1& lifted throu The thrust washer keeps the maximum lift of the rotor within 0. 3 to 1. 5 mm. However, in the event he filter gets clogged or obstructed, a bypass valve is provided so that oil will contimue to reach the bear The oil pressure relief valve is mainly to act both as a pressure regulator and as a safety device in lu brication system. As a pressure regulator, the valve prevents the oil pump from building up excessive pre ssure. When the oil passages of the engine rise too high, the relief valve will drain the excess filtered oil into the engine crankcase. As a safety device, the valve is set by the adjusting screw to secure the oil cir- culation through engine parts under proper pressure New words destruction n.损坏,破坏 feed v.供应 shock n.振动 silicone n.聚硅氧,硅铜,硅树脂 dipstick n,油尺,水[油]位指示器 periphery n.周边,周线,外围 intermeshing ad.相互啮合的 Impunity n.杂质,夹杂物,不纯 centrifugal adi,离心的,利用离心力的 spindle n.轴,转轴 clog v.阻塞 nior t.转子,涡轮 Bulator 调节器 Phrases and expressions lubrication oil润滑油 wash of冲洗,洗去 relief valve安全阀,卸压阀,溢流阀 main bearing cap主轴承盖 contra-mta rs反转齿轮 lubrication system润滑系 implex type单缸式 bypass valve旁通阀 remove…from…从……中除(消)去 oil pump油泵 oil filter机油滤清器 apart fror 除……之外
Notes 1.An automobile could not move itself without the aid of friction. 没有摩擦力的作用汽车就不能向前行驶。 2.,the oil is fed to the various moving parts of the engine, it absorbs and carries the heat away from the engine parts 当机油供向发动机的各运动部件时,机油就可吸收并带走发动机部件发出的热量。 3. As these particles of foreign matter are prevented from entering the engine by oil filter, the rate of wear of engine parts is reduced 由于机油滤清器阻止了杂质微粒进入发动机,这就降低了发动机部件的磨损率 4.."in the event the filter gets clogged or obstructed, a bypass valve is provided so that oil will continue to reach the bearings 如果机油滤清器被阻塞,就得起用分流阀以使机油继续流向各轴承 The oil pressure relief valve is mainly to act both as a pressure regulator and as a safety device in lubrication system 机油减压阀在润滑系中主要起着一个压力调节器和安全装置的作用
Chapter Two Chassis System Unit One Clutch The clutch is the friction device which is connected with the engine directly in the drive line.Its purpose is to provide smooth engagement and disengagement of the engine and manual transmission Since an intemal combustion engine develops little: power or torque at low rpm. It must gain speed before it will move the vehicle. However, if a rapidly rotating engine is suddenly connected to the drive line of a stationary vehicle, a violent shock will result. So gradual application of load, along with some lowing of engine speed, is needed to provide reasonable and comfortable starts. In vehicles equipped with a manual transmission, this is accomplished by means of a mechanical clutch The clutch is composed of four basic parts: driving members, driven members, pressing mechanisms od contml mechanisms. It includes a pressure plate, a driven disk, a cover, release levers, a release yoke, pressure springs and a control linkage. The clutch is a friction-type uncoupling device. It is lin to a clutch pedal in the driver's compartment. When the driver pushes down on the clutch pedal, th linkage forces a flat disk, or plate, to move. This movement releases the pressure from a friction disk With the pressure released, there is no friction at work in the clutch, and the power flow is therefore in terrupted. 'lhen, the engine runs without transmitting power to the power train The transmission of power through the clutch is accomplished by gradually bringing one or more ro- tating drve members connected to the engine crankshaft into contact with one or more driven member connected to the transmission input shaft. The pressure plate is coupled with the flywheel, while the driv en disk is fitted to the transmission input shaft. The driven members, prior to engagement with the driving embers, can be either stationary or rotating at a speed that is slower or faster than the driving members Contact bctween the members is established and maintained by spring pressure. The pressure exerted by the springs on the driven members is controlled by the driver through the clutch pedal and linkage.The positive engagement of the driving and driven members is made possible by the friction between the sur- faces of the: members. When full spring pressure is applied, the speed of the driving and driven members should be the same. At this point, the clutch is a direct connection between the engine and the transmis- sion The surface of the flywheel that mates with the driven discs is machined smooth. For the clutch to work properly, the flywheel must be perpendicular to the crankshaft with very little allowable run out The clutch cover is a steel stamping bolted to the flywheel. The clutch cover assembly contains the ressure plate, springs, and depending on the: design of the clutch-a variety of levers, sleeves, adjust ing rings, and retainers. The pressure plate is machined smooth on the side facing the engine and driven lisc and is itself driven by pins or lugs on the clutch cover. The plate is free to slide back and forth
2 the pins or lugs, and when spring presure is applied to the plate it meshes with the driven friction plates sandwiched between it and the flywheel The release levers are secured inside the cover on the supporting bolts. 'Ihe outer ends of the release levers are articulated to the pressure plate. Such a construction allows the pressure plate to approach the cover or move away from it, all the time rotating with the flywhe The springs spaced around the circumference between the pressure piate and the clutch cover clamp the driven disk between the pressure plate and the flywheel. The springs are installed with the aid of pro jections and sockets provided on the cover and pressure plate. The pressure plate sockets have thennal-in sulation gaskets for protecting the springs against overheating Some two plate clutches utilize an adapter ring when the clutch is installed on a flat flywhe adapter ring is bolted between the clutch cover and the flywheel. It is sized to provide the needed to accommodate the second clutch dise and the intermediate plate If the clutch has two driven discs, an intermediate, or center plate will separate the discs. The plate is machined smooth on both sides since it is pressed between two friction surfaces. An intermediate plate ne reases the torque capacity of the clutch by increasing the friction area, giving more area for the trans mission of torque. Some intermediate plates have slots in their edge. These slots mate with and are driven by pins in the flywheel housing. Other intermediate plates have four or more tabs that fit into and are driven by slots in the clutch cover or adapter ring The clutch release mechanism can be oper ated either mechanically or hydraulically, TH Mechanically operated release mechanism con 5 ists of a pedal a return spring, a shaft with le- ver,a md, a release yoke lever, a release yoke a release ball bearing with support and a clutch release spring. When the clutch pedal is de ressed, the rod and shaft with yoke shift the lease bearing and support assembly. The release aring presses the inncr cnds of the release le vers, the pressure plate is moved away from the driven disk and the clutch is disengaged. To en the clutch, the pedal is released, the lease veering and support assembly is shifted back by the retum spring thus releasing the re Fig 2-1 lease levers so that the pressure plate is forced I-chultth release n 2-hall m 3-woke lewer 4-retum spring by its springs towards the flywheel to clamp the 7-release yoke 8-clutch releae spring 9--shi driven disk and engage the clutch Fig 2-l shows the coinponents of a typical hydraulic clutch control system. The clutch is controlled and operated by hydraulic fluid pressure and is assisted by an air sero cylinder. This clutch consists of a master cylinder, hydraulic fluid reservoir, and an air-assisted servo cylinder. These are all connected by
2 metal and flexible hydraulic lines When the truck driver presses down on the clutch pedal, the plunger forces the piston in the master linder to move forward. This closes off the reservoir and causes the hydraulic fluid to move down the line to a reaction plunger and pilot valve in the servo cylinder As the hydraulie pressure increases, it forces the reaction plunger to move forward to close off an haust port and to seat the pilot valve. When the plunger is moved farther, it unseats the pilot valve, which allows air to enter the servo cylinder, exerting pressure onto the rear side of the air piston. The movement of the air piston assists in clutch pedal application As the clutch pedal pressure increases, the air piston is moved farther forward arid the air pressure overcomes the hydraulic pressure in the reaction plunger. This causes the pilot valve to reseat, preventing any more air from reaching the air piston. The pilot valve and reaction plunger will remain in this position until there is a change in the pressure When the hydraulic pressure decreases, the retum spring returns the reaction plunger and the pilot valve seats itself, which in turn uncovers the exhaust port and allows the air to escape from the servo cyl New Words disengagement n.断开,脱离,释放 manual ady.用手的,手动的,手动操作的 violent ad,猛烈的,激烈的,强烈的 application n.应用,适用,运用 reasonable a.合理的,适当的,比较好的 accomplish it.完成,达到,实行 release u.;n.释放,解放;释放,放松 Interrupt 1.打断;打扰 rod.在先的;优先的 静止的,固定的 erpendicular adj.垂直的n.垂直(线) allowable adj.容许的,承认的 冲压n.冲压 articulate.清楚说话,接合 cht.向……靠近n.靠近 circumference n.國周,馬长,圆周线 socket n.插座,插孔,插口 t.容纳;供应,供给 ntermediate adj.中间的;中级的 hydraulically ad,液压地 reseat 复位