Drive shafts for fire engines and special vehicles – reliable drive for special vehicles

Special vehicle construction requires higher standards than the classic commercial vehicle segment. This means that drive shafts for special vehicles must also be able to withstand demanding conditions and heavy loads. These include, among other things

• Tight space conditions in the drivetrain,
• high torques in a compact design,
• frequent load changes and extreme temperatures,
• long service life and
• high demands on the service life of the vehicle.

In addition, many rescue vehicles are also equipped with auxiliary units: pumps, power generators or hydraulic systems are used wherever electrical energy or mechanical power is required on site, for example to operate lifting gear or extinguishing systems. Power is therefore transmitted via a special PTO shaft that is perfectly designed for the design, application and power requirements of the auxiliary drive.

Not every drive shaft is equally suitable for every application profile. The load profile, design and installation situation are particularly important for special vehicles. Two designs are used particularly frequently in special vehicle construction: cardan shafts and double cardan shafts. Depending on the vehicle type and actual operating profile, different designs can be considered.

Cardan shafts, typically with a connecting tube and integrated length compensation, are a proven standard in vehicle construction – they are robust, durable and suitable for numerous applications. They are generally used when the input and output are not aligned, but are offset from each other in the vehicle. An example of this is the drive shaft between the transfer case and the driven axle in any commercial or special vehicle.
Double cardan shafts, or more correctly double cardan shafts, also have two joints, but these are connected to each other in a very confined space by a solid center piece. This arrangement allows significantly larger deflection angles and, if installed correctly, almost uniform torque transmission. This is necessary in almost every special vehicle with driven steering axles.

Double cardan shaft

In vehicles for special applications such as fire engines or military vehicles, drive components often have to withstand higher demands – for example when driving in rough terrain, under difficult environmental conditions, including climatic conditions, while at the same time requiring high technical availability. The selection of the right drive shaft is therefore always based on the specific vehicle type and its actual requirements profile:

• Standard drive shafts: Designed for use under relatively stable operating conditions, for example with longitudinal drives in a classic drive train of a fire-fighting vehicle.
• High-performance cardan shafts: Optimized for high torque peaks, changing loads and special climatic requirements – e.g. for swap bodies, all-terrain special vehicles such as wheeled armoured vehicles or for airport fire departments
• Customized drive shafts: For customer- or application-specific installation situations or special vehicles with special requirements for power take-offs, we at Elbe develop tailor-made special solutions for your specific application on request.

The more specific the vehicle profile, the more individual the requirements for the drive shaft. Do you have a technical question or are you planning a specific project? Then don’t hesitate to get in touch with us – we look forward to hearing from you, also via our contact form.

Wheeled armored vehicles | special vehicles

The universal joints are the central element of every drive shaft: they create a movable connection between the components and ensure that angular deviations are reliably compensated during operation.

Cardan shafts consist of at least two universal joints, a length compensation, a tube and matching connecting parts, the so-called flanges. This classic design has also proven itself in many special vehicles – such as fire engines, personnel carriers or emergency vehicles with a conventional axle structure. Power is transmitted via the universal joint, which can compensate for angular misalignments in the driveline. At the same time, the length compensation ensures the necessary mobility when the axle moves up and down or when the load changes.

The underlying cardanic principle enables a torsion-resistant but angularly flexible connection between two shafts. Torques are reliably transmitted even at offset installation angles – a key criterion for stable performance in special vehicle applications.

Flansch Half Round Yoke

In contrast to the classic cardan shaft, with length compensation and / or connecting tube, double universal joint shafts consist of two universal joints positioned directly behind each other, which are rigidly connected by a center piece. This design allows the individual angles of the joints to be combined to form an overall angle that is twice as large and, if the double joint is positioned correctly, the angular velocity fluctuations (cardan error) typical of cardan shafts can be reduced to a minimum, thus ensuring almost uniform power transmission.

Double joints are primarily used in driven steering axles and enable smoother running and greater driving comfort. The connection on the wheel side (planetary drive) is made via a positive-locking profile connection, just like on the differential side. There are different requirements for the gearing. While a simple spline is used as a connection in the differential, the requirements on the wheel side are often higher, as a spline often has to be applied to the short fork shaft. Thanks to their compact design, double joints can also be used efficiently in tight installation spaces.

As an experienced manufacturer of drive shafts, we have been developing and producing high-quality drive components for over 100 years – precisely tailored to your requirements. Our products are used worldwide and stand for tested quality and a long service life, even under demanding operating conditions.

Our service at a glance:

• Broad product range: From proven standard universal joint shafts to individually designed custom-made products.
• Tailor-made drive shafts: We can supply you with drive shafts that fit your (special) vehicle and its installation conditions exactly.
• High-quality materials: Designed for high torques, strong load changes and maximum service life.
• Fast delivery: Thanks to large stocks and optimized logistics, we deliver flexibly and on time.
• Expert advice: From selection and design to series delivery – our team will support you right from the start.

The technical design is always based on the load spectrum of your vehicle. Our theoretical calculations are validated by test bench results to ensure operational safety even under real conditions.

Regular maintenance of cardan shafts is crucial for the long-term and safe operation of special vehicles. Signs of wear on universal joints and profiles can become noticeable, especially with frequent chassis movements, high loads or changing operating conditions.

If signs are detected at an early stage, the condition of the shaft can be checked professionally and replaced if necessary – ideally with an original drive shaft from an authorized specialist workshop.

Are you looking for a customized drive shaft solution for your special vehicle?
Our offer is aimed at vehicle manufacturers, system suppliers and public clients with a need for reliable drive components for special vehicles. We are happy to support you in the design of individual drive shafts – whether for an individual project or series production. Take a look at our product catalog in advance or visit one of our locations.
Simply use our contact form for inquiries – we look forward to hearing from you.