Hydraulic Pump Assembly Centrifugal Lever Dynamics Control

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Solution Overview

Problem

Hydraulic pump assemblies in all-wheel drive systems face challenges in maintaining high dynamics while being robust against process disturbances such as external acceleration, vibrations, and temperature changes, leading to unwanted torque variations in non-desired frequency ranges.

Innovation Solution

The introduction of a defined friction surface between the centrifugal lever and radial flanges, along with spring means to resiliently bias the lever, helps control the dynamics of the regulator by providing a controlled axial force to counteract centrifugal forces, thereby stabilizing the torque regulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the hydraulic pump assembly operates with high dynamics to respond quickly to torque demands, then the response speed and torque regulation capability are improved, but the system becomes more sensitive to process disturbances such as vibrations and acceleration changes, causing unwanted torque variations

Engineering Contradiction:
Improveresponse speedVSAvoidrobustness against disturbances
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent introduces an intermediary damping element between the centrifugal lever and the radial flange. This intermediary component absorbs and dissipates disturbance energies (vibrations, acceleration changes) before they can propagate through the system and cause unwanted torque variations, while allowing the system to maintain its high dynamic response capability for legitimate torque demands

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the dynamic parameters of the regulator by introducing controlled friction and damping. This changes the frequency response characteristics of the system, filtering out high-frequency disturbances while preserving the ability to respond to lower-frequency torque demands, thus resolving the contradiction between speed and robustness

Inventive Principle:
Principle #35Parameter changes

2Reliability

If spring means are added to resiliently bias the centrifugal lever against the radial flange, then the control over regulator dynamics is improved and torque regulation is stabilized, but the device complexity increases

Engineering Contradiction:
Improvetorque regulation stabilityVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent designs the spring means to serve multiple functions simultaneously: it provides the biasing force for the centrifugal lever, contributes to the damping effect, and helps define the friction contact characteristics. This multi-functionality allows the system to achieve improved torque regulation stability without a proportional increase in overall device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines several functions into the spring means component: biasing force generation, damping contribution, and friction contact management. By merging these functions into a single integrated solution rather than adding separate components for each function, the increase in device complexity is minimized while achieving the desired torque regulation stability

Inventive Principle:
Principle #5Merging (Combining)

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 enhances the control over the dynamics of the hydraulic pump assembly, reducing unwanted torque variations and improving the balance between high dynamics and robustness against process disturbances, ensuring precise torque distribution without superimposed disturbances.

Implementation Method 1

spring means for resiliently biasing the lever against said one of the flanges

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the introduction of a defined friction surface between the lever and one of the radial flanges

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

centrifugal lever pivotally attached thereto for radial movements between radial flanges under the action of centrifugal force at rotation of the piston drum

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2978969B1A hydraulic pump assembly
Publication Date: 2020.04.29 BORGWARNER SWEDEN AB
  • EP2978969B1 patent drawingFigure 1~2
  • EP2978969B1 patent drawingFigure 3~4
  • EP2978969B1 patent drawingFigure 5~6

AI summary

A hydraulic pump assembly comprises a rotatable piston drum (20) with at least one centrifugal lever (23) pivotally attached thereto for radial movements between radial flanges (20') under the action of centrifugal force at rotation of the piston drum. The centrifugal lever (23) is arranged to control the position of a valve member, preferably a ball (22), at the opening end of a bore (21) in the piston drum (20). There is a defined friction surface (28; 32) between the lever (23) and one of the radial flanges (20'), and there are spring means (29-31; 25, 33) for resiliently biasing the lever against said one of the flanges.