彈簧設(shè)計(jì).ppt

1、彈簧設(shè)計(jì) Spring Design,一 概述 summary,彈簧的分類 spring classification 彈簧的分類有多種，一般按照如下區(qū)分: Spring has a variety of classification. Generally, spring is classified as the following ： 根據(jù)使用的材料分 According to the using material：,鐵制彈簧 Ferrous springs,非鐵金屬?gòu)椈?Non-ferrous springs,碳素鋼彈簧 Carbon steel springs,合金鋼彈簧 Alloy s

2、teel springs,不銹鋼彈簧 Stainless steel springs,銅合金彈簧 Cooper alloy springs,鎳合金彈簧 Nickel alloy springs,其他 The others,金屬材料 Metal material,其他 The others,一 概述 summary,非金屬材料 Nonmetal material,螺旋彈簧 Helical springs,板（片）彈簧 Leaf springs,特種彈簧 Special springs,壓縮彈簧compression springs,拉伸彈簧compression springs,扭轉(zhuǎn)彈簧 tor

3、sion springs,橡膠彈簧rubber springs,流體彈簧fluid springs,合成樹(shù)脂彈簧synthetic resin springs,其他類彈簧the other springs,根據(jù)形狀分：According to the appearance.,其他類彈簧the other springs,常用的三種彈簧 The common springs,一 概述 summary,壓縮彈簧 Compression springs Compression Springs are springs which absorb and store energy by offering

4、resistance to a pushing force. Most compression springs are a straight columniform spring made of round wire. 壓縮彈簧是通過(guò)推壓彈簧來(lái)存儲(chǔ)能量的，大部分的壓簧是直的圓柱型圓鋼絲彈簧。,拉伸彈簧 Extension springs Extension Springs are springs which absorb and store energy by offering resistance to a pulling force . Typically, extension sprin

5、gs are made from round wire and are close wound with initial tension. 拉伸彈簧是通過(guò)拉彈簧來(lái)存儲(chǔ)能量的，在初始狀態(tài)，大部分拉簧是圓鋼絲且彈簧 鋼絲之間是并緊沒(méi)有間隙的。,常用的三種彈簧的介紹 The introduction of three common springs,一 概述 summary,扭轉(zhuǎn)彈簧 torsion springs,A torsion spring is a spring that works by torsion or twisting; that is, a flexible elastic ob

6、ject that stores mechanical energy when it is twisted. The arms of the torsion springs rotate about the central axis.,扭轉(zhuǎn)彈簧力是通過(guò)是通過(guò)扭轉(zhuǎn)彈簧來(lái)存儲(chǔ)能量的，彈簧的臂是圍繞一個(gè)中心軸在轉(zhuǎn)動(dòng)的。,二、彈簧的設(shè)計(jì)應(yīng)力 Some design stress of springs,張應(yīng)力Tension stress 張應(yīng)力是由于軸向拉升材料所產(chǎn)生的應(yīng)力。 Tension stress is the stress state caused by an applied load tha

7、t tends to elongate the material in the axis of the applied load, in the other words the stress caused by pilling the material. 壓應(yīng)力Compression stress 壓應(yīng)力是由于軸向壓縮材料所產(chǎn)生的應(yīng)力。 Compression stress is the stress state caused by an applied load that acts to reduce the length of material in the axis of the app

8、lied load, in other words the stress state caused by squeezing the material. 張應(yīng)力和壓應(yīng)力的公式如下 The formulas as following： =F/A 其中， F為力(N) / A為面積(m2) where F is force (N) acting on an area A (m2);,Tension stress,compression stress,二、彈簧的設(shè)計(jì)應(yīng)力 Some design stress of springs,彎曲應(yīng)力 Bending stress 彎曲應(yīng)力是由于彎曲材料所產(chǎn)生的

9、應(yīng)力。 Bending stress is the stress state caused by an applied load that tends to bend the material in the axis of the applied load, in the other words the stress caused by bending the material. 對(duì)于扭簧，它給出的是扭力，但是有限元上主要應(yīng)力為彎曲應(yīng)力。 Torsion spring give torsional fore, but the wire are loaded in bending stress.

10、,Bending stress,注意！Tip!,二、彈簧的設(shè)計(jì)應(yīng)力 Some design stress of springs,扭轉(zhuǎn)應(yīng)力 Torsional stress 扭轉(zhuǎn)應(yīng)力是由一對(duì)平行的方向相反的力作用材料上所產(chǎn)生的應(yīng)力。 Torsional stress is state caused by a pair of opposing forces acting along parallel lines of action through the material。 對(duì)于壓簧和拉簧， 它給出的是軸向的力，但是有限元上主要應(yīng)力為扭轉(zhuǎn)應(yīng)力。 Tension and compression sp

11、rings give axial loads, but the wire are loaded in torsional stress.,注意！Tip!,torsional stress,二、彈簧的設(shè)計(jì)應(yīng)力 Some design stress of springs,疲勞強(qiáng)度Fatigue strength 疲勞強(qiáng)度是指材料在無(wú)限多次交變載荷作用下而不破壞的最大應(yīng)力稱為疲勞 強(qiáng)度。 Fatigue strength is the maximum stress level that a material can withstand an infinite number of cycles bef

12、ore damage.,S-N curve for steel,三、彈簧材料的強(qiáng)度和的特性 Strength of materials and material properties,3.1 材料的幾個(gè)強(qiáng)度定義 Definitions of some strength of materials ： 極限抗拉強(qiáng)度 Ultimate tensile strength-Sut（單位unit：MPa） 抗拉強(qiáng)度指材料在拉斷前承受最大應(yīng)力值. Ultimate tensile strength is defined as the stress at which a material begins to

13、break. (The maximum stress a material can withstand when subjected to tension, Sut可以通過(guò)查詢手冊(cè)得到，也可以通過(guò)以下公式計(jì)算： The values of Sut can select from some spring handbooks, also can calculate according to the following formulas. Sut=196000/d0.146 (Unit:psi-單位為英制的) Sut=1351/（d/25.4）0.146 (Unit:MPa) 其中,d為彈簧材料的線

14、經(jīng)。d means wire diameter.,三、彈簧材料的強(qiáng)度和的特性 Strength of materials and material properties,材料的幾個(gè)強(qiáng)度定義 Definitions of some strength of materials ： 屈服強(qiáng)度 Yield strength-Sy （單位unit：MPa） 屈服強(qiáng)度是材料開(kāi)始發(fā)生永久變形或者塑性變形的應(yīng)力。 The yield strength is defined as the stress at which a material begins to deform permanently or pla

15、stically. 剪切強(qiáng)度 Shear strength-Ssy （單位unit：MPa） 剪切強(qiáng)度是指材料承受剪切力的應(yīng)力. Shear strength is defined as the stress at which a material fails in shear. 三者關(guān)系見(jiàn)下圖（The relationship as following figure)：,三、彈簧材料的強(qiáng)度和的特性 Strength of materials and material properties,如：對(duì)于琴鋼絲的材料，有如下關(guān)系： For music wire, it has the followi

16、ng Relationship: Sy=0.75Sut Ssy=0.577Sy 對(duì)于設(shè)計(jì)扭簧的時(shí)候，材料主要承受的 應(yīng)力為彎曲應(yīng)力，所以設(shè)計(jì)應(yīng)力選用Sy；但 設(shè)計(jì)拉伸和壓縮彈簧時(shí)，設(shè)計(jì)應(yīng)力選用Ssy. For torsion spring, the wire are loaded in bending stress, so the design stress should be choose Sy, but the compression and extension spring should be choose Ssy.,Figure of stress-strain curve,三、彈簧材

17、料的強(qiáng)度和的特性 Strength of materials and material properties,以下是一些常用材料的Sut值 Some Sut for the common material as following：,設(shè)計(jì)彈簧時(shí)，初始的計(jì)算可以選用上表的數(shù)值。 Select values from the above table for initial calculation of spring.,三、彈簧材料的強(qiáng)度和的特性 Strength of materials and material properties,3.2 彈性模量 Modulus of elasticity

18、彈性模量是應(yīng)力-應(yīng)變曲線直線部分的斜率 。 Modulus of elasticity is defined as the slope of its stress-strain curve in the elastic deformation,Figure of Stress-strain curve,=Stress/Strain 單位(uint)：MPa,三、彈簧材料的強(qiáng)度和的特性 Strength of materials and material properties,兩者之間的關(guān)系 （the relationship between the two modulus)： E=2G(1+r

19、) 其中，r為泊松比 where, r stands for poisson ratio,每種材料都有兩種彈性模量Every material has two modulus of elasticity :,拉伸彈性模量（簡(jiǎn)稱彈性模量）E， 是用來(lái)設(shè)計(jì)扭轉(zhuǎn)彈簧。 Tensile Elasticity modulus (Youngs modulus E) which used to design torsion spring,切變彈性模量(簡(jiǎn)稱切變模量)G， 是用在拉伸或壓縮彈簧。 Shear modulus (G) which used to design of compression and

20、 extension spring.,三、彈簧材料的強(qiáng)度和的特性 Strength of materials and material properties,琴鋼絲的一些特性Some properties of music wire as following:,拉（壓）簧設(shè)計(jì)選用,扭簧設(shè)計(jì)選用,四、彈簧設(shè)計(jì)需要考慮的參數(shù) Design considerations for springs,1 根據(jù)使用的要求， 選擇合適的彈簧的形狀，種類和端部結(jié)構(gòu)。 Select the right kind of springs, the appearance and end of springs accor

21、ding to the using requirements. 2 根據(jù)給定的空間，定出彈簧的外形輪廓尺寸。如，允許的最大外徑， 最小內(nèi) 徑，變形量，彈簧剛度，彈簧的力值等。 According to the space, the basic sizes of spring could be determined. For example, the maximum out diameter (mm), the minimum inner diameter (mm), spring rate,the maximum deflections (mm) and the maximum loads (

22、N) during assembly. 3 根據(jù)使用情況， 如對(duì)工作溫度，環(huán)境介質(zhì)，使用壽命等選擇合適的材料。 Select the right material according to the operating temperature, environmental media, endurance lift and so on. 4 根據(jù)使用條件的載荷特性決定材料的許用應(yīng)力。 Decide the maximum allowable stress according to the loads.,五、彈簧設(shè)計(jì)公式和示例 Formula and examples,1 拉伸彈簧和壓縮彈簧設(shè)計(jì)的

23、公式 Design formulas of compression and extension springs (1) 彈簧剛度Spring rate k：,k也可以用下列公式計(jì)算： k also be calculate as following formula: k=P/F 注：當(dāng)選擇P,F計(jì)算時(shí)，需要大于彈簧變形量的20%，小于彈簧變形量的80%。如右圖中P1-P2及F1-F2之間。,Note: When choose the P and F to calculate rate, the values should between 20 percent and 80 percent of

24、 spring deflection.,（2）設(shè)計(jì)扭應(yīng)力Design torsional stress S： (3) 曲度修正系數(shù) The Wahl correction factor K:,Sk =KS,( C=D/d ),P值必需選用彈簧的最大 載荷在最大變形量下或者 固體長(zhǎng)度時(shí)。P=k*(L-H) The P must be the maximum load at maximum deflection or solid height.,對(duì)于拉伸彈簧，設(shè)計(jì)時(shí)需要注意端部的設(shè)計(jì)。 We should pay attention to the designing of extension sp

25、ring ends, the hooks need to stand the bending stress.,五、彈簧設(shè)計(jì)公式和示例 Formula and examples,上公式中的各參數(shù)的含義 The meaning of each parameter： k 彈簧剛度（Spring rate) (常數(shù) content） P- 軸向載荷（Loads) （N) F-變形量（Deflection) (mm) D-中徑（Mean coil diameter) (mm) d-材料線徑 (Wire diameter) (mm) G-切邊模量 (Shear modulus) (MPa) na-有效圈數(shù)

26、 ( Number of active coils) S- 扭轉(zhuǎn)應(yīng)力 (Torsional stress) (MPa) (未修正的應(yīng)力uncorrected stress) Sk-修正扭應(yīng)力 (Corrected stress) (MPa) C-彈簧纏繞比 (Spring index) N-總?cè)?shù) (Number of total coils) L-彈簧長(zhǎng)度 (Spring length) (mm) H-彈簧固體長(zhǎng)度 (Solid height of spring) (mm) P-節(jié)距 (Pitch) (mm),五、彈簧設(shè)計(jì)公式和示例 Formula and examples,下表中公式可以計(jì)

27、算na,N,H,P,L ： The table below gives formulas for calculating na,N,H,P and L.,五、彈簧設(shè)計(jì)公式和示例 Formula and examples,例 Example： 設(shè)計(jì)一壓彈簧，外徑為23.5mm,自由長(zhǎng)度為43.5mm, 在長(zhǎng)度為32.46mm時(shí)的 載荷量為222.422.2N,斷部并緊并磨平，最大的固體長(zhǎng)度為26.92mm,材料為 油淬火鋼絲。,P=222.4N,五、彈簧設(shè)計(jì)公式和示例 Formula and examples,計(jì)算：彈簧剛度：k=P/F=222.4/(43.5-32.46)=20.14N/mm

28、彈簧在固體長(zhǎng)度時(shí)的載荷量：P=F*k=20.14（43.5-26.92）=334N 彈簧的最大設(shè)計(jì)應(yīng)力值為0.451386MPa=621MPa 假設(shè)彈簧的線徑為2.54mm (小于外徑23.5mm），則有彈簧的中徑為 23.5-2.54=20.96mm 根據(jù)公式 ：,五、彈簧設(shè)計(jì)公式和示例 Formula and examples,可算出：d=3.07mm 建議使用 d=3.18mm的線徑,此時(shí)中徑D=20.32mm 有效圈數(shù)：根據(jù)公式：,na=6，所以總?cè)?shù)N=6+2=8 固體狀態(tài)的長(zhǎng)度為H=3.188=25.4mm 小于給定的26.92mm,可以接受。 根據(jù)公式 計(jì)算扭應(yīng)力值：S=540MPa C=20.32/3.18=6.4 曲度修正系數(shù)：K=1.23 Sk=1.23540=664MPa 而材料的最大許可應(yīng)力為0.451517=683MPa 大于Sk, 所以設(shè)計(jì)在材料的應(yīng)力范圍之內(nèi)。,五、彈簧設(shè)計(jì)公式和示例 Formula and examples,2 扭簧設(shè)計(jì)的公式 Design formulas of torsion springs (1) 扭力矩 Moment or torque M：,(2) 彎曲應(yīng)力 Bendin