TOOTH CONTACT ANALYSIS OF A DESIGNED PLANETARY GEAR DRIVE FOR THE VEHICLE INDUSTRY

A planetary gear drive consists of a sun gear, planet pinions and an internal gear. We designed a complex gear system which is usable in the field of the vehicle industry into the automatized robots. The system was designed by GearTeq software which is connected with the SolidWorks designer software. After the assembly and the motion simulations tooth contact analysis (TCA) was made to analyse the normal stresses and the normal deformations on the connecting surface of the planet pinions and the internal gear by different load moments.

Degradation detection for internal gear pumps using pressure reduction time maps

In this paper, a novel approach for detecting degradation in internal gear pumps is proposed. In a data-driven approach, pressure reduction time maps (PRTMs) are identified as a useful indicator for degradation detection. A PRTM measures the time for reducing the internal pump pressure from certain levels to any lower level when the pump engine is stopped and the valves are closed. The PRTM can thus be interpreted as an internal leakage indicator of the pump. For simplified evaluation, PRTMs are compressed to a single scalar indicator by computing their volume (PRTMV). When the internal leakage increases due to wear, the pressure in the pump decreases faster (implying a decreased PRTMV). The proposed approach has been developed and tested with data of real internal gear pumps with different operating times. The PRTMV shows a close relation to the operating time of the pump. Moreover, we compare PRTMV with the commonly used and well known approach of observing pressure holding speed (PHS). Especially for medium degradation, PRTMV shows better sensitivity then PHS.

Research on Quality Control of Precision Machining Straight Internal Gear by Abrasive Flow Based on large Eddy Simulation

Traditional finishing technology is difficult to realize the precision machining of complex geometric parts. Abrasive flow machining technology solves this problem well. Taking the spur internal gear as the research object, the wall shear force, static pressure, dynamic pressure and abrasive velocity vector of the internal channel of the straight internal gear under different inlet velocity, abrasive concentration and abrasive particle size are analyzed by using the large eddy simulation method, and the action law of different parameters on the machining of straight internal gear by solid-liquid two-phase abrasive flow is discussed. At the same time, orthogonal test was carried out. The results show that the solid-liquid two-phase abrasive flow machining technology can effectively remove the burrs, pits and bulges on the tooth surface of spur internal gear, reduce the tooth surface roughness and improve the surface quality. The optimal combination of processing parameters and the primary and secondary order of various factors affecting processing are obtained by range analysis and analysis of variance. The regression equation is constructed by regression analysis to verify the effectiveness and accuracy of the model, which provides theoretical support and data reference for actual processing and production.

Research on the Mechanisms of Internal Gear Honing by use of Cone-shape Honing Wheel with Tool Tilt Angle

Ring gear is an important transmission component, but restricted by its ring-shape structure, the tooth surfaces are pretty hard to be finished after heat treatment. Honing is the most commonly used finishing technique for external gear, but for ring gear, it is inconvenient. In this paper, a new type of cone-shape honing wheel is proposed and the honing mechanism is studied for improving the honing performance of ring gear. First of all, the mathematical model of the honing technology by use of cone-shape honing wheel is built, and the merits of the new honing method are discussed. Then, the contact conditions between the honing wheel and the work gear are analyzed, and it is found that the tool tilt angle of the honing wheel has good influences on the honing mark distribution of the work gear. Finally, the honing simulations for ring gear by use of cone-shape honing wheel are carried out, by which the feasibility of the new honing technique are verified.

Psychoacoustic Evaluation of Hydraulic Pumps

In this study, sound measurements of an axial piston pump and an internal gear pump were performed and subjective pleasantness judgements were collected in listening tests (to analyze the subjective pleasantness), which could be seen as the inverse of the subjective annoyance of hydraulic drives. Pumps are the dominant sound source in hydraulic systems. The noise generation of displacement machines is subject of current research. However, in this research only the sound pressure level (SPL) was considered. Psychoacoustic metrics give new possibilities to analyze the sound of hydraulic drive technology and to improve the sound quality. For this purpose, instrumental measurements of the acoustic and psychoacoustic parameters are evaluated for both pump types. The recorded sounds are played back to the participants in listening tests. Participants evaluate them regarding the subjective pleasantness by means of paired comparison, which is an indirect scaling method. The dependence of the subjective pleasantness on speed and pressure was analyzed for both pump types. Different regression analyses were carried out to predict the subjectively perceived pleasantness or annoyance of the pumps. Results show that a lower speed is the decisive operating parameter for reducing both the SPL and the annoyance of a hydraulic pump.

Dynamics Modeling and Experimental Investigation of Gear Mechanism with Coupled Small Clearances

Internal gear mechanism is widely used in micro-nano satellites due to its compact structure and high precision transmission. However, the vibration coupling caused by the small clearance coupling is more obvious and cannot be ignored under low speed, light load and zero gravity conditions. Based on the geometric relationship between radial clearance and backlash, a coupled model between dynamic backlash and radial clearance of internal meshing gear is established. Based on the conformal contact theory, the radial collision force model of the gear shaft and shaft sleeve considering the small clearances is established. Additionally, a multi-clearance gear rotor system test device is built to measure the vibration acceleration of the internal gear rotor system by an acceleration sensor and transmitted to the industrial computer through a signal collector for data processing. Through the comparison of simulation and experiment, the accuracy of the gear dynamics model is verified. The analysis results show that, compared with the traditional model, the calculation results of the gear mechanism model considering the small clearance coupling is closer to the experimental data.