1、毕业设计论文外文文献翻译要求及封面杭州电子科技大学毕业设计（论文）外文文献翻译毕业设计（论文）题目翻译（1）题目液压制动器基本翻译（2）题目有用产品学 院机械学院专 业车辆工程姓 名班 级学 号指引教师 液压制动基本空气制动系统得到更多关注，但更多车辆上安装液压制动器。理解它们是如何工作，是安全，具成本效益诊断和修复第一步。有无想过为什么不能只是其中一种制动？这是由于空气和液压制动器，使一种或某些应用程序其她抱负经营特色。重型组合车辆，空气是明确选取，由于将需要大量液体阿卡迪亚所有分泵。此外，布满液压油与制动分泵和软管将是混乱。但对于轻型和中型卡车直应用，液压制动器提供优势涉及：制动感觉- 那
2、就是，踏板越往下压，努力增长;高线压力，容许使用更轻，更紧凑制动组件;更少初始费用，由于用更小和更少元件;卫生，液压制动器是封闭系统;易于定位泄漏，由于液体是可见。液压制动系统有更多排列，比在空气系统中发现，但都基本相似。液压系统所有液压制动系统包括流体水库，主缸，液压，液压管路，对制动器进行加压流体软管和一种或各种轮缸（S）对每个车轮产生。分泵扩大流体压力下，迫使制动蹄对鼓内侧。如果使用盘式制动器，卡钳与不可分割气瓶打击转子时施加压力。由于车辆必要可以更迅速，它可以加速到停止，需要大量刹车力。因而，必要减速刹车产生马力发动机作用多次。为了发展须持有对鼓或盘制动器衬片力量，实现受控减速，这是要
3、乘原始力量施加在刹车踏板。当使用液压系统，机械杠杆是在脚踏板联动。然而，不同分泵或卡尺直径直径，关系到主缸内径，提供了一种额外增长比率。液压系统中，各分泵交付压力，直接影响由活塞地区。例如，如果一种轮缸活塞面积2平方英寸，另一种活塞面积1平方英寸，系统压力为400磅，2平方英寸活塞将针对制动器推一种迫使800磅。1平方英寸活塞施加一种400磅力量。总泵和分泵地区之间比例拟定在轮缸活塞力量倍增。为保持在头脑，直径较大轮缸，更流畅，必要提供由主缸行程较长研究生转化。请记住，直径较大轮缸，更流畅，必要由主缸提供，以弥补它。这意味着进入一种较长主缸行程。如果主缸孔直径增长和相似申请依然有效，更少压力将
4、在系统开发，但一种更大轮缸活塞可以用来实当前轮缸所需压力。显然，必要更换主缸，轮缸或卡尺相似设计，并作为原单位承担。液压系统中，各分泵交付压力，直接影响由活塞地区。例如，如果一种轮缸活塞面积2平方英寸，另一种活塞面积1平方英寸，系统压力为400磅，2平方英寸活塞将针对制动鞋推一种迫使800磅。1平方英寸活塞施加一种400磅力量。总泵和分泵地区之间比例拟定在轮缸活塞力量倍增。液压制动系统分割系统，涉及两个谨慎制动电路。一主缸活塞和水库是一种单独活塞及伺服制动器上其她桥（S）水库，用来驱动一轴刹车。虽然罕见，某些轻型制动系统分裂对角线而非桥桥。分割系统因素是，如果一种液压回路泄漏发展，将停止车辆。
5、固然，不应当被驱动车辆远超过必要制动系统修复。当液压回路发生故障，压力差开关感官两个电路之间不平等压力。互换机包括由弹簧片，并在每年年终电触头位于活塞。从一种液压回路中流体压力提供压力差开关一端，并从其她电路压力提供应另一端。随着压力一种电路，其她电路正常压力，迫使活塞失效一边，关闭接触，并照亮仪表板警示灯。动力辅助协助电力单位，或助推器，减少运营商努力，在刹车踏板。真空助力器，轻型汽车流行，使发动机真空隔膜一侧，对对方大气压力。一种阀门，使真空作用于刹车踏板行程中比例隔膜。这有助于踏板努力，并增长对制动液压力，无需过度增长在踏板努力。其她类型助推器使用液压压力-无论是从车辆动力转向泵，或从一
6、种单独电动泵，或两者兼而有之-协助刹车踏板被踩下踏板作用，阀门液压升压室申请增长压力在增长主缸活塞。有些系统使用真空和液压助力。在其她系统中，从船上压缩机空气压力产生液压系统压力。阀杆液压制动系统中常用阀门涉及：配比，或压力平衡阀门。这些限制液压比例后轮刹车系统压力达到预设高阻值。提高前轮/后轮在高速制动制动平衡时，某些车辆先后重量转移，并有助于防止后轮配料阀高度传感器。也就是说，她们调节后轮制动压力，在车辆荷载响应。随着车辆负载增长（减少高度）液压后轮刹车是不容许；测光阀门。这些保持了前盘式制动器压力，让后轮鼓式制动蹄克服返回弹簧压力，使接触后鼓。这可以防止锁定在湿滑路面上前刹车灯制动应用。
7、这些阀门不来硬制动过程中发挥作用。泊车停车功能液压制动系统之间差别很大。许多轻型车辆使用与后轮鼓式制动器杆和电缆相配合，逐渐加大杆或脚踏拉电缆，这反过来，拉杠杆总成，每个后轮结束客运车类型。杠杆迫使制动蹄外，她们对鼓机械棘轮被释放，直到举起。其她泊车系统涉及弹簧腔，像那些用于空气制动系统。这是弹簧控制，但由液压脱开而不是空气。防抱死许多轻型卡车液压制动，防抱死制动系统上使用后轮保持轻载时，这些车辆制动稳定性。前面和后轮防抱死普通是一种选项，GVWR超过10,000磅车辆，这是需要引导和驱动桥防抱死关闭。在当前液压防抱死系统，转储阀释放压力到一种累加器在即将车轮锁死状况下液压油。电子控制箱接受来
8、自传感器传播和/或在车轮速度信号（S）。当施加制动，控制箱检测在后轮速度，减少和激活转储阀（S），如果减速率超过预定限制。控制箱通电一系列流血轮液压迅速脉冲单向阀。继续转储阀是脉冲在防抱死模式，以保持车轮转动，同步保持控制减速。在最后停止，阀门勉励和累加器中任何液体返回到主缸，恢复正常刹车操作。基本刹车在液压系统基本制动器可以是鼓或光盘。在许多应用中，光盘上使用前轴后方鼓。鼓式制动器说是自激。这是由于制动蹄扩大和联系一种旋转滚筒，引导或向前制动蹄被推向对刹车制动箍由移动鼓力量。这个成果在更高衬里鼓比将仅由轮缸产生压力。随着制动器衬片磨损，必要定期移近鼓，以保证在制动过程中恰当接触。虽然某些旧鼓
9、式制动器总成，手动调节，大某些都是自动。这些使用一种星轮或棘轮大会，这感官分泵时已超过其正常行程前去，并扩大在另一端制动蹄支点。除了摩擦元素之一，制动鼓或转子也充当散热器。它必要迅速制动过程中吸取热量，并保持它，直到它可以将空气中消散。鼓或转子较重是，它可以容纳更多热量。这是很重要，由于制动器衬片热，她们更容易受到热衰退。热衰退是诱发重复硬盘停止和成果减少鼓形轮子连接摩擦和增长车辆制动距离。作为一项规则，高品质衬里，将显示低于劣质热褪色。此外碟式刹车比鼓式制动器耐热褪色性能更好。另一种褪色类型，刹车容易褪色水。鼓式制动器，其表面积大，在安全范畴内比盘式制动器每平方英寸之间需要更少衬力和鼓力。加
10、上鼓保水形状，鞋和鼓之间潮湿条件下增进水面滑行。成果是制动距离大大增长。盘式制动器，具备较小摩擦表面和高夹紧力，做一种良好工作从转子擦水，并显示在潮湿时停止能力几乎没有减少。HYDRAULIC BRAKE BASICSAirbrakesget more attention，buthydraulicbrakesare installed on more vehicles.Understanding how they work is the first step to safe，cost-effective diagnosis and repair.Ever wonder why there ca
11、nt be just one kind ofbrake?Its because air andhydraulicbrakeseach have operating characteristics that make one or the other ideal for certain applications.In heavy-duty combination vehicles，air is the clear choice because of the large volume of liquid that would be needed to acadia all the wheel cy
12、linders.Plus，dealing with gladhands and hoses filled withhydraulicfluid would be messy.But for light and medium-duty straight-truck applications,hydraulicbrakesoffer advantages including:Brakefeel that is，as the pedal is pressed farther down，effort increases;High line pressures，which permit the use
13、of lighter，more compact braking components;Less initial expense，due to smaller and fewer components;Cleanliness hydraulicbrakesare closed systems;Ease of locating leaks，since fluid is visible.There are many more permutations ofhydraulicbrakesystems than found in air systems，but all have basic simila
14、rities.THE HYDRAULIC SYSTEMAll hydraulic brake systems contain a fluid reservoir，a master cylinder，which produceshydraulicpressure,hydrauliclines and hoses to carry pressurized fluid to the brakes，and one or more wheel cylinder(s) on each wheel.The wheel cylinders expand under fluid pressure，and for
15、ce thebrakeshoes against the insides of the drums.If discbrakesare used，calipers，with integral cylinders，clamp down on the rotors when pressure is applied.Because a vehicle must be able to stop much more quickly than it can accelerate，a tremendous amount of braking force is needed.Therefore，the reta
16、rding horsepower generated by thebrakesmust be several times that of the engine.In order to develop the forces required to hold thebrakelinings against the drums or discs，and to achieve controlled deceleration，it is necessary to multiply the original force applied at thebrakepedal.When ahydraulicsys
17、tem is used，the only mechanical leverage is in the foot pedal linkage.However，varying the diameter of the wheel cylinders or caliper diameters，in relation to the master cylinder bore diameter，provides an additional increase in ratio.In ahydraulicsystem，the pressure delivered by the various wheel cyl
18、inders is directly affected by the areas of their pistons.For example，if one wheel-cylinder piston has an area of 2 square inches，and another piston has an area of 1 square inch，and the system pressure is 400 psi，the 2-square-inch piston will push against the brakeshoes with a force of 800 pounds. T
19、he 1-square-inch piston will exert a force of 400 pounds.The ratio between the areas of the master cylinder and the wheel cylinders determine the multiplication of force at the wheel cylinder pistons.Keep in mind that the larger a wheel cylinders diameter，the more fluid must be supplied by the maste
20、r cylinder to fill it.This translates into a longer master-cylinder stroke.If the master cylinder bore diameter is increased and the applying force remains the same，less pressure will be developed in the system，but a larger wheel-cylinder piston can be used to achieve the desired pressure at the whe
21、el cylinder.Obviously，a replacement master cylinder，wheel cylinder or caliper must be of the same design and bore as the original unit.Hydraulicbrakesystems are split systems，comprising two discreet braking circuits.One master-cylinder piston and reservoir is used to actuate thebrakeson one axle，wit
22、h a separate piston and reservoir actuating thebrakeson the other axle(s).Although rare，some light-duty brake systems are split diagonally rather than axle by axle.The reason for the split system is that if a leak develops in onehydrauliccircuit，the other will stop the vehicle.Of course，the vehicle
23、shouldnt be driven any farther than necessary to have thebrakesystem repaired. When one of thehydrauliccircuits fails，a pressure-differential switch senses unequal pressure between the two circuits.The switch contains a piston located by a centering spring and electrical contacts at each end.Fluid p
24、ressure from onehydrauliccircuit is supplied to one end of the pressure-differential switch，and pressure from the other circuit is supplied to the other end.As pressure falls in one circuit，the other circuits normal pressure forces the piston to the inoperative side，closing the contacts and illumina
25、ting a dashboard warning light.POWER ASSISTPower assist units，or boosters，reduce operator effort at thebrakepedal.Vacuum boosters，popular on light-duty vehicles，make use of an engine vacuum on one side of a diaphragm，and atmospheric pressure on the other side.A valve allows the vacuum to act on the
26、diaphragm in proportion tobrakepedal travel.This assists the pedal effort，and allows increased pressure on thebrakefluid，without an undue increase in pedal effort.Other types of boosters usehydraulicpressure either from the vehicles power steering pump or from a separate electric pump，or both to ass
27、ist pedal effort. As thebrakepedal is depressed，a valve increaseshydraulicpressure in a boost chamber to apply increased pressure to the master cylinder pistons.Some systems use both vacuum andhydraulicassist.In other systems，air pressure from an onboard compressor is used to generatehydraulicsystem
28、 pressure.VALVINGValves commonly found inhydraulicbrakesystems include：Proportioning，or pressure-balance valves.These restrict a percentage ofhydraulicpressure to the rearbrakeswhen system pressure reaches a preset high value. This improves front/rearbrakebalance during high-speed braking，when some
29、of a vehicles rear weight is transferred forward，and helps prevent rear-wheel lockup. Some proportioning valves are height-sensing.That is，they adjust rear-brakepressure in response to vehicle load.As a vehicles load increases (decreasing height) morehydraulicpressure to the rearbrakesis allowed；Met
30、ering valves.These hold off pressure to front discbrakesto allow rear drumbrakeshoes to overcome return-spring pressure and make contact with the rear drums.This prevents locking the frontbrakeson slippery surfaces under light braking applications.These valves do not come into play during hard braki
31、ng.PARKINGThe parking function varies greatly amonghydraulicbrakesystems.Many light-duty vehicles with rear drumbrakesuse a passenger-car type lever-and-cable setup. A ratcheted lever or foot pedal pulls a cable，which，in turn，pulls a lever assembly at each rear wheel end.The lever forces thebrakesho
32、es apart，and they are mechanically held against the drums until the ratchet is released.Other parking systems include spring chambers，like those used on air-brakesystems.These are spring-engaged，but are disengaged byhydraulicpressure instead of air.ANTILOCKOn many hydraulically braked light-duty trucks，antilockbrakesare used on the rear wheels to preserve braki
