1. Brief

1.1 Overview

Hydraulic motor It is an actuating element that converts liquid pressure energy into mechanical kinetic energy, works to output torque and rotates. It plays an important role in the hydraulic system.

Hydraulic motors are generally divided into small torque and large torque. In recent years, with the continuous progress of hydraulic technology towards high pressure and high power and the gradual attention to ecological environment protection, it is stipulated that hydraulic actuator has the characteristics of low noise, little damage, stable operation, etc. Therefore, large torque motor has become one of the development directions. Seen from the concept of energy conversion, hydraulic oil pump and hydraulic motor are hydraulic components that operate reversibly. Feeding running liquid into any hydraulic oil pump can change it into the working condition of hydraulic motor; On the contrary, when the external torque of the main shaft of the hydraulic motor drives the rotation, it can also become the working condition of the hydraulic oil pump. Because they have the same basic wood structure factors: the capacity that can be closed and periodically changed and the corresponding oil distribution mechanism.

Compared with the motor, the hydraulic motor has some advantages over the motor: the transmission shaft can reverse instantly.

② No matter how long the rotor is blocked, it will not cause damage;

③ The torque is controlled by the running rotation speed;

④ Convenient for dynamic braking;

⑤ If the ratio of motor efficiency to mass is set as 1, and the hydraulic motor can reach 10-12, that is, the lower limit is the hydraulic motor that transmits the same efficiency number.

one point two Oil motor Category of

Oil motor can be divided into transmission gear type, vane type, plunger type and other types according to its structural type; According to the rated rotation speed of the oil motor, it is divided into two categories: high speed and low speed; There are small, medium and large torques according to the torque that can be transmitted; According to the action frequency of work task side in each turn, it can be divided into single action type and multi action type. (1) Generally speaking, high-speed oil motor and low-speed oil motor are called high-speed oil motor if the rated rotation speed is greater than 500r/min, and low-speed oil motor if the rated rotation speed is less than 500r/min.

The main characteristics of high-speed oil motor are high rotation speed, small moment of inertia, favorable for starting and braking, and high sensitivity of adjustment (speed change and reversing). Generally speaking, the output torque of high-speed oil motor is small, so it is also called high-speed small torque oil motor. The main characteristics of the low-speed oil motor are large displacement, large size, low rotation speed (sometimes it can reach a few revolutions per minute or even a few revolutions per minute), high starting efficiency, small moment of inertia, and short acceleration and braking time? The output torque of the low speed oil motor is relatively large, so it is also called Low speed high torque oil motor 。 Because the high torque motor has low rotation speed and good stability at low speed, it can directly drive the low speed high torque load (work task structure) without speed reduction system, so the transmission mechanism is greatly simplified. However, if the structure must be braked, the brake system with large specifications must be assembled.

2 Small, medium and large torque motors

When the output torque of the oil motor is above 1000 N.m, it is called a high torque motor, otherwise it is called a low and medium torque motor. The torque of large displacement motor can reach ten sN. M, the high torque oil motor has a lower rotational speed, generally below 400 r/min. (3) Single action and multi action

According to the action frequency of the working task pair in each revolution, the oil motor can be divided into two categories: single acting type and multi acting type. The single acting oil motor has simple structure, few parts, good process performance and low project cost. However, the fluctuation of output torque and rotation speed is relatively large, and the radial force is unbalanced at the same time. Under the same pressure, the multi action motor can output more torque. Only the number of pairs of working tasks and the frequency of action are appropriate, which can balance the radial force and have a high starting torque efficiency; However, the structure is complicated, the number of parts is large, and the manufacturing cost is high.