Linde Hydraulic Drive System Becomes Hydrostatic Drive Expert

The so-called hydrostatic drive is to use the mechanical energy of the engine to drive the hydraulic pump to convert to hydraulic energy. The high-pressure liquid output by the hydraulic pump enters the hydraulic motor installed near the traveling wheel or directly in the wheel through the manipulation and adjustment device, and converts the hydraulic energy into Mechanical energy, which makes the wheel a rotational drive. In Europe and the United States, hydrostatic drive technology has been widely used in the construction machinery and agricultural machinery market. In China, hydrostatic drive technology has just emerged and many forward-looking OEMs have begun to stock hydrostatic drive technology products. Hydrostatic drive, unlike mechanical transmission, has its own unique advantages:

Can output large torque and thrust, realize low-speed large-tonnage transmission; this is the outstanding advantages of hydrostatic drive technology;

The same power, smaller size, lighter weight, more compact structure;

It can make the actuator move evenly and steadily, without commutation impact, fast response, quick start, braking and frequent commutation;

Can realize stepless speed regulation in a wide range;

Provide operators with better comfort and control;

The most successful case for the application of hydrostatic drive technology was the Linde forklift. Linde Forklift is the world's premier logistics expert. The product's accuracy, controllability and reliability are the benchmarks of the industry. Its hydrostatic drive part provides customers with 10 years (or 10,000 hours) warranty. Far above industry standards, it is also much higher than construction machinery and agricultural machinery standards. Where does Linde's forklift's excellence and self-confidence come from?

As early as 1958, Linde Forklift established the Linde Hydraulics Division, which mainly develops and provides hydrostatic travel driving systems for forklift trucks. Over the years, Linde Hydraulics has always provided a high level of hydrostatic drive system as its primary goal, and successfully developed the LinDrive drive system, which has greatly improved its controllability and reliability. Not only that, Linde Hydraulics also has LinDrive. Successfully transplanted to construction machinery and agricultural machinery. In 2012 Linde Hydraulics was detached from Linde forklifts and operated independently; in 2014 Linde Hydraulics established Linde Hydraulics (China) Co., Ltd. in China and brought the LinDrive system to China.

Actually, like a forklift, whether it is a construction machine or an agricultural machine, the driver not only controls the walking, but also controls other working mechanisms at the same time (such as lifting and handling of heavy loads, precise stacking of bales, and rapid vehicle movement between the two places). (Transfer, etc.), but its travel drive system accounts for the largest proportion of the entire work cycle, so the travel drive system determines the machine's operating efficiency. Simple and intuitive operation of the machine is conducive to improving the driving comfort, reducing the driver's working intensity and improving the production efficiency. This is LindDrive's unique drive concept accumulated over many years.

LinDrive will bring three significant advantages to the complete machine :

High control accuracy:

Simple, intuitive control

Low work intensity

Precise control

Perfect continuous action

high efficiency

High dynamic response:

Forward and backward rapid conversion

Accelerated faster and faster parking

Fast transitions

Adjustable load characteristics

Improve operating performance

High reliability:

Machine performance optimization

Actions can be precisely repeated

Set a plan for the entire machine to deal with possible system failures

Meet the high requirements for traffic access

Provides the best security for operators and the environment

LinDrive's three features are embodied in the development of Linde products. Its structure is different from the general hydraulic products, and is mainly reflected in the 21° swash plate angle technology and swash plate variable technology.

21° swash plate angle technology:

Linde 21° swash plate angle technology

The market is generally 18° for the swash plate hydraulics, while Linde's hydraulic angle is 21°. On the surface, it is to increase the displacement, reduce the volume and weight, but more importantly, the difference between the shoe and the plunger. The 18-degree slide shoe is all copper and the ball head is on the plunger. The structural strength of this copper-clad steel is not high and often becomes a point of failure. The 21-degree slide shoe is made of sintered steel and copper. The contact portion of the slide shoe is a copper alloy. The rest is steel. The ball head is located on the slide shoe and becomes the structure of the steel ladle. The strength is greatly improved. No longer a point of failure. 21 ° also brought another great advantage is that the plunger length increases, making the motor's low-speed stability much better than the general product.

Swashplate variable technology:

Linde Swashplate Variable Technology

Linde's swashplate variable technology is unique in the world. The position of the swash plate is locked by the two connected cylinders. When there is no input signal, the pressure of the two cylinders comes from the pilot valve, the pressure on both sides is equal, and is basically equal to the charge pressure, and the swash plate is locked at the zero position. Once there is an input signal (electrical or hydraulic), the signal plunger will displace and drive the pilot spool away from the neutral position. At this time, one variable cylinder maintains the charge pressure, and the other variable cylinder becomes the shell pressure. Generates a lot of torque, pushing the swash plate to swing. When the swash plate swings, the position feedback lever connected with it will cause the pilot valve core to move to the neutral position. When the swash plate reaches the position corresponding to the input signal, the pilot valve core returns to the neutral position, the pressure of the two cylinders. Again, the swash plate is locked in a new position.

Linde Hydraulic's swashplate variable technology can be abstracted into the schematic above. There are three main differences. First, when there is no input signal, Linde locks the swash plate to zero by the hydraulic pressure of the two cylinders, and other hydraulic pressures. The product is locked by springs. If the spring is too hard to help lock, but the dynamic response and sensitivity are too bad; if the spring is too soft, the dynamic response and sensitivity are good, but it cannot be well locked. Second, the pressure of the Linde variable cylinder comes from the pilot valve, which is equal to the charge pressure. The pilot valve is equivalent to the action of an amplifier for the control signal, and the pressure of the variable cylinder of the general hydraulic product comes directly from the signal pressure. When the input signal is small, the pressure is also low, and the compressive force of the other side spring must be overcome in order to drive the swash plate to swing. Therefore, the control accuracy, dynamic response, and sensitivity to signals are all inferior to those of Linde products. Thirdly, due to the impact of load pressure, Linde always acts on the swash plate due to a large charge pressure, and the torque generated by the load pressure is relatively small, with little impact on the control of the swash plate. The control pressure of general hydraulic products changes with the input signal. When the input signal is small, the control pressure is much smaller than the charge pressure, so the load pressure will have a significant impact on the swashplate control.

Linde Hydraulic's unique 21° angle of oscillating technology and swashplate variable technology brings reliability, comfort and agility to LinDrive. It also brings the best technical solutions for the upgrading of construction machinery and agricultural machinery in China. Linde Hydraulics' philosophy is to “convert power into motion” and make LinDrive your hydrostatic drive specialist.