Created on:2021-04-28 09:51

Application, parameter selection and type selection of radial piston motor

Application, parameter selection and type selection of radial piston motor

 

(l) Applications radial piston motor is a low speed high torque hydraulic motor, so it is mainly used to drive the load with low speed and high torque. Compared with the axial piston motor with high speed and small torque and other motors equipped with reducer, the radial piston motor has obvious technical advantages in size, layout flexibility, noise level, speed range, starting torque efficiency, acceleration performance and low speed stability, but the braking torque is larger. Because of its good performance, moderate speed and price, crankshaft connecting rod type hydraulic motor is the most widely used variety in low speed and high torque hydraulic motor. The inner curve hydraulic motor is mainly suitable for all kinds of main equipment which require large output torque, low speed, small volume and good low-speed stability.

(2) Parameter selection and selection, calculation and selection of displacement, calculation of actual working pressure, checking calculation of power and evaluation or checking calculation of service life, etc.

Some problems should be considered in the selection of radial piston motor are as follows.

① Efficiency for the transmission device with large power (more than 10kW), the efficiency should be considered first. Because the selection of high efficiency products can not only save energy, but also reduce the oil temperature of the hydraulic system and improve the stability of the system. Due to the small friction loss of high efficiency hydraulic motor products, the service life of the products is correspondingly improved. Generally speaking, it has the structure of end face flow distribution, plastic piston ring seal at plunger and no lateral force between plunger and cylinder block, which has high volumetric efficiency and hydraulic mechanical efficiency.

② Starting torque and low speed stability for most machines, the load is the largest when starting. Because at this time to overcome the inertia of the transmission and overcome static friction. Therefore, starting torque is also an important index to measure motor performance. Generally, the model and specification are selected according to the required starting torque. At the same time, the starting performance of the motor is closely related to the low-speed stability of the motor. In other words, the motor with high starting efficiency has good low-speed stability. For many machines, low-speed stability is also an important index, and the starting efficiency and low-speed stability are generally closely related to the volumetric efficiency of motor and hydraulic mechanical efficiency. Generally, products with high volumetric efficiency and hydraulic mechanical efficiency have good low-speed stability and start-up performance.

③ The life of main engine is generally required for the life of transmission parts. How to select the type reasonably to ensure the required service life is a problem that must be considered. For most users, there are always 2-3 models with the same or similar displacement. So it provides users with more choices. For users with low working pressure, short working life or less working hours per day, they can choose smaller size, lighter weight and smaller volume. In this way, on the basis of ensuring the service life, the motor is not only light and small, but also cheap. For users with high working pressure, long service life, large radial force on the output shaft and frequent work every day, they need to choose motors with larger specifications and dimensions, but the price is higher.

④ Compared with many main engines, speed adjustment is needed in motor operation. The ratio of the highest speed to the lowest speed in speed adjustment is called speed adjustment ratio. This indicator is also very important. If the motor can run smoothly at a very low speed (such as 1 R / min or even lower), and can work efficiently and reliably at a high speed, then the application scope of this kind of motor is quite large. At present, the speed regulation ratio of high-quality motor can reach more than 1000. For example, the S series swing cylinder crankshaft motor of Italian Sai company has a maximum speed of 2800r / min, and its minimum stable speed can reach 1R / min; therefore, its speed regulation ratio is 2800 / 1 = 2800.

⑤ With the improvement of environmental awareness, the noise requirements of the motor matching with the main engine are also increasing. The noise of the same type of motor is not only related to the running noise of the motor itself, but also related to the stiffness of the motor mounting frame, the working pressure and the working speed. If the installation rigidity is good, the pressure is low and the speed is small, the noise of the motor is small, otherwise, the noise is large. In order to comprehensively compare various types of motors, it is better for users to get the product samples provided by the manufacturer, and learn more about the performance of the products including noise (such as efficiency, starting torque, low speed performance and service life, etc.).

⑥ The parameters of prime mover and hydraulic pump in some main engines, as the oil source of hydraulic motor, the hydraulic pump and the internal combustion engine or motor driving the pump have been determined. At this time, the power to be transmitted is clear, and the flow rate of the supply motor, the working pressure and the maximum pressure of the system are limited by the oil supply hydraulic pump.

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