Today's farms are managed like large businesses. In the continuing trend to improve productivity and increase yield, equipment is pushed to the limit. At the same time, precision agriculture is changing traditional practices. So new machines must be more durable, reliable, and provide more versatile and efficient operation.
To meet these challenges, the trend in self-propelled agricultural machinery is to reduce or eliminate all unproductive tasks that reduce the overall output of a machine. As a result, new equipment designs aim to improve cab layout, reduce on-road transport time, increase machine size to boost throughput, increase working speed, and lower operational costs - especially fuel consumption and tire wear.
In the field of hydrostatic transmissions, a new concept of high performance transmissions based on pure hydrostatics has emerged: Speed+. The Speed+ concept is characterized by:
* a wide transmission ratio, which provides high gradeability performance in the field and high speed on the road,
* high efficiency at all speeds for optimum fuel consumption,
* automatic speed shift with continuously variable speed from 0 to 65 Km/h, ensuring best transmission configuration for any circumstance,
* multiple drive modes,
* speed control,
* dynamic braking management,
* anti-stall and diesel engine power management,
* traction control management, and
* default diagnostics.
A key element of these transmissions is the model MW multi-speed motor, which consists of a multi-speed cam-lobe hydrobase and high capacity bearing supports to accommodate larger, heavier machines. The MW also features dynamic and static brakes.
Higher efficiency with direct drive
The MW motors have multi-speed hydrobases, a high displacement ratio, and a maximum rotational speed of 250 rpm, which makes the Speed+ transmission especially well-suited to agricultural applications. They provide high gradeability performance in the field, and high speeds on the road, above 40 km/hr and up to 65 km/hr for sprayers.
For example, one can create a six-speed transmission using four 4-speed motors to obtain a wide range of speed and torque combinations:
Based on direct drive cam-lobe technology, MW motors have fewer moving parts than a motor-gearbox combination. Furthermore, the direct-drive motor maintains its mechanical efficiency across the whole spectrum of rotating speeds - from 1 to 250 rpm. On the other hand, a high-speed motor coupled to a gearbox exhibits a significant drop in mechanical efficiency at high speeds. Ultimately, then, the efficiency of the entire hydrostatic transmission suffers.
The higher efficiency can mean higher productivity, because less downtime will be spent refueling. But higher efficiency isn't the only benefit of the Speed+ drive system. In the Startup mode, full torque is available immediately. In the Field mode, less power is used by MW motors at work speed, so more power is available for implements. In the Road mode, the higher efficiency of direct drive at high speeds means the vehicle will consume less fuel.
Anther advantage of multi-speed cam-lobe motor is quieter operation at high speeds. Plus maintenance is simplified because only one hydraulic oil is needed. With a motor-gearbox combination, the gearbox requires requires gear oil, while the motor requires hydraulic oil. Requiring only one fluid only reduces inventory costs, but reduces the likelihood that the wrong fluid will be used.