Key points of using gear pump
Key points of using gear pump
(1) Application in all kinds of hydraulic pumps, the working pressure of gear pump is second only to plunger pump, and most of the gear pumps adopt aluminum alloy shell, floating shaft sleeve, bimetal bearing, bimetal fixed side plate and other structures, which have the characteristics of simple structure, strong self-priming ability, light weight, convenient use and maintenance, long-term high volume efficiency, low price and so on. They are often used as vehicles and traveling equipment Use the pressure energy of the equipment hydraulic system and various auxiliary pumps of the hydraulic system, such as the make-up pump in the closed hydraulic system, the low pressure control oil source in the pilot control oil circuit, etc. Figure V shows a closed hydraulic system. The two-way variable displacement hydraulic pump 2 and two-way quantitative hydraulic motor 3 form a closed circuit. The one-way quantitative hydraulic pump is used as a make-up pump, which can make up oil to the system through one-way valve 5 or 6. The make-up pressure is set by relief valve 4. The hydraulic system principle of YA32-200 four column universal hydraulic press is shown in Fig. W. the main hydraulic pump l of the system is a constant power variable piston pump with high pressure and large flow rate and pressure compensation. Its maximum working pressure is 32Mpa, which is set by the remote pressure regulating valve 5 and is used as the oil source for the main hydraulic cylinder 16 and the auxiliary (ejection) hydraulic cylinder 17. The auxiliary hydraulic pump 2 is a gear pump, which is mainly used as the low pressure control oil source of the pilot control circuit composed of Electro-hydraulic Directional Valves 6 and 21 and hydraulic control check valve 9. Its working pressure is set by relief valve 3.
In addition to a few low noise pumps (such as Parker PG600 series gear pump), the external gear pump generally has the defects of large flow pulsation and high noise, so it is not popular as the main pump in the field of fixed hydraulic machinery, and it is only used in the auxiliary pump and preloading pump under low pressure. Due to the lack of comprehensive gear and meshing performance, it is the best equipment in the field of rapid expansion. However, the development of modern manufacturing technology will greatly narrow the cost gap between the internal and external gear pumps, and the increasing popularity of electric drive technology such as frequency conversion and speed regulation in the industrial field will make up for the disadvantage that the internal gear pump itself can not be variable to a great extent. Therefore, the application of internal gear pump in fixed machinery and mobile machinery will expand rapidly.
Cycloidal gear pump with pin tooth ring rotation has the advantages of small volume, low price and strong self-priming ability. Besides being used as the main pump of hydraulic system of some light load machine tools, it is widely integrated on the back cover of through shaft piston pump (Fig. x) and used as low-pressure make-up pump or control oil source. This kind of pump can realize one-way oil supply and has nothing to do with input steering. This performance has special significance for some vehicles or walking machinery which need emergency steering and braking system driven by wheels.