We received a notice of allowance on November 14th, regarding our international patent application for heat pipe cooled wet rotating disc engagement systems, more commonly known as wet clutches or wet disc brakes. The potential applications are immense because virtually every heavy duty vehicle, virtually every piece of heavy machinery that’s powered by an engine incorporates either a wet clutch or a wet brake.
First: a bit of background for those who aren’t gearheads:
How clutches work
A driving shaft runs from the engine, connects to and, therefore, turns the driven shaft. In other words, the drive shaft transfers energy to the driven shaft which has no source of energy.
So how does the energy get transferred? Through the clutch
The clutch connects the driving shaft to a driven shaft, so that the driven shaft may be started or stopped at will, without stopping the driving shaft. Because vehicles must stop for traffic signals or to simply idle at the driver’s whim and because heavy machinery may need to be re-positioned, the driven shaft must stop, but the engine and consequently the driving shaft should continue to run.
Types of Clutches
A dry clutch uses friction to engage the driven shaft. It is not bathed in liquid.
A wet clutch is immersed in a fluid that cools the systems and provides smooth, quiet performance.
A single plate clutch uses both sides of one clutch plate to engage the driving shaft and the driven shaft.
Multi-plate clutches are used when large amounts of torque must be transmitted in applications such as trucks, cranes and heavy machinery. They’re also used when compact construction is required in applications such as motorcycles. All multi-plate clutches are wet.
I assume you know how brakes work, so I’m going to make a quick distinction. For our purposes, there are two
Types of brakes
Dry brakes are usually a single disc or drum. They heat up quickly under heavy use and wear out fast, costing more in parts and labor over the life of a vehicle.
Wet brakes are bathed in liquid. They offer increased durability and stopping power.
What do wet brakes and wet clutches have in common?
Most wet brakes and clutches incorporate multiple discs or friction plates that are aligned side by side on a common shaft. Since the surfaces of a wet clutch or brake can be slippery, stacking multiple discs compensates for the reduced friction. This eliminates slippage when the system is engaged. Thus, the extra discs provide more stopping power or better power transfer and they improve overall safety.
When engaged, the discs compress together which causes friction and generates heat. Both systems rely on fluid to transfer the heat away from the friction plates.
Because of the liquid cooling, wet clutches can take a lot of abuse. As a result, they excel in heavy duty applications that require frequent usage. Wet brakes virtually eliminate brake maintenance. Since the fluid absorbs the heat from the friction, the linings last far longer and require fewer adjustments and replacements than dry set-ups.
Wet disc brakes are located inside the rear housing of a vehicle. Normally, they’re found on the axle shaft, but sometimes on the differential shafts. Whereas wet clutches are always located between the engine and the gearbox. As both applications are completely sealed, they’re ideal for dirty applications where there’s a risk of contamination or corrosion to the brake or clutch components.
For all their advantages, the systems have inherent problems. Heavy usage and loads can raise temperatures. The enclosed, fully-sealed assembly can act like ovens concentrating and magnifying heat. While large amounts of fluid can easily absorb the increased temperature, during compression, all that remains is a very thin film which must transfer the heat to the outer surfaces of the discs to effectively remove it.
The result: thermal overload which can destroy the film, deform the discs and degrade the disc surfaces.
Heat treating and advanced metallurgy using exotic materials can help address the problems, but that involves the addition of significant costs.
CoolTech’s heat pipe technology can be incorporated within the discs and rapidly transfer heat to the surrounding oil before the temperature reaches critical levels. The result: increased capability to transmit more power from the application (which is also known as increased power density), fewer repairs and a longer life cycle.
Another significant benefit is that heat pipes are passive. Place them anywhere. As long as there is a difference in temperature between the location where one end of the heat pipe is placed and the other, the heat pipe is going to quickly transfer heat first time, every time.
So what does it mean to manufacturers?
All they need to do is modify their current designs to incorporate our heat pipe technology. They don’t need to add a power source for the heat pipes. They don’t need to add exotic materials and coatings or — worst case of all — redesign their products from scratch.
What are the potential applications?
Work Trucks, Snowmobiles, Motorcycles, Diesel Locomotives
Bulldozers, Excavators, Front End Loaders
Tractors, Combines, Harvesters
Cranes, Hoists, Forklifts
Tanks, Self-Propelled Artillery, Mechanized Infantry
Formula 1, Indy Car, Rally, Drag
So what’s next?
The first order of business will be to modify the top 3 clutch/brake manufacturers’ products, perform independent testing and certification then seek out and negotiate partnership/joint venture/license agreement with a clutch/brake manufacturer. We also plan to approach OEMs, end users and the aftermarket. For example, when we modify a motorcycle clutch, we will bring it to the OEM with their full feature/function and benefits intact. Show them that it is certified and can be produced today off their existing tooling/die and manufacturing processes.
The smaller size of the motorcycle clutches makes for faster testing and turn-around. A partnership with a wet brake manufacturer should follow, sometime thereafter. All it takes a just one successful test and introduction and we should be able to start rolling out new applications for years to come.
Any referrals, thoughts or recommendations are always welcome: firstname.lastname@example.org
Tim Hassett, Chairman & CEO