Power Capacitor Spring Pad Vibration Damping

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Solution Overview

Problem

Existing power capacitors are not effectively protected against vibrations, which can lead to instability and interference in electronic systems, particularly in applications like motor vehicles.

Innovation Solution

A power capacitor design featuring a mechanically resilient element, such as a plastic foam 'spring pad' with gas-filled closed cells, is integrated between the capacitor winding and housing to absorb volume expansion and dampen vibrations, ensuring a constant capacitance and improved electromagnetic compatibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a rigid mechanical fixing is used to secure the capacitor winding in the housing, then the capacitor winding is firmly positioned, but vibrations are transmitted and cause instability and interference in electronic systems

Engineering Contradiction:
Improveposition stability of capacitor windingVSAvoidvibration transmission
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent applies beforehand cushioning by introducing a mechanically resilient element (spring element) between the capacitor winding and the housing before vibrations occur. This spring element absorbs and dampens vibrations beforehand, preventing them from being transmitted to the capacitor winding and causing instability or interference in electronic systems.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent uses an intermediary approach by placing a spring element as a mediator between the capacitor winding and the housing. This spring element acts as a cushioning intermediary that decouples the rigid connection, allowing the capacitor winding to be securely positioned while preventing vibration transmission to the housing and other components.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If the capacitor winding is tightly fixed in the housing, then the capacitance remains constant, but thermal expansion causes stress and potential damage to the capacitor structure

Engineering Contradiction:
Improvecapacitance constancyVSAvoidstructural integrity under thermal stress
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The patent applies dynamics by replacing a rigid fixed connection with a dynamically adaptable spring element. This spring element can elastically deform to accommodate thermal expansion of the capacitor winding while maintaining electrical connection and capacitance stability, thus preventing structural damage from thermal stress.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent uses parameter changes by allowing the spring element to change its compression state in response to thermal expansion. As temperature increases and the capacitor winding expands, the spring element compresses accordingly, maintaining constant capacitance while accommodating the dimensional changes without causing structural damage.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If a solid resilient element is used to absorb vibrations, then vibration damping is achieved, but material fatigue occurs over time reducing service life

Engineering Contradiction:
Improvevibration dampingVSAvoidservice life due to material fatigue
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies pneumatics by using a spring element with closed-cell foam structure containing gas-filled pores. The gas compression and decompression within the closed cells provides resilient behavior that dampens vibrations while being highly insensitive to material fatigue, significantly extending the service life compared to solid resilient materials.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent uses porous materials by employing a spring element made of closed-cell foam with gas-filled pores. This porous structure allows the material to absorb and dissipate vibration energy through gas compression while maintaining high resistance to material fatigue, ensuring long-term reliability and service life.

Inventive Principle:
Principle #31Porous materials

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 solution effectively absorbs thermal expansion and vibrations, maintaining a constant capacitance and enhancing electromagnetic compatibility by positioning the capacitor winding securely within the housing, thereby reducing the risk of interference and ensuring long-term resilience without material fatigue.

Implementation Method 1

the volume expansion of the capacitor winding can be absorbed when it is heated

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

The spring properties are not primarily caused by the compression and decompression of a solid body, but rather by the closed gas bubbles and thus by the compression or decompression of a gas volume

Methodology Applied
Scientific EffectCompression and decompression of gas volume: Compression

Implementation Method 3

such a resilient element also has the advantage that vibrations, such as those that occur when operating a motor vehicle, can be damped

Methodology Applied
Scientific EffectVibration damping: Damping

Implementation Method 4

The spring properties are not primarily caused by the compression and decompression of a solid body, but rather by the closed gas bubbles and thus by the compression or decompression of a gas volume

Methodology Applied
Scientific EffectCompression and decompression of gas volume: Compression

Data Source

PatentEP2306477B1Power capacitor
Publication Date: 2013.07.03 TDK ELECTRONICS AG
  • EP2306477B1 patent drawingFigure 1
  • EP2306477B1 patent drawingFigure 2
  • EP2306477B1 patent drawingFigure 3

AI summary

The capacitor has a housing (1), capacitor windings (18a, 18b), and mechanical spring units (19a, 19b) arranged between the housing and the corresponding capacitor windings, where the spring units are formed as the spring-pad. The capacitor windings are designed based on metallized polymer multilayer winding technique. The dielectric of the capacitor windings is made of e.g. polyester, polypropylene. The thickness of the dielectric is 3 mu meter. Profiled insulation jackets are provided between the capacitor windings and the housing for mechanical fixation of the spring units.