• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    Influence Predicrions of Conracr Effecrs on Mesh Sriffness of Face Gear Drives wirh Spur Gear

    2015-02-09 06:08:58LiZhengminqing李政民卿WangJing王晶ZhuRupeng朱如鵬
    關(guān)鍵詞:王晶

    Li Zhengminqing(李政民卿)*,Wang Jing(王晶),Zhu Rupeng(朱如鵬)

    College of Mechanical and Electrical Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,P.R.China

    (Received 18 November 2014;revised 2 January 2015;accepted 12 January 2015)

    Influence Predicrions of Conracr Effecrs on Mesh Sriffness of Face Gear Drives wirh Spur Gear

    Li Zhengminqing(李政民卿)*,Wang Jing(王晶),Zhu Rupeng(朱如鵬)

    College of Mechanical and Electrical Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,P.R.China

    (Received 18 November 2014;revised 2 January 2015;accepted 12 January 2015)

    Absrracr:Mesh stiffness is one of important base parameters of face gear dynamic studies.However,a calculation solution of mesh stiffness of face gear drives is not to be constructed due to complex geometric flakes of face gear teeth.Thus,a calculation solution of mesh stiffness of face gear drives with a spur gear,which is based on the proposed equivalent face gear teeth and Ishikawa model,is constructed,and the influence of contact effects on mesh stiffness of face gear drives is investigated.The results indicate the mesh stiffness of face gear drives is sensitive to contact effects under heavy loaded operating conditions,specially.These contributions will benefit to improve dynamic studies of face gear drives.

    face gear drive;mesh stiffness;contact effect;equivalent tooth;Ishikawa model

    0 Inrroducrion

    A face gear drive can be defined as a kind of intersection gear drives with a spur gear.One of the most important applications of face gear drives can be considered as first stage gear drives of helicopter main gear boxes,which is indicated by Litvin et al.[1-2]Typically,the rotation speed of first stage gear drives of helicopter main gear boxes is very fast due to the output speed of turbo shaft engines.Thus,face gear dynamic studies are focused by scholars.Jin et al.proposed a nonlinear dynamic model of face gear drives[3].Wang et al.investigated dynamic responses of face gear drives[4].Yang et al.studied vibration characterestics of face gear drives[5-6].Wang et al.discussed dynamic responses of face gear drives in a split transmission system[7].Zhang et al.examined natural frequencies of torsional vibrations in a torque-split face gear transmission system[8].Li et al.not only studied the influence of setting errors on contact points,but also assessed coupled vibrations of non-orthogonal face gear drives[9-10]. According to the limited published issues,some achievements of face gear dynamic studies are obtained.However,a calculation solution of mesh stiffness of face gear drives is not to be constructed due to complex geometric flakes of face gear teeth.Thus,in this paper,a calculation solution of mesh stiffness of face gear drives with a spur gear,which is based on the proposed equivalent face gear teeth and Ishikawa model,is constructed.Furthermore,the impact of contact effects on mesh stiffness of face gear drives is discussed. These contributions will be helpful to improve face gear dynamic studies in the future.

    1 Numerical Model

    A face gear tooth can be assumed as a sequence in which modification involute gears are superimposed along its face width,as shown in Fig.1.

    In Fig.1,according to modification gear theories and engagements of face gear drives,modi-fication factors versus the extreme tooth radii,namely xi-limand xo-lim,and extreme inner and outer radii of face gear teeth,mean to ri-limand ro-lim,can be derived in a piecewise form as whereγis the shaft angle,αthe pressure angle,αt'the addendum pressure angle,zgthe tooth number of generation gears,zfthe tooth number of face gears,h*athe addendum coefficient,and c*the clearance coefficient.rfand rbare dedendum and base radii of generation gears,respectively;And a drive ratio for generations igfcan be expressed as

    Fig.1 Sketch of face gear tooth changes

    Moreover,a non-modified reference radius of face gears rfpmust be existed due to the range from positive modifications to negative modifications,and rfpcan be written in

    where m is the modulus of face gear drives.

    Due to avoiding offset loads in face gear drives,the tooth number of a pinion,which meshes with face gears,is always less one to three teeth than generation gears,which are used to generate face gears.Therefore,contact points of face gear drives must deviate from reference circles of face gears,and its modification factor can be given as

    where zpis the tooth number of pinions.Meanwhile,the distance between reference circles and contact positions along face gear face widths can be derived by

    Therefore,a contact radius on face gears can be deduces as

    In addition,according to Hertz contact theories,long and short radii of contact ellipses of face gear drives can be expressed as[11]

    whereρxis the long radius,ρythe short radius,and Fmthe load.ρpp,ρpf,ρfpandρffare the normal curvatures.u and v are the elliptic integral factors andθp/fcan be described as

    where E is the modulus of elasticity,andγthe Poisson ratio.Subscript p and f refer to the pinions and the face gears.

    Thus,mesh stiffness of face gear drives considered contact effects can be assumed as a superposition of a series of mesh stiffness of modification spur gear drives,which can be calculated on Ishikawa model[12-13],along face gear face widths,and the range of modification factors can be derived by

    2 Simularions and Analysis

    Geometric parameters of an example case of face gear drives are listed in Table 1,which are employed to investigate the impact of contact effects on mesh stiffness.A face gear tooth and its contact points,which are based on the proposed tooth modeling and the geometric parameters listed in Table 1,are simulated,as shown in Figs.2,3,respectively.

    Table 1 Geomerric paramerers

    Fig.2 Face gear tooth simulation of the example case

    Furthermore,in order to discuss the influence of contact effects on mesh stiffness,several operating conditions for this example case are listed in Table 2.

    Table 2 Operaring condirions

    Based on Eqs.(7,9),the maximum long radii of contact ellipses under three working conditions are calculated,as listed in Table 3.

    Fig.3 Simulation of contact points on face gear teeth of the example case

    Table 3 Maximum long radii

    Using Ishikawa model[12-13]associated with the proposed face gear tooth modeling,and without considering contact effects,the results of time-varying mesh stiffness and average mesh stiffness of this example case are simulated,as given in Fig.4.

    Employing Ishikawa model[12-13]associated with the proposed mesh stiffness solution of face gear drives,in which contact effects are considered,the results of time-varying mesh stiffness under three working conditions,which are conducted by fast Fourier transform(FFT),are simulated in Fig.5,and the results of average mesh stiffness under three operating conditions are calculated in Table 4.

    Fig.4 Mesh stiffness without contact effects

    Fig.5 Comparison of time-varying mesh stiffness under different working conditions

    Table 4 Average mesh sriffness wirh conracr effecrs

    In the case of Figs.4,5,a part of timevarying mesh stiffness at the engagement area of multiple tooth pairs will be decreased with increasing long radii of contact ellipses,but the other part of time-varying mesh stiffness will not be adjusted almost.The difference of average mesh stiffness between without and with contact effects can be defined as

    whereηis the difference,kcthe average mesh stiffness with contact effects,and k the average mesh stiffness without contact effects.

    Based on Eq.(10),the differences of average mesh stiffness between without and with contact effects,under three operating conditions,are calculated in Table 5.

    Table 5 Differences of average mesh sriffness

    The results as listed in Table 5,indicate mesh stiffness of face gear drives is sensitive to contact effects.

    3 Conclusions

    In the paper,two important works are extracted as follows:

    (1)A calculation solution of mesh stiffness of face gear drives associated with contact effects,which is based on the proposed equivalent face gear teeth and Ishikawa model,is constructed.

    (2)The impact of contact effects on mesh stiffness is investigated.The results indicate time-varying mesh stiffness of face gear drives will be changed with operating condition adjustments,and the difference of average mesh stiffness between without and with contact effectsmay be greater than 10%.Thus,contact effects should be considered for face gear mesh stiffness,specially under heavy loaded operating conditions.

    Acknowledgemenrs

    This work was supported by the National Natural Science Foundations of China(Nos.51105194,51375226)and the Fundamental Research Funds for the Central Universities(No.NS2015049).

    [1] Litvin F,Bossler R,Chen Y J,et al.Application of face-gear drives in helicopter transmissions[J]. Journal of Mechanical Design,1994,116(3):672-676.

    [2] Litvin F,Egelja A,Tan J,et al.Handbook on face gear drives with a spur involute pinion[M].Chicago:DTIC,2000:54-101.

    [3] Jin Guanghu,Zhu Rupeng,Bao Heyun.Nonlinear dynamical characteristics of face gear transmission system[J].Journal of Central South University,2010,41:1807-1813.(in Chinese)

    [4] Wang Z,Chen Q,Lin J C,et al.Study of the dynamic behavior of face gear transmission system[J]. Applied Mechanics and Materials,2013,268/269/ 270:1063-1066.

    [5] Yang Zhen,Wang Sanmin,F(xiàn)an Yesen,et al.Bifurcation charactristics of face-gear transmission system[J].Journal of Harbin Institute of Technology,2011,43(3):107-110.(in Chinese)

    [6] Yang Zhen,Wang Sanmin,F(xiàn)an Yesen,et al.Vibration characteristics of face gear transmission system with parametric excitation[J].Journal of Chongqing University,2011,34(1):26-35.(in Chinese)

    [7] Wang R,Zhao N,Tao L,et al.Floating shaft load sharing method for face gear split torque transmission system[J].Research Journal of Applied Sciences,Engineering and Technology,2013,5(12):3386-3392.

    [8] Zhang Le,Zhu Rupeng,Li Zhengminqing.Research on natural frequency of torsional vibration of torquesplit face gear transmission system[J].Jiangsu Machine Building&Automation,2012,41(5):21-24.(in Chinese)

    [9] Li X Z,Zhu R P,Li Z M Q,et al.Influence of setting error of tool on tooth profile and contact point of face gear drive[J].Transactions of Nanjing University of Aeronautics and Astronautics,2014,31(4):370-376.

    [10]Li Xiaozhen,Zhu Rupeng,Li Zhengminqing,et al. Analysis of coupled vibration of face gear drive with non-orthogonal intersection[J].Journal of Central South University,2013,44(6):2274-2279.(in Chinese)

    [11]Song Lemin.Tooth flank and strength of gear drive[M].Beijing:National Defence Industry Press,1987:164-174.(in Chinese)

    [12]Shi J L,Ma X G,Xu C L,et al.Meshing stiffness analysis of gear using the Ishikawa method[J].Applied Mechanics and Materials,2013,401:203-206.

    [13]Zhu Xiaolu,E Zhongkai.Analysis of load capacity of gears[M].Beijing:Higher Education Press,1992:25-42.(in Chinese)

    (Executive Editor:Xu Chengting)

    TH113Documenr code:AArricle ID:1005-1120(2015)05-0566-05

    *Corresponding aurhor:Li Zhengminqing,Associate Professor,E-mail:lzmq-cmee@nuaa.edu.cn.

    How ro cire rhis arricle:Li Zhengminqing,Wang Jing,Zhu Rupeng.Influence predictions of contact effects on mesh stiffness of face gear drives with spur gear[J].Trans.Nanjing U.Aero.Astro.,2015,32(5):566-570.

    http://dx.doi.org/10.16356/j.1005-1120.2015.05.566

    猜你喜歡
    王晶
    First principles study on geometric and electronic properties of two-dimensional Nb2CTx MXenes
    Pitman–Yor process mixture model for community structure exploration considering latent interaction patterns?
    顧費(fèi)淳、王晶作品
    王晶作品
    大眾文藝(2021年16期)2021-09-11 09:05:06
    婆媳育兒“持久戰(zhàn)”:隔輩親究竟是愛孫還是誤孫?
    票房大賣的秘訣,王晶說是:“別把自己看得太了不起”
    電影(2019年6期)2019-09-02 01:42:28
    國內(nèi)外城市安全防災(zāi)規(guī)劃和管理體系研究綜述
    王晶:人類命運(yùn)治理簡史
    Computational identifi cation and characterization of microRNAs and their targets inPenaeus monodon*
    Cell therapy for spinal cord injury with olfactory ensheathing glia cells(OECs)
    亚洲精品第二区| 久久久久久久国产电影| 日本与韩国留学比较| 99re6热这里在线精品视频| 日日啪夜夜爽| 欧美日韩国产mv在线观看视频| 91在线精品国自产拍蜜月| 亚洲精品久久午夜乱码| 久久99一区二区三区| 亚洲国产欧美日韩在线播放| 日韩三级伦理在线观看| 特大巨黑吊av在线直播| 免费大片18禁| 成人毛片a级毛片在线播放| 夫妻性生交免费视频一级片| 国产女主播在线喷水免费视频网站| 91国产中文字幕| 亚洲精品亚洲一区二区| 欧美老熟妇乱子伦牲交| 热99国产精品久久久久久7| 亚洲av成人精品一二三区| 亚洲无线观看免费| 欧美 日韩 精品 国产| 在现免费观看毛片| 如何舔出高潮| 少妇精品久久久久久久| 成人二区视频| 亚洲精品国产av成人精品| 一区二区av电影网| 国产成人精品无人区| 在线观看免费视频网站a站| 欧美精品亚洲一区二区| 天美传媒精品一区二区| 国产欧美另类精品又又久久亚洲欧美| 久久亚洲国产成人精品v| 国产精品蜜桃在线观看| 在线观看免费高清a一片| 搡女人真爽免费视频火全软件| 人妻夜夜爽99麻豆av| 亚洲,欧美,日韩| 久久精品国产a三级三级三级| 亚洲精品国产av成人精品| 中文精品一卡2卡3卡4更新| 亚洲精品aⅴ在线观看| 精品一区二区三卡| 狂野欧美白嫩少妇大欣赏| 中国国产av一级| 久久久久精品久久久久真实原创| 欧美日本中文国产一区发布| 乱人伦中国视频| 一级黄片播放器| 亚洲精品色激情综合| 男女边摸边吃奶| 日韩人妻高清精品专区| 国产成人精品福利久久| 特大巨黑吊av在线直播| 久久久精品94久久精品| 久久99精品国语久久久| 国产成人freesex在线| 亚洲美女搞黄在线观看| 另类精品久久| 蜜桃久久精品国产亚洲av| 欧美丝袜亚洲另类| 国产高清国产精品国产三级| 日韩伦理黄色片| 天天操日日干夜夜撸| a级片在线免费高清观看视频| 精品99又大又爽又粗少妇毛片| 99久久精品国产国产毛片| 日韩av免费高清视频| 欧美日韩在线观看h| 亚洲第一区二区三区不卡| 欧美一级a爱片免费观看看| 欧美亚洲日本最大视频资源| 91在线精品国自产拍蜜月| 国产男女内射视频| 这个男人来自地球电影免费观看 | 国产精品人妻久久久久久| 久久久久久久大尺度免费视频| 美女内射精品一级片tv| 精品国产一区二区久久| 母亲3免费完整高清在线观看 | 在线亚洲精品国产二区图片欧美 | 国产深夜福利视频在线观看| 国产无遮挡羞羞视频在线观看| 简卡轻食公司| 亚州av有码| 搡女人真爽免费视频火全软件| 大陆偷拍与自拍| 麻豆成人av视频| 国产精品不卡视频一区二区| 夫妻性生交免费视频一级片| 女性生殖器流出的白浆| 中文字幕久久专区| 一边摸一边做爽爽视频免费| 亚洲四区av| 天堂8中文在线网| 欧美精品国产亚洲| 只有这里有精品99| freevideosex欧美| 亚洲精品乱码久久久久久按摩| 国产成人精品福利久久| 久久狼人影院| 在线观看人妻少妇| 99热6这里只有精品| 国产成人a∨麻豆精品| 国产亚洲欧美精品永久| 亚洲国产精品专区欧美| 国产精品一国产av| 下体分泌物呈黄色| 视频中文字幕在线观看| www.色视频.com| 国产精品成人在线| 91午夜精品亚洲一区二区三区| 日本黄大片高清| 亚洲经典国产精华液单| 亚洲在久久综合| 国产精品99久久久久久久久| 狂野欧美白嫩少妇大欣赏| 插阴视频在线观看视频| 美女福利国产在线| 免费观看性生交大片5| 精品一区在线观看国产| 精品午夜福利在线看| 欧美日韩在线观看h| 国产国语露脸激情在线看| 五月伊人婷婷丁香| 精品国产露脸久久av麻豆| 婷婷成人精品国产| a级毛色黄片| 秋霞在线观看毛片| 国产精品熟女久久久久浪| videossex国产| 久久青草综合色| 观看美女的网站| av在线播放精品| 免费观看性生交大片5| 九色成人免费人妻av| 极品人妻少妇av视频| 免费播放大片免费观看视频在线观看| 老司机影院毛片| 成人午夜精彩视频在线观看| 国产深夜福利视频在线观看| 特大巨黑吊av在线直播| 飞空精品影院首页| 精品人妻熟女av久视频| 亚洲高清免费不卡视频| 午夜激情久久久久久久| 免费播放大片免费观看视频在线观看| 91aial.com中文字幕在线观看| 22中文网久久字幕| 国产成人一区二区在线| 18+在线观看网站| 一个人免费看片子| 亚洲不卡免费看| 亚洲国产成人一精品久久久| 91精品国产九色| 自线自在国产av| a级毛片黄视频| 欧美少妇被猛烈插入视频| 亚洲内射少妇av| 亚洲国产精品一区三区| xxxhd国产人妻xxx| 狂野欧美激情性xxxx在线观看| 中文字幕最新亚洲高清| 成人手机av| 日韩一本色道免费dvd| 日产精品乱码卡一卡2卡三| 看非洲黑人一级黄片| 最后的刺客免费高清国语| 嫩草影院入口| 亚州av有码| 日日撸夜夜添| 大又大粗又爽又黄少妇毛片口| 国产爽快片一区二区三区| 中文字幕精品免费在线观看视频 | 亚洲国产av新网站| 日产精品乱码卡一卡2卡三| 久久久亚洲精品成人影院| 你懂的网址亚洲精品在线观看| 精品少妇黑人巨大在线播放| 国产午夜精品一二区理论片| 久久久国产欧美日韩av| 日本91视频免费播放| 国产亚洲av片在线观看秒播厂| 国产高清三级在线| 日本免费在线观看一区| 边亲边吃奶的免费视频| 老司机影院毛片| 99精国产麻豆久久婷婷| 欧美人与善性xxx| 五月开心婷婷网| 国产毛片在线视频| 亚洲久久久国产精品| 国产精品不卡视频一区二区| 亚洲人成网站在线播| 亚洲国产av新网站| 最新的欧美精品一区二区| 久久精品国产亚洲av涩爱| 99国产精品免费福利视频| 夫妻性生交免费视频一级片| 蜜臀久久99精品久久宅男| 欧美亚洲 丝袜 人妻 在线| 精品熟女少妇av免费看| 国产男女超爽视频在线观看| 国产成人精品在线电影| 久久精品熟女亚洲av麻豆精品| 国产日韩欧美视频二区| 曰老女人黄片| av一本久久久久| 97在线视频观看| 国产男人的电影天堂91| 爱豆传媒免费全集在线观看| 亚洲av男天堂| 国产精品国产三级专区第一集| 一级,二级,三级黄色视频| 丝瓜视频免费看黄片| 晚上一个人看的免费电影| 日韩免费高清中文字幕av| 嫩草影院入口| 免费av中文字幕在线| 亚洲国产欧美在线一区| 美女xxoo啪啪120秒动态图| 国产日韩一区二区三区精品不卡 | 久久精品国产a三级三级三级| 色婷婷久久久亚洲欧美| 人妻人人澡人人爽人人| 色婷婷久久久亚洲欧美| 一级黄片播放器| 国产精品一区www在线观看| 亚洲精品成人av观看孕妇| 亚洲av综合色区一区| 久久久久久久大尺度免费视频| 另类精品久久| xxxhd国产人妻xxx| 日韩欧美精品免费久久| 国产高清有码在线观看视频| 人人妻人人添人人爽欧美一区卜| 各种免费的搞黄视频| 全区人妻精品视频| 日本免费在线观看一区| 国产精品 国内视频| 肉色欧美久久久久久久蜜桃| 欧美日韩一区二区视频在线观看视频在线| 欧美+日韩+精品| 寂寞人妻少妇视频99o| 看十八女毛片水多多多| 亚洲av二区三区四区| 久久国产精品大桥未久av| 欧美日韩综合久久久久久| 蜜臀久久99精品久久宅男| av在线观看视频网站免费| 亚洲天堂av无毛| 精品久久久久久久久亚洲| 少妇被粗大猛烈的视频| 中文字幕亚洲精品专区| 99久国产av精品国产电影| 女人精品久久久久毛片| 国产男女内射视频| 国产精品欧美亚洲77777| av电影中文网址| 高清毛片免费看| 免费少妇av软件| 久久鲁丝午夜福利片| 国产欧美亚洲国产| 精品熟女少妇av免费看| 天堂中文最新版在线下载| 亚洲国产日韩一区二区| 制服丝袜香蕉在线| 午夜av观看不卡| 精品久久蜜臀av无| 日本av手机在线免费观看| √禁漫天堂资源中文www| 亚洲色图综合在线观看| 日本-黄色视频高清免费观看| 国产成人av激情在线播放 | 免费观看a级毛片全部| 91久久精品国产一区二区三区| 婷婷成人精品国产| 亚洲人成77777在线视频| 我的女老师完整版在线观看| av在线播放精品| 丝袜脚勾引网站| 丝袜美足系列| 欧美3d第一页| 曰老女人黄片| 丰满饥渴人妻一区二区三| 99久久人妻综合| 精品视频人人做人人爽| 一级毛片黄色毛片免费观看视频| 伦理电影免费视频| 国产一区有黄有色的免费视频| 国产极品天堂在线| 国产成人a∨麻豆精品| 国产一级毛片在线| 亚洲国产精品一区三区| 国产精品久久久久成人av| 麻豆精品久久久久久蜜桃| 中文字幕免费在线视频6| 欧美变态另类bdsm刘玥| 亚洲国产日韩一区二区| 亚洲激情五月婷婷啪啪| 激情五月婷婷亚洲| 女性生殖器流出的白浆| 亚洲图色成人| 91精品国产九色| 午夜精品国产一区二区电影| 99久久精品一区二区三区| videosex国产| av免费观看日本| 91在线精品国自产拍蜜月| 九色亚洲精品在线播放| 热99久久久久精品小说推荐| 欧美最新免费一区二区三区| 街头女战士在线观看网站| 欧美日韩精品成人综合77777| 免费av中文字幕在线| 成人无遮挡网站| 韩国av在线不卡| av在线老鸭窝| 国产成人精品在线电影| 日韩一本色道免费dvd| 国产欧美日韩综合在线一区二区| 日本猛色少妇xxxxx猛交久久| av卡一久久| 大片电影免费在线观看免费| 日韩制服骚丝袜av| 中文字幕最新亚洲高清| 一级黄片播放器| 国产午夜精品一二区理论片| 久久久久国产网址| a级毛片在线看网站| 午夜久久久在线观看| 少妇猛男粗大的猛烈进出视频| 中文字幕亚洲精品专区| 免费人成在线观看视频色| 永久免费av网站大全| 在线观看免费日韩欧美大片 | 日本wwww免费看| 久久 成人 亚洲| 国产免费视频播放在线视频| 男男h啪啪无遮挡| 日韩免费高清中文字幕av| 成人二区视频| 午夜免费男女啪啪视频观看| 成年美女黄网站色视频大全免费 | 国产在线免费精品| 全区人妻精品视频| 最近中文字幕2019免费版| 在线精品无人区一区二区三| 国产免费福利视频在线观看| 国产精品免费大片| 日韩免费高清中文字幕av| 国产高清三级在线| 精品熟女少妇av免费看| 一本色道久久久久久精品综合| 久久97久久精品| 下体分泌物呈黄色| 熟女人妻精品中文字幕| 伦理电影免费视频| 蜜桃国产av成人99| 人人妻人人爽人人添夜夜欢视频| 亚洲经典国产精华液单| 91午夜精品亚洲一区二区三区| 男女边吃奶边做爰视频| 免费观看的影片在线观看| 国产乱来视频区| 久久久久久人妻| 大又大粗又爽又黄少妇毛片口| 国产成人精品久久久久久| 看非洲黑人一级黄片| 自拍欧美九色日韩亚洲蝌蚪91| 中文字幕av电影在线播放| 亚洲人与动物交配视频| 在线观看www视频免费| 日韩一区二区三区影片| 久久国内精品自在自线图片| 亚洲精品456在线播放app| 日韩在线高清观看一区二区三区| 精品国产露脸久久av麻豆| 99热国产这里只有精品6| 久久影院123| 97在线视频观看| 亚洲美女视频黄频| 亚洲av男天堂| 一级,二级,三级黄色视频| 精品一区二区三区视频在线| 久久影院123| 亚洲精品国产色婷婷电影| 十分钟在线观看高清视频www| 有码 亚洲区| 又粗又硬又长又爽又黄的视频| 在线观看美女被高潮喷水网站| 国产精品国产三级国产专区5o| 国产精品人妻久久久久久| 亚洲国产精品一区二区三区在线| 国产伦精品一区二区三区视频9| 国产亚洲最大av| 女性被躁到高潮视频| 自拍欧美九色日韩亚洲蝌蚪91| 国产欧美日韩综合在线一区二区| 一本色道久久久久久精品综合| 男男h啪啪无遮挡| 婷婷成人精品国产| 国产成人一区二区在线| 久久这里有精品视频免费| 欧美xxⅹ黑人| 最近最新中文字幕免费大全7| 一二三四中文在线观看免费高清| 丝袜在线中文字幕| 99久久人妻综合| 免费大片黄手机在线观看| 18在线观看网站| 精品午夜福利在线看| 高清欧美精品videossex| 乱码一卡2卡4卡精品| av有码第一页| 国产永久视频网站| 久久97久久精品| 飞空精品影院首页| 久久久久国产网址| 欧美人与性动交α欧美精品济南到 | 人人妻人人爽人人添夜夜欢视频| 中文天堂在线官网| 又粗又硬又长又爽又黄的视频| 国产精品嫩草影院av在线观看| 天天影视国产精品| 九九在线视频观看精品| 亚洲国产av新网站| 丝袜美足系列| 亚洲图色成人| 精品国产一区二区三区久久久樱花| 在线看a的网站| 亚洲欧美成人综合另类久久久| 国产一区亚洲一区在线观看| 日本av手机在线免费观看| 国产免费一区二区三区四区乱码| 纯流量卡能插随身wifi吗| 久久av网站| freevideosex欧美| 制服人妻中文乱码| 日本黄色片子视频| 久久精品熟女亚洲av麻豆精品| 日本-黄色视频高清免费观看| 日韩不卡一区二区三区视频在线| 一区二区三区四区激情视频| 999精品在线视频| 欧美日本中文国产一区发布| av免费观看日本| 天美传媒精品一区二区| 亚洲av综合色区一区| 欧美+日韩+精品| 99热网站在线观看| 观看美女的网站| 中文字幕免费在线视频6| 中文字幕人妻丝袜制服| 一本—道久久a久久精品蜜桃钙片| 一区二区三区免费毛片| 极品少妇高潮喷水抽搐| 国产av码专区亚洲av| 少妇被粗大猛烈的视频| 热99国产精品久久久久久7| 免费少妇av软件| 国产精品 国内视频| 黑人猛操日本美女一级片| 久久久久国产精品人妻一区二区| 免费少妇av软件| 成人毛片a级毛片在线播放| 天美传媒精品一区二区| 99热这里只有是精品在线观看| 中国美白少妇内射xxxbb| 蜜臀久久99精品久久宅男| 日本猛色少妇xxxxx猛交久久| 午夜老司机福利剧场| 午夜精品国产一区二区电影| 久久亚洲国产成人精品v| 人成视频在线观看免费观看| 中国三级夫妇交换| 亚洲色图综合在线观看| 老司机影院成人| 亚洲精品一二三| 亚洲av欧美aⅴ国产| 亚洲国产欧美在线一区| 老司机影院成人| 国产69精品久久久久777片| 99国产精品免费福利视频| 亚洲av日韩在线播放| 日本猛色少妇xxxxx猛交久久| 亚洲精品第二区| 高清视频免费观看一区二区| 免费观看a级毛片全部| 午夜福利视频精品| 乱码一卡2卡4卡精品| 伊人亚洲综合成人网| 亚洲av电影在线观看一区二区三区| 在线 av 中文字幕| 午夜免费观看性视频| 最新的欧美精品一区二区| 黄色毛片三级朝国网站| 新久久久久国产一级毛片| 男的添女的下面高潮视频| 国产在视频线精品| 伦理电影大哥的女人| av免费在线看不卡| 在线 av 中文字幕| 国产av一区二区精品久久| 18在线观看网站| 人人澡人人妻人| 精品一品国产午夜福利视频| freevideosex欧美| 在线观看免费高清a一片| 老熟女久久久| 一级毛片黄色毛片免费观看视频| 人人妻人人添人人爽欧美一区卜| 丝瓜视频免费看黄片| 亚洲第一区二区三区不卡| 2018国产大陆天天弄谢| 九色亚洲精品在线播放| 亚洲久久久国产精品| 人人妻人人澡人人看| 国产69精品久久久久777片| 成人亚洲精品一区在线观看| 亚州av有码| 水蜜桃什么品种好| 一本一本久久a久久精品综合妖精 国产伦在线观看视频一区 | 欧美3d第一页| 成人免费观看视频高清| 一本—道久久a久久精品蜜桃钙片| 国产精品久久久久成人av| 女人久久www免费人成看片| 久久久久视频综合| 曰老女人黄片| 亚洲欧美成人精品一区二区| 久久99蜜桃精品久久| av卡一久久| 久久婷婷青草| 国产精品无大码| 青春草亚洲视频在线观看| 国产69精品久久久久777片| av网站免费在线观看视频| 国产精品一区二区在线不卡| 国产一级毛片在线| 久久久久久久久久人人人人人人| 亚洲一级一片aⅴ在线观看| 亚洲欧美日韩另类电影网站| 免费看光身美女| 久久影院123| 中文字幕免费在线视频6| 大话2 男鬼变身卡| 色哟哟·www| 欧美一级a爱片免费观看看| 亚洲成人av在线免费| 97在线视频观看| 建设人人有责人人尽责人人享有的| 精品少妇黑人巨大在线播放| 少妇人妻久久综合中文| 蜜桃久久精品国产亚洲av| 欧美精品一区二区大全| 久久97久久精品| 久久精品国产a三级三级三级| 精品人妻偷拍中文字幕| 黑人欧美特级aaaaaa片| 91精品一卡2卡3卡4卡| 亚洲av.av天堂| 麻豆精品久久久久久蜜桃| 久久人妻熟女aⅴ| 免费大片18禁| 亚洲第一av免费看| 久久精品国产自在天天线| a级毛片黄视频| 亚洲性久久影院| 亚洲精品乱久久久久久| 亚洲av综合色区一区| 久久人妻熟女aⅴ| 91在线精品国自产拍蜜月| 欧美一级a爱片免费观看看| 91aial.com中文字幕在线观看| 国产无遮挡羞羞视频在线观看| 母亲3免费完整高清在线观看 | 黑人猛操日本美女一级片| 三上悠亚av全集在线观看| 免费观看a级毛片全部| 精品一区在线观看国产| 99热这里只有精品一区| 最近中文字幕2019免费版| 黑人欧美特级aaaaaa片| 成年女人在线观看亚洲视频| 美女主播在线视频| av电影中文网址| 伊人久久精品亚洲午夜| 国产精品一国产av| 51国产日韩欧美| 成人亚洲欧美一区二区av| 午夜免费鲁丝| 男人添女人高潮全过程视频| 草草在线视频免费看| 三级国产精品片| 你懂的网址亚洲精品在线观看| 观看美女的网站| 久久久精品免费免费高清| 日本vs欧美在线观看视频| 亚洲人与动物交配视频| 制服丝袜香蕉在线| 精品卡一卡二卡四卡免费| 日韩成人伦理影院| 观看美女的网站| 赤兔流量卡办理| 自拍欧美九色日韩亚洲蝌蚪91| 中文字幕亚洲精品专区| 亚洲美女视频黄频| 日韩 亚洲 欧美在线| 国产成人精品无人区| 性色avwww在线观看| 岛国毛片在线播放| 久久韩国三级中文字幕|