining the integrated design.
Data Source
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AI summary
An electric vehicle drive device (1) includes: a motor body portion (5); a motor housing (6) to which a stator (5c) is fixed on an inner side and which opens on one side in an axial direction; a motor bracket (7) which covers the one side in the axial direction of the stator (5c) and a rotor (5b) and has a center through hole (7a) through which a one-side shaft part (5a1) extending toward the one side in the axial direction from the rotor (5b) penetrates; and a speed reducer (4) which outputs rotation with a speed reduced from a rotational speed of a shaft (5a). The motor bracket (7) has one or more outer through holes (7b) penetrating in the axial direction, on a radially outer side of the center through hole (7a). The motor housing (6) or the motor bracket (7) has a tubular surrounding portion (13) which surrounds, over an entire circumference, a radially outer side of openings on the one side in the axial direction of all the outer through holes (7b). An end surface on the one side in the axial direction of the surrounding portion (13) contacts, over an entire circumference, with a case member (4a) of the speed reducer (4) via a seal member (14) so as to be sealed.