Low speed high torque hydraulic motor In recent years, it is a kind of hydraulic actuator with rapid development trend and more application at home and abroad. Its types, specifications and models are diverse, and the common specific ones are "more curved radial plunger type in Sichuan", "crankshaft connecting rod type", "cycloid type", "vane type", "static balance type", "ball plug type", "sleeve telescopic swing cylinder type", etc. Although low speed High torque hydraulic motor The structure and principle of the plunger can be divided into single action and multi action according to the action times of the base pair of the central column per revolution. According to the arrangement method of the plunger, it can be divided into radial plunger type and axial plunger type. stay Plunger type hydraulic motor The plunger holes are evenly distributed along the circumference in the cylinder block, and the plungers are radially arranged. Multi action internal curve Radial plunger hydraulic motor It is the key one.
Multi acting internal curve radial plunger type low speed high torque Hydraulic motor Due to the advantages of small size, compact structure, sensitive installation, high working efficiency, good low-speed stability (which can simultaneously promote low-speed operation task structure) and large output torque, as a hydraulic driving component, it is widely used in mining, engineering project lifting, transportation, ships windlass And other mechanical equipment, and still has a great industry prospect.
Multi action Inner curve hydraulic motor Under the same pressure, the output torque of the motor is larger than that of the single acting motor, and the weight of the unit power is lighter, and only the number of plungers is 7, and the number of acting times × the selection is appropriate (usually X and 7 are both selected for even numbers, and the number of basic motors is ma2), which can make the radial hydraulic pressure of the motor fully balanced. Because of the symmetry of the cylinder hole, the indexing production and processing are simple. The guide rail curve is effectively selected in the design, and the argument is distributed according to the non pulsation. In theory, the output torque pulsation can be zero. Therefore, good low-speed stability performance can be obtained. The force transmission method of the multi action internal curve radial plunger hydraulic horse is divided into plunger force transmission, beam force transmission, roller force transmission and other types, in which the beam force transmission is used, The roller force transmission hydraulic motor is widely used.
This article specifically describes the development trend of the internal curve multi action radial plunger type low speed high torque hydraulic motor, discusses that the end face flow distribution is the development trend of this hydraulic motor flow distribution structure, and outlines the composition, principle and design method of the end face flow distribution structure.
1. Overview of development trend of hydraulic motor
Overview of development trend of hydraulic motors with internal curve multi action radial piston type low speed and high torque hydraulic motors
The development trend of low speed and high torque hydraulic motor with internal curve multi acting radial plunger originated in the 1950s.
At the beginning of the fifties of the 20th century, the multi action internal curve radial plunger hydraulic motor developed by Samm Enterprise in France was mainly used in the hydraulic steering system. The rated working pressure of the motor was 10 MPa. Then the enterprise optimized the M10 hydraulic motor with flow distribution shaft and developed various models and specifications in the whole process of research and development, On this basis, M20 hydraulic motor with end face flow distribution structure was also developed.
In the 1950s, German Haglunds focused on the development of the multi action internal curve radial plunger shell type rotary motor with roller force transmission structure. With the deepening of scientific research, this motor has made great progress. The hydraulic motor with a text displacement of 417L/r increased its working pressure by 312 times, rotation speed by 4176 times, and power by 15 times between 1961 and 1981. In the middle and late period of the era, the enterprise also developed a plunger force transmission structure motor. The beam revolves around the plunger, which is compact in structure and much smaller in size. After the eighties, in order to meet the needs of mining equipment, MA series axial marathon hydraulic motors with a rated working pressure of 3115MPa were developed, which greatly enhanced their comprehensive performance and increased their service life.
Poclain, a French enterprise, has developed a cross beam transmission structural motor for excavators since the 1950s. In the 1960s, it produced G series in large quantities. In the era, it produced and manufactured series. The annual output of the internal outlet motor for end face distribution developed by Poclain was more than 10000 sets. In the 1980s and 1980s, it also developed a housing transformation development series wheel motor; Later, in order to meet the functional requirements of the main engine and enhance the low-speed high torque hydraulic motor, Poclain developed an internal curve hydraulic motor with multiple end face flow distribution. Its rated working pressure is 30MPa. The enterprise has recently developed a wheel motor with end face flow distribution, which has been further improved and enhanced the motor function.
Renold, a British enterprise, developed the IM series of plunger force transmission roller type axle motor in the 20th century era, and Sumitomo, a Japanese enterprise, carried out research and development in 1967 Inner curve motor And realized the R&D of RB type hydraulic motor series in - 1970; the first batch of multi acting radial plunger hydraulic motors installed in the wheel hub developed by Finnish Sisu enterprises were organized and manufactured in 1964.
In the mid-1960s, sample survey and imitation of low-speed and high torque hydraulic motors were carried out in China, and a few specifications and models such as crankshaft connecting rod motor and internal curve motor were initially established. In the early 1970s, engineering machinery, construction machinery, mining machinery and ship deck machinery all adopted hydraulic technology, and the number of departments studying low-speed and high torque hydraulic motors also increased to 4 (many. The types and applications of main engines have made great progress, but they are important for supporting the use of main engines.
Since the 1970s, a variety of specifications and models of multi action internal curve radial piston hydraulic motors have been designed and developed in China, such as the axial rotation NM series NKM shell rotor series Q (K) M series, ZM series, CNM series, etc. So far, NM series hydraulic motors have nearly 20 displacement specifications and models, and the higher pressure has reached 3115MPa;
Domestic NM series hydraulic motors are of chip guide rail and cross beam force transmission structure. According to the displacement, the rated pressure pa=16~25MPa, and the higher pressure pmax=20~3115MPa. This series has a total of 16 specifications and models. This series of hydraulic motors have relatively good working efficiency characteristics, and the bench test service life is nearly 8000~10000 h.
Compared with foreign countries, domestic multi action internal curve radial piston hydraulic motors are basically of axial flow distribution structure. At the same time, the basic experimental research on important motion pairs and various mechanisms still needs to be further deepened.
3 Evolution of valve distribution mechanism
In the multi action internal curve hydraulic motor, the flow distribution mechanism is one of the most important components. The design technology of the flow distribution mechanism is the key technology, which directly affects the operation reliability, efficiency, service life and stability of this type of hydraulic motor. The progress of the port pair indicates the progress of the hydraulic motor at a large level.
The structure of hydraulic motor port pair has progressed from the original mechanical support shaft port structure to a series of several types including hydrostatic balance shaft port structure, valve port structure and end port port structure. The axial flow distribution structure is an important flow distribution mechanism for the single acting internal curve hydraulic motor in foreign countries earlier and at present in China. This flow distribution mechanism has the following characteristics:
(1) Simple structure and few spare parts;
(2) Waist shaped shanks need a longer sealing surface when operating under a larger diameter; H. There is relative movement between sealing surfaces, interfering with sealing effect;
(3) The requirements for sealing clearance are relatively strict. Due to the long distribution length, higher requirements are put forward for the production, processing and assembly process of distribution shaft and shaft sleeve, as well as the oil filtration precision-
As the radial hydraulic pressure balance on the flow distribution shaft is not very satisfactory during design, the interference caused by external force or the deformation of the flow distribution shaft during production, processing, installation and operation will cause damage to the flow distribution shaft and tooth engagement, and the gap after grinding is difficult to compensate, resulting in increased leakage, and even reducing the service life of the motor;
(5) When the oil temperature of the working fluid in the oil tank is high, when the hydraulic motor starts after turning off the refrigeration, the hot oil suddenly enters the motor, which is easy to produce "thermal shock" at the port, causing the "seizure" of the port shaft.
At present, foreign single acting low-speed high torque hydraulic motor
End face flow distribution has been widely used to replace shaft flow distribution structure. For example, some motors of DUSTER2LOH in Europe and Samm in France Some motors of Poclaim, MC type motors of Japan Steel, MA series motors of Hagglunds of Sweden, etc. Multifunctional low-speed high torque hydraulic motors have also completed some end face flow distribution, and even produced symmetrical double end face flow distributor structure, which is also a relatively new type of flow distribution structure, with many outstanding advantages.
The main tasks of scientific research and design of relevant end face distribution mechanisms in China are
Concentrated on single function low speed high tensile strength and eight A cattle production Intel hydraulic motor Joint venture production with Italian SAI and other companies
NIM end face distribution crankshaft connecting rod hydraulic motor, Harbin Institute of Technology
Similar Germany has been selected in the "Shanghai Certification System" jointly with Xuzhou Hydraulic Parts Factory
Hydraulic motor end face flow distribution mechanism of DUSTERLOH Company. Multiplication
Few low-speed and high torque hydraulic motors use end face flow distribution mechanism.
At the present stage, the public P junction surface of Zhuzhou Lida Machinery Equipment Manufacturing Co., Ltd. is used as a high-power multi-function internal curve radial plunger end face assembly for scientific research and production
Hydraulic elevators and large crane ships have been used. The end face flow distribution type shell rotary motor and the symmetrical double end face flow distribution structure multi-function motor are also in use
Under development planning.
At the research level of end face flow distribution theory, relevant scholars in China
Bearing force of spare parts Calculation of pressing force and separating force of friction pair, friction damage and
The concept, experiment and scientific research of the project have made great progress. However, these researches are still limited to the crankshaft connecting rod motor, which is also a single functional hydraulic type
The flow distribution mechanism and working condition standard of the internal curve multi-function hydraulic motor are much more complicated than them.
The scientific research task at the end face flow distribution level of the multi-function internal curve low speed high torque hydraulic motor still needs to be further deepened, but there are relatively perfect axial piston pumps, and the concept and work experience of the end face matching pair of the single function low speed high torque hydraulic motor are specifically guided, and we firmly believe that we can achieve greater results in the future. The key of end face port design is to deal with the problem of static pressure balance between port plate and cylinder surface. At present, the key points in the research of end face flow distribution of multi-function internal curve low speed high torque hydraulic motor are: ① the calculation of hydraulic working pressure and the regular research of working pressure field in sealing areas; 2 the experimental research of flow distribution clearance; ③ The pulsation characteristics of port plate structure affect scientific research; ④ Analytic calculation of the compressive strength and deformation of the auxiliary parts of the valve distribution.
