Tooth Profile Angle Research Articles

Investigation of contact ratio and dynamic characteristics of non-circular planetary gear train in hydraulic motor

As a basic component of the non-circular gear hydraulic motor (NGHM), the non-circular planetary gear train (NPGT) offers a number of advantages, including low velocity, high output torque and compact design. Two different types of NPGT pitch curves have been designed using the 4-6 type of NGHM as an example. Aiming at two kinds of pitch curves, the contact ratio solution methods for the planetary gear meshing respectively with the sun gear and the inner gear ring are proposed. A comparative analysis of an integrated pitch curve design and a segmented pitch curve design is conducted to evaluate the effects of varying addendum coefficient (AC) and tool tooth profile angle (TTPA) on the contact ratio. Furthermore, the influence of load, velocity, and contact ratio on the dynamic characteristics (DC) of the NPGT with a segmented pitch curve is investigated through dynamic simulation. The results show that AC and TTPA significantly affect the contact ratio, with an increase in contact ratio observed as TTPA decreases and AC increases. Additionally, the load has a notable impact on the dynamic meshing force and its fluctuation. A higher contact ratio is associated with greater transmission stability in the gear train. This study provides a theoretical foundation for the design and optimization of NGHMs, and expands the potential application of contact ratio effects on NPGTs in this field.

Simulation and analysis of propulsive performance for screw propulsion inspection robot

Screw propulsion mechanism is a kind of special walking mechanism suitable for traveling on the loose terrain, with the characteristics of small grounding specific pressure, strong trafficability and small turning radius. Based on this, a screw-propelled inspection robot for sandy land is designed. To evaluate the propulsive performance of the robot, The DEM-MBD coupling method was used to analyze the influence law of rotary-screw propulsor blade diameter, tooth profile Angle, lead and spiral blade number on the propulsive performance of screw-propelled inspection robot. The results show that the rotary-screw propulsor with larger blade outer diameter has stronger propulsion speed and better directivity, while its stability gradually deteriorates. The rotary-screw propulsor with smaller tooth Angle has better propulsive ability and stability. For the rotary-screw propulsor with single helix, the driving ability becomes stronger with the increase of the lead, and the stability deteriorates exponentially. When the pitch is similar, the directivity and stability of double helix are better than that of single helix and triple helix. The research results provide basic data for the performance optimization of screw propulsion mechanism and have practical significance.

Stability prediction and optimization of multi-regenerative weak stiffness grinding system based on microstructured tool

Chatter is a serious problem in grinding, which will directly affect machining accuracy, efficiency, tool wear and even damage machine tools. In order to understand and avoid grinding chatter, a stability prediction and optimization method of multi-regenerative weak stiffness grinding system based on microstructured tool is innovatively proposed. It is the first time to use microstructured tools to ensure the system stability without sacrificing the material removal rate, which offers promise for weak stiffness grinding. Firstly, a multi-random geometric model of microstructured grinding wheel is established, considering the shape, distribution, microstructure patterns and truing conditions of abrasive grains. On this basis, considering the regulating effect of microstructure patterns on workpiece regeneration delay and tool wear delay of grinding system with large aspect ratio, a multi-regeneration stability model based on microstructure tool is established. Then, the experiments of grinding wheel microstructuring, internal thread grinding and profile measurement are carried out. The results show that the theoretical model established can accurately predict the grinding stability boundaries. The microstructure types can be arranged in descending order according to the optimization degree of grinding chatter: composite type, cross type, oblique type and linear type. Compared with the grinding wheel without microstructures, the microstructured grinding wheel can increase the speed limit deviation by 12.2 % − 54.0 %, which basically solves the chatter problem at high rotation speed. The wear resistance of microstructured grinding wheel is improved by 44.2 %, the tooth profile angle error and bottom fillet radius of workpiece are reduced by 92.3 % and 90.4 % respectively, and the maximum tooth height difference and average tooth height error are reduced by 90.6 % and 87.5 % respectively.

Meshing theory of face worm gear drive with hardened cylindrical worm

This article proposes a novel linear contact face worm gear drive. The novel face worm gear drive consists of a face worm gear and a cylindrical worm enveloped by a tapered surface. The meshing theory for the novel face worm gear drive is systematically built up. The meshing theory on the base of the reference point is further developed aimed at the worm pair where the indexing surfaces are planar and cylindrical. The design methods of the rough size for the face worm gear are introduced. The computing method for the worm limit axial mounting distance is presented by employing the meshing limit line function. The asymmetry of the tooth surfaces for the worm pair is evaluated using the helix angle at the midpoint on the line of section for the worm gear tooth surface and the tooth profile angle for the worm axial section. Numerical results show that the geometric characteristics and the meshing properties for the tooth surface on both flanks of the novel face worm gear drive are asymmetrical. However, the meshing properties for the novel face worm gear drive are satisfactory.

Pulse laser precision truing of the V-shaped coarse-grained electroplating CBN grinding wheel

The machining difficulty has limited the further application of ultra-hard materials. For V-shaped coarse-grained electroplated cubic boron nitride (CBN) grinding wheel, a precise and efficient pulse laser truing method was proposed. Firstly, a theoretical model of the pulse laser truing process was established in order to optimize the laser truing energy distribution. Secondly, the effects of truing depth, grinding wheel speed, laser power and truing time were analyzed. Finally, the grinding performance of laser trued wheels were evaluated. The results showed that larger grinding wheel speed n would bring higher energy value and more stable energy distribution, truing depth h would not affect the value and stability of energy. CBN would not undergo phase transition and could bear more laser power Pavg. With the increase of truing time t, the geometric precision of V-shaped grinding wheel could be improved. The angle of V-shaped grinding wheel could reach 90.15° (deviation 0.02°), the bottom fillet radius was 53 μm (less than 100 μm). The surface roughness and grinding force corresponding to laser truing were less than that of mechanical truing, the truing time required was reduced by 72%∼83%, and the corresponding tooth profile angle and bottom fillet were basically the same.

Parallel axis precision grinding of micro-tooth internal thread with the coarse-grains CBN wheels

As an important part of precision transmission system, internal threads with high precision, high hardness and small pitch are widely used in the fields of aerospace, numerical control machine tools, medical equipment and construction machinery. Aiming at micro-tooth internal thread, the research on parallel axis precision grinding of micro-tooth internal thread with the coarse-grains CBN wheels is carried out. Firstly, the grinding wheel section is designed based on the principle of parallel axis grinding of micro-tooth thread, and the theoretical error is systematically analyzed. Secondly, the maximum undeformed chip thickness of parallel axis thread grinding based on coarse-grains is established. Finally, the precision grinding experiment of internal thread is carried out. The optimal parameters can be obtained: the grinding wheel diameter is 17.08 mm, the grinding wheel angle is 90.13°, the lead is 3 mm, the pitch diameter is 21.06 mm. In this case, the maximum axial error is about 0.1 μm, the tooth profile angle error is 0.01° and the rounded radius error is about 3.5 μm. Considering the machining effect and efficiency, the truing depth is 150 μm, the feed rate is 0.2 mm/s, the grinding speed is 17,000 r/min and the grinding depth is 5 μm.

A generalized meshing analysis method and its application to toroidal surface enveloping conical worm drive

A generalized method for the meshing analysis of conical worm drive is proposed, whose mathematical model is more general and whose application scope is expanded. A universal mathematical model, which can be conveniently applied to left-handed and right-handed conical worm pairs and their tooth flanks on different sides, is established by introducing the helical spin coefficient and tooth side coefficient of the conical worm. The pressure angle at the reference point, which is a key parameter for calculating the curvature parameters and lubrication angle, is determined based on the unit normal vector of the worm helical surface and is no longer determined by the tooth profile angle in the worm shaft section. The above improvement breaks away from the limitation of the classic meshing analysis method based on the reference-point-based meshing theory and thus expands its application scope. The toroidal surface enveloping conical worm drive is taken as an instance to illustrate the proposed method and the numerical example studies are conducted. The approaches to determine the reference point, the normal unit vector, and the curvature parameters at the reference point are all demonstrated in detail. The numerical results all manifest that the method presented in the current work is correct and practicable.

Study on Clamping Mechanism of Internal and External Variable Diameter Lifting Tool for Offshore Foundation Pile

Large marine foundation piles are an important part of offshore structural pile foundations, and their lifting operations have always been a major problem in the construction and construction of marine structures. Based on IHC’s bilateral marine foundation pile spreader, this paper proposes a structural scheme of “internal and external clamping type variable diameter marine foundation pile spreader”. It solves the problem of poor adaptability of spreaders to foundation piles of the same specification and different pipe diameters. At the same time, this article has conducted in-depth research on the two clamping methods of friction clamping and wedge tooth embedded clamping. Through experiments, it is found that under the same lateral load, the load capacity of the wedge teeth tightening is three times that of the friction clamping. Aiming at the embedding and clamping method of the wedge teeth of the spreader, first of all, the influence of the tooth profile angle of the wedge teeth on their embedding performance was studied by the plastic mechanics slip line field theory and Abaqus simulation analysis. Subsequently, the elastic mechanics theory and Abaqus simulation analysis were used to study the stress characteristics of the wedge teeth during the lifting process, and the internal stress distribution was obtained. The article aims to provide a reference for the design of spreaders in actual projects.

An effective thread milling force prediction model considering instantaneous cutting thickness based on the cylindrical thread milling simplified to side milling process

An effective thread milling force prediction model considering instantaneous cutting thickness is presented based on the cylindrical thread milling simplified to the side milling process. Firstly, based on the thread milling process simplified to side milling, an effective calculation model of instantaneous cutting thickness and a milling force model of single-layer cutter teeth are established considering the specific geometric profile of the cutting edge, chip groove angle, and tooth profile angle of the threaded milling cutter. Then, according to the time-domain difference of each layer of cutter teeth, a simplified thread milling force prediction model corresponding to the number of layers can be obtained. Finally, comparing the predicted values of the proposed model with the experimental results of cylindrical thread milling forces, the results show that the average prediction accuracy of Fx, Fy, and Fz are 90.75%, 83.56%, and 78.79%, respectively. The established simplified cylindrical thread milling force prediction model is accurate and reliable.

Analysis and Experiments of Embedded Gripping Mechanism Used in Large-scale Tools Holding Up Pile Foundation in Ocean

Abstract With the rapid development of the marine economy and continuous improvement of the industry, the scale of the offshore engineering is increasing. This raises interest in studying, theoretically and experimentally, gripping and bearing mechanisms for large-scale holding and lifting tools used in foundation pile installations. In this paper, the embedded gripping mechanism is studied based on the theory of elastic-plastic mechanics. The embedded and bearing performance of the tooth is simulated and the influence factors are studied. In addition, the device used in the simplified embedded experiment on the tooth of the embedded block is designed. The relationship between embedded depth, load, and tooth profile angle is identified and validated. Meanwhile, the embedded performance of linear and ring type teeth is compared experimentally in order to select the suitable type of tooth for various situations. This comparison makes the basis for designing an upending gripper for the marine pile foundation, which can realize the operation of holding the pile to prevent its falling.

Evaluation of the Strength of Flat Gears According to the Criterion of the Onset of Plastic Deformation

In this article, with the help of modern methods of mechanics of a deformable body and the means of computer mathematics, the simulation of contact interaction of gears was performed. For contacting profiles outlined on the involute, the solution of the planar problem was implemented by using the ANSYS Workbench program. This paper compares gears with different tooth profile angles and considers the difference in the use of elastic and inelastic material in gearing. The obtained stress results are compared with results obtained by the AGMA standard. In conclusion, the results are shown in the comparative table.

Process Parameters Decision to Optimization of Cold Rolling-Beating Forming Process through Experiment and Modelling

The cold roll-beating forming (CRBF) process is a particular cold plastic bulk forming technology for metals that is adequate for shaping the external teeth of important parts. The process parameters of the CRBF process were studied in this work to improve the process performance. Of the CRBF process characteristics, the forming forces, tooth profile angle, surface roughness, and forming efficiency were selected as the target indices to describe the process performance. Single tooth experimental tests of ASTM 1045 steel were conducted with different roll-beating modes, spindle rotation speeds, and feed speeds. Using analysis of variance (ANOVA) and regression analysis, the influence of the process parameters in each index was investigated, and regression models of each index were established. Then, the linear weighted sum method and compound entropy weight method were used to determine the process parameters for multi-objective optimization. The results show that the impact capacity and optimum value range of the process parameters vary in different indices, and that, to achieve the comprehensive optimum effect of a small forming force, high product quality, and high forming efficiency, the optimal process parameter combination is the up-beating mode, a spindle rotation speed of 801 r/min, and a feed speed of 960 mm/min.

Meshing theory and tooth profile geometry of toroidal surface enveloping conical worm drive

The toroidal surface enveloping conical worm gearing is put forward, whose worm is generated by a grinding wheel with generating torus. The meshing theory of this worm drive is comprehensively constructed and the case with the non-orthogonal axial lines is also included. The tooth profile equation of the worm is developed and the method and formula to compute the tooth profile angle are brought forward, which have theoretical guiding significance for the manufacture and inspection of the worm and the related conical hob. On the grounds of the theory established, the simulating studies on the meshing performance of the worm pair are made systematically and the comparative investigation is implemented with the conical surface enveloping conical worm drive. Via the numerical calculation, the value regularity of the parameters is discovered and this is quite useful to determine the meshing points of the worm gear set iteratively. The numerical outcome makes clear that, the meshing quality of the proposed gearing is considerably favorable and the meshing asymmetry between the two sides of one tooth is weak.

AXIAL TOOTH PROFILE OF CONICAL SURFACE ENVELOPING SPIROID

The tooth profile characteristics of the conical surface enveloping spiroid are taken into consideration. According to the formation mechanism, the equation of the helicoid of an enveloping spiroid is deduced. From this, the equation of the axial tooth profile is obtained. An approach is proposed to portray the axial tooth profile by means of the aforesaid equations. Two techniques are put forward to compute the tooth profile angle of the enveloping spiroid. One is based on the computation of the tangential vector of the tooth profile, and the other is based upon interpolation. The results attained from these two techniques are nearly accordant. Consequently, the theory and methodology are well verified and validated. A numerical example is provided and the effect law of the leading processing parameters on the axial tooth profile is pointed out.

Effect of fluid-structure interaction on sealed flow field and leakage rate based on computational fluid dynamics

This paper addresses the issue of reciprocating compressors staggered labyrinth seal structure. The internal flow field of sealed structure, the displacement of cylinder and piston for different tooth profile angles are analyzed synchronously using FLUENT software, and the effects of fluid-structure interaction on the performance of the labyrinth seal are revealed. The results indicate that with the growth of tooth profile angle, the leakage rate of labyrinth seal tends to decrease first, and then increase. The results of fluid-structure interaction analysis are close to those of actual engineering. The effect of fluid-structure interaction makes tiny deformation in calculation mesh of piston and cylinder structure, and the coupling interaction affects the performance of the labyrinth seal.

Developing a mathematical model of the tooth profile angles of thread milling cutter with helical flutes.

Developing a mathematical model of the tooth profile angles of thread milling cutter with helical flutes.

Design and research of calculation models of the tooth profile angles of thread milling cutter with helical flutes

Design and research of calculation models of the tooth profile angles of thread milling cutter with helical flutes