The hydraulic wrench is an important tool for the installation and disassembly of large-size bolts. There are two types of hydraulic torque wrenches: driven hydraulic torque wrenches and hollow hydraulic wrenches. Driven hydraulic torque wrenches are used with standard sleeves and belong to general-purpose hydraulic wrenches. The thickness of the hollow hydraulic wrench is relatively thin, so it is suitable for use in places with relatively small space. Hydraulic wrenches are so widely used, do you know what hydraulic wrenches are made of?
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　　 What constitutes a hydraulic wrench
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The hydraulic torque wrench is composed of a body, an electric hydraulic pump, a double high-pressure oil pipe, and a high-strength sleeve. After the hydraulic pump starts, pressure is generated by the motor, and the internal hydraulic oil is transmitted to the hydraulic torque wrench through the tubing medium, and then the piston rod of the hydraulic torque wrench is pushed. The pre-tightening disassembly work. The pump for hydraulic torque wrench can be driven by electric or pneumatic drive.
1. Hydraulic wrench body
The body of the hydraulic torque wrench is mainly composed of three parts, the body (also called the shell), the oil cylinder and the transmission parts. The output force of the oil cylinder, the piston rod of the oil cylinder and the transmission part form a motion pair. The distance between the center of the oil cylinder and the center of the transmission component is the hydraulic arm amplified force arm. The output force of the oil cylinder is multiplied by the force arm, which is the theoretical output torque of the hydraulic wrench.
2. Power unit
Hydraulic wrench pump is the power unit of hydraulic wrench. Hydraulic wrench pumps are high-pressure pumps with a maximum working pressure of 70 MPa. Electric hydraulic pumps and pneumatic hydraulic pumps are common.
Hydraulic wrench pumps are composed of motors (motors or gas motors), pumps, pipelines, electrical controls, etc .; pumps commonly have two-stage pumps and three-stage pumps. The general two-stage pumps are low-pressure gear pumps and high-pressure plunger pumps. The gear pump provides hydraulic oil under pressure for the plunger pump, and the exchange pressure of the gear pump and plunger pump is 7-10MPa. The structure of the three-stage pump is diverse, and the typical structure is a plunger pump. The low-pressure 4 large-diameter plungers, the medium-pressure 2 small-diameter plungers, and the high-pressure 2 small-diameter plungers. There are also three-stage pumps that use the first-stage pump as the gear pump, and the second- and third-stage pumps as plunger pumps; the first-stage, second-stage, and third-stage pumps of the three-stage pump are called low pressure, medium pressure, and high pressure, respectively.
When the working piston of the hydraulic wrench moves, it is generally in the state of medium pressure of 10-32MPa, and the flow of medium pressure is 2.2 times of the flow of high pressure (32-70MPa). Comprehensive three-level pressure and flow curve, the speed of the three-level flow pump is two-level Flow pump nearly doubled. It can be seen that the speed of the three-stage pump is much faster than that of the two-stage pump.
Electric hydraulic wrench pump motor is divided into carbon brushless motor and carbon brush motor. Brushless motors are generally induction motors and require capacitors. In order for the pump to start with pressure, it is necessary to install a starting capacitor and a running capacitor. Brushed motors are generally series-excited motors with high speeds, which can provide a large flow for the pump, but have a large noise and vibration.
The brushless motor usually has a service life of tens of thousands of hours, but it is very easy to cause the motor to overheat. According to different working conditions, it is not a very effective option. The continuous working life of the carbon brush motor is 1-10 Years, and conventionally equipped with a cooler, so carbon brush motors are more suitable for hydraulic wrench special pumps to work continuously for a long time, and these hydraulic pumps are the mainstream configuration.
3. Synchronization system
The main purpose of the hydraulic wrench synchronization system is to avoid the unilateral compression mode of the flange face. This mode will cause the gasket on the flange face to fail due to excessive squeezing, resulting in leakage. The synchronization system is used when two or four hydraulic wrenches are connected to a pump at the same time. According to the principle of hydraulic pressure, multiple hydraulic wrenches work at the same time and output the set torque at the same time, which can achieve parallel closure of the flange, and the torque accuracy reaches 3%. The synchronous system can lock the bolts at a time, while the single system needs to be loaded multiple times and locked in steps, which shows that the efficiency of the synchronous system is much greater than that of the single system.
The above content is to introduce to friends the knowledge about what the hydraulic wrench consists of. When purchasing hydraulic wrenches, bolt specifications and strength grades are the most critical parameters for the selection of hydraulic torque wrenches. Generally, the hydraulic wrench is selected according to the bolt specifications. This is the most convenient and accurate method of selection, and it is more suitable for use.
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