•Numerical analysis of hybrid metal-composite gear meshing by using an analytical-FE gear contact model.•Experimental analysis of the Static Transmission Error in hybrid gears under different ...operating conditions.•Experimental evaluation of the impact of the manufacturing process on the meshing behaviour of transmissions with hybrid gears.
The aim of this work is to provide a numerical analysis and an experimental characterization of the meshing behaviour of hybrid metal-composite gears, manufactured by press-fitting a carbon fibre reinforced polymer (CFRP) web into a steel gear structure. Hybrid gears have been recently proposed as an answer to the quest for lighter mechanical transmissions, with improved meshing performance in comparison to conventional lightweight gears. Numerical and experimental studies at single-gear level as well as gear-pair testing demonstrated a huge potential for such a technology to contribute to system-level weight reduction.
In this paper, the meshing behaviour of a hybrid gear, manufactured by interference fitting and engaging with a conventional steel gear, is analysed numerically by using a hybrid gear contact model that combines, in a multibody simulation environment, an analytical description of the non-linear contact phenomena with a Finite Element (FE) formulation of the overall gear compliance. An experimental characterization of the Static Transmission Error (STE) is also given by using a high-precision gear test-rig, where quasi-static tests have been carried out under different load conditions. Important indications on how the manufacturing process must be implemented to prevent from poor meshing performance are illustrated.
Injection-moulded composite gears using fibre-reinforced thermoplastics often exhibit increased performance compared with those made from unreinforced polymers. In general, materials are chosen on ...cost or simple performance grounds (such as, nominal flexural modulus or heat deflection temperature).
Aspects of the performance of polymeric gears have been studied by a number of workers and efforts have been made to simulate the contact conditions during gear running. However, until now the wear performance of gears made from polymer matrix composites has not been studied systematically. While such materials have been studied using pin-on-disc or twin disc roll/slide wear techniques, no attempt has ever been made to directly compare the results from such studies with those from gear tests. This paper attempts to explain the comparative methods of measurement of various polymer matrix composite gear materials and to relate their performance to results obtained in contact simulation experiments by other workers.
Methods of wear testing are compared including direct gear testing and disc testing, together with electronic (displacement) measurement, weight loss and direct measurement. A new method of characterising the wear of gears is presented, which relates actual contact conditions and gear tooth wear. This co-ordinate measurement technique provides wear rates as a function of roll angle, and hence load, sliding speed and slip ratio. It allows comparisons between gear tests and a simpler test configuration, the twin disc roll/slide test. The conclusions reached have interesting commercial implications for the producers and end users of polymer composite gears and for those involved in testing them.
•Numerical prediction methods for elastic behavior of anisotropic and quasi-isotropic webs are proposed.•The iterative calculation methods of meshing behavior for two hybrid metal-composite gears are ...unified.•The calculation accuracy and efficiency of the proposed method are verified.•Detailed discussion on effects of hybrid gears replacing full metal gears.•Multi-parameter design to reduce mesh stiffness fluctuations.
Thin-web structures are the primary strategy for lightweight gears in the aerospace and automotive fields, but current research mainly focuses on metal thin web, lacking understanding of the application of anisotropic and quasi-isotropic composite thin-web gears. Focusing on accurate and efficient calculations of mesh stiffness and load sharing ratio, this work develops a unified numerical analysis method to assess the meshing behavior of the two hybrid metal-composite gears. Multi-scale numerical prediction methods for elastic properties of anisotropic composite and homogeneous laminated webs are established, and two tooth-loading deformation calculation methods for metal-composite-metal gear bodies with different web widths are developed separately. A numerical analysis method is proposed by unifying the iterative calculation process of the two hybrid gears through deformation coordination relationships, which is also applicable to full metal gears. Finally, extensive comparisons with the finite element method (FEM) and existing numerical method verify the proposed analytical method (PAM). The investigation results reveal the impact of replacing full metal gears with these two hybrid gears on the meshing behavior and further elucidate the advantages of using composite webs for micro and macro parameters design in adjusting the mass and stiffness and reducing mesh stiffness fluctuations. This work provides a new analytical method for the structural design and performance assessment of lightweight hybrid metal-composite gear systems.
The sustainability of today’s industry turned into a critical requirement on account of energy cost increases, environmental pollution, and carbon emissions. As an important segment in mechanical ...drive, the vibration and noise from gear transmission negatively impact the physical and psychological health of workers and interfere with the machine running. This paper proposes a new temperature-controlled vibration-damping lightening polymer composite gear model with a modified lightweight web structure. The characteristic of polymer (mechanical properties changed by structure temperature) was trying to be used for the gear damping variable control. The spur gear web was replaced with a spoke-like structure connected with a ring structure that adheres to the heating film. That was required to assure torsional rigidity and compliance meanwhile controlling the web structural damping performance. For experimental purposes, the gears were manufactured from three kinds of viscoelastic polymer using additive manufacturing technology. The gear frequency sweeping excitation testbed was built in the experiment. The vibration exciter and gear dynamic responses were measured through the force and torque sensor. In the tests, the modal frequency and damping of gears were measured at different temperatures by control heating films. The experimental result coincides with vibration analysis in the finite element (FE) method. Variable damping could be achieved by changing the viscoelastic polymer temperature and gear web structure. This research can provide guidance for the polymer material gear damping control in mechanical transmission applications.
Gear whine noise has become one of the primary challenges facing noise, vibration, and harshness engineers; this is because the electrification of the powertrain has largely eliminated engine masking ...noise while increasing the working speed of the E-powertrain. In this study, a hybrid metal-composite gear was proposed to reduce gear whine noise, and its performance was evaluated by means of dynamic transmission error (DTE). The test results showed that the hybrid metal-composite gear produced an effectively lower DTE than that of alternatives, particularly when approaching resonance speeds. In addition, a reduction in resonance DTE was verified by acquiring and comparing the frequency response functions of a steel gear and a hybrid metal-composite gear. As DTE is the primary excitation source contributing to whine noise, the hybrid metal-composite gear is expected to be a significant candidate for the reduction in powertrain whine noise.
Nylon with various reinforcements is utilized for composite gear preparation; however, the composite specimens have less strength and a higher wear rate. Moreover, the materials and processing costs ...are high when selecting various mix proportions. Hence, this research has examined the impacts of adding Graphene oxide (GO) and Tungsten disulphide (TD) with Nylon 66 (PA66) on the tribological and mechanical properties. The research aims to identify the best hybrid nylon-reinforced composite specimen for composite gear manufacturing. The GO was prepared by the Modified Hummers-based method and coated with epoxy resin by dip coating. Further, a novel Decision Buffalo-based Mix Selection (DBbMS) has been developed for selecting the best mix proportions to reduce the processing time and material cost. The test specimens are set up by varying the rates of coated GO and TD blended with PA66. In addition, the test examples for tribological and mechanical tests were shaped using an injection moulding machine. The mechanical and tribological properties of PA66, TD, and GO mixed with PA66 hybrid composites were identified. The PA66 composite with 4wt% TD and 15wt% coated GO (PTO-3) uncovered better strengths and higher wear and erosion resistance. In this work, PTO-3 hybrid composite material has been utilized for gear manufacturing.
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