汽車齒輪齒條式轉(zhuǎn)向系設(shè)計(jì)【齒輪齒條式轉(zhuǎn)向器】

汽車齒輪齒條式轉(zhuǎn)向系設(shè)計(jì)【齒輪齒條式轉(zhuǎn)向器】,齒輪齒條式轉(zhuǎn)向器,汽車齒輪齒條式轉(zhuǎn)向系設(shè)計(jì)【齒輪齒條式轉(zhuǎn)向器】,汽車,齒輪,齒條,轉(zhuǎn)向,設(shè)計(jì),轉(zhuǎn)向器 Kuen-Bao Sheu , Tsung-Hua Hsu and low cost. Kinematic analyses and design are achieved to obtain the size of each component of this system. A design example is fabricated and tested. oline motorcycles cause serious environmental pollution in TaiwanC213s cities. The Environ- mental Protection Administration of the ROC has implemented some policies to reduce * Corresponding author. Tel.: +886 05 6315697; fax: +886 05 6321571. E-mail address: kbsheusunws.nfu.edu.tw (K.-B. Sheu). Applied Energy 83 (2006) 959974 APPLIED ENERGY 0306-2619/$ - see front matter C211 2005 Elsevier Ltd. All rights reserved. C211 2005 Elsevier Ltd. All rights reserved. Keywords: Hybrid electric motorcycle; Transmission; CVT 1. Introduction Motorcycles/scooters are a popular mode of transportation in many urban areas of Asia, such as Taiwan because of limited space, short daily trip distance, population density and the easy operation and maintenance of motorcycles. However, the exhausts from gas- Institute of Mechanical and Electro-Mechanical Engineering, National Formosa University, 64 Wunhua Road, Huwei, Yuenlin 63208, Taiwan, ROC Received 30 July 2005; received in revised form 2 October 2005; accepted 8 October 2005 Available online 19 December 2005 Abstract This hybrid power system incorporates a mechanical type rubber V-belt, continuously-variable transmission (CVT) and chain drives to combine power of the two power sources, a gasoline engine and an electric motor. The system uses four dierent modes in order to maximize the performance and reduce emissions: electric-motor mode; engine mode; engine/charging mode; and power mode. The main advantages of this new transmission include the use of only one electric motor/generator and the shift of the operating mode accomplished by the mechanical-type clutches for easy control Design and implementation of a novel hybrid-electric-motorcycle transmission * doi:10.1016/j.apenergy.2005.10.004 960 K.-B. Sheu, T.-H. Hsu / Applied Energy 83 (2006) 959974 air pollution, such as the strict exhaust standards for gasoline vehicles, an electric motor- cycle development action plan, and a subsidy for purchasing electric scooters 1. To facil- itate this, the government and industry have been applying fuel-cell technology to power scooters 25. However, the goal of replacing polluting combustion-engine motorcycles with battery powered ones has not been successful in Taiwan 6. Existing and proposed battery/fuel cell powered motorcycle designs have low performance and are not likely to displace the gasoline motorcycle in the near future 7,8. Another approach to reduce both pollution and get better performance is to utilize a hybrid concept of internal-com- bustion engine and battery at this stage. Over the past few years, hybrid electric vehicles (HEVs), primarily automobiles, have been actively developed and marketed 914. This study considers the design of a hybrid power-transmitting system that is suitable for motorcycles. In 1997, Honda Motors released a hybrid two-wheeler concept in the Tokyo motor show with the key goals of a 60% reduction in CO 2 emission and 2.5 times better fuel-eciency. In this system, a water-cooled 49 cc gasoline engine is packed with a DC brushless electric-motor together driving the rear wheel. The gasoline engine delivers power for high-speed performance and for hill climbing while the electric motor engages for low-speed cruising. In 1999, AVL Company proposed a hybrid system that used a 50 cc carburetted lean-burn two-stroke engine with a 0.75 kW electric motor mounted on the engine crankshaft mainly to provide increased torque during acceleration 15. Matsuto and Wachigai also proposed a motorcycle hybrid-drive system 1618. The main components of this system consists of the two power sources of an engine and an electric motor, a traction drive continuously-variable transmission (CVT), a final reduction drive and three clutches. The transmission shaft and the electric motor shaft are coaxial in series in the longitudinal direction of the vehicular body and in parallel with the crank shaft of the engine. Traditionally, the transmission devices used for motorcycles are divided into two cate- gories: (1) stepped transmission devices, that work by alternating the gear drives, and (2) CVTs, that transmit power by using a rubber V-shaped belt. Advantages of the rubber V-belt CVTs include smoother-speed characteristics, adequate speed ratio, a simpler mech- anism, low cost, less maintenance, etc. However, the mechanical eciency of the mechan- ical-type rubber V-belt CVT is quite low, especially, at the instant of speed ratio change with frequent stops 19,20. This paper presents a novel hybrid electric motorcycle transmission whose primary fea- ture is a mechanical type rubber V-belt CVT and chain drives to combine the power of two power sources, a gasoline engine and an electric motor. The hybrid power system is to run the electric motor at start-up and during low speeds, so that the emissions in urban areas are limited. As the vehicle speed increases to and passes a medium speed, the engine power is transmitted to the rubber V-belt CVT driving the vehicle. This combination can avoid the low-eciency regions of the CVT and retain good handling. This paper begins with a description of the hybrid-electric transmission and proceeds with a kinematic analysis and design to obtain the size of each component of this system. Finally, the prototype of this new design is fabricated and tested. 2. Parallel hybrid transmission Traditionally, HEVs for the automotive industries were classified into two types, series hybrid and parallel hybrid. With the recent developments of HEVs, they can now be cat- egorized in four kinds: series hybrid, parallel hybrid, seriesparallel hybrid, and complex hybrid 21. A series HEV uses the engine driving force after converting it into electricity via a generator. In a parallel hybrid, two power sources such as an engine and an electric motor are used to drive the vehicle simultaneously. The seriesparallel HEV is a combina- tion of both the series and parallel hybrid systems. In addition, a complex hybrid system involves a complex configuration which cannot be categorized into the above three types. As shown in Fig. 1, the proposed motorcycle hybrid system, a parallel hybrid, consists of a gasoline engine, an electric motor, a transmission, a power inverter, and an electronic con- troller. The transmission connects the engine, the electric motor, and the rear wheel of the motorcycle 22. The transmission is made up of a mechanical type rubber V-belt CVT with a shoe-type centrifugal clutch (engine clutch), two chain drives with two one-way clutches, and a final drive consisting of two gear-pairs. The electric motor can function as an electric motor or a generator, according to the driving condition and battery power levels. The electronic controller receives commands from the driver and feedback signals from sensors to select the operating mode and to decide how much power is needed to drive the wheels and how much to charge the battery. K.-B. Sheu, T.-H. Hsu / Applied Energy 83 (2006) 959974 961 The proposed hybrid power system can operate in four dierent modes to maximize the performance and reduce emissions: (1) electric motor mode; (2) engine modes 1 and 2; (3) engine/charging mode; and (4) power mode. (1) Electric motor mode As in start-up or low-speed situation, the electric motor converts chemical energy stored in the battery to drive the motorcycle while the gasoline engine is shut down to reduce emissions. As shown in Fig. 1, the electric motor transmits power via the chain drive 2 and the final drive alone powers the motorcycle by engaging the one-way clutch 2, whereas the one-way clutch 1 and engine clutch are disengaged. (2) Engine mode 1 and mode 2 During moderate and high speeds, the engine clutch is disengaged and both the one- way clutches 1 and 2 are engaged to operate the engine mode 1. Here, the engine alone drives the motorcycle via the chain drive 1 and 2 and through the final drive. As the engine speed increased, the engine clutch engaged and the one-way clutch 2 is automatically V-belt CVT Chain drive 2 Final drive One-way clutch 1 Motorcycle Engine clutch Battery Controller Inverter Operator commands Feed-back signals Engine Motor/ Generator Chain drive 1 One-way clutch 2 Fig. 1. Schematic diagram of the hybrid-electric motorcycle transmission. the chain drive is 962 K.-B. Sheu, T.-H. Hsu / Applied Energy 83 (2006) 959974 r c x cn =x cr Z cr =Z cn ; 1 where x cr (x cn )andZ cr (Z cn ) denote the angular speed and the number of teeth on the input (output) sprocket of the chain drive, respectively. The final drive assembly consists of two gear pairs. The speed ratio of the final drive is r f Z f1 C2Z f3 =Z f2 C2Z f4 ; 2 where Z f1 , Z f2 , Z f3 , and Z f4 are the numbers of teeth on the four gears of the final drive, respectively. 3.2. Speed ratio of the CVT The mechanical-type CVT used here operates by a speed-sensing pulley as the driver and a torque-sensing pulley as the driver jointed by a rubber V-belt. The driver consists of a movable flange, a fixed flange, and several centrifugal rollers (see Fig. 3(a) and the driven components consist of a movable flange, a fixed flange, a torsioncompression spring, and a torque-sensing mechanism (see Fig. 2). There is an axial force and torque acting on the driver and driven pulleys, respectively. The force balance between both the force acting on the driver and driven pulleys determines the actual speed-ratio of disengaged. Here, the engine alone drives the motorcycle through the rubber V-belt CVT and the final drive to operate the engine mode 2. If a higher speed of the shift point from the electric motor mode to the engine mode is selected, the engine mode 1 can be automat- ically discontinued. In addition, since the engine and the electric motor output shaft are coupled with chain drive 1, the electric motor can be switched into a neutral mode to allow the electric motor output shaft to spin freely. (3) Engine/charging mode During moderate or high-speed cruising, both the engine clutch and one-way clutch 1 are engaged and the one-way clutch 2 is disengaged. Part of the engine power is transmit- ted to the motorcycle through the rubber V-belt CVT and the final drive, and the other part to the electric motor via the chain drive 1 and one-way clutch 1. If the battery power is low, the electric motor is switched into the generator mode for charging the battery. Since the engine can be operating under high-load conditions, by reducing the low-load driving time in this operating mode, the hybrid system has less fuel consumption. (4) Power mode When climbing hills, the motorcycle is operated in a power mode. Here, the electric motor power via the one-way clutch 2 and the engine power through the rubber V-belt CVT are coupled together to drive the motorcycle simultaneously. 3. Kinematic analysis and design 3.1. Speed ratio of the chain drive and final drive The speed ratio is defined as the ratio of the output to the input link speeds. The trans- mission mechanism here uses two chain drives and a final drive assembly. The chain drive consists of an input and output sprocket connected with a silent chain. The speed ratio of the CVT in a running situation. There have been numerous analyses of the mechanical- K.-B. Sheu, T.-H. Hsu / Applied Energy 83 (2006) 959974 963 type CVTs 2328. Here, we utilize the results of Sheu et al. 28 with some modification to analyze the CVT of the hybrid-electric motorcycle transmission. The axial force acting on the movable flange of the driver and driven pulley depends on the engine speed and the external load of the motorcycle, respectively. The external load F road results from rolling force, wind force, the inclination force and acceleration force as F road l r W coshC n V 2 W sinhW DWa=g; 3 where V = R w x w represents the vehicle speed, in which R w is the driver wheel radius and x w output speed; W is the total weight of the vehicle and people; DW is the equivalent vehicle weight; l r is the rolling friction coecient; C n is the equivalent drag-coecient; a is the instantaneous acceleration of the vehicle; h is the angle of slope, and g is the gravity acceleration. Letting g f be the mechanical eciency of the final drive, the torque acting on the driven pulley of the CVT can be written as T vn F road R w r f 4 Fig. 2. Drive pulley of the rubber V-belt CVT. g f and the belt tension dierence (F 1 C0 F 2 ) can be expressed as F 1 C0F 2 T vn R n ; 5 where R n is the pitch diameter of the driven pulley. Referring to Fig. 2, the driven pulley has a movable flange that can slide axially along the shaft. Vehicle load on the driven shaft is converted to an axial force on the belt in the groove by the helical cam. Based on the force equilibrium acting on the movable flange by the torsioncompression spring F s and the force F hc , due to the vehicle load acting on the helical cam, the axial force of the driven pulley F vn , operating at an impending opening condition of a pitch diameter D n and belt tension dierence, can be expressed as F vn F hc C0F s D n D a C2 F 1 C0F 2 2 C2 cosbC0l a sinb sinbl a cosb F p K n D n0 C0D n tana=2; 6 where b is the angle between the helical cam surface of the torque-sensing mechanism and the shaft centerline; D a is the diameter of the helical cam; D n0 is the minimum pith diam- eter of the driven pulley; F p is the compression preload of the torsioncompression spring; K n is the spring rate of the torsioncompression spring; a is the groove angle of the pulley; and l a is the coecient of friction on the helical cam. For the axial force of the driver pulley, as seen in Fig. 3(b), based on the force equilib- rium, the axial force of the movable flange of the driver pulley acted on by the centrifugal roller can be derived as F cl my m x 2 e coscl h sinc sincC0l h cosc C16C17 sindl b sind cosdC0l b sind C16C17; 7 where l b and l h denote the coecients of friction between the roller and the roller back contact plate and the roller housing, respectively; m is the total mass of the centrifugal roll- er; d is the angle between the roller back contact plate and the perpendicular to shaft cen- terline; c is the contact angle of the housing and the centrifugal roller; and x e is the input angular velocity of the driver pulley. The distance between the center of the roller and the 964 K.-B. Sheu, T.-H. Hsu / Applied Energy 83 (2006) 959974 Fig. 3. Drive pulley of the rubber V-belt CVT. (a) Layout of the CVT drive pulley. (b) Control parameters of the CVT drive pulley. shaft centerline y m can be expressed as y m = y m0 C0 S m cosd, where y m0 is the location of the roller at zero rpm. The housing and centrifugal roller contact angle c is related to the location of the cen- trifugal roller, as expressed by cosc R m C0y off C0S m cosd qC0R m ; 8 where q is the radius of curvature of the roller housing, R m is the radius of the centrifugal roller, y o is the distance between the center point of the roller housing and the shaft sur- face, and S m is the travel of the roller along the roller center point. In addition, the axial displacement of the movable flange S r can be expressed as S r qC0R m 2 C0R m y off 2 q C0 q C0R m 2 C0R m y off S m cosd 2 q S m sind D r C0D r min tan a 2 ; 9 where D r is the pitch diameter of the driver pulley and a is the groove angle of the pulley. Substituting Eq. (9) into Eq. (8), the housing and centrifugal roller contact angle can be obtained. When the driver and driven pulley are combined in a drive, the axial force applied to the belt by the driven pulley is transmitted to the driver pulley. The equations that relate the belt tension and axial force of the driver pulley F vr and the driven pulley F vn are 23 F vr F 1 h r 2 1C0ltana=2 ltana=2 C20C21 ; 10 F vn F 1 C0F 2 cosa=2C0lsin/sina=2 2lcos/ C20C21 ; 11 F 1 F 2 exp lh n con/ lsin/cosa=2sina=2 C20C21 ; 12 where h r is the belt wrap angle on the driver pulley, h n is the belt wrap angle on the driven pulley,F 1 andF 2 arethebelttensionofthetightsideandslackside,listhecoecientoffric- tionbetweenthebeltandpulley,/isthefrictionangle,andaisthegrooveangleofthepulley. From Eqs. (5) and (6), the axial force of the driven pulley F vn and the belt tension dif- ference (F 1 C0 F 2 ) are given, and substituting Eqs. (11) and (12), the belt tension of the tight side and slack side can be determined as F 1 F 1 C0F 2 1C01=F 1 =F 2 ; 13 F 2 F 1 C0F 1 C0F 2 . 14 For a given F 1 , the axial force F vr of the driver pulley provided by the belt can be deter- mined from Eq. (10). When the axial force F vr of the driver pulley provided by the belt and the axial force F cl of the driver pulley supplied by the centrifugal roller are balanced, the drive is operated at a steady-state condition. The speed ratio r cvt of the CVT can be determined from the ratio of the diameters of the driver pulley D r and driven pulley D n . A computer program for analyzing and designing the mechanical-type CVT can be developed based on the design procedure described above. Fig. 4 shows the operating characteristics between simulations with the presented model and measurements carried K.-B. Sheu, T.-H. Hsu / Applied Energy 83 (2006) 959974 965 out with an existing 125 cc gasoline-engine scooter. The solid lines and symbols represent the analytical and experimental results, respectively, as the driving forces under the run- ning conditions of a steady speed on a flat-level road. The coecients of friction of the CVT used in the simulation program are 25: l a = 0.2, l = 0.45, and l b (l h ) = 0.05: the parameters of the driving forces are l r = 0.01, W = 170 kg, h =0C176, a = 0, and C n = 0.37. This existing transmission is tested on a test stand, as shown in Section 4. The analytical and experimental results for the operating characteristics of the existing 125 cc gasoline scooter are generally in good agreement. Therefore, this model can be used to develop the computer program for analyzing and designing the mechanical-type CVT of the hybrid-electric motorcycle transmission. 3.3. The speed ratio of the hybrid-power system (1) Electric-motor mode In this, the one-way clutch 2 engaged, whereas the one-way clutch 1 and engine clutch are disengaged. The electric motor power via the chain drive 2 and the final drive alone drives the motorcycle. Letting r c2 and r f be the speed ratio of the chain drive 2 and final 966 K.-B. Sheu, T.-H. Hsu / Applied Energy 83 (2006) 959974 drive, the speed ratio of this mode is r M r c2 C2r f . 15 (2) Engine mode 1 and mode 2 In the engine mode 1, the engine clutch is disengaged and both the one-way clutches 1 and 2 are engaged. The engine alone drives the motorcycle via the chain drives 1 and 2 and through the final drive. The speed ratio of the engine mode 1 can be written as r E1 r c1 C2r c2 C2r f ; 16 where r c1 denotes the speed ratio of the chain drive 1. In the engine mode 2, the engine clutch is engaged and the one-way clutch 2 is automatically disengaged. The engine alone drives the motorcycle through the V-belt CVT and the final drive. Letting r cvt be the speed ratio of the CVT, the speed ratio of the engine mode 2 is r E2 r cvt C2r f . 17 0 10 20 30 40 50 60 70 80 90 100 9000 8000 7000 6000 5000 4000 3000 2000 1000 0 Measured Simulation A 125cc gas-engine scooter running on flat level road (r cvt ) max(r cvt ) min Engine speed (rpm) Vehicle speed (km/hr) Fig. 4. Operating characteristics of a 125 cc gasoline-engine scooter. 4. Design examples 4.1. Prototype development The minimum speed ratio of a transmission system aects the start-up acceleration. In the electric motor mode of the hybrid power system, for the given output torque of the electric motor T M and the total eciency g M in this mode, the traction force F rear of the motorcycle can be calculated as F rear T M g M r M R w . 20