01 May 2008
What are the fundamental elements of any construction machine? An engine and drivetrain system to provide traction and power, hydraulics combined with electronics to provide work functions, controls, instrumentation and seating for the operator, and of course, steel and plastic for the structure. These are the essentials.
It is how the Original Equipment Manufacturer (OEM) brings together and matches these various elements that often determines how effective a machine is at doing what it is designed to do. Component suppliers can help an OEM achieve optimum efficiency by providing effective, often tailored solutions.
Take transmissions as an example. We are all aware of the emission legislation that is driving engine developments, but what may be less well known is the effect that this legislation is also having on developments in drivetrains.
For instance, Dana has launched a new Spicer TE15 transmission, designed to provide greater capacity for Tier 3 (Stage IIIA) engines.
The new unit will replace the company's well-proven 320000 series and is claimed to deliver a +15% rating increase through the use of larger bearings and stronger shafting and gearing. The new unit is rated at 190 kW (250 hp), and offers both aluminium and stamped steel torque converters to provide a wide range of capacity to match Tier 3 engines. And it features a new, quieter PTO drive that the company claims provides a +35% increase in capacity.
Dana has addressed one potential area of concern for OEMs. When a new transmission or driveline is developed, any possible changes in its physical envelope over previous models can have potentially serious implications for an OEM, possibly requiring a redesign of the engine compartment to accommodate the new unit. In the case of the new TE15, Dana is making use of many components common to the previous 32000 series, and it therefore presents largely the same silhouette to minimise engineering effort.
Another way that transmission/driveline manufacturers can assist OEMs is by developing solutions for specific applications. Such is the case with another of Dana's recent product launches.
The Hercules 37R116 and 43E175 axles have been designed specifically for wheeled loaders with a lift capacity up to 27 tonnes, and are intended for use in a Spicer package consisting of the axles, the Spicer HSE 2+3 hydrostatic/electronic transmission and the Spicer GWB 2035 driveshaft. This provides an integrated driveline solution.
According to Dana, the axle structure uses extra-high capacity wheel end bearings and heavy section modular components to allow for a wider range of vehicle weights, tracks, tires and chain combinations, with dual, extra wide flotation tires being approved for most vehicle configurations.
ZF Passau is another transmission manufacturer that develops solutions tailored to specific machine types. One of its most recent launches was the HL Series transmissions, for mobile excavators with tractive torques of 550 to 950 Nm, with all vehicle classes with a service weight of up to 25 tonnes being covered. The HL 250, HL 270 and HL290 units have been designed with specific goals in mind. ZF wanted to develop a more compact installed size with standardised mounting points, improved gearshift quality, noise level reductions, a standard brake design on both axles and improved tractive power. ZF's aim is to provide greater versatility and significantly increased power ranges for today's wheeled excavators.
As part of this, it has also developed a new axle designed specifically for excavators. The MS/MT-E 3000 series units feature -25% fewer parts as a result of ZF's modular design and component selection strategy. The 3050 is suitable for use on machines up to 15 tonnes, the 3060 on machines up to 19,5 tonnes and the 3070 on machines up to 25 tonnes. Both front and rear axles feature standardised brake design with encapsulated wet multiple-disk brakes. The brake configuration, acting directly on the wheel hub, is claimed to reduce on site swaying of the vehicle under braking. To aid in maintenance, extended service intervals and fewer lubrication points offer potential savings in both time and maintenance costs.
The provision of increased power and torque was also the aim behind the launch of a new series of transmissions by Allison Transmission. Designed for the non-North American markets, the new International Model family, consisting of four units (the 1000, 2000, 3000 and 4000), provide optimised technology and increased ratings. They will be available from July and replace the existing S1000, S2000, MD3000 and HD4000.
As an example of an integrated package, you only need to look at the new JCB 3CX and 4CX backhoe loaders. The company has redesigned the machine for improved performance and serviceability, but most noticeably, it will be offering an integrated driveline, including its own 63,5 kW (85 hp) naturally aspirated, 68,5 kW (92 hp) turbocharged or 74,5 kW (100 hp) turbocharged diesel engines, integrated into an International Transmissions gearbox and axles. These machines will initially only be available in Europe. The engine and driveline package has been developed with the performance needs of backhoe loaders very firmly in mind. Other manufacturers, notably Case, Volvo, Liebherr and, of course, Caterpillar, also have the ability to provide this kind of integration.
The effect of emissions regulations has also been felt by hydraulic system manufacturers. Sauer Danfoss for one has been developing new solutions to meet the demands of its OEM customers for more efficient machine management solutions. According to the company, the future of hydraulics is system integration and more efficient machine operation. Its new generation of H1 servo controlled hydrostatic pumps, PVG 100 electrohydraulic proportional valves and the Plus 1 electronic communications network has been developed with this in mind.
The H1 family of pumps, the company says, bring intelligent incorporation of the propulsion drive into the machine management architecture and expands the functionality of the vehicle, across a wide range of potential application areas, including construction. The new pumps feature common design technologies and assembly techniques. Overall, they offer simpler, high performance designs with fewer parts than previous hydrostatic products. Significant performance benefits include improved pump efficiency, which reduces unit power losses, and reduced noise levels.
The first in the series to be launched is a single pump configuration with displacements of 147 and 165 cc/rev. Additional models will be released over the course of this year with displacements of 78, 53 and 45 cc/rev. The 53 and 45 cc units will be available in both single and tandem pump configurations, and other displacements will follow.
PVG 100 valves have been designed to function as smart valves that electronically interface with mobile machinery. They are well suited to open circuit applications that require maximum control. As a load independent proportional valve, they provide equitable flow under all load and supply conditions, with post compensated flow-sharing. Effective working pressures for PVG 100 are up to 350 bar (5076 psi) with a compensated flow of 180 litre/min and return flows of up to 350 litre/min.
The Plus1 control solution was launched at Bauma in 2004 and makes use of DSP technology and CANbus communications to provide OEMs with easy customisation of mobile machinery control. The system is built around a line of rugged reliable microcontrollers and input/output terminals, along with Plus 1 compatible joysticks and graphical interfaces.
The use of proportional hydraulics by Sauer Danfoss is an interesting solution. When this technology was first introduced, it was generally fitted to only the larger machines, where the perceived additional cost was considered more acceptable. Today, however, proportional hydraulic systems are increasingly being fitted to smaller and smaller machines. The key is electronics.
Machines of all sizes increasingly feature an electronic control network, and this can be used to both aid installation and then control the proportional hydraulics, thus removing the need for hydraulic control valves to control machine functions, especially from the cab. Electronic remote control systems, or ‘drive-by-wire', is becoming increasingly common.
It is not just the basic hydraulic systems that are receiving attention. Hydraulic drives and motors are also increasingly being optimised for specific applications. Italian drive manufacturer Bonfiglioli recently launched a new slew drive, designated as the 700 TK series, that has been designed specifically for excavators. Intended for use on machines from 1,5 to 20 tonnes, the new unit is compact and powerful, and can be installed in small spaces. The hydraulic motor that provides the power has been developed in conjunction with Kayaba and offers torque ratings from 750 to 9 000 Nm. The motor is a fixed displacement unit with a shockless pressure relief valve that comes with a wide variety of standard drive pinions, although non-standard pinions can be developed to meet specific needs.
A Hagglunds Drives motor was selected for use by Gomaco for its 9500 concrete trimmer and placer. The Compact CA motor offers a high power capacity and Developments in hydraulics extend down to simple attachment couplings, such as the new high flow units from Holmbury JCB's new backhoes feature a state-of-the-art seat mounted control system.
Gomaco was therefore able to go from two drives to a single unit to drive the trimmer head, with obvious cost reduction implications. And there was another benefit offered by the Hagglunds unit – individual motors in the series have the same frame size. This meant that Gomaco was able to use different motors from the series in trimmer heads that had different power requirements without having to redesigning the attachment to Penny + Giles is using Hall Effect non-contact technology to provide a service life up to 15 million operations.
Accommodate different motor sizes, resulting in major time savings.
Linde too has been active in the development of new hydraulic motors for construction equipment applications. It recently launched two new motors/pumps with nominal displacements of 165 and 2 10 cm 3/rev. These, it claims, provide the opportunity to reduce both noise and fuel consumption, and extend service life. The power characteristics of the motors also ensure smooth and sensitive motive control in all speed ranges. The motors can also be used in four wheel drive applications, once again reducing cost for an OEM by eliminating the need for the drop box that is normally required.
Step into the cab of modern construction equipment and you will see a far more pleasing view than might have been the case only a few years ago.
With OEMs increasingly benchmarking leading automotive manufacturers where cab interior design is concerned, they are striving to provide a high quality in-cab ‘experience'. As a result, high quality seats, state-of-the-art control systems and displays, along with easy clean, high quality finishes are the norm in today's construction equipment
Perhaps the most dominating feature of any cab is the seat itself. A number of manufacturers currently vie to supply OEMs with ergonomically designed, often gas suspended, products. Typical of these is German manufacturer Grammar, which recently launched the Primo seat for fork-lifts and compact construction equipment and the Actimo high comfort seat for larger construction equipment.
Designed to compensate for low frequency vibration in the cab, they minimise vertical vibrations and jolts. The company claims that the new seats result in a less stressful operator environment both physically and mentally, aiding productivity and efficiency.
And then there are the vehicle controls. Joysticks on arm rests are increasingly common, as are multiple functions being controlled from a single joystick. Gone are the days of a multitude of manual levers controlling a single function.
Again take JCB as an example. Its new Precision Control System on the new backhoes features seat mounted levers on left and right hand pods that have been positioned according to ergonomic principles to provide optimum ease of use and comfort. This positioning can be adjusted to suit individual operators.
The loader functions are all controlled by a single lever that features a proportional roller to operate auxiliary attachments with added controllability, and switching between loader and excavator functions is simply by pressing a button on the right hand lever. And the pods are even provided with suspension of their own so that they move with the operator.
Penny + Giles is one of the leading suppliers of joystick control solutions. One of the latest additions to its product range is the JC6000, which makes use of non-contact Hall effect technology. This allows the unit to have a service life of up to 15 million operations, twice as long as would be the case with potentiometer-based equivalents, the company claims. Available in a range of standard configurable handle designs, the unit is fitted with a die-cast case to protect the sensing mechanism and is rated to IP66 above the mounting panel when installed.
It is often said that the basic technologies that lie under the surface skin of construction equipment is mature, with current developments just being a case of refining the existing technologies. If this is true, the refinement process has brought equipment a long way from the machines of even 10 years ago, and looks set to take them ever further.