587_輕型載重貨車設計(轉向系及前橋設計)（有cad圖）
587_輕型載重貨車設計(轉向系及前橋設計)（有cad圖）,輕型,載重,貨車,設計,轉向,前橋,cad
車輛與動力工程學院畢業(yè)設計說明書
外文資料及翻譯
Steering system
(1)To change the control mechanism basically mainly by the steering wheel, the steering axle, the steering tube column and so on to be composed.
(2) Diverter becomes steering wheel's rotation steering arm's swinging or the rack axis straight reciprocating motion, and to changes the control force to carry on the enlargement the organization. The diverter fixes generally on the automobile frame or the automobile body, changes the control force after the diverter generally will also change the transmission direction.
(3) Steering transmission system the strength which and the movement outputs the diverter passes to the wheel (knuckle), about and causes the wheel to carry on the deflection according to certain relations the organization.
Type
Crooked to energy difference, the steering system may divide into the machinery steering system and the power steering system two broad headings crooked.
Mechanical steering system: And changes the transmission system by the diverter to be composed.
Diverter: By the steering wheel, the steering wheel steering axle, changes meshing to pay (diverter) to be composed.
Steering transmission system: By drop arm (drop arm), drag link, drag link arm, about trapezoidal arm, steering knuckle tie rod, if a dry bulb joint composes.
Power steering system: Changes the augmenter constitution by mechanical steering system Canada.
1.Mechanical steering system The mechanical steering system changes the energy by pilot's physical strength achievement, all power transmission are the machinery. The mechanical steering system by changes the control mechanism, the diverter and changes the transmission system three major part to be composed.
(1) steering control mechanism
Changes the control mechanism by the steering wheel, the steering axle, the steering tube column and so on to be composed, its function is rotates the pilot steering wheel's control force to pass to the divertor.
(2) Divertor
The diverter (also often is called steering unit) is completes from the rotary motion to the translation (or approximate straightline motion) a group of gear mechanism, simultaneously is also in the steering system speed reducer drive. At present the commonly used toothed wheel rack type, follows round the world the crank to refer to sells the type, the worm bearing adjuster crank to refer to sells the type, to follow round the world - the tooth rack tooth fan type, the worm bearing adjuster hoop type and so on. We mainly introduce the first several kinds.
1) Gear rack type divertor
The gear rack type diverter divides the both sides output type and among (or single end) the output type two kinds .The both sides output's gear rack type diverter, changes the gear shaft as the transmission vice-host moving parts and installs through the bearing in the diverter shell, its upper extreme through spline and universal joint sliding yoke and steering axle connection. With the steering gear meshing steering rack level arrangement, the both sides with change the steering knuckle tie rod through a ball place to be connected. The spring presses through the briquetting the rack depending in the gear, guarantees ceaseless meshing.
Spring's pretightening up force available adjustment thread plug adjustment. When rotates the steering wheel, the diverter gear-driven, causes with it meshing rack along the end motion, thus about causes the steering knuckle tie rod to lead about the knuckle to rotate, causes to change the wheel deflection, thus realizes motor turning.
Middle output gear rack type diverter, its structure and principle of work and both sides output gear rack type diverter basic same, the difference lies in it to change the steering knuckle tie rod in steering rack's middle with the bolt with about to be connected. On single-ended output's gear rack type diverter, a rack's end with changes the steering knuckle tie rod through the inside and outside bracket to be connected.
2) Follows round the world-like the divertor
Follows round the world-like the diverter is one of present domestic and foreign application most widespread structure patterns, generally has two-stage drive, the first level is screw rod nut transmission, the second level is tooth rack tooth fan transmission.
In order to reduce between the steering screw steering nut's friction, the two's thread immediate contact, during is loaded with many steel balls, realizes the rolling friction. On the steering screw and the nut processes the profiled outline is two section or three section of not concentric circular arc composition approximate semicircle spiral groove. The two's spiral groove can coordinate to form the approximate circular cross section the spiral tubular channel.
The nut side has two pair of through holes, may henceforth the vent plug enter the steel ball in the helix channel. Outside the steering nut has two steel ball drive pipes, each drive pipe's both sides insert the nut side separately in a pair of through hole. In the drive pipe has also packed the steel ball. Thus, in two drive pipes and nut's spiral tubular channels combine two respectively independent seals the steel ball " the flow channel ".
When the steering screw rotates, passes to the steering nut through the steel ball the strength, the nut namely along the end motion. At the same time, friction couple function between the screw rod and the nut and under the steel ball, all steel balls then rolls in the spiral tubular channel, formation " ball class ". When the diverter works, two rows steel balls are only in the respective seal flow channel internal recycling, will leave.
3) The worm bearing adjuster crank refers to sells the type diverter
The worm bearing adjuster crank refers to sells the type diverter's transmissionvice-(by the steering worm primarily moving parts, it is installs from the moving parts in the rocker arm shaft crank nose refers to sells. When the steering worm rotates, refers to with it meshing sells namely circles the rocker arm shaft spool thread along the circular, and leads the rocker arm shaft rotation.
(3) Steering transmission system
Steering transmission system the function is the strength which and the movement outputs the diverter passes to the steering axle both sides the knuckle, causes the both sides wheering wheel deflection, and causes two wheering wheel deflection angles according to certain relational change, guarantees when motor turning the wheel and the ground relative sliding is as far as possible small.
1) Uses for parts with the non-independent suspension fork changes the transmission system mainly to include the steering arm, to change the drag link, the steering, and the steering trapezium. In the front axle is only in the steering axle situation, by changes the steering trapezium general arrangement which the steering knuckle tie rod and the left and right trapezoidal arm are composed after the front axle, when the wheering wheel is in with the automobile straight line travel corresponding neutral point, trapezoidal arm and steering knuckle tie rod in and path parallel plane (horizontal plane) in angle of intersection >90.In the engine position is low or in the steering axle concurrently sufficient driving axle's situation, to avoid the movement interference, often steering trapezium arrangement before the front axle, this time above angle of intersection <90, if the steering arm is not around swings in the automobile fore-and-aft plane, but is shaking right toward left with the path parallel plane, then may change the drag link horizontal, and sells taking advantage of ball leads directly changes the steering knuckle tie rod, thus pushes somebody into doing something the both sides trapezoidal arm rotation.
2) Uses for parts with the independent suspension fork changes the transmission systemWhen wheering wheel independent suspension, each wheering wheel needs to be opposite in the frame makes the independence movement, thus the steering axle must be the separation type. With this corresponding, changes in the transmission system the steering trapezium also to be the separation type.
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As shown in Figure 9 b. If Pitman is not in the vehicle longitudinal plane backwards and forwards, but is in the plane parallel to the road to shake, you can bring the steering linkage 3 exhaust, and ball head pin directly driven steering tie rod 6, thus pushing the sides of a trapezoid arm. 2) and independent suspension with the steering linkage when steering wheel independent suspension, each steering wheel needs relative to the frame for independence movement, thereby steering bridge must be disconnected. And accordingly, steering linkage of steering or must be disconnected.
The role of steering lever is passed from the Pitman force and motion to steering arm (or steering). It force existing tension and pressure, so direct lever is is the use of high-quality special steel manufacturing, in order to ensure reliable operation. Linkage of typical structure as shown in Figure 11. In the steering wheel to deflect or elastic deformation due to the suspension and relative to the frame beats, steering lever and Pitman and steering relative movements are spatial movement, in order not to occur, the interference of the three connections takes the ball PIN. 4) Steering damper as speed increases, the modern automobile steering wheel sometimes generate shimmy (steering wheel around the kingpin axis reciprocating swing, even whole body vibration), which not only affect vehicle stability, but also affected comfort, aggravate the nose wheel wear and tear. In the steering linkage in setting steering damper is to overcome the steering wheel shimmy of effective measures. Steering damper side of the body (or front axle) articulated, the other end and steering lever (or articulated steering).
Use mechanical steering can implement steering, when steering axle load larger that the pilot's manual as steering energy is difficult to turn smoothly. Power steering system is in mechanical steering system on the basis of a set of steering device. Steering device reduces driver operated steering wheel. Steering energy from the driver's physical strength and motor (or motors), engine (or motors) accounted for the major part, through the steering device. Normally, pilots can easily control the steering. But in the steering device failure, I went back to mechanical steering system state, in general but also by the driver's steering tasks independently. (1) hydraulic power steering systems-which belongs to the steering device part is: steering pump 7, steering tubing 8, steering, and is located in the integral oil tank 6 EPS 4 internal steering control valve and steering power cylinder 5, etc. When the pilot turned the steering wheel 1 by mechanical steering makes steering tie rod 9 mobile, and driven steering, the steering wheel deflection, thus changing the car driving direction. At the same time, the steering shaft also driven steering internal rotation of the steering control valve, the hydraulic steering power cylinder produces helps the driver's steering forces. Because of the role of the steering device, the driver simply than mechanical steering system is much smaller, steering torque of the steering wheel deflection. Advantages and disadvantages: high energy consumption, especially when slow turning, think the comparison engine driving direction also relatively easy. And because the hydraulic pump pressure, is also easier to damage to the power system. (2) electric power steering system, referred to as EPS or EPS (electric, Electronic Power Steering system) in mechanical steering mechanism, increase signal sensor, electronic control unit and the Steering Body. EPS is the use of electric motor as a power source, depending on the speed of help and steering parameters, and other factors, by the electronic control unit to complete the power-assisted control, its principles can be summarized as follows: when handling and steering wheel, mounted on the steering wheel shaft torque sensor constantly measured steering shaft torque signal, the signal and the vehicle speed signal input to the electronic control unit. The electronic control unit according to the input signal, determine power torque in magnitude and direction, which is the selected motor currents and rotation direction, adjusting the size of the auxiliary power steering. Motor torque by electromagnetic clutch by gear reducer by moments later, the car's steering mechanism, to achieve a vehicle condition of steering forces. For example, Fox's EHPAS e hydraulic system from a computer according to engine speed and vehicle speed and steering angle and other signal, drive e pump to deliver power steering system. Power feel very natural. So many people on Fox in the direction of the feeling is quite good, feeling of steering control can be as long as you want. Some vehicles also claims the use of electronic power, but just motor power, no hydraulic aided, prone to noise. Power effects are far behind Fox this type of electronic power.
轉向系統(tǒng)
汽車轉向系統(tǒng)：汽車上用來改變或恢復其行駛方向的專設機構稱為汽車轉向系統(tǒng)。汽車的轉向系統(tǒng)是用來改變汽車行駛方向和保持汽車直線行駛的機構
基本組成
(1)轉向操縱機構主要由轉向盤、轉向軸、轉向管柱等組成。
(2)轉向器將轉向盤的轉動變?yōu)檗D向搖臂的擺動或齒條軸的直線往復運動，并對轉向操縱力進行放大的機構。轉向器一般固定在汽車車架或車身上，轉向操縱力通過轉向器后一般還會改變傳動方向。
(3)轉向傳動機構將轉向器輸出的力和運動傳給車輪(轉向節(jié))，并使左右車輪按一定關系進行偏轉的機構。
類型
按轉向能源的不同，轉向系統(tǒng)可分為機械轉向系統(tǒng)和動力轉向系統(tǒng)兩大類。
機械轉向系：由轉向器和轉向傳動機構組成.
轉向器：由方向盤，方向盤轉向軸，轉向嚙合付(轉向器)組成.
轉向傳動機構：由轉向臂(轉向垂臂)，直拉桿，直拉桿臂，左右梯形臂，橫拉桿，若干球頭關節(jié)組成.
動力轉向系：由機械轉向系加轉向加力裝置構成.
1．機械轉向系
機械轉向系以駕駛員的體力作為轉向能源，其中所有傳力件都是機械的。機械轉向系由轉向操縱機構、轉向器和轉向傳動機構三大部分組成。
（1）轉向操縱機構
轉向操縱機構由方向盤、轉向軸、轉向管柱等組成，它的作用是將駕駛員轉動轉向盤的操縱力傳給轉向器。
（2 ）轉向器
轉向器(也常稱為轉向機)是完成由旋轉運動到直線運動(或近似直線運動)的一組齒輪機構，同時也是轉向系中的減速傳動裝置。
目前較常用的有齒輪齒條式、循環(huán)球曲柄指銷式、蝸桿曲柄指銷式、循環(huán)球-齒條齒扇式、蝸桿滾輪式等。我們主要介紹前幾種。
1）齒輪齒條式轉向器
齒輪齒條式轉向器分兩端輸出式和中間（或單端）輸出式兩種。
兩端輸出的齒輪齒條式轉向器，作為傳動副主動件的轉向齒輪軸通過軸承和安裝在轉向器殼體中，其上端通過花鍵與萬向節(jié)叉和轉向軸連接。與轉向齒輪嚙合的轉向齒條水平布置，兩端通過球頭座與轉向橫拉桿相連。彈簧通過壓塊將齒條壓靠在齒輪上，保證無間隙嚙合。
彈簧的預緊力可用調整螺塞調整。當轉動轉向盤時，轉向器齒輪轉動，使與之嚙合的齒條沿軸向移動，從而使左右橫拉桿帶動轉向節(jié)左右轉動，使轉向車輪偏轉，從而實現汽車轉向。
中間輸出的齒輪齒條式轉向器，其結構及工作原理與兩端輸出的齒輪齒條式轉向器基本相同，不同之處在于它在轉向齒條的中部用螺栓與左右轉向橫拉桿相連。在單端輸出的齒輪齒條式轉向器上，齒條的一端通過內外托架與轉向橫拉桿相連。
2）循環(huán)球式轉向器
循環(huán)球式轉向器是目前國內外應用最廣泛的結構型式之一， 一般有兩級傳動副，第一級是螺桿螺母傳動副，第二級是齒條齒扇傳動副。
為了減少轉向螺桿轉向螺母之間的摩擦，二者的螺紋并不直接接觸，其間裝有多個鋼球，以實現滾動摩擦。轉向螺桿和螺母上都加工出斷面輪廓為兩段或三段不同心圓弧組成的近似半圓的螺旋槽。二者的螺旋槽能配合形成近似圓形斷面的螺旋管狀通道。
螺母側面有兩對通孔，可將鋼球從此孔塞入螺旋形通道內。轉向螺母外有兩根鋼球導管，每根導管的兩端分別插入螺母側面的一對通孔中。導管內也裝滿了鋼球。這樣，兩根導管和螺母內的螺旋管狀通道組合成兩條各自獨立的封閉的鋼球"流道"。
轉向螺桿轉動時，通過鋼球將力傳給轉向螺母，螺母即沿軸向移動。同時，在螺桿及螺母與鋼球間的摩擦力偶作用下，所有鋼球便在螺旋管狀通道內滾動，形成"球流"。在轉向器工作時，兩列鋼球只是在各自的封閉流道內循環(huán)，不會脫出。
3）蝸桿曲柄指銷式轉向器
蝸桿曲柄指銷式轉向器的傳動副(以轉向蝸桿為主動件，其從動件是裝在搖臂軸曲柄端部的指銷。轉向蝸桿轉動時，與之嚙合的指銷即繞搖臂軸軸線沿圓弧運動，并帶動搖臂軸轉動。
（3）轉向傳動機構
轉向傳動機構的功用是將轉向器輸出的力和運動傳到轉向橋兩側的轉向節(jié)，使兩側轉向輪偏轉，且使二轉向輪偏轉角按一定關系變化，以保證汽車轉向時車輪與地面的相對滑動盡可能小。
1）與非獨立懸架配用的轉向傳動機構
與非獨立懸架配用的轉向傳動機構主要包括轉向搖臂、轉向直拉桿、轉向節(jié)臂、和轉向梯形。在前橋僅為轉向橋的情況下，由轉向橫拉桿和左、右梯形臂組成的轉向梯形一般布置在前橋之后，當轉向輪處于與汽車直線行駛相應的中立位置時，梯形臂與橫拉桿在與道路平行的平面(水平面)內的交角＞90。
在發(fā)動機位置較低或轉向橋兼充驅動橋的情況下，為避免運動干涉，往往將轉向梯形布置在前橋之前，此時上述交角＜90，若轉向搖臂不是在汽車縱向平面內前后擺動，而是在與道路平行的平面向左右搖動，則可將轉向直拉桿橫置，并借球頭銷直接帶動轉向橫拉桿，從而推使兩側梯形臂轉動。
2）與獨立懸架配用的轉向傳動機構
當轉向輪獨立懸掛時，每個轉向輪都需要相對于車架作獨立運動，因而轉向橋必須是斷開式的。與此相應，轉向傳動機構中的轉向梯形也必須是斷開式的。
3）轉向直拉桿
轉向直拉桿的作用是將轉向搖臂傳來的力和運動傳給轉向梯形臂(或轉向節(jié)臂)。它所受的力既有拉力、也有壓力，因此直拉桿都是采用優(yōu)質特種鋼材制造的，以保證工作可靠。在轉向輪偏轉或因懸架彈性變形而相對于車架跳動時，轉向直拉桿與轉向搖臂及轉向節(jié)臂的相對運動都是空間運動，為了不發(fā)生運動干涉，上述三者間的連接都采用球銷。
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