1、 Brief description:
The cycloidal hydraulic pump was born in the late 1850s, which led to the birth of Cycloid hydraulic motor 。 This kind of early orbit motor After its debut, after years of evolution, another kind of motor with needle teeth gradually appeared. This type of motor is equipped with cylindrical rollers in the built-in gear ring, and the output shaft can produce stable output at low speed. According to the direction of changing input and output flow, the motor can quickly reverse, and the same torque can be generated in both directions. The motors of each series of products have various displacement choices to meet the requirements of various speeds and torques.
cycloid Hydraulic motor It is also called Orbit motor. It is a slow speed medium and large torque multi action hydraulic motor. Its structure is simple and compact, small in size, small in mass, good in slow speed characteristics, wide in rotating speed range, affordable, widely used and reliable in application.
The cycloidal hydraulic motor is composed of an internal gear ring (external rotor or stator) and a matching cycloidal gear (internal rotor or rotor). There is a tooth difference between the two. The basic working principle of the planetary reducer with one tooth difference is adopted, so this kind of motor takes into account High speed hydraulic motor And institutions Reducer It is composed of slow speed and high torque hydraulic components. It is widely used in mechanical equipment, petroleum machinery, shipbuilding movement, light industrial machinery and other machinery.
The key foreign manufacturers of cycloidal motors include Eaton Vikers, Ross and Parker in the United States, Danfoss in Denmark, Adan in the United Kingdom, Tokyoko and Yingchang in Japan, and some companies in Italy, Bulgaria and other countries.
Nanjing Hydraulic Machinery Manufacturing Factory (formerly Nanjing No.3 Hydraulic Parts Factory, Nanjing Hydraulic Parts Factory), Jining Eaton Hydraulic Co., Ltd. (introduced the technology of Eaton Vikers of the United States), Ningbo Zhongyi Hydraulic Motor Company (introducing the technology and process of relevant Italian companies), etc. There are about more than ten series of products in dozens of specifications and models, with displacement of 50~1250mL/r, inlet pressure of 7~3.5MPa, rotation speed of 5~100or/min, output torque of 55~1960N. m, and total efficiency of more than 85%.
2、 Basic working principle of cycloidal hydraulic motor
1) Basic working principle of cycloidal hydraulic motor with shaft flow distribution (oil)
The cycloidal hydraulic motor for shaft oil distribution is an internal mesh made by using the basic working principle similar to the planetary reducer (the basic working principle of small tooth difference) Cycloidal gear hydraulic motor , referred to as cycloidal motor.
The rotor and stator are a pair of cycloid pin teeth meshing gears. The rotor has a short amplitude epicycloid fixed distance profile of Zi (Zi=6 or 8) teeth, the stator has 2257.+1 arc pin teeth, and the rotor and stator have 22 closed inter tooth volumes. In the figure 22=7, there are seven closed interdental volumes: 1, 2, 3, 4, 5, 6, 7. Half of them are in the high pressure area and half are in the low pressure area. The stator is fixed, the center point of its gear ring is 02, and the center point of the rotor is Oi. Under the action of the hydraulic torque generated by the pressure oil, the rotor rotates around the center point o of the stator for the radius of eccentricity g. That is, the rotor rotates slowly around its center point 01
Since the stator is fixed, the rotor forms a force distance under the influence of pressure oil [7, 6 and 5 cavities are pressure oil], and makes planetary motion around the stator center point O2 with eccentricity g as the radius. In this way, the rotating motion of the rotor includes rotation and revolution. Revolution is the rotation of the rotor center point 01 around the stator center point 02. The rotation of the rotor is transmitted to the output shaft through the drum spline shaft coupling. When the output shaft rotates, the position of the longitudinal groove on its periphery changes with respect to the position of the port hole in the housing, so that the slot capacity can be transferred from the high pressure area to the low pressure area in time to achieve flow distribution, Therefore, the output shaft is also the oil distribution shaft, which makes the rotor rotate continuously.
It can be seen that the rotation direction of the rotor is opposite to the operation direction of the high pressure oil chamber from the displayed change of the oil chamber during rotor operation. When the rotor rotates 16 times from the origin to Fig. 3-2 (f), the center point 01 of the rotor wraps around the center point 02 of the stator to Р It rotates for one week for eccentricity, so the high pressure oil chamber changes relatively for one week. Therefore, if the rotor rotates for one week, the change of oil chamber will be 6 weeks, and the displacement will be 6x7-42 slots. Therefore, it can be seen that this is equal to that a reducer with a reduction ratio of 6:1 is connected behind the motor output from the rotor shaft at the same time, which makes the output torque six times larger. Therefore, the torque of the cycloidal hydraulic motor is relatively large to the mass index value. In addition, every week the output shaft rotates, there are 42 slots running one by one, so stable slow rotation can be achieved.
If zi=8, then 22-8+1=9. When 8 teeth are rotated once, the capacity of 9 chambers is changed once (high pressure low pressure). When the rotor is rotated once, 8 revolutions are required to form 8x9-72 chamber capacity changes. Therefore, although the cycloidal motor is small in size, it has a large displacement of multi influence type, which not only expands the torque, but also plays a role in slowing down the speed (6:1 or 8:1), so it is a slow medium and large torque motor. At the same time, because the rotating parts are small, the inertia force is small, which makes the starting, reversing and speed changing of the motor more flexible; The mass of unit power is about 0.5kg/kW, and the size of unit power is about 332cm2/kW, which greatly exceeds the same standard of other types of hydraulic motors. However, when the cycloidal motor rotates, there is no gap compensation. The rotor and stator are sealed by line contact, and the sealing line in one hydraulic motor is long, which causes air leakage. The working efficiency needs to be improved. The distribution shaft and output shaft are integrated, rotating at the same time, and the oil distribution under different angles (2) Basic principle of end face distribution cycloidal hydraulic motor
1 - Cycloidal gear; 2-pin cylinder; 3-Valve plate; 4 - Auxiliary panel; 5 - port shaft} 6 - transmission shaft; 7 - Output shaft; 8 - Rear housing
The pressure oil affects the rotor teeth to make the rotor rotate; Under the influence of hydraulic pressure, the cycloid wheel rotates to the side of the low pressure chamber under pressure. The cycloid wheel rotates and revolves relative to the center point of the needle cylinder, and transmits its rotation to the output shaft 7 by virtue of the transmission shaft 6. At the same time, the port plate and the cycloid wheel rotate simultaneously by virtue of the port shaft 5 to achieve continuous oil distribution. The return oil discharges the low pressure oil from the reduced low pressure area of the closed chamber. In this way, the cycloidal rotor motor shaft rotates continuously and outputs the torque for continuous operation.
