How to produce car steering gears efficiently?

In the next few years, hardly any aspect of automotive design will change as radically as the steering system. It faces a veritable revolution, as a McKinsey study has revealed. According to that study, self-driving cars could make up a large part of road traffic in about 20 years' time. Link to report: https://www.mckinsey.com/industries/automotive-and-assembly/our-insights/autonomous-driving-disruption-technology-use-cases-and-opportunities

This development will obviously have an impact on steering wheels, steering columns, and steering gears. In fact, significant changes can be observed already: Efficient EPS steering systems are on the advance—which, in turn, is changing automotive production. A key question for planners is: How can the components of these systems, such as pinions, worms, and worm wheels be produced (more) efficiently, with high precision and flexibility, on a single machine?

Focus on steering gears

Of course, this change has an impact on steering gear production especially: On the one hand, suppliers have to handle ever-changing components because the entire technology is changing rapidly. On the other hand, typical toothed elements of the steering gear such as pinions, worms and worm gears should ideally be produced on a single machine—ever faster, more flexibly, and more cost-efficiently. However, what are the production solutions that will allow the greatest possible variety of toothed components to be cut efficiently? “This is the crucial question that has occupied our developers in recent years,” says Jörg Lohmann, Head of Technology & Product Management at EMAG KOEPFER based in Villingen-Schwenningen, Germany. Our answer is the horizontal gear cutting machine HLC 150 H. It's a solution that does it all. This machine can process a huge range of workpieces—gear and armature shafts, steering pinions, worm wheels, and planetary gears, with lengths of up to 500 millimeters. All relevant gear-cutting technologies are used, such as hobbing, skive hobbing, screw milling, screw skiving, and chamfer technology.” (For the technical specifications of the machine, see: https://www.emag.com/machines/gear-hobbing-machines/horizontal-gear-hobbing-machines/hlc-150- h.html

Focus on low costs

A closer look at the processes within the machine reveals the benefits of this approach. Take transmission shafts as an example: Gear hobbing (rough-machining) is the first step in the HLC 150 H, followed by press deburring of the gearing. Finishing is completed in the second hobbing step. The result is an entirely burr-free chamfered gear. Numerous technical details contribute to workpiece quality and process reliability. During the milling operation, for instance, the cutter head with its very rigid suspension always moves in its entirety. As a result, the whole milling process runs smoothly and with high precision. In addition, there is a carefully engineered chip disposal system: Users benefit from a free downward chip flow inside the machine. This prevents any chip build-up during dry machining. Various conveyor solutions are available including scraper conveyors and permanent-magnetic conveyors. “The discharge process runs very smoothly. High process reliability is guaranteed,” says Lohmann.

Focus on economic efficiency

EMAG develops the machines with an eye to their economic efficiency: A whole range of details ensure lower machine costs. For example, the hydraulic units are very energy-efficient. Next, the media supply is only activated when required. Equally important is that operators need very little time to change tools in the HLC 150 H. A quick-clamping system is provided for this, and all relevant areas are easy to reach. This means that in the event of a tool change, the machine stops only for a very short time—after all, such downtime costs money in production.

Finally, how does EMAG integrate this system into a complete production line? The answer is in the company's modular automation concept: To begin with, the HLC 150 H can be loaded both manually and by automation. In the latter case, lighter components up to 2.5 kg are handled by an integrated high-speed gantry loader with rotating twin gripper. However, for heavier workpieces up to 10 kg, a V-shaped linear gripper is available. Integration into complete EMAG production lines is therefore no problem. (For more information: https://www.emag.com/blog/en/hlc-150-h-perfect-gear-cutting-solution-multiple-workpieces Short chip-to-chip times are always the objective.

Video shows many details

By the way: This video gives a good idea of the processes within the machine: http://www.mtdcnc.com/tv/product-reviews/emag-hlc–new-at-emo-2017 “We show some interesting details here. At the same time, the video conveys the dynamics of the machine with its powerful 28 kW milling head,” says Lohmann, EMAG KOEPFER's Head of Technology & Product Management. “All in all, the new HLC 150 H brings a lot together: It is an economical, all-purpose gear-cutting solution incorporating all the relevant machining techniques, including chamfering and press-deburring. In addition, we offer excellent value for money because the basic machine structure is built using highly efficient processes. For all these reasons, the machine has great market potential.”

What do line solutions for steering pinions look like?

The steering pinion is where the typical challenges of car production collide: On the one hand, it is an essential component for driver safety and must satisfy high quality standards; on the other hand, cost pressures are as high as ever. Therefore, its production also calls for lots of speed. How EMAG meets these requirements in the context of large multi-technology lines is shown in the example of this supplier in eastern Germany: https://www.emag.com/blog/en/steering-pinion-the-emag-production-line-guarantees-both-speed-and-flexibility/