Steering Apparatus Vibration Damping via Electronic Control
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Solution Overview
Problem
Conventional steering apparatuses experience inefficiencies in motion conversion and torque transmission, leading to discomfort for drivers due to rotational vibrations from disturbance inputs, particularly when using rack-and-pinion type electric power steering devices.
Innovation Solution
The steering apparatus employs two rack-and-pinion type electric power steering devices, each connected to a swing arm member, with an electronic control unit that detects steering torque, calculates target assist torques, and applies correcting torques to reduce rotational vibrations, thereby enhancing steering assist and minimizing driver discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If rack-and-pinion type electric power steering devices are used to apply assist torque to swing arm members, then steering assist can be applied smoothly to both left and right wheels, but rotational vibration from disturbance inputs is transmitted to the steering wheel causing driver discomfort
Solution Approach 1:
A vibration reduction device is introduced as an intermediary component between the rack-and-pinion type electric power steering devices and the swing arm members. This device includes a damper that generates damping torque to counteract rotational vibrations transmitted from the wheels to the steering wheel, thereby reducing driver discomfort while maintaining smooth steering assist functionality
Solution Approach 2:
The invention converts the harmful rotational vibrations into beneficial damping torque through the vibration reduction device. The damper detects rotational vibration around the steering axis and generates counteracting damping torque, transforming the harmful vibration energy into useful opposition force that reduces the transmitted vibration to the steering wheel
2Power
If recirculating ball-type steering gears with multiple motion conversion components are used, then assist torque can be applied to both swing arm members, but efficiency of motion conversion and torque transmission is not high
Solution Approach 1:
The steering system is segmented into independent left and right rack-and-pinion type electric power steering devices, each directly applying assist torque to its corresponding swing arm member. This segmentation eliminates the need for multiple intermediate motion conversion components (sector gears, arms, drag links) found in recirculating ball systems, thereby reducing energy loss and improving overall torque transmission efficiency
Solution Approach 2:
The invention extracts and removes the unnecessary intermediate motion conversion components from the steering system. By directly connecting the rack-and-pinion electric power steering devices to the swing arm members, the system eliminates energy-wasting components while maintaining the capability to apply assist torque to both swing arm members
Data Source
AI summary
A steering apparatus includes left and right swing arm members, left and right tie rods pivotally attached to the arm portions of the swing arm members at their inner ends, relay rods pivotally attached to the arm portions at both ends, and a steering input transmission system. Rack-and-pinion type electric power steering devices are connected to the arm portions of the left and right swing arm members. A control unit calculates correcting steering torques for reducing rotational vibrations generated in the electric power steering devices due to a disturbance, and correct target steering assist torques calculated based on a steering torque with the correcting steering torques and control the electric power steering devices with the corrected target steering assist torques.