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Received 21 February 2007Developmentofa TestMachine for IVECO DriveAxleWANG Liang-mo, WANG H e-fu, CHEN Jin-rong, LING Zhi-liang, CAO Yu-huaSchool ofMechanicalEngineering, NanjingUniversity of Science andTechnology, Nanjing 210094, P. R. ChinaAbstract: To improve the automation level of the vehicle drive axle test and better simulate a vehiclecsactual operation, an advanced testmachine has been developed. The load system of themachine consistsof hand brakes and electric cylinders. It is simple-structured and low-cost. Themajormotor of thema-chine is controlled by a transducer and its speed can be adjusted easily. In addition, the programmedmachine can automatically test such parameters as the grinding condition, the differential speed, thenoise level, etc. It can also adjust the test procedures according to different requirements. Detailed dis-cussion of the structure and mechanism of the testmachine is given in this paper.Key words: vehicle, testmachine, drive axle, IVECO1 IntroductionThe drive axle of a vehicle is composed of a final drive, a differentia,l a shel,l hal-f axles andbrakes, etc. It comes into play at the last transmission stage of the vehicle transmission system. Thegrinding functionality, the transmission stability, the braking capability, and the noise volume,etc., of the drive axlewillallaffect a vehiclecs quality and performance. Therefore, after the driveaxle is assembled, it is necessary to test such functionalities as the grinding, differential speeding,and noise levels, etc.Currently, only a few manufacturers test the functionalities of vehicle drive axles in their domesticassembly lines. In addition, the automation levelof thesemanufacturersc testmachines is relativelylow. For example, theYuejinMotorGroupCorporation uses amanually-operated and single-speeddrive axle testmachine. Thismachinedoes nothave ameasuring system for testing the speed, load,and noise levels. Thus, themachine cannot control its test time accurately. Furthermore, the simu-lated operation deviates quite far from the actualoperation, so that it can not ensure theperformanceand quality of the drive axle.However, the drive axle testmachine of the IVECO vehicle has a relatively high levelof automationand provides some advanced functionalities. It enables abetter simulation of avehiclecs actualoper-ation and also increases the accuracy of the tes.t This paper introduces the advanced functionalitiesof the IVECO testmachineby illustrating themachinecs structure, mechanism, aswell as thedesignfeatures of themachinecsmechanicaland electricalcontrolling system.InternationalJournalofPlantEngineering andManagement Vo.l 12 No. 1 March 20072 The structure andmechanism of the testmachineFigure 1 Illustration of the IVECOcs drive axletestmachineFigure1 illustrates IVECOcs drive axle testma-chine. The testmachine primarily consists of atransmission device, a locating and holding de-vice, a loading device, and an oil intake and re-lease device, etc.( 1) The transmission deviceThe transmission device consists of a drive shaftwith a spline, amovable spline liner, a b-idirec-tionalacting cylinder, universal joints and pegs,etc. The transmission device joins themotorwiththe testdrive axle. This device ispneumatic. V iathe displacement sensor and the programmablecontroller, the transmission device not only canautomatically transmit themotorcs force to the tested drive axle, but also can automatically separatethe two.IVECOcs testmachine for the first timeuses the transducer andhas achieved thestepless speed regu-lation between 0 and 3000 r/min, thus allowing a better simulation of a vehiclecs actual operation.Furthermore, the transm ission deviceworks fas,t easily, and reliablywithoutnoticeable shocks, v-ibrations and noises.( 2) Locating and holding deviceWhen the transmission device and the drive axle are joined, it is required that the axis of the driveshaft be alignedwith the axis of the final gear in order to reduce shocks, vibrations and noises. Tomeet this requiremen,t a locating device is designed for the testmachine. Based on the principle ofcomplete location, the locating device uses threeV-shaped pieces for locating. Among them, twopieces are positionedon the edges of thehal-f axle liner, while the thirdpiece is positionedunder thedrive axle, within the limit of 6 degrees of freedom.During the tes,t the drive axle vibrates violently because of the high speed of the hal-f axle andwheels. To reduce the vibration, a pneumatic board is installed above the two V-shaped pieceswhich are positioned outside the hal-f axle liner, holding the drive axle tightly.( 3) Loading deviceThe drive axle testmachinegenerallyuses the electric eddy currentbrake, or the asynchronous gen-erator, as its loading device. The loading effectswillbe imposedwhen the brake or the generator isjoinedwith the left and rightwheels of the drive axle. This type of testmachines have notable andlasting loading effects, and can perform loading testson thedrive axle fora long time. However, thearrangement of thesemachines is crowded and the cost of thesemachines is also relatively high, be-cause two electric eddy currentbrakes, or two asynchronous generators, willbe added into the testmachines for the loading.25Development ofaTestMachine for IVECO DriveAxleComparedwith the conventional loading device, the loading deviceof IVECOcs testmachine is inno-vative in two aspects. Firs,t itworkswithhandbrakes. Second, it adopts thedomestically newly in-troduced and developed electric cylinders. These cylinders are simple-structured, and their loadscan be easily adjusted. When the loading device isworking, the electric cylinders tighten the handbrakescsteelrope andmove thebrakes. The load levels canbe changedby adjusting themovementsof the hand brakescsteel rope. Concurrently, differential transmissions of thedrive axle can also beachievedwith thehand brakes.( 4) Oil intake and releasedeviceBefore the tes,t kerosene needs to be fed into theoil intakedevice and then themachine is cleaned.After the cleaning, kerosene needs to be released completely and then engine oil is added. Engineoil can be recycled during the tes.tThe critical techniqueof the oil intakedevice is the designof the quick oil intake and release joints.The principles and structures of these two joints are basically the same. During the operation, thecylinder pushes the intake and releasedevice to connectquickly and accurately through a connectingrod. In addition, a special device is also used to ensure the sealing performance of the intake andrelease device.In the oil release system, oil is first released from a releasing hole into an oi-l separating box. Then,through an oi-l separating valve, which is connectedwith the oi-l separating box, kerosene is separa-ted from the engine oi.l3 Controlling systemFigure 2 The controlling system of the testmachineCurrently, there are three types ofwel-ldevelopedme-chanical and electrical controlling systems: the relaycontact controlling system, the programmable contro-lling system, and the industrially-controlled computersystem. The relay controlling system is slow, clumsy,and only allows for simple contro.l The industrially-controlled computer system is expensive, and difficultto program, while the programmable controlling systemis smal,l reliable, wel-l functioned, and easy to pro-gram. Therefore, the programmable controlling systemis selected here for the testmachine. Figure 2 showsthe controlling system of the testmachine.The design procedure of the testmachinecs controllingsystem is as follows:( 1) Analyzing theworkflowsThe drive axlecs testmachine operates in two phases: the preparation and the tes.t The preparationphase proceeds in the sequence of installing thedrive shaf,t connecting the drive axlewith the drive26 InternationalJournalofPlantEngineering andManagement Vo.l 12 No. 1 March 2007shaft, feeding kerosene, rotating the generator clockwise and counter-clockwise ( cleansing the driveaxle) and releasing kerosene through air pressure.The test phase proceeds in the sequence of feeding engine oi,l rotating the generator clockwise, a-lternative loading or simultaneous loadingwith the lefthand brake and right hand brake, differentialand delayed transmission, grinding, measuring noise, rotating the generator counter-clockwise, a-lternative loadingwith the left hand brake and right hand brake, differential and delayed transm is-sion, restoring the lefthand brake and righthandbrake, stopping the generator, testing the oil sea-ling performanceof the oil intake and releasedevice, releasing engine oil throughairpressure, resto-ring the oil intake join,t restoring thedrive shaf,t restoring theholding device to the end of the tes.t( 2) Determ ining the inputbits and output bitsThe input bits prmi arily include the signalof thedrive shaftcs position, the signalof theholding devicecsposition, the signal of the oil intake and release jointscposition, aswell as the signals of the automaticstopping button and stepping button, etc. Altogether, there are53 inputbits. The output bits prmi arilyinclude the start signalof thegenerator, the start signalof each valveof thepneumaticsystem, aswellasthe start signals of the electric cylinders, etc. Altogether, there are 33 output bits.( 3) Selecting the program controllerCurrently, there aremany types ofprogram controllers. In terms of theirbitnumbers and functiona-lities, they can be classified into three categories: smal-l sized, medium-sized, and large-sized. Thesmal-lsized controlling system is selectedheremostly for the purpose ofproducing suchon-off actionsas sequential controlling, time controlling andwarning and locking, etc. The totalnumber of inputand output bits is 86. Mitsubishics F1 series of programmable controllers are used, with a 60-bitmain engineF1-60MR and a40-bitextended engineF1-40ER. Altogether, they generate100 inputand output bits, with amargin of14 bits.( 4) Drawing the inputandoutput terminaldistributionchartanddefining each inputandoutputnumber.( 5) Drawing theworkflow diagram and programm ing the process based on thework flows.The system thus designed has the following features: ( a) The system allows flexible control andswitching among variousmodes ( such as automatic contro,l stepping contro,l etc. ); ( b) The sys-tem provides the stepping contro.l This controlmode is easy to operate. The test programswillpro-ceed to the next stepwhen the stepping button is pressed. Theprocedures are simple and clear. Allof thesewillbe useful for adjusting the test programs; ( c) The system also allows diagnosingma-chinebreakdowns on the line. When the input and output lights of the program controller are dis-played, then the program stopsworking at this poin,t indicating breakdowns occur, thusmaking d-iagnostics and repairs easy. Using the relay controller can not achieve this.4 ConclusionsPractical experience has shown that IVECOcs driving shaft testmachine is wel-l functioned, andhighly automatic. It has good stability, suitable for testing the five types of the IVECOcs vehicledrive axles. At the same time, its testprograms canbe adjusted according to different requirements.27Development ofaTestMachine for IVECO DriveAxleThis testmachine is relatively cheap and simple-structured. It also allows stepless speed, and load-ing with hand brakes. Thus, the test machine enables the drive axle test to better simulate avehiclecs actualoperation. The successfuldevelopment of this testmachine notonly incre