Electric Motor Axial Controller Mounting for Compact Design
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Solution Overview
Problem
Existing electric motor devices face challenges in miniaturization and weight reduction while maintaining performance, as well as issues with extraneous material entering the motor casing, which can adversely affect the operation of the stator and rotor.
Innovation Solution
The electric motor device incorporates a motor casing with a cylindrical wall and axial end plate, a stator, and a rotor, along with a power module and heat sink connected via an intermediate member, which allows for a compact design and prevents extraneous material entry by fixing the intermediate member before assembling the stator and rotor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the controller is attached to the electric motor with flanged portions and projecting portions to reduce radial size, then the radial size is reduced, but the outer diameter becomes too small causing a decrease in motor output
Solution Approach 1:
The invention transitions from radial arrangement to axial arrangement by extending the cylindrical wall portion axially and placing the controller axially adjacent to the motor casing, thereby utilizing the axial dimension instead of radial space. This allows the radial size to be reduced while maintaining sufficient outer diameter for motor output.
2Area of stationary object
If the controller is attached parallel to the rotating shaft to reduce mounting space, then mounting space is reduced, but the radial size becomes too large
Solution Approach 1:
The invention changes the attachment orientation from parallel to the rotating shaft (radial direction) to axial direction, utilizing the axial dimension for controller placement. This resolves the contradiction by reducing radial size while maintaining compact mounting space through axial integration.
3Ease of manufacture
If opening portions are formed in the motor casing and controller for lead wire passage, then electrical connection is enabled, but extraneous material may enter the motor casing adversely affecting operation
Solution Approach 1:
The invention replaces open lead wire passages with sealed flexible cable penetrations through the motor casing and controller housings. This maintains electrical connection capability while preventing extraneous material entry, resolving the contradiction between ease of manufacture and protection against harmful factors.
4Temperature
If the heat sink is directly attached to the motor casing to absorb heat from the power module, then heat dissipation is improved, but extraneous material can enter through the attachment interface
Solution Approach 1:
The invention introduces a sealing intermediary element at the interface between the motor casing and controller housing where the heat sink is attached. This intermediary provides both thermal conduction path for heat dissipation and sealing function to prevent extraneous material entry, resolving the contradiction between temperature control and protection against harmful factors.
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 enhances motor output without increasing the radial size, suppresses unfavorable operations due to extraneous material, and improves design flexibility and detection accuracy of the position sensor.
Implementation Method 1
a heat sink provided at the outside of the motor casing, the power module being fixed to the heat sink so that heat generated at the power module is absorbed by the heat sink
Data Source
AI summary
A power module for supplying driving current to coils wound on a stator of an electric motor and a heat sink for absorbing heat generated at the power module are provided at an axial outside of a motor casing. An intermediate member is provided between the motor casing and the heat sink. The intermediate member has a bottom plate portion fixed to an axial end plate of the motor casing and a cylindrical side wall axially extending from the bottom plate portion. An outer peripheral surface of the heat sink is in contact with an inner peripheral surface of the cylindrical side wall, so that the power module fixed to the heat sink is arranged in a space, which is within a range smaller than an outer diameter of the motor casing.