Design & Analysis of Steering System for Solar Vehicle

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Design & Analysis of Steering System for Solar Vehicle

1Prof.Rahul R. Patil , 2Mr. Saurabh Pandurang Mahind,3Mr. Nikhil Ravindra Bhosale

  1. Assistant Professor,Mechnical Engineering Dept., PVPIT,Sangli-Tasgaon Road,Budhgaon,Sangli,Maharashtra,416304
  2. U.G. Students of Mechanical Engineering, PVPIT, Sangli-Tasgaon Road, Budhgaon, Sangli, Maharashtra, 416304
  3. U.G.Students of Mechanical Engineering, PVPIT, Sangli-Tasgaon Road, Budhgaon, Sangli, Maharashtra, 416304Abstract This research paper aims for making prototype, steering system for single-seat solar vehicle. Designs are made according to the rules and regulations of the National Solar Vehicle Challenge 2019-20.The decreasing fuel resource in the world makes it a necessary to search for renewable options. This vehicle is a four-wheeler and drive by BLDC hub motor.and also driven by a battery which charged via the solar panels.We are using rack and pinion steering system to turn the vehicle.Rack and pinion steering system selected because of its simplicity,less effort and less cost.Our project requires engineering skills according to the rules of the competition.

    Keywords: Analysis, Solar Car, Automobile, Design,rack and pinion,steering system

    1. INTRODUCTIONThe aim of steering arrangement is to turn the front wheels using hand operated steering wheel which is in front of driver through steering column it contains universal joint to allow it to deviate from straight line.

      The steering provides stability to vehicle on road.Wear and tear reduces because of steering system. It prevents road shocks reaching to driver.The steering provides self rightening effect after taking a turn.

      We are using rack and pinion steering system for our solar vehicle.Because it is simple and most common in cars,small trucks,suvs.A rack and pinion gearbox is enclosed in metal tube.A rod,called tie rod connects to each end of rack.The pinion gear is attached to steering shaft.When you turn steering wheel,gear spins,moving the rackThe tie rod at each end of rack connects to steering arm on spindle.

      The steering ratio is the ratio of how you can turn the steering wheel to how far the wheels turn.Generally lighter cars have lower steering ratios than larger cars and trucks.The lower ratio gives steering a quicker response.Smaller cars are light that with lower ratio effort required to steering wheel is not excessive.

    2. METHODOLOGY
      1. Material SelectionWe referring different literatures [1][2] and taken material as Mild Steel (Grade 2)(SAE1018).It has generally good mechanical properties.The mechanical properties of mild steel are given below in table 1.

        TABLE 1 MECHANICAL PROPORTIES OF M.S. SAE1018

        PropertyValue
        Density7850kg/m3
        Melting Point13700C
        Yield Strenth240 Mpa
        Tensile Strength370 Mpa
        Modulus of Elasticity205 Gpa
        Poisson,s Ratio0.33
        Brinell Hardness126BHN
      2. Mathematical Calculation-

      TABLE 2 ACKERMAN GEOMETRY WITH VALUES

      GeometryAckerman Geometry
      Steering typeRack and Pinion
      Wheelbase1700mm
      Track width1200mm
      Inner wheel angle300
      Outer wheel angle22.360
      Ackerman angle32.900
      Inner turning radius3.35m
      Outer turning radius4.0m
      Steering ratio7.2

      We made calculations considering ackermans mechanism.

      So We will explain all mathematical calculation by showing ackerman diagram below [1].Table 2 shows important parameters required to design steering system.

      Figure 1: Ackerman Mechanism

      According to rules of competition wheelbase,trackwidth and

      Kingpin distance selected. Wheelbase (b)=1700mm Trackwidth (a)=1200mm

      Distance between kingpin (c)=1100mm Inner wheel angle ()=300

      Outer Wheel angle()=22.360 Ackerman angle()=tan-1(c/b)=32.900

      Turing Radius

      Inner turning radius Outer turing radius

      Rin = b/sin()-(a-c/2) Rout=b/sin()+(a-c/2)

      =3.35m =4.01

      Steering Ratio

      Maximum turn=250 .(Assume) Steering wheel movement=1800 Therefore,

      Steering Ratio(S.R.)=180/25=7.2

      Design of Pinion

      1. Material for rack and pinion =Mild Steel ..(I.S. specifications)
      2. Minimum No. of teeth for pinion:- Zpmin=2/sin2(outer wheel angle)=17.09 =18.

        Module=2 .(Assume)

      3. For 200 full Depth involute system (outer wheel angle=200)
      4. Addendum (ha) = 1*m = 2mm.
      5. Deddendum (hf) =1.25*module = 2.5mm.
      6. Pitch circle diameter (d!)=module*Z = 36mm.
      7. Addendum circle diameter (da) = M*(Z+2) =40mm.
      8. Deddendum circle diameter (df) = M*(Z-2.5) =31mm.
      9. Clearance (c) = 0.25*M = 0.5mm.
      10. Whole depth = 2.25*M = 4.5mm.
      11. Tooth thickness = 1.5708*M = 3.14mm.
      12. Circuler pitch = (3.14*d)/Z=(3.14*36)/18

        =6.28mm.

      13. Diametral pitch =Z/d! =0.5

      Steering Wheel Torque

      T = W*u*2 + 2

      8

      Where,

      W = axle weight = 8Kg. u = 0.7.

      E = king pin offset. = 55 mm. = 2.1 inch. B = width of tire = 7 inch.

      Therefore,

      T = 28.8*103 N.mm.

      Torque on Pinion

      (T) = (T*Zr/Zp)/dp

      = 12*103 N.mm.

      Beam Strength Equation

      Sut = 1500 Mpa.

      Bending strength = Sut/3 = 500 Mpa. No. of teeth on pinion. = 18

      Pr. Angle = 200.

      Lewis form factor (Yp) = 0.308 FOS recommended by 1.5 to 2. Therefore,

      FOS = 1.5.

      Sb = Peff. * FOS But,

      Peff. = (Cs/Cv)*Pt. Cs = 1.05

      Cv= 3/3+v ..(v<10 m/sec.) Cv= 0.9836.

      Pt = (2* max. Torque) / (No. of teeth * Module)

      = 1600 N.

      Hence,

      Beam strength (Sb) = M*b* /3*Yp

      =3080 N.

      Wear Strength

      (Sw) = b*Q*dp*K Where,

      b = Face width of gear (Assume 10mm.) Q = Gear ratio factor

      =(2Zr) / (Zr+Zp)=1.47

      K = Material constant (250)

      dp = pitch circle diameter of pinion. (36 mm) Sw = b*Q*dp*K

      = 10*1.47*36*250

      = 132.3 * 103 N

      Steering Effort

      Mass of vehicle = 230+70 = 300 Centre of gravity = 250 mm.

      Diameter of steering wheel = 14.5 inch. = 368.5 mm. Radius of pinion = 20 mm.

      Therefore,

      Steering effort = 97.69 N.

      Torque of pinion (T) = (T*Zr/Zp)/d!p

      = 12*103 N.mm.

      Dimensions Of Rack

      Rack shaft length = 15 inch = 381 mm. No. of teeth on rack = 50.

      Steering lock = 300.

      Rack eye to eye length = 14 inch = 355.6 mm. Rack center lock = 3.5 inch = 88.9 mm.

      Rack tooth thickness = 3.25 mm

      Rack pitch = 6.5 mm.

      Addendum and deddendum = 2 mm. Clearance = 0.5 mm.

      Travel lock to lock = 4.48 inch = 113.79 mm Pinion Radius = 0.78 inch = 20 mm.

      ( Note :- As per standard rack size.) Length of tie rod = 8 inch = 203.2 mm. Arm length = 4.3 inch = 109.22 mm.

      Steering shaft length = 750 mm.

      Steering shaft diameter = 12 mm. (pinion to column joint)

      Seering Wheel

      According to standard dimensions steering wheel diameter ranges from 141/2 to 171/2 inch and grip circumference ranges from 23/4 to 41/4 inches.

      Generally from 2009, 141/2 inch wheel diameter is used with grip circumference of 23/4.

      Steering wheel travel for one complete revolution=2*3.14*r

      =19.72mm

        1. ad ModelingCad modeling of steering system is done using Solidworks. Finite element models are developed using Ansys 16.0.A stress analysis can be carried out to determine stress produced in rack and pinion.Figure [2],[3],[4] shows CAD models of rack and pinion before assembly and after assembly.And figure [5] shows final CAD model of steering system.

          Figure 2: CAD model of rack before assembly

          Figure 3: CAD model of pinion before assembly

          Figure 4: CAD model after assembly of rack and pinion

          Figure 5: CAD model of final steering system

    3. ANALYSIS OF STEERING SYSTEMSolving therotical calculations are tough due to comlex equation so we deside to use software for analysis and validation.Finite Element Analysis(FEA) is generally used.We choose ANSYS APDL Mechanical 16.0 software to do analysis of rack and pinon in steering system

      TABLE 4 RESULTS OF ANALYSIS OF RACK

      Force Applied1600N
      Max. stress (Von-Mises)9.830Mpa
      Max. Deformation0.00037 mm
          1. Analysis of RackIt has been assumed that if maximum stress is applied on rack then it can not break but we apply 1600N force because this is effort required to rotate rack as well as pinion.So considering this force we can carried out analysis of rack.As shown in figure [6].Results shown in table 3.

            Figure 6: Analysis of Rack

            Force Applied1600N
            Max. Stress (Von-Mises)2.90Mpa
            Max. Deformation0.00004mm
            Force Applied1600N
            Max. Stress (Von-Mises)2.90Mpa
            Max. Deformation0.00004mm

             

            TABLE 3 RESULTS OF ANALYSIS OF RACK

          2. Analysis of Pinion

      It has been assumed that we are applying same force of 1600N because it has same material as that of rack.Now considering this force analysis of pinion is carried out.As shown in figure [7].Results shown in table 4.

      Figure 7: Analysis of Pinion

    4. CONCLUSION

We compare values therotically and also with ansys software from we can conclude that deformation produced will be negligible and it can sustain at above mentioned stress.So design is safe.The manual rack and pinion steering system not used in heavy weight vehicles due to high axle loads but it is simple in design and easy to manufacture.Therefore it is commonly used in light vehicles.

REFERENCES

  1. Rules and Regulation of National Solar Vehicle Challenge 2020.
  2. Design and simulation of manual rack and pinion steering system in July 2016 at JSART by Prasant L Agrawal, Sahil Shaileshbhai Patel,Shivanshu Rajeshbhai Parmar
  3. Design of steering system for solar car at BRAC University Dhaka,Bangladesh.
  4. Design and fabrical of electric- solar vehicle in September 2018 at IRJET by Rishabh S Khobragade,Swapnil L Mandawkar,Kalpak A Mahajan,Jay S Takalkhede
  5. Design of steering gear system in passenger cars in January 2018 at IRJET by Rayappa Mahale,Mohit Jaiswar,Gaurav Gupta,Abhishek Kumar

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