Overmolded Cable Grommet Box Sealing for Heat Pump Refrigerant Leaks

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Solution Overview

Problem

Existing cable entry systems for heat pump systems using flammable refrigerants are complex and expensive, often failing to provide adequate air-tightness against refrigerant leakage, particularly around electronic components.

Innovation Solution

A box with overmolded cable grommets that fit snugly into slots on the box panel, restricting movement and ensuring air-tightness, allowing easy installation and compatibility with various wire sizes and dimensions, even for bulky components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional cable entry systems are used to seal openings in the box, then air-tightness against flammable refrigerant is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:

Improveair-tightnessVSAvoidcable entry system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The cable grommet and sealing function are merged into a single integrated component. The overmolded cable grommet combines cable protection, sealing, and mounting functions in one piece that is directly integrated into the box panel, eliminating the need for separate sealing elements and complex assembly steps.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The overmolded cable grommet serves multiple functions simultaneously: it protects the cable from damage, provides air-tight sealing against flammable refrigerant, facilitates easy mounting through the box panel, and accommodates cable movement. This multi-functional design replaces traditional multi-component cable entry systems.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If traditional cable entry systems are used to ensure air-tightness, then refrigerant leakage prevention is improved, but manufacturing cost increases

Engineering Contradiction:

Improverefrigerant leakage preventionVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The sealing function and cable grommet are combined into a single overmolded component that is directly integrated into the box panel during manufacturing. This eliminates the need for separate sealing elements and reduces assembly steps, thereby lowering manufacturing costs while maintaining refrigerant leakage prevention.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The cable grommet is pre-overmolded onto the cable at a predetermined position before final assembly into the box. This preliminary action ensures proper positioning and sealing capability are built-in during cable preparation, simplifying the final box assembly process and reducing manufacturing complexity.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If traditional cable entry systems are used to seal openings, then air-tightness is improved, but assembly time and complexity increase

Engineering Contradiction:

Improveair-tightnessVSAvoidassembly time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The cable grommet and sealing function are merged into a single integrated component that is directly mounted into the box panel. This integration eliminates the need for separate sealing elements and multiple assembly steps, significantly reducing assembly time while maintaining air-tightness.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The cable grommet is pre-formed and positioned on the cable before insertion into the box panel. This preliminary preparation ensures that during final assembly, the cable with its attached grommet can be quickly inserted and secured in one action, reducing assembly time compared to traditional multi-step sealing procedures.

Inventive Principle:

Principle #10Preliminary action

4Reliability

If cable entry systems are used to seal openings, then refrigerant contact prevention is improved, but adaptability to different wire sizes decreases

Engineering Contradiction:

Improverefrigerant contact preventionVSAvoidwire size compatibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The overmolded cable grommet is designed with adjustable parameters including different outer diameters, lengths, and material properties to accommodate various cable sizes. By varying these parameters, the same basic grommet design can adapt to different wire and cable dimensions while maintaining the air-tight seal and refrigerant contact prevention.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP4615176A1Box, heat pump box comprising the box, method for manufacturing the box, and use of an overmolded cable grommet installable in the box

Publication Date: 2025.09.10 BDR THERMEA GRP

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AI summary

A box adapted to be installed inside a heat pump box, the box optionally being one of an electric equipment box and a refrigerant box, the box comprising: a box panel comprising a slot; and an overmolded cable grommet, molded around a wire, wherein the overmolded cable grommet is arranged inside the slot, contacts an edge of the slot and extends onto a first surface of the box panel, such that the overmolded cable grommet is restricted from moving in at least one direction that is perpendicular to the first surface, and wherein the box is substantially air-tight when an electronic device inside the box is connected to a source that is external to the box via the wire passing through the overmolded cable grommet.