Hybrid Motor Rotor Clamp Ring Staked to Hub Groove
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Solution Overview
Problem
Existing methods for securing the rotor in hybrid motor vehicle drive trains, such as staking and nut clamping, lack a reliable and durable mechanism to axially fix the rotor, leading to potential instability and inefficiency in torque transmission.
Innovation Solution
A rotor carrier hub with a groove and a clamping ring that is staked into the groove, using a non-ferrous material like bronze or high-strength low-alloy steel, which is heated to expand and then cooled to fit onto the hub, creating a spring-like retention mechanism that maintains a residual clamp load on the rotor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional staking or nut clamping methods are used to secure the rotor, then the rotor can be fixed axially, but the connection lacks reliability and durability leading to potential instability in torque transmission
Solution Approach 1:
The clamping ring is divided into multiple segments that can be independently deformed during the staking process. Each segment can be radially deformed into the grooves of the rotor hub, creating multiple discrete anchoring points that collectively provide superior axial fixation reliability and torque transmission stability compared to conventional monolithic clamping methods
Solution Approach 2:
The clamping ring undergoes parameter changes through thermal expansion and plastic deformation. The ring is heated to expand its dimensions for easier installation, then cooled to contract and create residual clamping force. During staking, radial deformation changes the ring's shape to lock into the rotor hub grooves, providing durable and stable torque transmission
2Ease of manufacture
If a forged material hub with higher ductility is used to enable staking, then the staking process can work effectively, but the device complexity increases compared to simpler clamping methods
Solution Approach 1:
The rotor hub is pre-formed with grooves during the forging process before final assembly. These grooves are prepared in advance to receive and lock the clamping ring segments, enabling the staking process to work effectively without requiring complex post-assembly operations or additional fastening components
Solution Approach 2:
The solution combines a forged ductile hub material with a clamping ring made of bronze or high-strength low-alloy steel. This composite material approach allows the hub to provide structural support and ductility for staking, while the clamping ring provides durable retention, achieving ease of manufacture without excessive device complexity
3Reliability
If threads and nut clamping are used to secure the rotor, then axial fixation is achieved, but the mechanism lacks durability and creates additional device complexity
Solution Approach 1:
The invention extracts and eliminates the need for separate nuts and threaded fasteners by integrating the clamping function directly into a single staked ring component. The ring itself provides both the clamping force and the retention mechanism through its deformation into the hub grooves, simplifying the overall assembly while maintaining or improving axial fixation reliability
Solution Approach 2:
The clamping ring combines multiple functions into a single component: it provides axial clamping force, radial locking into the hub grooves, and residual spring-like retention. This merging of functions eliminates the need for separate nuts, washers, and fasteners, reducing device complexity while enhancing durability
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 solution provides a robust and durable axial fixation of the rotor, enhancing torque transmission efficiency and stability by creating a form-fitting connection between the clamping ring and the rotor carrier hub, preventing axial displacement and maintaining a consistent preload.
Implementation Method 1
which is heated to expand and then cooled to fit onto the hub
Implementation Method 2
staking the clamping ring such that material of the clamping ring protrudes into the groove
Data Source
AI summary
An electric motor includes a rotor, a stator for rotationally driving the rotor and a rotor carrier hub for supporting the rotor on an outer circumferential surface thereof. The rotor carrier hub includes a groove on the outer circumferential surface. The electric motor also includes a clamping ring configured for holding the rotor axially in place on the rotor carrier hub. The clamping ring being fixed on the outer circumferential surface of the rotor carrier hub by at least one inner radial protrusion of the clamping ring extending into contact with the rotor carrier hub in the groove.