Precise modulation of the clutch offers many benefits, not only with regard to improved performance but also when it comes to service life and cost-effectiveness. Users of agricultural and construction machinery perform heavy-duty work on a daily basis. This is made possible by a so-called powershift transmission. As the name suggests, this type of transmission is characterized by its ability to shift gears under load – a process in which fine-tuning of the clutch is particularly important. To ensure smooth shifting in such systems, the gears are controlled electronically and shifted hydraulically. Thomas provides solutions covering the entire range of electrohydraulic valves: the PPCD08 or PPCD09 for smaller machines, complemented by the PPCP09 HF 2.0 for high-precision clutch control of large machinery.
Maximum performance in the smallest of spaces
The Thomas-engineered PPCD08 and PPCD09 directly operated clutch valves, together with the PPCP09 HF 2.0, are the most compact solutions currently available on the market. With a flow rate of 30 l/min, the PPCD09 valve boasts the highest performance in its class. Engineered with power and performance in mind, the PPCP09 HF 2.0 is specially designed for large construction and agricultural machinery.
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Precise clutch actuation ensures instantaneous shifting even under load or when the oil is cold. Our specially developed PPCD08, PPCD09, and PPCP09 HF 2.0 clutch control valves regulate the oil pressure, while the hydraulics are responsible for the shift function. The key to a smooth driving experience lies in the precise and fast pressure control of these valves.
Combining the benefits of extremely reliable pressure control and low flow resistance, Thomas’s electrohydraulic valves provide immediate and precise clutch actuation that remains constant even under fluctuating supply pressure. This enables fast, smooth, and precise gear changes for comfortable handling. The valves have proven to be particularly robust in practice. They are insusceptible to oil contamination and resistant to the effects of temperature and vibration, in addition to having a long service life. These properties prove invaluable in extreme conditions in particular, such as those frequently encountered in agriculture or the construction industry.
Graphic: Excellent pressure/flow characteristic curve of the PPCP09 HF 2.0 in heavily contaminated oil (X/20/17)
Among the key aspects when selecting transmission valves are the control pressure and the flow rate, which largely determine the torque to be transmitted and the actuation time of the clutch. The PPCP09 HF 2.0 is also available with a 90° connector version, allowing even greater freedom in design and installation:
Which valve is suitable for which application?
|
REQUIREMENTS |
 PPCD08 |
 PPCD09 |
 PPCP09 HF 2.0 |
|---|---|---|---|
|
Typical application |
120 Hp Tractor |
Wheel Loader |
Wheel Loader |
|
Connector and alignment |
DT Connector – straight |
DT Connector – straight |
DT Connector – straight |
|
Supply pressure |
up to 50 bar |
up to 50 bar |
up to 32 bar |
|
Control pressure |
20 bar |
22 bar |
22/30 bar |
|
Leakage de-energized |
<50 ml/min |
<80 ml/min |
<1,25 l/min |
|
Flow demand |
<20 LPM |
<30 LPM |
<40 LPM |
|
Energy efficency |
important |
important |
less important |
|
Oil cleanliness |
high |
high |
low |
Customized adaptations for maximum flexibility
In addition to combining the benefits of high performance and durability, Thomas also offers a cost-effective solution for customer-specific adaptations. Thanks to the Thomas modular system, existing products can be quickly and easily adapted to customer requirements without a great deal of development effort. This provides the basis for a high degree of flexibility and ensures that customers always receive the best possible solution for specific applications.
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