The commercial vehicle market consistently requires stronger defenses against hazards such as temperature, vibration, and exposure to moisture or chemicals, all of which can cause failure. As a result, suppliers are developing ruggedized connectors that meet stringent requirements and ratings.
Connector Innovations for Commercial Vehicles
Connector manufacturers are taking advantage of slower demand in the heavy-duty Class 8 truck and bus markets to make significant investments in new product development, aggressively going after market share and preparing for a market uptick by introducing forward-thinking products. At the center of most of this innovation is harsh environment performance.
Improved Seal Performance
According to a survey1 conducted by Molex, 90% of the failures experienced during agricultural vehicle manufacturing and field use involve sealing issues. With the increase in electrification of these vehicles, Molex observed that the sealing issues could be attributed to two primary causes. First, chemical contaminants and fuel can cause the cross-link structure within the silicone seal material to break down, causing the seal to fail. Second, bends occur in cables near their connector entry points. This bowing occurs in the field due to the harsh environments to which they are exposed, and it can cause the connector system to pull at the seal, exposing leaks. Yet, even with the high rate of these incidents, the connector industry hasn’t been compelled to change the sealed connector systems – until now.
Molex introduced the ML-XT Sealed Connection System to offer market-leading high-performance seal technology. The rear seals are made from high-consistency rubber (HCR), which provides greater tear resistance and protection from water ingress. The front seal employs a two-shot LSR seal that will not fall off, which is a concern in some other designs. The ML-XT system is IP69K-rated, J2030 power-wash test-capable, and passes the full rigid SAE J2030 testing.
Unique Designs Enhance Ruggedness
Delphi is also a leader in the ruggedized connector space. The manufacturer offers Harsh Environment Series (HES) Connection Systems, which include circular connectors, terminals, and a rectangular 50- and 60-way header. The systems are built to withstand the harshest environments, at a cost advantage compared to standard pin-and-sleeve systems. Delphi also addressed seal performance with the HES Connection Systems. Its recessed three-rib design maintains sealing properties even if a tight wire dress is applied, providing up to 30% better sealing capability compared to previous designs. Constructed through sonic welding of the seal container and designed with a wave spring, the connection system maintains face seal compression, even when subjected to the high-vibration commercial vehicle SAE J2030 standard. The circular connector is equipped with a specialized finger design that results in 40% better retention when compared to existing designs, a trait that virtually eliminates terminal unseats. The HES system also features visual guides that enhance ease of assembly and quality: Arrows direct engagement of the locking collar, a window visually displays lock engagement, and color-coded seals distinguish between cable and terminal specifications. The HES Connection System has excellent current-carrying capabilities and passes the full J2030 testing.
ITT Cannon’s APD High Power line offers a solution for engine-, transmission-, and brake fluid-resistant connection systems. The APD connectors are designed for harsh environments that require compact sizes and high power consumption. Derived from ISO 15170, the APD connectors function in many harsh environment applications. From one-way through 51-way, the APD line offers a variety of shell styles, and accessories allow for easy adoption to OEM specifications.
Uncompromising Under Extreme Vibration Conditions
Sumitomo Wiring Systems meets the demands of the CV industry with ruggedized connectors designed to reliably withstand extreme temperatures and vibration ratings. Sumitomo’s HYHV 2.8mm Series are ultra-high-performance connectors that can withstand more than 90Gs of vibration. The female connectors feature a separate inner and outer housing with a rubber ring in between the housings. This unique design compresses the rubber ring when the connector is mated, and it reduces the clearance between the mating connectors, which lessens the effects of vibration on the terminals. This design paved the way for the US Series 2.8mm and 1.2mm connectors, which are lower-cost versions of the HYHV series but pack just as much punch with regard to vibration performance. Designed to a USCAR-2 footprint, the US 1.2 series follows the two-piece design for severe vibration capabilities. In fact, when tested by a major Class 8 engine OEM, the US 1.2 series outperformed all of the other USCAR-compliant connectors it tested.
These are just a few examples of the innovation occurring in ruggedized connectors. As CV OEMs continue to demand even more stringent requirements for performance in harsh environments, connector manufacturers will rise to the challenge to introduce new ruggedized solutions.
Authors Lee Iken and Quang Luong are the director of the transportation business unit and the director of sales engineering at TTI Inc., respectively.