Research on fatigue crack of low speed and heavy load gear
Taking low-speed and heavy-duty gear as the research object, the fatigue crack propagation and fatigue fracture of gear teeth are […]
Taking low-speed and heavy-duty gear as the research object, the fatigue crack propagation and fatigue fracture of gear teeth are […]
In order to obtain the actual coordinate points of the hourglass worm tooth surface, the coordinate machine or gear measuring
Before carrying out the bending fatigue test, it is necessary to determine the stress level of the test. Two of
The figure shows the rotor model of a typical integral 5-stage centrifugal compressor. As shown in figure a), TST, WST,
Fatigue cracks often occur when the component is under the condition of alternating load for a long time. The initial
In general, the fatigue failure of gear is to produce microcracks at the position of the maximum stress of gear
When the pitch circle of the gear shaper cutter rolls along the pitch curve of the non-circular gear, it not
The fatigue crack growth mechanism of 42CrMo steel was studied by fatigue crack growth test. The law of fatigue crack
Figure 1 is the contact pressure diagram of the gear in the process of meshing, and the pressure distribution of
The diagram of stepless transmission mechanism is shown in Figure 1. The driving noncircular gears 1 and 3 are the
Fatigue fracture is the surface formed by the fatigue fracture of the test sample or component during the test or
The results of the overall equivalent stress of the gear are shown in Figure 1. The variation law of dynamic
On the basis of space curve meshing theory, the tooth surface construction of parallel shaft pure rolling internal meshing line
The macro morphology of fatigue fracture of low speed and heavy load gear teeth can be divided into three obvious
Macro analysis It can be seen from Fig. 1 (a) that the cracks are exposed on the forging surface, the
With the continuous improvement and innovation of fatigue crack testing methods, the research on small fatigue cracks has gradually changed
Wu Zhenpeng and others took the helical gear as the research object, modeled the helical gear, simulated the crack propagation
Since the test data under each stress level obey the lognormal distribution, when the normal probability density function is known,
The normal chord tooth thickness is the shortest distance between the two theoretical contact traces (spatial helix) on the left
The following equation can be obtained from the geometric knowledge of involute gear: Where, α T is the end face
Robert Basan proposed the mathematical model of slip line contact and the calculation model of multiaxial fatigue life based on
The number of fatigue cycles under four stress levels is counted in the order from small to large, and the
Although the strength of mechanical gear bearing capacity does not entirely depend on gear hardness, improving gear hardness is still
Gear transmission is one of the most commonly used transmission in all kinds of machinery, which has the advantages of
Before calculating the tooth root stress of the gear, it is necessary to find the exact position of the load
Because the mechanical operation is mostly heavy load, medium and low speed transmission, most of them start frequently and often
Before carrying out bending fatigue strength, the primary task is the design and manufacture of gear specimens. Because the object
Comparison of machinability and forgeability between Ni Cr and Ni Cr Mo steels The machinability of different materials is mainly
In order to study the problem of fatigue crack propagation and fatigue life of low-speed and heavy-duty gear, a low-speed
For the statistical analysis of this section, the relevant data of stress ratio r = 0.6 is also used. The
According to the theory of elastohydrodynamic lubrication, the lubricant entering into the crack will form a certain pressure inside the
Other countries in the world mainly use Cr Ni and Cr Ni Mo carbon steel. Compared with Mn Cr steel
In order to verify the accuracy of the fatigue crack growth test of the compact tensile specimen, the data of
In order to verify the correctness of the numerical model, Hertz pressure distribution is applied on the contact model, and
Gear is a kind of mechanical element with continuous meshing transmission of motion and power on the rim, which plays
The theoretical Mises stress nephogram distribution law of the numerical simulation model of compact tensile specimen under macro state is
1. Data acquisition In the experiment, the gear fatigue life test-bed as shown in Figure 1 is used to monitor
Although the deep carburizing of large heavy duty gears improves the bearing capacity and prolongs the service life, it still
Tooth wear is one of the main failure forms of low speed and heavy load gear transmission. H. Winter has
The model used for numerical simulation of fatigue crack growth is the same as that of 42CrMo steel compact tensile
The important parameters to ensure the load-bearing capacity of low-speed and heavy-duty hard face gear are: enough central strength and
In order to more clearly reflect the output classification status of features in each layer of RESNET model, t-sne technology
With the continuous progress of the test, under the action of cyclic load, cracks appear on the sample and continue
The deep carburizing of large heavy duty gears has a history of more than 10 years in foreign countries, with
1. Selection of residual unit module In RESNET, there are two kinds of residual unit modules: original residual unit module
The fatigue crack growth rate DA / D N and the stress intensity factor at the crack tip under different
It is very important to choose the hardening heat treatment method of low speed and heavy load gear reasonably. The
The data of crack tip stress intensity factor (SIF) and crack length under different stress ratios collected through the test
The main damage form of gear in soft tooth surface rolling mill is severe plastic deformation of gear surface, which
Using normalizing big gear and quenching and tempering small gear, the tooth surface after use can be extruded into mirror
The fatigue crack growth test of compact tensile specimen was carried out according to the national standard GB / T
The maximum meshing force reflects the maximum load of planetary gear. The dynamic load coefficient is the ratio of the
As the cement mill, mine hoist and other soft tooth surface reducer gear, the main problem is to eliminate early
The fatigue crack growth test was carried out in the State Key Laboratory of new metal materials, University of science
After the detailed grid data is predicted, if the output torque of P20 row is expressed as 1, then the
When gears work, they bear two kinds of stress, so there are few two kinds of failure. One is that
42CrMo steel is a kind of ultra-high strength steel, which has strong resistance to plastic deformation, less possibility of brittle
The modeling of Pro / E software is based on the characteristics of 3D model, and it can also carry
There are three ways to improve the bearing capacity of gears, namely, ① improving the structure of reducer, such as
The existence of the worst speed in the boundary lubricated gears has not been discussed in the literature. There is