This study aims to clarify the relationship between the lateral motion of a slender endless flat belt and the parameters of a two-roller belt system, such as misalignment angle, distance between rollers, and roller diameter. A calculation method to predict the lateral motion the aforementioned configuration with in-plane misalignment was proposed based on the results of our previous study on an open-end belt system, which revealed that the lateral belt motion was determined by the relative displacement of the belt between the upstream and downstream rollers in the axial direction of the roller. An experimental setup was employed to investigate the lateral motion of such a system with in-plane misalignment and verify the validity of the method. The results based on the proposed method agreed well with the experimental results of the lateral belt motion. Furthermore, a formulation that could predict the change in the lateral belt motion, referred to as the tracking ratio or skew rate, of the slender endless flat belt in a two-roller belt system with in-plane misalignment based on the calculation method of the lateral belt motion was proposed. The computed tracking ratio based on this formulation agreed well with the experimental results. Our results demonstrated that the tracking ratio was influenced by the misalignment angle, distance between the rollers, and roller diameter.

To analyze self-lubricating mechanism of copper-based graphite composites, the discrete element method (DEM) was used to study motion law of graphite particles of copper-based graphite composite/45 steel during friction. The research results show the film-forming particle layer was formed on the composite surface after a period of friction, which maintained dynamic balance depends on continuous supply of graphite in the composite. At different position, the trajectory of graphite particles is different, but the motion tendency of the graphite is the same, that is, the graphite x movement direction is consistent with the sliding direction of 45 steel, the graphite y movement direction is from the inside of the composite to the friction interface, and the motion displacement in y direction is greater than that in x direction. The load and sliding speed have an important influence on the motion law of graphite. Load or speed change the trajectory of graphite particles. However, the load and speed did not change the movement trend of graphite particles, which were consistent with motion trend at different position.

In the field of image segmentation, there are still some technical problems, such as the segmentation accuracy of the image with intensity inhomogeneity is not high enough. Level set method has the advantages of solid theoretical foundation and stable algorithm for segmentation of small sample data, so far it has played a significant role in image segmentation. In this paper, with the level set method for the research framework, we present a new approach to segment noise and weak boundary images that is supported by an adaptive velocity correction function. Based on the properties analysis of noise and edge information, this correction function is replaced the original constant to largely improve the segmentation accuracy. In addition, on the basis of some theoretical analysis, we use the edge stop function constructed by entropy to effectively improve the accuracy of image segmentation. Finally, a large number of challenging image experiments show that the proposed segmentation model performs better than other classical models in segmentation accuracy.

The cooling method for machining center spindles commonly involves utilizing a fixed-side jacket cooling system with lubricating oil or coolant as the refrigerant. The jacket cooling on the fixed side can be optimally designed so that the coolant flows where it is desired to be cooled. It should have a closed loop cooling circuit and a temperature control unit. On the other hand, since the spindle shaft rotates, it is necessary to cool the shaft by flowing a refrigerant from the fixed part to the rotating part. Cooling of the spindle shaft is expensive because it requires a complex mechanism such as a well-balanced high-precision component and a rotating joint for cooling. In addition, this cooling technology causes a loss of torque due to fluid resistance because the coolant flows through a shaft that rotates at high speed. Such a complicated and high-loss cooling method enables high precision and high speed. However, it is necessary to consider improvement. In recent years, based on such a demand, a cooling method using a heat exchanger (HE), which does not use refrigerant for the rotating spindle shaft, has been studied. In this study, the effects of the HE and jacket cooling were confirmed with spindles for machining centers. Specifically, by mounting a heat pipe (HP) in the spindle shaft that transfers heat to the HE at high speed, it was possible to reduce the temperature inside the bearing by 5 K and suppress thermal displacement by 47 %. On the other hand, the heat removal amount calculated from the temperature difference of the coolant for jacket cooling did not change with or without HEs. In other words, it was found that the HE can reduce the heat quantity by the bearing and the temperature of the shaft without increasing the jacket cooling capacity.

In order to improve the cutting performance of the hourglass worm gear hob and improve the cutting conditions of the teeth on both sides, it is necessary to constrain the absolute value of the rake angle of each tooth to be small and control the balance of the rake angles on the left and right sides. Based on the principle of enveloping tooth surface formation (Dong, 1989; Wu, 2009), this paper proposes a method of forming a spiral groove rake face with a variable transmission ratio, so that the rake face of each tooth is formed in segments to achieve the design requirements of small absolute value and balance on both sides. Taking the basic worm speed ω of the hob, the moving speed v of the machine tool cutter, and the installation offset Δx of the cutter as experimental factors, taking the rake angle on both sides of five teeth of the hob as response values, a three-factor three-level response surface analysis method is used to establish mathematical models between each experimental factor and the rake angle on both sides, and analyze the interaction between each factor. The results show that: The order of influence of the three selected factors on the rake angle on both sides is: basic worm speed, machine tool cutter moving speed, cutter installation offset; optimize and obtain the optimal parameter combination for each of five teeth in a spiral groove, perform simulation processing and measure rake angle. The results show that the rake angles on both sides of five teeth are controlled within ±0.3°, which is 94% lower than that when five teeth are processed simultaneously with a fixed transmission ratio. This indicates that rake faces of small rake angle can be designed by optimizing processing parameters, which is conducive to improving and balancing the cutting performance of hobs.

In view of the pollution and safety hazards caused by the damage of supporting roller type coal baffle in coal discharge ditch of thermal power plant, the traction type coal baffle was designed. However, in the one-year experiment, it is found that the device has a hidden danger of self-locking. This paper aims to design a self-locking avoidance compliant mechanism. First, the self-locking areas and causes were identified through computer simulation analysis. To avoid the jamming problem between the roller push rod and the push plate when the impeller coal feeder stops at optional position by increasing the flexibility of the push rod. We established the contradiction matrix between the length of the roller push rod and the opening degree of coal baffle. Furthermore, three kinds of self-locking avoidance compliant mechanisms were designed based on the separation principle of TRIZ theory. In order to obtain the optimal design scheme of mechanism, the orthogonal experiments were carried out to evaluate the design schemes, and the optimal self-locking avoidance compliant mechanism was obtained. Finally, the system was tested in a plant for a year. The results shows that the avoidance self-locking compliant mechanisms can solve the self-locking problem between the roller push rod and the push plate, and it is of great significance to the long-term stable operation of the traction coal baffle.