Dual-Motor Ball Screw Suspension for Damping and Wheel Steering
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Solution Overview
Problem
Current vehicle suspension systems that incorporate a ball screw cannot steer a wheel, limiting their ability to eliminate the need for a separate steering system and perform various vehicle control functions.
Innovation Solution
A suspension system that includes a shaft with both screw and spline grooves, a ball screw nut, a ball spline nut, a ball screw-specific motor connected to the ball screw nut, and a ball spline-specific motor connected to the ball spline nut, allowing the system to generate damping forces and steer a wheel by rotating the unsprung mass relative to the sprung mass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a ball screw is used to generate damping force between sprung mass and unsprung mass, then the damping force generation capability is improved, but the ability to steer the wheel is lost
Solution Approach 1:
The invention divides the single ball screw mechanism into two separate mechanisms: a ball screw for generating damping force (axial movement) and a ball spline for enabling wheel steering (rotational movement). This segmentation allows each mechanism to perform its specific function independently, resolving the contradiction between damping force generation and wheel steering capability.
Solution Approach 2:
The suspension system is designed to perform multiple functions through integrated control of the two mechanisms. The ball screw provides damping control while the ball spline enables steering, allowing the suspension system to simultaneously achieve vibration suppression and directional control, enhancing overall system versatility.
2Adaptability or versatility
If a separate steering system is equipped, then the wheel steering function is achieved, but the device complexity increases
Solution Approach 1:
The invention merges the steering function into the suspension system by integrating the ball spline mechanism with the existing ball screw structure. Both mechanisms share the same shaft and are controlled by a unified system, eliminating the need for a separate steering system and reducing overall device complexity while maintaining steering functionality.
3Device complexity
If the motor causes the axial force of the screw shaft to act between sprung mass and unsprung mass, then the damping force generation is simplified, but the wheel steering capability is eliminated
Solution Approach 1:
The motor system is segmented into two independent motors: a ball screw-specific motor for controlling axial movement and damping force generation, and a ball spline-specific motor for controlling rotational movement and wheel steering. This segmentation allows each motor to independently control its respective mechanism without interfering with the other function.
Solution Approach 2:
The system dynamically switches between damping force generation mode and wheel steering mode by independently controlling the two motors. The ball screw-specific motor activates for vibration suppression while the ball spline-specific motor activates for steering maneuvers, allowing the system to adapt its functionality based on real-time operational requirements.
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 system effectively generates damping forces between the sprung and unsprung masses, enabling wheel steering, which can eliminate the need for a separate steering system and allow for various vehicle control functions such as correcting oversteering and adjusting toe-in for improved stability.
Implementation Method 1
a shaft (5) having a screw groove (5a) and a spline groove (5b) formed thereon; a ball screw nut (6) assembled to the shaft (5) via a ball (17)
Implementation Method 2
a ball spline nut (7) assembled to the shaft (5) via a ball (10); the ball spline-specific motor (9) rotates the ball spline nut (7) and the shaft (5) relative to the case (18)
Implementation Method 3
a ball screw nut (6) assembled to the shaft (5) via a ball (17); a ball spline nut (7) assembled to the shaft (5) via a ball (10)
Data Source
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AI summary
A suspension is provided which can not only generate a damping force between sprung mass and unsprung mass but also steer a wheel. A suspension (3) includes: a shaft (5) coupled to sprung mass of a vehicle, the shaft (5) having a screw groove (5a) and a spline groove (5b) formed thereon; a ball screw nut (6) assembled to the shaft (5) via a ball (17); a ball spline nut (7) assembled to the shaft (5) via a ball (10); a ball screw-specific motor (8) connected to the ball screw nut (6); a ball spline-specific motor (9) connected to the ball spline nut (7); and a case (18) coupled to unsprung mass of the vehicle, the case (18) being configured to hold the ball screw-specific motor (8) and the ball spline-specific motor (9). The ball spline-specific motor (9) rotates the ball spline nut (7) and the shaft (5) relative to the case (18).