From passenger cars to engineering and agricultural equipment, modern vehicles are equipped with complex electronic devices, all of which require compact and reliable interconnected components. The electric vehicle (EV) battery pack is a typical example. As battery density increases, designers are under pressure to find connecting components that can save space and simplify the assembly process. Achieving this goal is not an easy task, as connectors still need to maintain long-term reliability under harsh conditions.
Industrial and agricultural vehicles face similar demands. Let's consider a satellite navigation autonomous tractor: if the connector malfunctions, the only safe response may be to stop and check. However, crops and weather will not wait for service technicians to arrive, and unplanned shutdowns may result in income losses or even complete crop failure.
The wiring challenges of modern vehicles
These applications face a common challenge: as vehicle electronic devices become increasingly complex, the number of interconnected devices is also increasing. With the increase in the number of interconnected devices, the volume also increases, and the number of fault points also increases, which brings new challenges to wiring and installation.
To overcome these challenges, interconnected systems need to have the following characteristics:
Compact and easy to integrate, suitable for space constrained designs
The contact should have high mechanical strength and high anti vibration characteristics to ensure reliability
Adopting safety protection design to prevent electric shock and incorrect connection during maintenance process
In consumer applications, flexible printed circuits (FPC) and flexible flat cables (FFC) have long been the preferred solutions for space constrained multi conductor interconnects. In automotive applications, these interconnects commonly known as ribbon cables have always been questioned. On the contrary, automotive system designers tend to choose traditional wiring harnesses known for their reliability.
In view of this, Hirose has launched the TB4 series high-performance FPC/FFC board connectors. This series of connectors not only significantly enhances the robustness of flexible cable interconnection and provides the reliability of traditional wiring harnesses, but also has a very compact and easy to assemble appearance.
Effective methods for building vehicle interconnection
The TB4 series interconnect system (Figure 1) consists of three parts, including an onboard socket, a center locking plug that ensures reliable connection without the need for additional fasteners, and an orange fixator that can lock FPC or FFC cables in place. This design is very space saving: the mating height of the horizontal connector is only 4.5 millimeters (mm), and the 1 mm contact spacing minimizes the overall width to the greatest extent possible.
Figure 1: The TB4 series interconnection system adopts a simple three part structure, which can achieve ultra-thin and robust vehicle level interconnection. (Image source: Hirose)
The TB4 series has a rated current of 1.0 ampere (A) and a rated voltage of 100 volts, and can support various vehicle interconnection requirements. In addition to these electrical specifications, the design also addresses the key issue of using flexible cables in harsh environments. The specific characteristics are as follows:
Two point gold-plated contact mechanism is used in each socket to maintain high signal integrity even under thermal cycling and vibration
The unidirectional mating feature can prevent incorrect insertion and improve safety during maintenance
Protecting the guide rail helps prevent accidental finger contact and reduce the risk of electric shock
Adopting a structure that complies with RoHS3, halogen-free, and UL94V-0 flammability standards, and meets USCAR-2 requirements for automotive grade electrical connector systems
Using two key code types, black and gray, helps prevent incorrect connections when using multiple TB4 components at close range
All of these features combined make flexible cable connections as reliable as traditional wire harnesses and significantly reduce space occupation.
Check TB4 series connectors
The TB4 series offers a variety of sizes and configuration options to accommodate different applications. When larger interconnect devices are required, the 26-TB4-30S-1H (800) (Figure 2) socket achieves 30 pin positions in a compact size of 8.75 × 37.9 mm. This socket has a small polarization mark that helps service technicians verify if the mating direction is correct. There are similar markings on the corresponding plugs.