Design and analysis of a 4-speed, dual input hybrid gear box.

Transcription

1 Volume 118 No ISSN: (on-line version) url: Design and analysis of a 4-speed, dual input hybrid gear box. PNV Sai Mahesh 1, Cheerlaganesh 2, MVV sai ram 3, N. harikrishna 4,N.sivateja 5 1,2,3,4 Mechanical engineering,klef Guntur, India 5 Assistant Professor,Mechanical engineering,klef Guntur, India May 29, 2018 Abstract the purpose of this paper is to design and analyse a 4- speed hybrid gearbox which can transmit power from two power sources namely IC engine and motor. This Gearbox is designed especially for a student formula design of gears followed by the analysis of the gears and shafts along with the casing of the gearbox. The powertrain consists of engine with a displacement of 306 cc and a 2 KW, 48V, 7.5A motor. The gearbox is intended to amplify and transmit a power of 5.35 KW from the engine and 2KW from the motor to the wheels. With this kind of gearbox, the limitations that are present in the two dominant kinds of power sources for commercial vehicles i.e., IC engines and electric motors can be overcome. The vehicle can be used as a complete fossil fuel powered vehicle, completebattery powered vehicle or as a combination of both. The result of this paper deals with the designing and analysis of a hybrid gearbox which can be used as a solution for the limitations pertaining to the fossil fuel powered and battery powered vehicles and leverage the benefits of a hybrid vehicle. Key Words:hybrid gearbox;ic engine; motor; hybrid vehicle 1

2 1 INTROUDCTION Transmission is the heart of the vehicle, and gearbox is the crucial part of the transmission unit. It is used for the calculated variation in torque and rpm for a vehicle. With this hybrid gearbox we can combine both IC engine and electric motor drives. There are few drawbacks in IC engine powered vehicles namely, environmental pollution, higher costs of fuel, higher number of mechanical parts in the transmission units etc. and the battery powered vehicles too have limitations namely, less energy density of batteries, frequent recharge of batteries and unsuited for long distance travels etc. Hybrid vehicles can work as a bridge between the transition of commercial vehicles from IC engine to battery until more advanced technologies are invented in the field of battery powered vehicles. The focal point of this hybrid gearbox is its gear shifting mechanism. There are basically two shifters provided for the gearbox, one is for the shifting of gears from first to fourth and vice-versa and the other shifter is for changing the power input to the gearbox from IC engine to motor and vice-versa. The differential used in the gearbox is an open differential. Appropriate heat treatments were performed on all the elements present in the gearbox so as to ensure exceptional load bearing capacities for all the elements. Various research papers have been referred to get some background idea about the research being done. FARSHID ZABIHIAN et al. designed and manufactured a ball lock mechanism for the mini Baja sae car. This type of transmission reduces the width of the gear box which resulted in lesser space requirement and lesser weight of the vehicle. Prof. B.R. Borkar et al. studied the stresses acting on the gear wheels of the gearbox and found out that one of the reason for gear failure was due to the wear of the gear tooth tip. They made few modifications to the tooth and obtained an increase in gear life by 3 years. Ashwani Kumara et al. analysed the influence of vibrations on the material properties of the material used in gearbox casings. They have concluded that the mechanical properties are directly related with natural frequency and vibration mode shapes. Nilson Barbieri et al.analysed the damage caused ingears due to vibrations using five accelerometers placed at different positions. They introduced a computational tool which is reliable and provides more capabilities for inspection and diagnosis system. 2

3 2 BALL LOCK MECHANISM Ball lock mechanism is used in the gearbox because of its compactness and lesser number of parts compared to other kinds of transmission systems. When the shifter rod /plunger moves axially inside the drive axle, it pushes the balls radially outwards into the groves provided in the gear wheels this locks the balls into the groves and the power transmission takes place from the drive axle to the gear wheels through the balls. The gear shifting takes place with the help of a single plunger rod which moves in axial direction inside the drive axle. The transverse motion from the gear rod is converted to longitudinal motion of the plunger with the help of a 90 degree angled link. The precise movement of the plunger rod is required for the accurate gear shifting so we have provided a slotted plate in the drivers cabin which helps in guiding the gear rod while shifting gears. The slots in the plate are made accurately keeping in mind the plunger travel required for each gear shift. 3 MODE SHIFTING MECHANISM (MSM): - 3

4 The msm is the vital mechanism which causes the shift of power input to the gearbox from motor to engine and engine to motor. The msm has cross-shapedgroves on one shaft and cross-shaped ribs on the other shaft which when engaged result in power transmission from the motor and when disengaged result in power transmission from the engine. The shafts are axially moved with the help of a c-shaped forks attached to it. The forks are moved with the help of a shifter provided on the top of the gearbox for shifting modes. The shifter has three stops i.e, engine input, neutral and motor input. So the neutral gear is provided in the msm instead of the ball lock shifter mechanism. A connection to the msm is provided in the drivers cabin with the help of a rod linkage which will aid in the shifting of modes. Same as the gear shifting mechanism a slotted plate is provided for the mode shifter rod (present in the drivers cabin) for the accurate movement of the shifter. 4 Gearbox power flow chart: Figure 4 5 Calculations:- The weight of the vehicle considered is, GWV=150kg=1471.5N maximum static resistance= GVW (COF)static =1471.5*0.46 (for tarmac road) = N Rollingresistance(RR) : The force which required to overcome the rolling friction of a wheel is called as rolling resistance. RR= gross weight*rolling resistance constant(k) = GVW (COF)kinematic 4

5 = =36.8N Gradient resistance (GR): The force required to climb an inclination on the road is called as gradient resistance. GR=gross weight sin(θ) = GV W sin θ(θ = 2 ) = sin ( ) =50.6N Load rate=rr+gr+msr Load rate= =764.29n. The value of the load rate is N. Torque required: Treq=load rate rolling radius of wheel Treq=(TL) Rw = =184.43N-m After torque is obtained, it is essential to know the coefficient with which the initial torque is multiplied. That coefficient is gear ratio and is denoted by (i). Gear Ratio First gear ratio, G1= required torque(treq)/motor torque(tm) = /24 G1 (i =7.7) Second gear ratio, G2= motor rpm/rpm required = 3000/750 G2 (i=4) Third gear ratio, G3= motor rpm/rpm required = 3000/ G3 (i=2.1) Fourth gear ratio, G4= motor rpm/rpm required= 3000/3000 G4 (i=1) Output rpm and torques:- 6 Material selection: While choosing material without expanding the weight and ought not trade off the quality of the gears, shaft and bearing. Predomi- 5

6 nantly material choice assumes imperative part in the gearbox. For gears we must through solidifying process and additionally shafts too. This solidifying procedure will give more quality which can withstand any sort of loads we should consider all the bowing loads keeping in the mind the material ought to have quality, consumption, security and so forth., Mainly the gear box housing ought to be high safe it ought not experience corrosion. It additionally acts damper vibration and can spare weight. Theoretical force and Stress calculations on the gears: A sample calculation for gear no1.1 is shown below Stress on gear, σ = ((wt h)t/2)/(bt 3 /12) (according to Lewis bending equation) Tangential load, Wt=T/R=(24N-m)/0.045m=533.3N Gear tooth width, b=15 Gear tooth height, h=6.87 Gear tooth thickness, t=5.79 σ=(( )(5.79/2))/((15 (5.79) 3 )/12)=43MPA analysis= 33.69mpa module,m=(pitch dia)/(no.of teeth) PITCH=Π module Lewis factor, Y = (t 2 )/((6 h m)) = ( )/(( )) m=90/28=3.21 bending moment, M = F t h = =3.66N-m 7 Design Methodology: By considering all the necessary criterions to design the gearbox proper modelling of Gearbox was done using solidworks software. After the modelling and assembly was done in SW and analysis was performed in ansys

7 In this paper design and analysis of all the gear wheels and shafts present in the gearbox was done but the pictures of only four gears and few shafts is shown but all the results are shown in the tables below. Modelling of gears: - modelling of gears is done in solidworks as shown in figure 7(b) Meshing of shafts, Gears and casing: - before performing the analysis the shafts, gears and casing were meshed with mesh size5mm as shown in figure7 (d). 7

8 Total deformation: - the total deformation results of the gears and shafts is shown in the figure7 (e). Equivalents stress: - equivalent stress results of the gear and shafts is shown below in figure7 (f). Vibrational analysis: vibrational analysis is done on the gearbox casing and the results are shown below in figure7 (g). 8

9 The detailed results of the analysis performed on all the gears and shafts is shown in the following table 8 CONCLUSION In this paper an attempt to design and analyse a gearbox which can transmit power from two power sources was done. After performing all the analyses we compared both theoretical and practical values of bending stress and 90% accuracy of both values was found. We can conclude that the gearbox designed will be effective in conserving fuel, it will assist in longer driving duration with a lesser capacity and smaller size battery, which, at present is possible only with higher capacity batteries which are larger in size, increasing the weight of the vehicle. The ball lock mechanism is useful in this gearbox as it requires very less space compared to other conventional gearboxes. The mode shifting mechanism is the vital part of 9

10 the gearbox as it assists in the shifting of modes as and when required. Vibrations are caused due to improper alignment of shafts, gears, bearings etc. which should be taken care while manufacturing and assembling and moreover the vibrations in the gearbox can be reduced by using dampers while installing the gearbox in the vehicle. 9 SCOPE FOR FUTURE WORK As we have now seen a hybrid gearbox which can transmit power from both power sources. But there is onemore alteration that can be done in the gearbox i.e. simultaneous power transmission from both thesources. The present gearbox can either transmit power from engine or motor but if we could make anarrangement that would transmit power from both sources then the overall fuel consumption can bereduced in conjunction with charging of the batteries while running which will increase the viability ofbattery driven cars.the gearbox casing was made in the shape of a box due to financial and time constraints, but it can beconverted into a more compressed shape resulting into lesser space consumption and lesser weight.and instead of using these many gears for gear reduction, we can use a cvt on the engine side tocompensate for the required gear ratios. This will drastically reduce the overall number of gear wheels usedin addition to reduced weight of gearbox.instead of manually shifting gears and modes we can incorporate electronic stepper motors and Arduino programming to automatically shift gears and modes based on user requisites, making the gearbox a semi-automatic gearbox. References [1] Rahul Mokal, R.V. Mulik, S.B. Sanap, Design and Analysis of Gearbox for Tractor Transmission System, International Engineering Research Journal (IERJ) 2 Page , 2015, ISSN

11 [2] Jianxing Zhou, Wenlei Sun, and Qing Tao, Gearbox Low-Noise Design Method Based on Panel Acoustic Contribution, Volume 2014, Article ID , 10 pages [3] Yunyun Yang, Sen Wu, The research on gearshift control strategies of a plug-in parallel hybrid electric vehicle equipped with EMT, 2014, 6(6): , ISSN : CO- DEN(USA) : JCPRC5 [4] Abhijith B K Pillai, AbhijithSankar S, AnuVijayan, Anwarshah A, Riswan K, Jinshah B S, Design of Planetary Gear Transmission System for Hybrid Scooter, International Journal of Scientific & Engineering Research, Volume 7, Issue 4, April-2016, ISSN [5] G.COCKERHAM, D.WAITE, COMPUTER-AIDED DE- SIGN OF SPUR OR HELICAL GEAR TRAIN, VOLUME 8, ISSUE 2, APRIL 1976, PAGES [6] WEIGANGHUZHIMINGLIUDEKUNLIUXUEHAI, FA- TIGUE FAILURE ANALYSIS OF HIGH SPEED TRAIN GEARBOX HOUSINGS, VOLUME 73, MARCH 2017, PAGES [7] ETTOREPENNESTRALORENZOMARITIAPIER PAOLO- VALENTINIAVICTOR H.MUCINOB, EFFICIENCY EVAL- UATION OF GEARBOXES FOR PARALLEL HYBRID VE- HICLES: THEORY AND APPLICATIONS, VOLUME 49, MARCH 2012, PAGES [8] v.k.kamble, k.n.wagh, dr. p. v. washimkar, Development and testing of advance hybrid savonius and arm gear based structure for electric power generation, (ijmet), volume 7, issue 1, jan-feb 2016, pp , article id: ijmet , journal impact factor (2016): (calculated by gisi) issn print: and issn online: , iaeme publication [9] Joginder Singh, Dr. M R Tyagi, ANALYSIS OF STRESSES AND DEFLECTIONS IN SPUR GEAR, (IJMET), Volume 8, Issue 4, April 2017, pp Article ID: IJMET , ISSN Print: and ISSN Online:

12 [10] Dr.V. Balambica, Ravi Kumar Soni, Satyam Kumar, Subodh Kumar, Suraj Kumar, DESIGN AND ANALYSIS OF AN EPICYCLIC GEAR TRAIN USING CORRECTED GEARS, (IJMET), Volume 8, Issue 8, August 2017, pp , Article ID: IJMET , ISSN Print: and ISSN Online: [11] Mrinal Gupta, Mayank Pant and AkshitKhandelwal, DESIGN AND ANALYSIS OF GEARBOX WITH INTEGRATED CV JOINTS, (IJMET), Volume 8, Issue 8, August 2017, pp , Article ID: IJMET , ISSN Print: and ISSN Online: [12] N. Siva Teja, K. Dinesh Babu, M. Siva Nagendra, Ch. Phanideep, J. Sai Trinadh, DESIGN AND ANALYSIS OF DIFFERENTIAL GEAR BOX IN AUTOMOBILES, (IJMET), Volume 8, Issue 5, May 2017, pp Article ID: IJMET , ISSN Print: and ISSN Online: [13] Rahi Jain and Pratik Goyal, DESIGN AND ANALYSIS OF GEAR-BOX USING SPUR GEAR AND ELIMINAT- ING THE DIFFERENTIAL UNIT, (IJMET), Volume 7, Issue 6, NovemberDecember 2016, pp , Article ID: IJMET , ISSN Print: and ISSN Online: IAEME Publication [14] V Balambica, Dr. J Hameed Hussain, Er. Vishwa Deepak, ANALYSIS OF A SPUR GEAR WITH NX NASTRAN, (IJMET), Volume 8, Issue 8, August 2017, pp , Article ID: IJMET , ISSN Print: and ISSN Online: