SUVBOSCH制动系统设计计算书

,,,SUV-BOSCH制动系统设计计算书,,,,,,,,,,,

,,,,,,,,,,,,,,,

1.结构简述:,,,,,,,,,,,,静力半径,滚动半径,

"SUV-4x4制动系统前采用盘式制动器，后采用浮动盘式制动器结构,前制动器为浮动单缸，后制动器为",,,,,,,,,,,265/70R16,348,378,pk

"浮动盘式结构,并具有串联式双管路制动总泵的液压制动驱动系统（系统配ABS+EBD，后期选装ESP）。",,,,,,,,,,,255/70R15,330,359,

2.整车参数:,,,轴距L=,2805,,,,,空载,满载,P265/70R16,348,378,suv

,参数,,,空载,满载,,Ψ=a/L=,,0.435294118,0.513492063,P265/65R17,350,377,

,质心距前轴a(mm),,,1221,1440.345238,,X=Hg/L=,,0.30745098,0.32855615,,,,

,质心高hg(mm),,,862.4,921.6,,Z=a/g=(0.1、0.2、0.3……),,,,,,,

,总质量Ga(kg),,,1950,2520,,oa=1-Ψ=,,0.564705882,0.486507937,,,,

,前轴负荷G1(kg),,,1101.176471,1226,,oc=Ψ=,,0.435294118,0.513492063,,,,

,前轴质量分配%,,,0.56,0.49,1.0b=,Fμ1b=1-Ψ+X=,,0.872156863,0.815064086,,,,

,后轴负荷G2(kg),,,848.8235294,1294,1.0d=,Fμ1d=Ψ-X=,,0.127843137,0.184935914,,,,

,后轴质量分配%,,,0.44,0.51,,f=(1-Ψ)/X=,,1.836734694,1.480745184,"(0,f)",,,

3.汽车动轴荷分配计算:,,,,,,,r=Ψ/X=,,1.415816327,1.562874607,"(r,0)",,,

3.1动轴荷计算:,,,,,,,,,,《BOSCH曲线图》,,,,

"当汽车以减速度jt制动时,由于减速度而产生的惯性力,使轴荷分配相应改变:",,,,,,,,,,,,,,

式中:G1＇制动时前轴负荷G2＇制动时后轴负荷jt/g=φ道路附着系数,,,,,,,,,,,,,,

其中减速度jt为了计算方便，通常取以重力加速度的若干倍。表一是根据不同的jt/g值计算出,,,,,,,,,,,,,,

汽车空载和满载时动轴荷分配值：,,,,,,,,,,,,,,

表一,,,,,,,,,,,,,,

jt/g=φ,,0.11,0.15,0.23,0.418454442,0.4,0.55,0.65,0.8,0.63,1,,,

G1',空载,1167.124706,1191.105882,1239.068235,1352.052216,1340.988235,1430.917647,1490.870588,1580.8,1478.627821,1700.705882,,,

(kg),满载,1317.075765,1350.194225,1416.431144,1572.464167,1557.184599,1681.378824,1764.174973,1888.369198,1747.267479,2053.961497,,,

G2',空载,782.8752941,758.8941176,710.9317647,597.9477837,609.0117647,519.0823529,459.1294118,369.2,471.3721789,249.2941176,,,

(kg),满载,1202.924235,1169.805775,1103.568856,947.5358334,962.8154011,838.6211765,755.8250267,631.6308021,772.7325205,466.0385027,,,

3.2动载荷分配比：,,,,,,,,,,,,,,

对汽车在不同的减速度jt/g值时前后轴动载荷分配比按下式计算：,,,,,,,,,,,,,,

前轴动轴荷：G1＇/Ga×100%,,,,,,,,,,,,,,

后轴动轴荷：G2＇/Ga×100%,,,,,,,,,,,,,,

表二为汽车制动时前后在不同减速度jt/g值时动轴荷分配比：,,,,,,,,,,,,,,

,表二(见下页）：,,,,,,,,,,,,,

jt/g=φ,,0.11,0.15,0.23,0.418454442,0.4,0.55,0.65,0.8,0.629579372,1,,,

G1',空载,59.9,61.1,63.5,69.3,68.8,73.4,76.5,81.1,75.8,87.2,,,

,满载,52.3,53.6,56.2,62.4,61.8,66.7,70.0,74.9,69.3,81.5,,,

G2',空载,40.1,38.9,36.5,30.7,31.2,26.6,23.5,18.9,24.2,12.8,,,

,满载,47.7,46.4,43.8,37.6,38.2,33.3,30.0,25.1,30.7,18.5,,,

4.汽车制动力的计算:,,,,,,,,,,,,,,

4.1.汽车制动时所需的制动力Pτ(轴制动力),,,,,,,,,,,,,,

"当汽车以减速度jt/g制动时,前后各自所需的制动力为:",,,,,,,,,,,,,,

前轴:Pτ1=G1＇×jt/g×9.8(N),,,,,,,,,,,,,,

后轴:Pτ2=G2＇×jt/g×9.8(N),,,,,,,,,,,,,,

表三为汽车在不同jt/g值时所需的制动力:,,,,,,,,,,,,,,

jt/g=φ,,0.11,0.15,0.23,0.418454442,0.4,0.55,0.65,0.8,0.629579372,1,,,

Pt1',空载,1258.160433,1750.925647,2792.859802,5544.56811,5256.673882,7712.646118,9496.845647,12393.472,9122.953034,16666.91765,,,

(N),满载,1419.807674,1984.78551,3192.635799,6448.445236,6104.163628,9062.631859,11237.79458,14804.81451,10780.42691,20128.82267,,,

Pt2',空载,843.9395671,1115.574353,1602.440198,2452.096283,2387.326118,2797.853882,2924.654353,2894.528,2908.308763,2443.082353,,,

(N),满载,1296.752326,1719.61449,2487.444201,3885.705672,3774.236372,4520.168141,4814.60542,4951.985489,4767.665258,4567.177326,,,

4.2制动器实际所产生的制动力及制动力分配比:,,,,,,,,,,,,,,

4.2.1.汽车前轴制动器所产生的制动力Pτ1＇:,,,,,,,,,,,,,,

前轴制动扭矩:,,,,,,,,,,,,,,

,,,,,,,,,,,,,,

,,,,,,5.7E-04,P0(Nm),,,,,,,

,,,,,,,,,,,,,,

,,,,,,,,,,,,,,

,,,,1.5E-03,P0(Nm),0.007573312,,,,,,,,

式中:MT1:单个前轮能发出的制动扭矩,,,,,,,,,,,,,,

BEF1:前制动器效率因数,,,,,0.76,,,,,,,,,

d1:前制动器分泵直径(φ)m,,,,,0.0635,,,,,,,,,

Rk1:前轮滚动半径(m),,,,,0.378,,265/70R16轮胎,,,,,,,

Rr1:前制动器有效半径(m),,,,,0.119,,,,,,,,,

4.2.2.汽车后轴制动器所能产生的制动力Pτ2＇:,,,,,,,,,,,,,,

后轴制动扭矩:,,,,,,,,,,,,,,

,,,,,,2.5E-04,P0(Nm),,,,,,,

,,,,6.7E-04,P0(Nm),,,,,,,,,

式中:MT2:单个后轮能发出的制动扭矩,,,,,,,,,,,,,,

BEF2:后制动器效率因数,,,,,0.76,,,,,,,,,

d2:后制动器分泵直径m,,,,,0.04200,,,,,,,,,

Rk2:后轮滚动半径m,,,,,0.378,,,,,,,,,

Rr2:后制动器有效半径(m),,,,,0.1203,,,,,,,,,

4.2.3.前后制动器实际制动力分配比：,,,,,,,,,,,,,,

,,,,0.69,,k=(1-β)/β=,,0.44225199,,,,,,

,,,,,,,,2.261154323,,,,,,

4.3同步附着系数：,,,,,,,,,,,,,,

,,,,满载,空载,,,,,,,,,

,,,,0.63,0.418454442,,,,,,,,,

4.4满载时前后轴附着力矩：（道路附着系数Φ=0.48时的附着力矩）,,,,,,,,,,,,,,

前轴附着力矩:,,,,,,,,,,,,,,

,,,,,4075,(N.m),,,,,,,,

后轴附着力矩:,,,,,,,,,,,,,,

,,,,,1802,(N.m),,,,,,,,

4.5最大管路压力:,,,,,,,,,,,,,,

"产生最大管路压力矩时(Φ=0.8)的管路压力为最大管路压力,故当Φ=0.8时,",,,,,,,,,,后轮先抱死,,,,

此时前轮制动所需的油压小于后轮制动所需油压:,,,,,,,,,,,,,,

即:,,,,,,满载时,,,,,,,,

,,,,,,5.7E-04,P0=,5596,（N.m）,,,,,

,,0.000572542,P0=,4075,,,P0=,9.77E+06,(Pa),管路压力偏大,,,,

,,P0=,7117379.165,(Pa),,,,9774332.614,,,,,,

4.6制动踏板力计算:,,,,,,,,,,,,,,

式中:Pp:制动踏板力,,,,,,,,,,,,,,

Sm:制动总泵活塞面积,,,,,总泵直径为:d=,,0.0254,m,,,,,,

,Sm=π/4×d2=,,0.000506451,m2,,,,,,,,,,

P0:制动管路压力,,,,,,,,,,,,,,

I:踏板杠杆比,,,,I=,4,,,,,,,,,

故:,Pp=,0.000126613,P0(N),,,,,,,,,,,

汽车满载时制动管路油压P0为(Φ=0.88):,,,,,,,,,,,,,,

,Pτ2=G2＇×jt/g×9.8,,,,,,,,,,,,,

,,0.000669862,P0=,4767.665258,,,,,,,,,,

,,Pp=,901.2,(N),,,,,,,,,,

"因BJ1049制动系统采用真空助力机构,所以实际踏板力取决于真空助力器的助力因数K,所以",,,,,,,,,,,,,,

"实际踏板力为PF=PP/K(见表四）,现该车型真空助力器的K=",,,,,,,,7.3,7.3,,,,,

另助力器的最大输出拐点为。,,,,,4800,N,,,,,,,,

此时助力器推杆的输入力为,,,,,770,N,,,,,,,,

,,,,,,,,,,,,,,,

,,,,,,,,,,,,,,,

,,,,,,,,,,,,,,,

表四:,,φ,0.418454442,0.4,0.55,0.65,0.8,0.63,1,,,,,

,,P0(Mpa),5.80,5.63,5.98,7.42,9.77,7.12,13.29,,,,,

,,PP(N),734.4,713.4,757.5574619,939.3822094,1237.554154,901.2,1682.6,,,,,

,,PF(N),73.8,69.9,103.8,128.7,230.1,123.4,675.1,,,,,

从表中得出：踏板力符合GB7258-1997《机动车运行安全技术条件》的规定和要求（≤500N）。,,,,,,,,,,,,,,

4.7制动距离计算:,,,,,,,,,,,,,,

"当汽车以均匀减速度jt制动时,其理论制动距离为:",,,,,,,1000,,,,,,,

,,,,,,,156,,,,,,,

,式中:Va:汽车制动时的初速度(Km/h),,,,,,,,,,,,,

,jt:制动减速度jt=g·Φ,,,,,,,,,,,,,

,"实际上,在汽车制动时,由踏下踏板到开始产生制动力尚有一段作用时间,取此值为0.2秒,所以实",,,,,,,,,,,,,

际制动距离St必须考虑这一作用时间。,,,,,,,,,,,,,,

,即：,,,,,,,,,,,,,

,,,,,,,按照φ=0.8时的整车制动强度计算（后轮先抱死）,,,,,,,

,,,,,,P0max=,,,（Pa）,,,,,

,所以：,,,,,整车制动力=,,,（N）（前轮实际产生的制动力+后轮所需,,,,,

,,,,,,整车制动强度=,,,,制动力是整车的制动力）,,,,

,,,,,,则jt/g=φ=,,0.72,,,,,,

,计算时取制动初速度,,,80,Km/h,,,0.72,,,,,,

,则：,,,,,,,,,,,,,

,,,39.37,m≥,22m,,不能满足要求,,,,,,,

,所以，制动距离符合GB7258-1997《机动车运行安全技术条件》的规定和要求。,,,,,,,,,,,,,

4.8总泵容量及踏板行程的计算：,,,,,,,,,,,,,,

4.8.1前后轴管路所需的排量：,,,,,,,,,,,,,,

4.8.1.1前制动回路所需的排量：,,,,,,,,,,,,,,

其中：,,——前制动分泵截面积,,,,,,,,,,,,

,,——活塞行程,,,1.2,,,,,,,,,

,,——前制动管路膨胀量,,,,,,,,,,,,

,,——前制动软管的长度L=,,,0.395,m,,,,,,,,

,,——前制动软管的数量n=,,,2,,,,,,,,,

则：,,,1090.2,mm3,,,,,,,,,,

,,,8687,mm3,,,,,,,,,,

4.8.1.2后制动回路所需的排量：,,,,,,,,,,,,,,

其中：,,——后制动分泵截面积,,,,,,,,,,,,

,,——活塞行程,,,1.2,,,,,,,,,

,,——后制动管路膨胀量,,,,,,,,,,,,

,,——后制动软管的长度L=,,,0.477,m,,,,,,,,

,,——后制动软管的数量n=,,,2,,,,,,,,,

则：,,,1316.52,mm3,,,,,,,,,,

,,,4640,mm3,,,,,,,,,,

4.8.1.3实际总泵排量：,,,,,,,,,,,,,,

,总泵的行程为：前腔L前=,,,,0.025,m,,102,,,,,,

,,,后腔L后=,,0.017,m,,,,,,,,

,前腔：,,,,,,,失效,,,,,,

,,,,12661.265,mm3≥,8687,mm3,144.6463856,前,,,,,

,后腔：,,,,,,,,,,,,,

,,,,8609.6602,mm3≥,4640,mm3,144.610514,后,,,,,

4.8.1.4排量的匹配结果：,,,,,,,,,,,,,,

总泵的排量足够。,,,,,,,,,,,,,,

4.8.2踏板行程Lp的计算:,,,,,,,,,,,,,,

踏板杠杆比:I=,,,,4,,,,,,,,,,

总泵最大空行程:2mm,,,,,,,,,,,,,,

,,,,,113.26,mm≤,150mm,,,,,,,

制动踏板行程符合标准规定和要求。,,,,,,,,,,,,,,

5.制动器容量的计算,,,,,,,,,,,,,,

用磨擦片的比能量耗散率[每单位衬片（衬块）磨擦面积的每单位时间耗散的能量]、比磨擦力,,,,,,,,,,,,,,

[每单位衬片（衬块）磨擦面积的制动器的磨擦力]来衡量制动器的热容量和磨损容量。计算结果见,,,,,,,,,,,,,,

表五：,,,,,,,,,,,,,,

,,,,计算值,,推荐值（最大）,,,,,,,,

,,e1（w/mm2）,,6.69,,6.0,,前制动片容量不够,,,,,,

,,e2（w/mm2）,,5.02,,6.0,,,,,,,,

,,f1（N/mm2）,,0.34,,0.48,,,,,,,,

,,f2（N/mm2）,,0.15,,0.48,,,,,,,,

其中:,,,,,,,,,,,,,,

式中：,,,,,,,,,,,,,,

Vmax——制