Capacitor unit, and electric compressor

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Solution Overview

Problem

The vibration between the circuit board and the capacitor unit in vehicle-mounted air conditioners causes stress on the board side terminal, leading to potential deformation or damage, which needs to be reliably prevented.

Innovation Solution

A capacitor unit design featuring a board side terminal with notch portions that absorb vibration, reducing stress concentration and preventing deformation or damage by forming a curved section between the base and distal end, which can be efficiently created using a conductive metal plate without increasing processing steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the board side terminal is rigidly connected to the circuit board, then the electrical connection is stable, but the terminal deforms or damages due to vibration stress

Engineering Contradiction:

Improveelectrical connection stabilityVSAvoidterminal resistance to vibration stress

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent introduces a curved portion in the board side terminal that acts as a cushioning element before vibration stress reaches the solder connection. This curved portion absorbs and mitigates vibration stress through elastic deformation, protecting the solder joint from damage while maintaining electrical connectivity.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent changes the geometric parameters of the board side terminal by introducing a curved portion with specific radius and angle. This parameter change allows the terminal to flex under vibration stress, transforming it from a rigid structure vulnerable to stress concentration into a flexible structure that can absorb stress through controlled deformation.

Inventive Principle:

Principle #35Parameter changes

2Strength

If the board side terminal is made flexible to absorb vibration, then the terminal resists stress, but the connection reliability may be compromised

Engineering Contradiction:

Improveterminal resistance to vibration stressVSAvoidconnection stability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent applies local quality by creating a curved portion only in the middle section of the board side terminal, while keeping the distal end portion (connection area) and base portion rigid. This localized curvature provides vibration absorption exactly where needed, while maintaining rigid connections at the interface points with the circuit board and housing.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The curved portion is positioned to intercept vibration stress before it reaches the solder connection. By placing the cushioning element upstream in the stress transmission path, the design protects the critical connection point while maintaining overall connection stability.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Strength

If a curved portion is added to the terminal, then vibration stress is absorbed, but the manufacturing complexity increases

Engineering Contradiction:

Improveterminal resistance to vibration stressVSAvoidterminal fabrication simplicity

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent uses a curved portion with a specified radius of curvature to absorb vibration stress. This curvature can be efficiently manufactured using standard sheet metal forming processes such as rolling or bending, which are commonly available in production environments without requiring complex or specialized equipment.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent specifies concrete parameter ranges for the curved portion (radius: 5-20mm, angle: 30-120 degrees) that balance vibration absorption performance with manufacturability. These parameter ranges are optimized to achieve adequate stress absorption while remaining compatible with conventional manufacturing processes.

Inventive Principle:

Principle #35Parameter changes

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 design effectively suppresses vibration input to the board side terminal, preventing deformation or damage to the connection part between the terminal and the circuit board, ensuring reliable operation.

Implementation Method 1

the vibration of the distal end portion in the second direction with respect to the base portion is absorbed by the region in which the notch portion is formed

Methodology Applied

Scientific EffectVibration absorption: Damping

Implementation Method 2

the vibration transmitted from the circuit board to the board side terminal can be absorbed by the region in which the first notch portion and the second notch portion are formed

Methodology Applied

Scientific EffectVibration absorption: Damping

Data Source

PatentUS11509186B2Capacitor unit, and electric compressor

Publication Date: 2022.11.22 MITSUBISHI HEAVY IND THERMAL SYST

AI summary

A capacitor unit (20) includes: a harness side terminal (23) provided in a housing (22) for accommodating a capacitor main body therein and connectable to an electric power harness for supplying DC power from an outside; and a board side terminal (24) connectable to a circuit board from which the DC power is output via the capacitor main body. The board side terminal (24) extends in a plate shape from a base portion (24b) held in the housing (22) toward a distal end portion (24a) connected to the circuit board, and has a notch portion (40) recessed inward of the board side terminal (24) in a width direction between the base portion (24b) and the distal end portion (24a).