What are hydraulic tools?

A complete hydraulic tool system consists of five parts, namely power elements, actuators, control elements, auxiliary elements and hydraulic oil.

Contents:

1 Introduction

2 Classification and application

3 Advantages

4 Disadvantages

Introduction

Hydraulic tools are the organic combination of hydraulic systems and ordinary tools into a whole. Convert powerful hydraulic power into mechanical motions such as reciprocating linear motion, rotational motion, and cycloidal motion. A complete hydraulic tool system consists of five parts, namely power elements, actuators, control elements, auxiliary elements and hydraulic oil. Hydraulic tools include: hydraulic wrenches, electric pumps for hydraulic wrenches, hydraulic jacks, hydraulic bolt tensioners, hydraulic flange separators, hydraulic nut cutters, hydraulic pullers, etc. Hydraulic tools have the advantages of high efficiency and convenience.

The function of the power element is to convert the mechanical energy of the prime mover into the pressure energy of the liquid. Refers to the oil pump in the hydraulic system, which provides power to the entire hydraulic system. The structural forms of hydraulic pumps generally include gear pumps, vane pumps and plunger pumps.

The function of actuators (such as hydraulic cylinders and hydraulic motors) is to convert the pressure energy of the liquid into mechanical energy and drive the load to make linear reciprocating or rotary motion.

The control element (i.e. various hydraulic valves) controls and adjusts the pressure, flow and direction of the liquid in the hydraulic system. According to different control functions, hydraulic valves can be divided into pressure control valves, flow control valves and directional control valves. Pressure control valves are further divided into overflow valves (safety valves), pressure reducing valves, sequence valves, pressure relays, etc.; flow control valves include throttle valves, regulating valves, flow diversion and flow collection valves, etc.; directional control valves include check valves, hydraulic control check valves, shuttle valves, reversing valves, etc. According to different control methods, hydraulic valves can be divided into switch control valves, fixed value control valves and proportional control valves.

Auxiliary components include oil tanks, oil filters, oil pipes and pipe joints, sealing rings, pressure gauges, oil level and oil temperature gauges, etc. Hydraulic oil is the working medium for transmitting energy in hydraulic systems. There are several major categories such as various mineral oils, emulsions and synthetic hydraulic oils.

The principle of hydraulics:It consists of two cylinders of different sizes, which are filled with water or oil. The one filled with water is called a "hydraulic press"; the one filled with oil is called an "oil press". There is a sliding piston in each of the two cylinders. If a certain pressure is applied to the small piston, according to Pascal's law, the small piston transfers this pressure to the large piston through the pressure of the liquid, pushing the large piston up. Suppose the cross-sectional area of the small piston is S1, and the downward pressure applied to the small piston is F1. Therefore, the pressure of the small piston on the liquid is P=F1/SI, which can be transmitted by the liquid in all directions without changing its size. The pressure on the large piston must also be equal to P. If the cross-sectional area of the large piston is S2, the upward pressure F2=PxS2 generated by the pressure P on the large piston. The cross-sectional area is a multiple of the cross-sectional area of the small piston. From the above formula, if a small force is added to the small piston, a large force will be obtained on the large piston. For this reason, hydraulic presses are used to press plywood, press oil, extract heavy objects, forge steel, etc.

Classification and application

Hydraulic tools include: hydraulic wrenches, electric pumps for hydraulic wrenches, hydraulic jacks, hydraulic bolt tensioners, hydraulic flange separators, hydraulic nut cutters, hydraulic pullers, etc. Hydraulic tools have the advantages of high efficiency and convenience.

Advantages

1. Generally, mineral oil is used as the working medium, and the relative moving surface can be self-lubricated, with a long service life. 

2. Light weight, small size, small inertia, and fast reaction speed. 

3. Various components of hydraulic transmission can be arranged conveniently and flexibly according to needs. 

4. Overload protection can be automatically realized. 

5. Convenient operation and control, and a wide range of stepless speed regulation can be realized (speed regulation range up to 2000:1). 

6. It is easy to achieve linear motion. 

7. It is easy to realize the automation of the machine. When electro-hydraulic combined control is adopted, not only a higher degree of automatic control process can be achieved, but also remote control can be achieved.

Disadvantages

① Leakage is prone to occur: The oil pressure of the hydraulic system is high, and the hydraulic oil is easy to leak through the seal or gap, causing hydraulic medium consumption and environmental pollution.

② Low transmission efficiency: In the process of energy transmission, hydraulic transmission often has more energy loss (pressure loss and flow loss, etc.), which makes the transmission efficiency low

③ Inaccurate transmission ratio: Due to the compressibility of the transmission medium, leakage and elastic deformation of the pipeline, the hydraulic system cannot strictly guarantee the fixed ratio transmission.

④ Sensitive to temperature: The viscosity of the oil changes with temperature. The change in viscosity causes changes in flow, leakage and resistance, which can easily cause unstable movement of the working mechanism.

⑤ High manufacturing cost: In order to reduce leakage, the manufacturing accuracy of hydraulic components is required to be high, which increases the manufacturing cost.