1、 8. Mai 2008 tut-003-03-VehicleGearboxWithPlanetaryDifferential-E.doc 1 / 35 KISSsys Tutorial: Gear transmission with planetary differential Structure of the tutorial The tutorial has two parts to be studied in this order. Introduction explains the most important points in this modeling task and int
2、roduces how to start KISSsys. Building a model explains techniques how to build a KISSsys model of a complex gearbox with sevelra power path possibilities. During the study of this tutorial, questions may arise or problems may occur. The KISSsoft customer support can be reached through the address a
3、nd phone number given above. KISSsys tutorail: Transmission with planet differential2 / 35 1 Table of contents 1 Table of contents.2 2 Introduction.4 2.1 Summary of the most important points.4 2.2 Systematic procedure 4 2.3 Errata and remarks 4 2.4 Modelling task 4 2.5 Starting KISSsys .5 2.6 Select
4、ion of the project directory5 2.7 Opening an empty KISSsys model .6 2.8 Loading the templates .6 3 Building a model.7 3.1 Tree structure 7 3.1.1 Machine elements .7 3.1.2 Loads due to overlaid shafts7 3.1.3 Connections.9 3.1.4 Power flow 12 3.1.5 Adding KISSsoft analysis modules.14 3.2 Input of Gear
5、-, shaft- and bearing data .15 3.2.1 Gear data .15 3.2.2 Shafts and bearings .16 4 3D View 19 4.1 Adding 3D view in the tree structure19 4.2 Location of the shafts19 4.2.1 Positioning of the shafts s1a and s1b 19 4.2.2 Positioning of the shaft s2.19 4.2.3 Positioning of the shaft s6.20 4.2.4 Positio
6、ning of the shaft s3.20 4.2.5 Positioning of the shaft s4.20 4.2.6 Positioning of the shaft s5.21 4.2.7 Positioning of the planet spindle.21 4.3 Work with the 3D Viewer.21 4.3.1 Inside diameters of the gear wheels 21 4.3.2 Color and transparency .22 4.3.3 Visualizing bearings in a shaft bore22 4.4 I
7、nsert data from CAD system .23 5 Changing of gears .24 5.1 Background Information about clutch elements .24 5.2 Applied in the current example.24 5.3 Start of the function.26 6 User Interface27 6.1 Input of the power.27 6.2 Execute buttons for function in the User Interface .28 7 Completing the mode
8、l.29 7.1 Calculation of the bearing speed in system with overlaid shafts 29 7.2 Input of the speed ratio for front and rear drive30 7.3 Input of efficiency.31 7.4 Settings to calculation methodology.32 8 Calculation of multiple tooth contact of a gear wheel 32 8.1 Remarks 32 8.2 Calculation on-road
9、and off-road gear selection.32 8.3 Functionality .33 3 / 35 9 Annex A, Set Speed“.35 9.1 Code (line numbers are not part of the code)35 9.2 Clarification 35 4 / 35 2 Introduction 2.1 Summary of the most important points 1) Where two or more shafts overlap, the bearing load from the around shaft must
10、 be transferred by a force element to the shaft which is under it. (see chapter 3.1.2) 2) For this transfer of bearing loads from one coaxial shaft to the other, call OnCalcTorque during calculation of torque” has to be activated. (see chapter 7.4) 3) Further, the relative speed of the bearings betw
11、een overlaid shafts must be calculated as the difference in speed between bearing outer ring and bearing inner ring. (section 7.1) 4) The speed at the two output shafts (front and rear axle) are placed with one to another in reference. Therefore the speed at one output shaft has to be set as “Constr
12、aint=Yes“ and an expression is set to compute one speed (those of the front axle) from the other (the rear axle). In addition, an iteration is necessary for the calculation of the relative speed) ( section 3.1.2 and 7.1) 5) “Iteration for torques” and “speed with damping“ must be set to execute the
13、iteration. (Section 7.4). 2.2 Systematic procedure The following steps are involved when building a KISSsys model: 1. Planning: Naming, range and goals of the model 2. Insert mechanical component in the tree structure (red Icons) 3. Connect mechanical component to each other (grey Icons) 4. Define s
14、ources of power flow 5. Add KISSsoft calculation to the mechanical components (blue Icons) 6. Add 3D graphic, and position elements in the graphic 7. Add tables / User Interfaces 8. Program own functions 9. Tests, debugging 2.3 Errata and remarks 1) If questions or difficulties arise during the tuto
15、rial, KISSsoft Hotline can be used for assistance (e-mail address, tel. no. etc. see front of document). 2) The planetary differential used for this example in practice would be a double planet planetary where the sun and the planet carrier have the same sense of rotation. However, to prevent the ex
16、ample becoming too complex, a simple planetary train is used. Therefore both outputs rotate contrary to each other. 3) The original idea for this tutorial had planned a differential lock between the annulus and the planet carrier. This clutch is called c3. In reality it will be not used although in
17、the tutorial it is described. It is recommended to proceed exactly according to the tutorial instructions (i.e. the clutch c3 is to be modeled although this is not used). 4) An error occurs with the nomination of the forces on s2 due the overlap of shaft s6. 2.4 Modelling task A transfer gearbox for
18、 a 4x4 off-highway vehicle is to be modeled. The transmission possesses an on- and off -road gear as well as a lockable epicyclic differential acting as a longitudinal differential. A part of the power is continually taken off over a PTO. The bevel gear differentials in the axles are not modeled. Th
19、e unlocked gears z1 and z2 on the input shaft clutches can be switched on or off. 5 / 35 Figure2.4-1 Sketch of the gear train to be modeled Following names and characters are used s = shaft; z = gear; c = clutch/couplings; b = bearing (b1: left side bearing, b2: right side bearing) red arrow is powe
20、r input respective power output red arc is power transmitted through virtual coupling c3 2.5 Starting KISSsys First, a project folder has to be created. Then, KISSsys 03/2008 is to be started and the intended folder is chosen as project folder. Using “Options”, activate the administrator mode. Then,
21、 the templates should be opened using “File/Open templates”. Make sure the latest Patch version is installed on your computer. (Download from www.KISSsoft.ch) 2.6 Selection of the project directory KISSsys works with so called projects to manage the files. These are listed directory names, in which
22、the KISSsys model and pertinent KISSsoft files are stored. Before a model can be opened in KISSsys, a directory must be defined in which the KISSsys model is to be stored. Therefore a new appropriate directory name has to be created in the main directory KISSsys before starting to model. Through the
23、 button in the red marked circle the new directory can be selected. Please notice, the appropriate directory shows up only if you have created the directory as described in the sentence above. In our case: C:ProgrammeKISSsoft 03-2008KISSsystutorial-003. After the selection of the directory in the Wi
24、ndows dialogue with “opening“ is to be confirmed, press “open” and KISSsys is launched. 6 / 35 Figure2.6-1 Selection of the project directory 2.7 Opening an empty KISSsys model KISSsys starts now with an empty model. As a first step, the “administrator“ mode must be activated under the main menu “Op
25、tions“. Figure2.7-1 Activate the administrator mode under “Estras” in the main menu If the option “administrator“ can not be selected, then the KISSsys license is missing. In this case contact KISSsoft AG. 2.8 Loading the templates As a first step when creating a new KISSsys model, the templates are
26、 to be imported through the menu “File”, “Open templates”, “templates.ks”. In the templates, all elements are now listed which can be used in KISSsys: Figure2.8-1 Element library Templates“. After having imported the templates, the model can now start to be built. 7 / 35 3 Building a model 3.1 Tree
27、structure In a first step all existing mechanical components must be defined in a tree structure. It is highly recommended to name gears, shafts, bearings and couplings in such a way as shown in the illustration down. User can define first shaft (e.g. “s1” with bearings “b1 and “b2”) and then copy i
28、t to avoid adding all bearings one by one. 3.1.1 Machine elements Figure3.1-1 Shafts, Shafts with bearings, shafts with bearings /couplings, elements for modeling epicyclic gear trains The same names can be used several times for different mechanical components, as long as the mechanical components
29、are in a different path of the tree. Please note all bearings are called “b“. The left hand bearing is “b1“; the right hand bearing is “b2“. The following is important when modeling an epicyclic gear train: 1) The planet is supported only by one bearing. I.e. on the shaft sp“ there is only one beari
30、ng b1“(kSysRollerBearing“ from the templates) placed. 2) The planet carrier needs a special coupling: ”kSysPlanetCarrierCoupling“. Do not mix up this element with kSysCoupling“. This special coupling should be named as cc“ and will be positioned on the shaft s5. This element is necessary to rotate t
31、he planet in the world coordinate system. After these two elements are added, the tree structure looks like in illustration 3.1-1 (above right). All spur gears must be arranged on the respective shafts, the tree structure looks as follows in Figure3.1-5 3.1.2 Loads due to overlaid shafts Force eleme
32、nts on the shafts “s1” and “s2” have to be added. These force elements are to lead the bearing loads of “s1a” and “s1b” as well as “s6“ in each case on those under it lying shaft (s1 and s2). From the templates the element “kSysCentricalLoad“ is used. Four forces are used in total on “s1”, on “s2” t
33、wo forces are applied. The names of these forces should identify the origin of the force. 8 / 35 The names of the forces expose themselves together: For example f_s1ab1“: f“ for force s1a“ marks the shaft that the force is taken over b1“ marks the bearing that the load is taken over Figure 3.1-2 For
34、ces due to the overlaid shafts on s1 and s2 The force components of the inserted forces must be connected with the components of the bearing loads. To do this the right mouse button must be clicked on a force (e.g. f_s1ab1), whereupon the “characteristics“ (Properties) appear and must be selected, a
35、nd after selecting “Fx” under “expression” the following text has to be inserting: GB.s1.s1a.b1.Fx. The expression makes sure the load on the shaft affecting the load on the other shaft (respectively their x-component) equals the x-component of the bearing load b1 on s1a. The appropriate expressions
36、 must be registered also for Fy, Fz, Tx and Tz For Fy: GB.s1.s1a.b1.Fy For Fz: GB.s1.s1a.b1.Fz For Tx: GB.s1.s1a.b1.Mx For Tz: GB.s1.s1a.b1.Mz These linkages of the forces must be done for all forces provided: f_s1ab1, f_s1ab2, f_s1bb1, f_s1bb2, f_s6b1, f_s6b2.Figure 3.1-3 Linking force component Ad
37、d as well automatic positioning for the forces on the shaft according to the positions of the bearings. For this use functions l_p() to set positions. The expression makes sure the load position on the shaft is equal to the position of the mating bearing (respectively their y-component). This functi
38、on looks for reference element and point on parent element and converts coordinates. Finally only y-direction is taken (*01,0) l_p(GB.s1.s1a.b1,0,0,0)*0,1,0 The appropriate expressions must be registered also for all other forces. Figure 3.1-4 Linking force positions 9 / 35 Finally add gear componen
39、ts to the model. Figure3.1-5 Tree structure and KISSsys sketch with mechanical components 3.1.3 Connections In the next step the following connections are defined: 1) Connections of the shift clutches for the road gear (c1, c1): It uses “kSysCouplingConstraint“ from the templates. Action: First copy
40、 from the templates “kSysCouplingConstraint“ and paste it to the tree structure within the group “GB“. The name will be specified with “C1“, thus it is clear which clutches are connected (namely c1 on s1 with c1 on s1a). In a second step the clutches which can be connected are to be selected. In add
41、ition it must be defined whether the clutch is closed (activated) or open (not activated). 10 / 35 Figure3.1-6 Definition of a clutch connection, here for road course 2) Connect the shift clutches for the off road gear (c2, c2). This clutch will be open.(Activated=No“) because both gears can not be
42、closed at the same time: Figure3.1-7 Definition of the clutch for off road course 3) Connect both clutches c3, differential lock. The clutch will be open (Activated=No“): Figure3.1-8 Connection between clutches c3 After all clutches are connected within the transmission, the individual gears must be
43、 connecting together. For the spur gears, the type “kSysGearPairConstraint“ is necessary. The planets need the type “kSysPlanetaryGearPairConstraint “ two times. One where the sun wheel connects the planet, the other the planet connects the annulus. The connections are copied from the templates into
44、 the tree structure, below the group of “GB“: Gear pair gp1 Gear pair gp2 11 / 35 Gear pair gp3 Gear pair gp4 Figure3.1-9 Definition of gear pairs. Gear pair sun zs between Planet zp “sp” Gear pair planet zp between annulus zr “pr”Figure3.1-10 Definition of a planet gear connection in the system 12
45、/ 35 The tree structure with the connections defined in the KISSsys sketch should look now as follows: Black line connections: active / close connections Grey line connections: inactive / open connections Figure3.1-11 Tree structure and KISSsys sketch with connections 3.1.4 Power flow The definition
46、 of the power flow in the gearbox is through the element kSysSpeedOrForce“. This element is to be copied from the templates and pasted four times directly into the tree structure (not under GB“) During the power input “Input“ speed and the torque are given. Both values are signed sizes. If the produ
47、ct of the two signs is positive, then the power is positive, i.e. it concerns a positive input power. Figure3.1-12 Definition of Input power Input“(Motor) The PTO torque is set to 10Nm (acceptance for this example). The direction of rotation is counter clockwise. The number of revolutions is therefo
48、re negative. The torque has to be entered positively thereby the power output becomes negative. Figure3.1-13 Definition of the power take off (PTO) 13 / 35 Rear-wheel drive RWD (OutR) As a consequence, number of revs and torque follows by the input data and the type of transmission. No values are gi
49、ven. Figure3.1-14 Definition of the RWD Front wheel drive FWD (OutF) The condition for the front wheel drive is defined as follows: Front axle and rear axle turn with the same speed, but contrary. This condition will be still specified in section 7,2. Thus the number of revolutions at this output (the front axle) is the same as from the number of revolutions of the output “OutR“, therefore “speed of constrained=yes“ must be set. With the right mouse-click on the power output “OutF“ and the choice in “Properties“ of “speed“, an expression for the speed can be
