Active Chassis Axle Damping Mount for Motor-Pump Vibration
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Solution Overview
Problem
The motor-pump unit of an active chassis damping arrangement in motor vehicles vibrates excessively during travel, leading to undesirable noise and acoustic disturbances.
Innovation Solution
Attaching the motor-pump unit to a subframe or auxiliary frame via a carrier, which is preferably connected to the stabilizer areas, to reduce vibrations without affecting noise levels. This can be achieved by using a carrier that extends in the design space of the stabilizer or by integrating the motor-pump unit into the carrier, with specific bearing stiffness configurations to shift natural frequencies away from excitation frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the motor-pump unit is directly mounted on the axle or body, then the structure is simple and easy to install, but the motor-pump unit vibrates strongly during vehicle travel
Solution Approach 1:
A carrier is introduced as an intermediary component between the motor-pump unit and the subframe/auxiliary frame. This carrier serves as a vibration-isolating interface that reduces the transmission of vibrations from the motor-pump unit to the vehicle structure, thereby reducing harmful vibrations while maintaining mounting simplicity
Solution Approach 2:
The carrier is designed with vibration-reducing features that cushion and dampen vibrations before they can propagate through the vehicle structure. This beforehand cushioning approach prevents strong vibrations from occurring in the first place, rather than attempting to mitigate them after generation
2Object-affected harmful factors
If the motor-pump unit is rigidly attached to reduce vibrations, then vibration is reduced, but noise development is affected and acoustics are impaired
Solution Approach 1:
The carrier is designed with differentiated local properties: certain regions provide vibration isolation while other regions maintain acoustic transparency. This allows the structure to selectively reduce vibrations in specific frequency ranges while preserving noise characteristics and acoustic quality in other ranges
Solution Approach 2:
The natural frequencies of the motor-pump unit are shifted by modifying the carrier's structural parameters (stiffness, mass distribution, mounting geometry). This frequency shifting moves the vibration frequencies away from the excitation frequency range, reducing vibrations without affecting the acoustic properties at other frequencies
3Object-affected harmful factors
If the carrier is rigidly attached to the subframe to reduce vibrations, then the motor-pump unit vibrates less, but the complexity of the mounting structure increases
Solution Approach 1:
The carrier is designed to perform multiple functions simultaneously: it serves as a mounting structure for the motor-pump unit, a vibration-isolating element, and a structural connector to the subframe/auxiliary frame. This multi-functionality reduces the need for separate vibration isolation components, thereby limiting the increase in overall structural complexity
Data Source
AI summary
A damping arrangement of an active chassis for an axle of a motor vehicle, wherein a damping system cooperates with each wheel of the axle. Each of the damping systems includes a damper having a double-acting hydraulic cylinder and a piston. The damper is couplable to a wheel suspension system of the respective wheel. A hydraulic pump and an electric motor drives the respective hydraulic pump, wherein the hydraulic pump is driven by the electric motor in different directions of rotation to provide different conveying directions. A hydraulic unit includes a hydraulic reservoir and valves, wherein the hydraulic pump and the hydraulic unit of the respective damping system cooperate with hydraulic chambers of the hydraulic cylinder of the respective damping system, such that, depending on the conveying direction of the hydraulic pump, a movement of the piston in either a first or second actuation direction can be provided.