Hydraulic Motors & Valves
With the market becoming competitive, major players are focusing on introducing intelligent solutions for higher productivity and environment-friendly solutions to comply with stricter emission norms.
Motors and control valves are essential components of any hydraulically operated machine as they are instrumental in creating the required motion. To explain it simply through an analogy with the human body, motors can be compared to our limbs and control valves to our brain. Just as the brain decides whether the arm is to be raised or lowered, a control valve enables the motor to rotate either clockwise or anticlockwise. The control valves decide on the type of motion, whereas the motors or cylinders provide the motion, either rotational or linear.

The fundamental feature of the hydraulic system is the ability to apply force or torque multiplication in an easy way without the need for mechanical gears or levers. Hydraulic systems convert the energy of the prime mover into scalable mechanical force or torque.

A hydraulic motor is a rotary actuator that converts hydraulic pressure and flow into torque and angular displacement (rotation). Hydraulic motors transform the energy of the fluid into rotary mechanical power which is applied to a load via a shaft. Control valves regulate the flow and pressure of fluid in a hydraulic system. Valves regulate force, direction and speed of actuator in a machine.

Productivity and hydraulic systems
As mentioned earlier, motors and control valves are the components that create the required motion of a hydraulic system. Naturally, this is directly related to the productivity of the system. So it is certainly important to have proper hydraulic motors and valves in the system as per the type of application. Hans Banger, Managing Director, Bosch Rexroth, explains, ?Hydraulic motors are used for converting hydraulic energy into mechanical energy. The productivity of equipment that uses hydraulic motor is largely determined by the torque produced by the motor and its power output. The torque and power output produced by a hydraulic motor, on the other hand, is dependent on the flow and pressure drop at the motor. High torque motors and high speed motors are designed depending upon the type of application.?

Selection process also plays a vital role, as Banger further adds, ?The selection of valves should be done to reduce pressure drops which in turn reduces heat generation in the system. Optimum selection of control valves is very important for improved efficiency and productivity of the machine function. On the other hand, over-design leads to wasted capacity and increased dimensions of the system.?

According to Subhasis Chatterjee, Managing Director - India, Hydraulics Group, Eaton, there are various factors responsible for productivity of a machine. He elaborates, ?Motors and valves enable movement and their efficient working results in faster response time and smooth, jerk-free operation of the machine, thereby making it more productive. Lower pressure drop in valves and no load pressure drop in motors are important measures for better efficiency of the equipment. Effective and superior motors and valves (with higher tolerance) can offer higher accuracy, faster response time, shorter and better controlled operating range for a hydraulic equipment and positively impact productivity.?

On the current trend in valves, Raj Dabholkar, CEO, Tucson Hydrocontrols, says, ?With the next quantum jump to screw-in cartridge valves (SiCVs), Hydraulic Integrated Circuits (HICs) will address the issue of size, piping as well as visual appeal. This, along with greatly reduce operating costs, system complexity and a major elimination of leakages while providing improved serviceability. Their compact size, low cost, reduced component requirement and a minimum effort towards customer end engineering would mean a much lower initial installed cost. Consumer interest and the initiative to invest in this new technology has only been energising rapid market growth.

Products and solutions
Technology drives innovation which in turn leads to the development of new products and solutions to meet the ever-changing requirements across the industry. Be it for increasing productivity, improving economy and fuel efficiency, achieving better operational efficiency and being environment-friendly, major players in this segment have come out with new products and solutions to their customers.

Bosch Rexroth is a major player in this segment. It offers hydraulics, electric drives & controls and linear motion & assembly technology - all from one source. According to Banger, economical, precise, safe and energy efficient drive and control technology from Bosch Rexroth moves machines and systems of any size. The company bundles global application experience in the market segments of Mobile Applications, Machinery Applications & Engineering and Factory Automation to develop innovative components as well as tailored system solutions and services.

Banger gives an in-depth description on the product range, ?Bosch Rexroth hydraulic motors open up new possibilities for higher productivity and reliability, which leads the way to lower overall investments and increased long-term revenue. It offers the widest range of hydraulics in the world comprising standard products, application-related systems and tailored (customer-specific) hydraulic solutions. Bosch Rexroth offers three types of hydraulic motors: axial piston motors, external gear motors and radial piston motors. Space is often limited in industrial applications, making the physical size and flexibility of installation a key factor. Radial piston motors have a high power-to-weight ratio which means great performance, also lower energy consumption. While maintaining the small and compact shape, these motors are made for high power capacity and can work at high speed and high pressure, e.g., direct drives for bucket wheel excavators and wagon tipplers are some examples of applications where Bosch Rexroth solutions are proven.?

Positioned as a complete hydraulic systems solution provider, Eaton in India manufactures and markets a wide range of competitive power and motion control offerings and trades in a variety of hydraulic and fluid conveyance products practically for both Mobile and Stationary segments.

Chatterjee explains Eaton?s expertise, ?Eaton offers a diverse portfolio of motors for hydraulic equipment in almost all family types such as Gear, Vane, Piston, Orbitrol and Radial (Cam Lobe) Motors. These motors also operate at wide range starting from 1 cc/rev and going up to 50,000 cc/rpm. Eaton offers motors which can run at 7,000 rpm and also has motors which have excellent stability at 1 rpm as well. This diverse portfolio has enabled Eaton to be present in widest range of applications both in Mobile and Industrial Platforms.?

Eaton also has one of the most advanced control valve portfolios in the market called Ultronics. Chatterjee elaborates on this range, ?Conventional mobile valves have single spool per section whereas Ultronics has two spools per section with electronic control. This two-spool configuration based technology gives these valves a unique capability of having pre- and post-compensation (flow sharing), regeneration, meter-in and meter-out control, one section controlling two actuators. The valve also has embedded sensors for temperature and pressure and embedded controllers with CAN Bus control. These features during test trials on certain applications have shown efficiency improvement up to even 55 per cent.?

He adds, ?Eaton also makes other control valves which are electronically, hydraulics or manually controlled for mobile applications. Some of the valves we make are very specific to applications like excavators, tractors, and forklifts, etc. Eaton also offers one of the widest ranges of solenoid valves starting from 40 lpm, to 1,100 lpm at 315 Bar. In a similar range Eaton offers proportional valves both with on-board electronics and servo proportional performances.?

Eaton has recently introduced a next gen proportional valve called Axis-Pro. According to Chatterjee, these valves have inbuilt pressure and temperature sensors and have response time of less than 6 mil sec and bandwidth of 150 Hz. These valves also have open architecture for programming - giving customers the benefit of individual axis control on their machines.

Dabholkar elaborates on the products and solution offered by his company, ?Tucson has always been the go-to company for load holding valves, be it for excavators, cranes, backhoes or MHE. We have now started catering to clients for complete hydraulic solutions as far as the main circuit is concerned. With complicated systems, it is always a hassle to procure various items from different suppliers and assemble and test on location. What we do is design and manufacture the system at our end, assemble and test it and provide the complete package. With this, you are ensured that all parts are working find and in tandem and only the final test is to be done. This exercise is being carried out for agricultural combines, excavators, underground mining equipment as well as drilling rigs.?

Myriad applications
According to Banger, power and performance are the two important parameters in any of the applications. At the same time, the customer looks for more production with high quality and increased reliability. For processes to be at their most productive, the control of speed and torque in relation to the process is essential.

?Based on the type of application and required output with maximum efficiency, the type of motor and valve varies with each application. For example, axial piston motors are used in mobile and stationary applications while external gear motors can be used in road construction machines, agricultural machines, etc., and radial piston motors are used for high power capacity where work at high speed and pressure is required like in mining, bulk materials handling equipment, cement industries etc.,? explains Banger.

Since applications vary in each industry, they require specialised components. According to Chatterjee, there has been a significant shift in the industry in recent times from generic products cutting across different platforms offering ordinary specifications to innovative solution-driven components that are specific to a particular application offering the tighter tolerances and best performance specifications. Especially in the mobile segment, each equipment demands ?designed-to-application? solution.

?Eaton offers proven hydraulic solutions (in both mobile and stationary segments) to key industries such as agriculture, construction, mining, material handling, transportation, healthcare, alternate energy, and oil & gas. Being ?Customer Centric? is one of Eaton?s core values and our focus has been to collaborate with our customers to create innovative and customised solutions for them, helping them manage fluid power more safely, reliably, efficiently and sustainably,? states Chatterjee.

Technology trends
As the industry is becoming more competitive, major players are always in the race for new technologies and solutions. Says Banger, ?Intelligent Connected Hydraulics using highly advanced microelectronics is the key to increase productivity and competitiveness. More and more customers are opting for hydraulic solutions that are smarter, more flexible and more capable.?

He adds, ?Industry 4.0 (connected industry), coupled with machine safety, energy efficiency, integrated axis controls and explosion protection are some of the new development trends seen in this category. The product range needs to meet your environmental and application requirement. It ensures that the customer production remains efficient and reliable through many system variables. Moreover, Smart Interplay of Hydraulics and Electronics combine the features and multiply the advantages of both the technologies viz., hydraulics and electric drives and controls.

This significantly lowers energy consumption (up to 70 per cent) and reduces noise considerably. This trend is seen in some of the important applications like plastics, presses, etc.?

Eaton has increased focus on emission compliance as Chatterjee explains, ?Emission norms are driving efficiency improvements in almost all our product ranges. For example, Eaton has introduced a new range of Orbitrol Motors which has 50 per cent reduction in No Load pressure drop. Similarly, Eaton is working towards high-pressure products which will help in addressing the parasitic losses in line. However, we believe that use of electro-hydraulic technology would be vital to meet the emission norms and that?s one of the reasons why Eaton has developed products like Ultronic, Axis Pro and similar electro-hydraulic controls and controllers for our pumps and motors. Also, stricter emission norms will drive more focus on developing and offering solutions that have lower noise level, more compact design with higher power density and ensure lower carbon footprint through smart use of environment-friendly components and processes that reduce waste and power consumption.? Dabholkar elaborates on the new product lines of the company, ?Amongst the many cartridge valves and systems that we are indigenously manufacturing, we have a whole range of load sensing products that monitor the required pressure and regulate it accordingly. This reduces a great deal of power consumption from the pump end. With systems that can be retrofit onto existing pumps and motors, even a standard fixed volume displacement pump can be made comparable to a top of the line load sense pump. With standard interfaces and mounting abilities, these can be used over wide range of pumps.?

Outlook 2020
Research analysts predict that the global hydraulic equipment market will grow steadily at a CAGR of close to 5 per cent until 2020. According to Banger, the surge in construction activities in developing countries has notably contributed to the growing demand for hydraulic equipment. ?Further, the growth of industrial machinery, oil & gas, transport, agriculture and automotive industries will subsequently lead to the accelerated growth of the hydraulic equipment market. In addition, new trends like connect industry and electrification will also contribute towards the growth of this market,? he adds.

Chatterjee also foresees a substantial increase in CAGR in the mobile market. However, this would depend on the scheduled implementation of announced infrastructure projects and regularity of the monsoons in India, he feels. Says Dabholkar, ?Very evidently, the current market is slow. Not just for hydraulics but for the entire mobile equipment fraternity. With low investment interest and problems in coal production, there was a lull in the market. However, the earthmoving, construction and mining equipment industry are definitely showing signs of a slow recovery. Expectations from the current government were much higher than what is being delivered. The policy was thought to be taking positive measures to reassure investors, both domestic and foreign, that they are pro-industry and pro-growth but it hasn?t reflected on the ground. The promise of bringing clarity and transparency to portfolios such as mining, housing and infrastructure had galvanised businesses both big and small but only time will tell how correct our assumptions are.?

All in all, the growth of hydraulic motors and valves will depend on how the allied OEMs perform in the coming years, which in turn depends on the infrastructure development and the growth in project execution rate.

?Intelligent Connected Hydraulics using highly advanced microelectronics is the key to increase productivity and competitiveness.?

Hans Banger, Managing Director, Bosch Rexroth

?Lower pressure drop in valves and no load pressure drop in motors are important measures for better efficiency of the equipment.?
Subhasis Chatterjee, Managing Director - India, Hydraulics Group, Eaton

Control valves regulate the flow and pressure of fluid in a hydraulic system. Valves regulate force, direction and speed of actuator in a machine.

?The earthmoving, construction and mining equipment industry are definitely showing signs of a slow recovery.?
Raj Dabholkar CEO, Tucson Hydrocontrols

Global hydraulic equipment market will grow steadily at a CAGR of close to 5 per cent until 2020.