Front suspension design of the lightweight vehicle

ScienceDirect Transportation Research Procedia 00 (2019) 000–000 ScienceDirect Available online at www.sciencedirect.com

Available online at www.sciencedirect.com

Transportation Research Procedia 00 (2019) 000–000

ScienceDirect

www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia

Transportation Research Procedia 40 (2019) 623–630 www.elsevier.com/locate/procedia

13th International Scientific Conference on Sustainable, Modern and Safe Transport (TRANSCOM 2019), High Tatras, Novy Smokovec – Grand Hotel Bellevue, 13th International Scientific Conference Sustainable, Modern and Safe Transport Slovak Republic,on May 29-31, 2019 (TRANSCOM 2019), High Tatras, Novy Smokovec – Grand Hotel Bellevue, Slovakdesign Republic,of May 29-31, 2019 Front suspension the lightweight vehicle

Front suspension the Smetánka lightweight vehicle Benko Milanª,*,design Kučera of Ľubošª, Lukᚪ , ªUniversity of Žilina, Univerzitná 8215/1, Žilina 010 26, Slovakia Benko Milanª *, Kučera Ľubošª, Smetánka Lukᚪ

Abstract

ªUniversity of Žilina, Univerzitná 8215/1, Žilina 010 26, Slovakia

In this paper going to be described process of designing of a front suspension of wheels for electric light weight vehicle. This Abstract suspension must be fully adjustable. It means that we need to adjust angle of camber, high of wheelbase. Functional conditions of suspension aregoing cushioning, deceleration and cornering. Geometry of this suspension will be specific because unconventional car In this paper to be described process of designing of a front suspension of wheels for electric lightofweight vehicle. This body style. Due case, there is aItneed to that design suspension musttobethis fully adjustable. means we new needone. to adjust angle of camber, high of wheelbase. Functional conditions of suspension are cushioning, deceleration and cornering. Geometry of this suspension will be specific because of unconventional car body style. Due to this case, there is a need to design new one. © 2019 The Authors. Published by Elsevier B.V. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the scientific committee of the 13th International Scientific Conference on Sustainable, Peer-review under responsibility of the scientific committee of the 13th International Scientific Conference on Sustainable, Modern and Safe (TRANSCOM 2019). © 2019 The Published by Elsevier B.V. Modern andAuthors. Safe Transport Transport (TRANSCOM 2019). Peer-review under responsibility of the scientific committee of the 13th International Scientific Conference on Sustainable, Keywords: suspension; extended(TRANSCOM arm suspension; 2019). electric light weigh vehicle; Modern and Safe Transport Keywords: suspension; extended arm suspension; electric light weigh vehicle;

1. Introduction

1. Introduction Today is topic about electric car very popular. What comes with this concept is not only the change of motor from gas engine to electric motor, but also look of bodywork by Camargo (2017). The main reason why the electric car Today is topicbodywork about electric car very popular. What(2017). comes Thanks with thistoconcept is not only theshould changecar ofdrive motorlonger from need not causal is aerodynamics by Bistak aerodynamics shape gas engine electric but also lookreason of bodywork by Camargo (2017). Thedrop main the electric car distance fortoone batterymotor, recharge. For this were chosen the shape of water byreason Gajdáčwhy (2017). This shape need not is aerodynamics by Bistak (2017). Thanks design, to aerodynamics shape should carfitdrive longer resists thecausal best tobodywork aerodynamic resistance. After the part of bodywork it comes to us the task to suspension distance for one battery recharge. For thisinreason were chosen thejust shape water dropexisting by Gajdáč (2017). This shape in it and that’s what going to be described this article. We can’t copyoffrom some car suspension because resists of thecar best aerodynamic resistance. Afterreason the partisof bodywork it comesspace to usfor theusual task to fit suspension shape is to very unconventional. The main that we don’tdesign, have enough suspension. Our in it and that’s whattogoing be described this article. fromfrom some existing car suspension because suspension needs be ontoextended armsinwhich comesWe outcan’t as ajust bestcopy results several proposed concepts. Then shape of car is very unconventional. The main reason is that we don’t have enough space for usual suspension. Our suspension needs to be on extended arms which comes out as a best results from several proposed concepts. Then * Corresponding author.. E-mail address: [email protected] * Corresponding author.. 2352-1465 © 2018 The Authors. Published by Elsevier B.V. E-mail address: [email protected] Peer-review under responsibility of the scientific committee of the 13th International Scientific Conference on Sustainable, Moder n and Safe Transport (TRANSCOM 2352-1465 © 2018 The Authors.2019). Published by Elsevier B.V. Peer-review under responsibility of the scientific committee of the 13th International Scientific Conference on Sustainable, Moder n and Safe Transport (TRANSCOM 2019). 2352-1465  2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the scientific committee of the 13th International Scientific Conference on Sustainable, Modern and Safe Transport (TRANSCOM 2019). 10.1016/j.trpro.2019.07.089

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followed the part of designing where we want to find easy and working solution of many construction nodes which will be not so expensive to realize. Just one note to this article that there will be not described steering components, this article will deal only with suspension parts. 2. Methods There was a need of invention of the special front suspension. This suspension has to be controllable in the meaning of wheel steering and also has to be adjustable because we need to be able to change chamber angle of wheels that allows us set the right angle considering the conditions of car weight. We calculate with relative weight of 250 kg with driver, but if it will be more or less, thanks to this suspension we could set the right chamber angle and car will be able go thought the twist even better. At this moment the usage of existing double wishbone suspension or MacPherson is not possible. As we can see from Fig. 1, we already get the study of bodywork of car and our goal is to fit the suspension in it. At the Fig. 2 we see unconventional shape of bodywork and the wheels are extended from driver on the upper arms. So the place of usual suspension needs to be free in our case. During design of this new suspension we were very limited of space in the bodywork and also we get the frame of car because we are cooperating with other group of designers and they already design the frame and the suspensions are up to us. In this article will be not described steering wheel and things connected to it. This article deals with just suspension system.

Fig. 1. Isometric view of bodywork concept

Fig. 2. Front view of bodywork concept

3. Results 3.1 Suspension concept

Fig. 3. Suspension concept with extended arms fitted in transparent bodywork



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At the Fig. 3 we can see the whole suspension and also bodywork which is transparent, so we can imagine how it fits in it. At the next Fig. 4 we can see detailed view of suspension where on right side is exploded view. It’s visible every part which is mounted there. The main parts are: swing arm (a), adjusting pin (b), spring (c), adjusting nut (d), tapered roller bearings (e) and wheel (f). The wheel parts will be described below. This assemble of suspension (Fig. 4) is mounted in these steps. Swing arm with its counter part is bolted to tube of frame. To make rotational movement is in the hole of swing arm embedded two-piece sliding bearing. Arm going to have function of swing axle and also serves for adjusting chamber angle. Fixed parts of suspension are two rectangular beams which are welded to frame and on to these beams are welded base sheet with four holes, where adjusting pins are mounted. On pins are springs and under the spring is the arm of suspension and on the end of pins are threads, where the adjusting nuts are bolded. The nuts must have specific shape so they have spherical top. Attracting or releasing of nuts is set the chamber angle. On the end of swing arm is hole for hub, in which are two tapered bearings, which serves for knuckle attachment.

a

c

b

d e f

Fig. 4. Detailed view of suspension with exploded view

At the Fig. 5 is shown assembled wheel suspension. Way more interesting view of suspension is at Fig.6, where we can see exploded view, so we are able to recognize every part of it. The wheel suspension consists of wheel (a), wheel hub (b), brake disc and brake pad (c), knuckle (d), double row angular contact ball bearing (e), flange (f) and tapered roller bearings (g).

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g

b

d

a Fig. 5. Wheel assembly

c

e

f

Fig. 6. Exploded view of wheel assembly

3.2 base of suspension At this section we are going to deal with strength analysis of those part, which has to stay critical load. First of them is base of suspension (Fig. 7), which consists of two rectangular beams with dimension of 50 x 30 mm and length of 1400 mm. These beams are welded to frame and at the simulation is shown only segment of frame where is the weld area. To the beam are welded sheet plates with width of 5 mm and have four holes for adjustment pins. At the Fig. 8 are shown boundary conditions of analysis. The frame is fixed and force cause on each pin with the size of the force of 500 N each. It means that total load of each wheel suspension is equal to 2000 N. This value is a critical value multiplied by safety factor so the operating load will be lower.

Fig. 7. Base of suspension

Fig. 8. Boundary conditions of suspension base



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Fig.9 describes total deformation of suspension base. We want from this part to be rigid during operating load and it is so next we were dealing with critical load. This case at Fig. 9 is a base loaded with critical force causing on adjustment pins. Red colored areas show the biggest deformations and the value is about 2,248 mm and it’s on the

Fig. 9. Analysis of total deformation

both ends of the beams. Fig. 10 shows the equivalent stress during critical load of 2000 N on each side of sheets. The largest value is placed on the contact area where are the beams welded to frame. The maximum size of stress is about 636 MPa. From this simulation we find out that we need to strengthen the weld, but as mention before the load is sized by safety factor so this case should never happen. 3.3 Extended arm of suspension

Fig. 10. Analysis of equivalent stress

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Second simulation is the analysis of arm assembly which contains arm with its counter part and hub. The arm has length of 550 mm, width of 160 mm and thickness of 10 mm. Shape of it was designed up to previous simulations and this is the lightweight shape. The hub on the end of arm serves for bearing attachment and the other end of arm serves as rotational joint to frame. Though four holes go adjustment pins and the two big rectangular holes have lighten function.

Fig. 11. Boundary conditions of extended suspension arm

At the Fig. 11 are boundary conditions. Blue colored area is place where the arm is jointed to frame and it’s defined as a cylindrical support with free of radial direction. First force is causing on the area around four holes and is causing by the action of springs. This value was calculated as 900 N. Second force is causing from wheel and depends also from weight of vehicle. This value was also calculated and is equal to 500 N, but it is operating load so we multiplied it by 2 as a safety factor and we set the second force as 1000 N of critical load.

Fig. 12. Analysis of total deformation



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Fig. 13. Analysis of equivalent stress

Case at Fig. 12 is analysis of total deformation. It should seem kind a big of 12 mm, but there is a cylindrical support so we allow it to move. It will be more relevant to review this assembly by stress aspect. Simulation of equivalent stress is shown at Fig. 13. Blue and green areas seems to be alright, but what bothers us are the places of red and orange area. There is accumulated maximum stresses about 200 MPa. Thanks to this we consider that we need to make it out of material with minimal 200 MPa elastic limit. 4. Conclusion The purpose of study described in this paper was to design the whole new suspension. The reason why we can’t use some existing suspension was that we get the unconventional shape of bodywork. Our solution comes out from extended arms, which are attached to frame. On the other end of arm is embedded knuckle, which hold the wheel hub and wheel. During the phase of designing we want to make easy, adjustable and if it’s possible cheap solution. Designing parts was based on many calculations and simulations of strength analysis. Simulations of most critical parts are also published in this paper. First of them is base of suspension, which we want to have rigid, because it is only fixed part, to which are every other part movably assembled. Simulation of this part told us that critical load of 2000 N bends the ends of beams only 2 mm and stresses during this load is in weld area so now we know that we need to strengthen the weld. Second simulation deals with strength analysis of extended arm. On this part causes two loads. First by acting of springs and second depends from weight of vehicle. From simulation comes out that we over dimensioned this part so we make several changes including lightening holes and in this paper is shown the final shape of arm. Realization of this suspension in time of writing of this paper is still far away, because design od suspension is just one from many task that we need to solve before final realization of build this electric lightweight car. Acknowledgements This publication is the result of the Project implementation: Competency Centre for Knowledge technologies applied in Innovation of Production Systems in Industry and Services, ITMS: 26220220155, supported by the Research & Development Operational Programme funded by the ERDF.

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