II. FEATURES AND PROBLEMS OF BEVEL GEAR

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1 International Journal of Advances in Marine Engineering and Renewables, 2015, 1(2), ISSN: (printed version); ISSN: (online version); url: Modelling and Analysis of Spiral Bevel Gear M. Muralidhara Rao, C. Thiyagarajan, M. Srinivasan and S. Srither Department of Mechanical Engineering, Aarupadai Veedu Institute of Technology, India RESEARCH ARTICLE Received 4 June 2015 / Accepted 2 July 2015 Abstract: The spiral bevel gear used in BMW K75 motor bike of material SAE 9310 is selected. Bevel gear has applications such as these gears has to turn the corner from the internal combustion engine to the rear drive gear. The material is changed with FLEXOR, with these difficult operating conditions; an improved analytical capability is paramount to increasing safety and the designing of bevel gear has been compared to that for normal gears. The Spiral bevel gear is modeled and subjected to analysis and the variation in result is plotted. Keywords: Bevel gear, tooth flank form measurement, tooth contact analysis I. INTRODUCTION A necessary part of a Shaft drive is always been a gear. The shaft drives includes bevel gears, shafts and bearings assembled in a closed lubricated housing and it is widely used in the transmission system. They are available in a broad range in terms of sizes, capacities and speed ratios. A noiseless operation is the most important thing in any machinery so well defined characteristics of the gear system has become necessary. In the automobile industry more number of gears is used as compared to other industries so higher reliability and lighter weight gears are necessary considering the demand of lighter automobiles. Spiral bevel gears have curved teeth. The teeth are formed along a spiral angle to the cone axis. The most commonly used spiral angle is 35 with the inclusion of pressure angle 20.In spiral bevel gear the gears engage more gradually. The contact commences at one end of the tooth that increases until there is contact across the whole length of the tooth. This reduces the risk of tooth breakage and a smoother transmission of power is also enabled. As a result of this, spiral bevel gears are quieter and it requires smaller diameter for the transmission of same load than straight bevel gears. In addition, the development of simulation technique to grasp a meshing condition of bevel gears has advanced and this technology has begun to be applied to the development of automobiles Literature survey: Matthew D Brown: This paper gives a detailed approach to spiral bevel gear design and analysis. Key design parameters are investigated in accord with industry standards and recommended practices for use in a medium class helicopter. A final gear design is proposed and analyzed to show that proper margins of safety have been included in the design. Upon completion of the design phase of the gear, analysis was conducted to ensure appropriate margins of safety had been implemented into the design. Calculated values of Hertz stress and bending stress are less than the allowable stresses as per AGMA Robert F Handschuh: Experimental and analytical studies have been conducted with respect to the thermal behavior of spiral bevel gears. The experimental effort was conducted on aerospace quality spiral bevel gears at rotational speeds to rpm and 537 kw (720 hp). The experimental results indicated that load, jet location, flow rate, and oil inlet temperature all can affect the steady state operating temperature of the spiral bevel pinions that were instrumented. Also an analytical modeling method was developed to analyze the thermal behavior via the finite element method. S H Gawande : In this paper mechanical design of crown wheel and pinion in differential gear box of MFWD (FWA) Axle (of TAFE MF 455) is done. Detailed modeling, assembly and analysis of tooth of crown gear and pinion is performed in Pro-E. Finite element analysis is performed to analyse the crown gear tooth for working load. Induced equivalent stress is less than allowable stress. From this it is concluded that design is safe. A Bensely : In this paper failure investigation of crown wheel and pinion has been done. A fractured gear was subjected to detailed analysis using standard metallurgical techniques to identify the cause for failure. The study concludes that the failure is due to the compromise made in raw material composition by the manufacturer, which is evident by the presence of high manganese content and non-existence of nickel and molybdenum. This resulted in high core hardness (458 HV) leading to premature failure of the pinion. II. FEATURES AND PROBLEMS OF BEVEL GEAR Spiral bevel gears, a subject in this report, are gears used for an axle of a dump truck and rotating shafts are intersecting at right angles to transmit power output from the engine to wheels Displacement of the meshing position called deflection occurs in the bevel gear and pinion because the entire differential is deformed during power transmission due to the tooth flank form of the bevel gear set and structural characteristic of the differential. of deformation is not

known, and as this changes depend on gear specifications (spiral angle and pressure angle) and supporting structure, gears and structure have been designed empirically.

2 known, and as this changes depend on gear specifications (spiral angle and pressure angle) and supporting structure, gears and structure have been designed empirically. Modelling of 3-D Entity: Gear: Modeling gear and pinion : When the teeth of bevel gear are inclined at a angle to the face of the bevel, these gears are known as spiral bevel gear. They run quieter in action and have point contact.. If spiral gear has curved teeth but with zero degree spiral angle, it is known as zero bevel gear. A right hand spiral bevel gear is one in which the outer half of a tooth is inclined in the clockwise direction from the axial plane through the midpoint of the tooth as viewed by an observer looking at the face of the gear. A left hand spiral bevel gear is one in which the outer half of a tooth is inclined in the counter clockwise direction from the axial plane through the midpoint of the tooth as viewed by an observer looking at the face of the gear. Pinion:

Proposal of Material design method: Flexor: FLEXOR steel is a Chromium-molybdenum-Tungsten alloy steel which exhibits a fine grain microstructure. All FLEXOR steel heats are a vacuum degassed.

3 Proposal of Material design method: Flexor: FLEXOR steel is a Chromium-molybdenum-Tungsten alloy steel which exhibits a fine grain microstructure. All FLEXOR steel heats are a vacuum degassed. FLEXOR is typically stocked in an as rolled condition. Quantity Designation: Number of teeth z Hand of spiral Right Transverse module [mm] Pressure angle 20 Shaft angle 90 Spiral angle 3 15 Mean cone distance R [mm] Face width b [mm] Tooth contact (meshing) analysis: The tooth contact analysis method has been jointly developed by Komatsu and Kyoto University based on the software developed by Kyoto University for hypoid gears so that Komatsu s large bevel gears can be analyzed. The tooth contact of the measured tooth flank forms of the pinion and gear schematically. A method used in the tooth (a) Result from tooth contact test In analysis, the advantage is the capability of calculating contact pressure, sliding velocity, flash temperature, transmission error, etc. during meshing in addition to tooth contact under load, and if assumed or actually measured deflection is inputted, tooth contact close to actual state under load can be reproduced. Fig. 10 shows examples of the analysis output, and items necessary for studying strength and noise, such as contact pressure, flash temperature, transmission error, etc., can be evaluated.

(a) Contact pressure (b) Flash temperature Load analysis: Torque application to a spiral bevel gear mesh induces tangential, radial, and separating loads on the gear teeth.

4 (a) Contact pressure (b) Flash temperature Load analysis: Torque application to a spiral bevel gear mesh induces tangential, radial, and separating loads on the gear teeth. For implicitly, these loads are assumed to act as point loads applied at the mid-point of the face width of the gear tooth. The radial and separating loads are dependent upon the direction of rotation and hand of spiral, in addition to pressure angle, spiral angle and pitch angle. The tangential loads are defined. Evaluation of meshing condition: In bevel gears, for adjustment during assembly and movement amount of tooth contact, the axial direction and offset direction of the pinion and gear,measurement and evaluation are made based on the relative difference in each axis. Definition of each axis of bevel gear

5 Obtained Deflection: Development of bevel gear for new dump truck: The tooth flank form of bevel gears in a newly developed model of a large dump truck has been designed using a new design method of bevel gears shown in Fig. 5. As deflection cannot be actually measured at the design stage in the case of new design, deflection of the development model is set with reference to the measured result of an existing differential whose supporting structure is similar and whose vehicle size is close, and the tooth flank form has been set so that the target durability can be obtained. Gear Calculations: Gear heel pitch diameter = 220mm Ratio i = 2.12 (As per Data book) Hand of spiral = Right Shaft angle Ʃ = 90 Number of tooth on gears =35 (As per Data book) Number of tooth on pinion =12(As per Data book) Gear face width = 30mm Pressure angle α = 20 Spiral angle β = 35 Addendum: ha1 = Mt Ca Ca=1.23(from data book) = = 5.09mm Dedendum: hf 1 = h ha1 h =188 Mt = =9.23mm hf1 = =3.31mm hw =1.7Mt = = 8.16 ha1 = HW ha2 ha2 = Mt.Ca = = 0.96mm ha1 = = 7.2mm

6 face contact ratio Pressure angle: Coefficient of friction:μ CONCLUSIONS In this paper, the gear model is created by Solidwork software. Then the model created by Solidworks was imported to ANSYS software. The maximum deformation appears at the centre of gear surface. The maximum stress appears at the fillets between the gear and pinionr. The deformation was mainly bending deformation under the lower frequency. And the maximum deformation was located at the inner surface between gear and pinion. Base on the results, we can forecast the possibility of bevel gear. REFERENCES 1. Artoni A., Gabiccini M., Guiggiani M., (2008), Nonlinear identification of machine settings for flank form modifications in hypoid gears, Journal of Mechanical Design, 130 (2008), Gabiccini M., Artoni A., Guiggiani M., (2012), On the identification of machine settings for gear surface topography corrections, Journal of Mechanical Design 133, (1-8). 3. Litvin F. L., Fuentes A., Hayasaka K. (2006), Design, manufacture,stress analysis, and experimental tests of low-noisehigh endurance spiral bevel gears, Mechanism and Machine Theory, 41, Marciniec A. (2003), Synthesis and analysis of eshing for spiral bevel gears, Publishing House of Rzeszow University of Technology, Rzeszow (in Polish).

7 5. Marciniec A., Sobolewski B. (2010), Simulation of spiral bevel gear cutting process in environment of Inventor 2010, Engineering Forum ProCAx, Sosnowiec-Siewierz (in Polish). 6. Marciniec A., Pisula J., Płocica M., Sobolewski B. (2011), Design of bevel gears using mathematical modeling and simulation in the CAD environment, Mechanik, 7, (in Polish). 7. Pisula J.; Płocica M. (2012), Analysis of meshing of bevel gears on the basis of a mathematical model of machining processes and direct simulation of cutting in Inventor, Mechanik, 1, (in Polish). 8. Rating the Pitting Resistance and Bending Strength of Generated Straight Bevel, Zerol Bevel and Spiral Bevel Gear Teeth. ANSI/AGMA 2003-B97 (1997). 9. United Technologies Corporation. Sikorsky Structures Manual. Connecticut: Sikorsky Aircraft Corporation, United Technologies Corporation. transmissions Design Manual. Connecticut: Sikorsky Aircraft Corporation, F.L Litvin, Local synthesis and tooth analysis of face-milled of spiral bevel gears. NASA, CR4342, Zhang, Y., Computering analysis of meshing and contact of gear real tooth surfaces[j]. ASME Journal of Mechanical Design, 1994, 116(1): [3] Z.D Fang. Optimization of Dynamic Meshing Behavior of High Speed Spiral Bevel Gears[J]. Acta Aeronautica et Astronautica Sinica, 2001,22(1): (in Chinese) 13. John Argyris., Computerized integrated approach for design and stress of spiral bevel gears[j]. Comput. Methods Appl. Mech. Engrg. 191 (2002): Z.D Fang. Tooth Contact Analysis of Spiral Bevel Gears Based on the Design of Transmission Error[J]. Acta Aeronautica et Astronautica Sinica, 2002,23(3): (in Chinese) 15. F.L Litvin, Computerized design, simulation of meshing, and contact and stress analysis of face-milled formate generated spiral bevel gears. Mechanism and Machine Theory,37(2002): A. Fuentes, F.L Litvin, Design and stress analysis of low -noise adjusted bearing contact spiral bevel gears, ASME Journal of Meshanical Design 124(2002) M. Sakawa, Genetic Algorithms and Fuzzy Multiobjective Optimization. 2001

Thermal Analysis of Helical and Spiral Gear Train

International Journal for Ignited Minds (IJIMIINDS) Thermal Analysis of Helical and Spiral Gear Train Dr. D V Ghewade a, S S Nagarale b & A N Pandav c a Principal, Department of Mechanical, GENESIS, Top-Kolhapur,