2.2.4 performance parameters
The main performances of gear motor include pressure (pressure difference), displacement, speed, output torque, volumetric efficiency, pulsation and noise.
(l) At present, the rated pressure range of gear motor is about 7 ~ 32Mpa. The rated pressure of the involute external gear motor is higher than that of the cycloid gear motor, and the rated pressure of the small displacement motor is higher than that of the large displacement motor.
(2) Displacement estimation and range the displacement of gear motor is the main specification parameter, and also mainly depends on the geometric parameters such as the number of teeth Z, modulus m, tooth width b, etc. the displacement of gear motor with various structures is similar to that of gear pump with the same name.
The displacement range of hydraulic gear motor products is very wide, from 4 to 16000ml / R. the displacement range of internal meshing cycloid and non-circular planetary gear motor is large, and that of external meshing gear motor is small, and the common displacement range is 4 to 120ml / R.
(3) The rated speed of speed external gear motor and internal and external rotor cycloid motor is higher, the former can reach 4000R / min, the latter can reach more than 7000r / min, while the rated speed of planetary rotor cycloid motor is generally lower, the speed is generally less than 900r / min.
In terms of low-speed stability, cycloid motor is better than external gear motor (cycloid motor can obtain the lowest stable speed of 1or / min, while the lowest stable speed of external gear motor is usually greater than 150r / min).
(4) The output torque of external gear motor is smaller than that of cycloid motor.
The starting torque efficiency of cycloid motor is better than that of external gear motor (the starting torque efficiency of cycloid motor ranges from 76% to 90%, while the starting torque efficiency of external gear motor ranges from 75% to 80%).
(5) The volumetric efficiency of external gear motor ranges from 85% to 94%, and that of cycloid motor can reach 94%.
(6) Pulsation and noise the pulsation and noise of external gear motor are generally greater than that of cycloid motor.
(2) Parameter selection and type selection
① For basic performance parameters, such as output torque of gear motor, there should be 1.3-1.5 times reserve.
② The efficiency of gear motor is 15% ～ 20% lower than that of gear pump of the same specification.
③ Selection of nominal displacement.
④ Precautions for model selection. There are many kinds of structure types of gear motor. The selected motor should first meet the requirements of load and speed, and then comprehensively consider the starting performance, low speed stability, efficiency, noise, reliability, economy, convenience of use and maintenance, timeliness of supply and other indicators and conditions of the selected gear motor. Priority should be given to products that have passed the appraisal of relevant national departments and industries and have mature technology.
(3) Precautions take cycloid motor as an example, the precautions in the use of gear motor are as follows.
① The configuration of hydraulic system the hydraulic system of gear motor should be equipped with corresponding filters according to the product instructions to ensure the cleanliness of the working medium used in the system. The hydraulic circuit must be equipped with cooling device to prevent the oil temperature from being too high. Pressure gauge and thermometer must be installed in oil inlet pipe. A pressure gauge should be installed in the oil circuit of the hydraulic pump.
② The type and brand of hydraulic working medium should be selected according to the ambient temperature and service conditions. The medium used should have good viscosity temperature performance, good defoaming performance, anti-oxidation, anti rust and high flash point. During the operation of the motor, its viscosity is between 25 and 70mm2gs. Impurities in the oil, such as water, alkali and iron chips, shall not exceed the allowable value. It is suggested that the filtration accuracy of the system is better than 20um. The short-term working temperature should not be higher than 25 ~ 65 ℃.
③ Before the installation of the motor, check whether the rotation direction of the motor is consistent with the direction marked on the product; check whether the motor is damaged. The oil in the motor that has been stored for a long time needs to be drained and washed to prevent sticking of internal moving parts. The motor mounting bracket must have enough rigidity to prevent vibration during rotation. The mounting bolts must be tightened evenly.
When the motor is running at low speed, it can be eliminated by applying back pressure, which is not less than 0.2MPa.
It should be noted that some motors can not operate under pump conditions or can not be used as pumps.
The hydraulic motor cannot be installed by knocking or by force or twisting.
The mounting surface of the motor should be flat. The size of connecting flange, stop and output shaft extension is accurate. It should be ensured that the output shaft and its connecting transmission device have a good coaxiality, and the axial jacking phenomenon between the output shaft and the connecting device should be prevented during the installation. In the process of installation, attention should be paid to the protection of the smoothness and smoothness of the connecting plate of the oil inlet and outlet, so as to prevent bumping and reducing the oil sealing effect, resulting in oil leakage.
The inlet and outlet pipes and drain pipes should be correctly selected, processed and connected according to the requirements of the manual. Do not remove the plastic plug before the pipe and oil pipe are installed.
When the system is connected, the relationship between the installation position of the oil inlet and outlet of the motor on the installation drawing and the rotation of the motor should be recognized. During installation, it is found that the oil inlet and outlet are not suitable for the corresponding rotation direction of the output shaft, which can be corrected by changing the oil inlet and outlet pipes.
④ Before using and running the motor, check whether the motor installation and connection are correct and firm, and whether the system configuration is correct.
Check whether the oil inlet and outlet direction and motor rotation direction meet the working condition requirements.
The pressure of the relief valve of the oil supply pipeline is adjusted to the lowest value and gradually adjusted to the required pressure after operation.
Tighten the inlet and outlet pipes and drain pipes.
After the motor runs in at least 10 minutes under no-load, gradually increase the pressure to the working pressure, and observe whether the motor runs normally at any time during the operation.
During the operation of the motor, the working pressure, flow rate, output power and oil temperature shall not exceed the specified value in the product manual. During operation, the working condition of motor and system should be checked frequently. If abnormal temperature rise, leakage, vibration and noise or abnormal pressure pulsation are found, the machine should be shut down immediately to find out the cause. In the process of use, when the temperature of the oil outlet exceeds the standard, check whether the cooler works normally to ensure the normal working temperature of the motor surface.
It is necessary to regularly check the status of each indicating element in the hydraulic system, such as the accuracy of pressure gauge, thermometer and other indicating instruments. The condition of hydraulic working medium should be checked regularly; the oil change cycle varies according to different working conditions. Generally, the oil change cycle is half a year. Waste oil should be sent to the unit for centralized treatment to avoid environmental pollution.
According to the size of the motor, the motor should be packed with appropriate wooden cases and cardboard boxes, and the surface of the motor should be packed with plastic paper to prevent moisture from eroding the motor and causing the motor to rust. Avoid placing the motor directly on the ground.
The motor that has not been used for a long time should be coated with anti rust oil. The cavity should be filled with oil and the oil ports should be sealed. The surface of the output shaft should be coated with grease and wrapped up. The storage environment of motor is 10% ～ 90% RH, - 20 ～ 65 ℃. During transportation and storage, water, moisture and any corrosive gas should be avoided as much as possible.
⑤ The maintenance of hydraulic motor needs to be installed, debugged and maintained by professional personnel. Generally, users are not allowed to disassemble and repair by themselves. If there are disassembly conditions, it should be carried out after reading the instructions in detail, but the following matters must be paid attention to.
a. In the process of decomposition, pay attention not to scratch the parts, especially to protect the moving surface and sealing surface of the parts. The disassembled parts should be placed in a clean container to avoid collision with each other. It is forbidden to knock with a hammer during disassembly and assembly.
b. The removed parts should be inspected carefully, and the worn parts should not be repaired by themselves but replaced. In principle, all seals should be replaced.
c. Before assembly, all parts should be cleaned and blown. Cotton yarn and rags should not be used to wipe the parts. The assembly site and tools should be clean. After assembly, the output shaft should be rotated flexibly without sticking.