The right valve platform for every tractor size07.10.2017 9.01
With three hydraulic valve platforms, Bosch Rexroth covers the current and future requirements for mobile hydraulics in tractors across the whole performance range from 40 kW up to 400 kW. The new Rexroth SBx4 platform meets the requirements of the premium class. Rexroth SM12-EHR12 supports the mid- and low-range power segments and the valve platform ROS12 (OC) was specially developed by Bosch Rexroth for the Asian market. Bosch Rexroth also offers the corresponding valves for electrohydraulic hitch control for all versions. Tractors above the 200 h.p. limit are almost exclusively used with electrically controlled valves with high flow rates. The new Rexroth SBx4 valve platform meets these requirements with freely combinable mechanically and electrically actuated sandwich valves. Compared to the world's bestselling predecessor valves for tractors, Rexroth SBx3, the flow rate has increased to 120 or 170 l/min at an operating pressure of up to 220 bar. The hydraulic ports are uniformly aligned in all variants. The modular combination of valves with varying flow rates in one control block reduces the piping work and provides every consumer with the exact amount of energy required. In addition, the new series also includes matching hitch valves. These cover the whole range from single- to double-acting system solutions with scalable additional functions. Designers can combine up to seven valve sections in one block and therefore control a comprehensive range of tractor peripherals. By using an end valve instead of an end plate, new options are available and the solution requires less installation space and weighs less too. The new valves make maintenance easier with their separately exchangeable electronics. The newly constructed Rexroth SB24-M, SB24-EHS1 and SB34-EHS1 valves with leak-free check valve and optional thermal unloading generate lower internal friction and pressure losses in comparison to the previous version. Even in tractors between 100 h.p. and 200 h.p., the majority of them use electronically controlled valves. Along with the SB24-EHS1 valves, Bosch Rexroth has developed the compact, highly integrated platform SM12-EHR12 for this segment. This platform is based on tried-and-tested components and expands the performance range to a flow rate of 60 l/min at an operating pressure of 200 bar. With the modular block, tractor manufacturers can control up to ten consumers and thereby implement all tractor-relevant functions: from pulling and alternating plows to free-moving front loaders with locking and kickout function. For small tractors there tends to be an increased range of functions. With ROS12 (OC), Bosch Rexroth provides a highly flexible locally manufactured platform for open circuits specially for the Asian market. The functions include flow control with integrated priority valve. The valve block can be supplied by means of either gear pumps or variable pumps. The platform is compatible with SM12 and the hitch valve EHR 12. The Electrohydraulic Hitch Control EHC-8 from Bosch Rexroth replaces traditional mechanical control and allows significantly improved soil cultivation, even with small tractors. |