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大半径小圆弧测量方法分析

时间:2018年07月03日 信息来源:本站原创 点击: 【字体:

DABANJINGXIAOYUANHU,SHIYIGEYONGHENGDECELIANGWENTI,YONGSHENMEYANGDEFANGFACELIANGZUIZHUNQUECHENGWEILEYEJIEZHENGZHIBUXIADEQIANNIANWUJIEFANGCHENGSHI。JINTIAN,WOMENJIANGWEIRAOYIXIAJIGEWENTIZHANKAIYANJIU,KANKANSHIFOUZHENDEWUJIE。

 

1、什么叫做大半径小圆弧?

1.png

如上图,当弧长小于1/4周长C的时候,我们统称为大半径小圆弧,当弧长远远小于半径时,比如弧长等于1/32周长,要通过测量该小段圆弧确定半径R,这个测量过程会产生巨大的半径偏差。


2、大半径小圆弧的测量不确定性到底有多大?

 

2.png

 

RUSHANGTU,YAOJIANCEYIGEZHIYOU15°DEYUANHU,BANJINGWEIR10,SHIYONGOMMCELIANG5GEDIANGOUZAOYUANHUSHUCHUBANJING,ZHEIGESHIHOUHONGSEDIANHELVSEDIANZHIJIANZHICUOWEILEYIGEDIANWEIZHI,CESHIJIEGUOQUECHANSHENGLEJUDAPIANCHA。

 

大电竞WOMENZAIJUYIGESHIJIANLI。JIASHEXIAOYU1/4YUANZHOU(<90°)DEYUANHUJIAODUWEI66°,LILUNZHIJINGWEI2.10+0.08/-0.03.

 

3.png

DIYIZHONGZHUANGTAI:

假设圆心无偏移。通过理论圆心分别标出上限2.18和下限2.07,这个时候圆弧的半径正偏差是0.04,负偏差是-0.015。也就是说,假设圆心在实际测量中不会发生偏差,那么这个测量公差带可以在0.04+0.015=0.055这个范围内波动,这个偏差理论上设备是完全可以满足的



                                     4.png

DIERZHONGZHUANGTAI:

DANSHIZAISHIJICELIANGHUODONGZHONG,YUANXINYIDINGHUIFASHENGPIANCHA。TONGGUOZUOJIAOPINGFENXIAN,JIASHEYUANHULIANGDUANBUWURENHEPIANCHA,CISHIJINGGUOJIAOPINGJUNXIANSHANGDEBANJINGPIANCHAZUIDA,ZHEIYANG,JINGGUOYUANHULIANGDUANDIANFENBIEZUO2.18HE2.07YUAN,WOMENFAXIAN,JINGGUOJIAOPINGJUNXIANSHANGDEZHENGPIANCHAWEI0.003,FUPIANCHAWEI-0.007。

ZHEISHUOMINGLEJIARUYUANZAI2.10+0.08/-0.03FANWEINEIBIANDONG,BINGQIEYUANHULIANGDUANBUWURENHEBIANDONGDEQINGKUANGXIA,JIAOPINGJUNXIANSHANGYUNXUDEZUIDAPIANCHAZHINENGKONGZHIZAI+0.003/-0.007FANWEINEI,ERZAISHIJICELIANGZHONG,YUANHULIANGDUANDEDIAN、JIAOPINGJUNXIANSHANGDEDIANYIJIYUANHUQITARENHEWEIZHISHANGDEDIANDOUHUICHANSHENGBUTONGCHENGDUDEBIANDONG,WOMENJIASHEZHEIXIEDIANDOUZAI0.005+0.005/-0.005FANWEINEIBIANDONG,SUIRANZHEIGEBIANDONGFEICHANGJIEJINCELIANGSHEBEIDEJIXIANJINGDU,DANSHI,SUOYOUBIANDONGDIANGOUZAOCHENGDEYUANHUYIDINGSHICHANSHENGDAPIANCHADE。

 

6.png

大电竞RUSHANGTU,SUOYOUCESHIDIANDOUZAIμJIYINEIPIANCHA,DANSHIYUANZHIJINGYIJINGCHAOCHA+/-0.05,ZHEICHONGFENSHUOMINGLEDABANJINGXIAOYUANHUDECELIANGSHIBUZHUNQUEDE,BINGFEICELIANGSHEBEIWENTI,ERSHIDABANJINGXIAOYUANHUDETEZHENGXIANZHILEQIBINGBUJUBEIZHUNQUECELIANGDEZIGE。

 

类似大半径小圆弧的测量,最理想的公差设定方式应该是根据零件实际装配需求,转换成带基准的线轮廓度。

BIRUYISHANGANLIZHONG,JIASHESHIJIZHUANGPEIXUQIUSHIYUANHUDEMEIGEDIANYUNXUPIANCHAWEI+0.04/-0.015,NEIMEPAICHUCANKAOJIZHUNDEGONGCHALEIJI,ZHUANHUANWEIXIANLUNKUODUZEWEI0.055U0.04,XIANGDUIYUSHEBEIμJIDEBIANYI,ZHEIYANGDEGONGCHASHIWANQUANKEYIZHUNQUEKONGZHIDE。

 

 

3、为什么现在的设计图纸都要求管控这些圆弧?

 

YINWEIDUIYUYIXINGLINGJIAN,ZAIZUZHUANGGONGCHAPEIHEYAOQIUYUELAIYUEGAODESHICHANGXUQIUXIA,YUANHUYUYUANHUZHIJIANDEPEIHEFEICHANGPINFAN,SHEJITUZHISHIBUKEBIMIANDEXUYAOGUANKONGYUANHUCHICUN,ERXIANZAIDETUZHISHEJIZHESHEJISHUIPINGCANCHABUQI,YOUQISHIDUIGD&TLIJIEQIANQUEDEQIANTIXIA,SHEJIZHEWANGWANGHUIQUXIANGYUZHIGUANBIAOZHUCHICUNDESILU,HULVELELINGJIANZHIJIANSHIJIPEIHEGONGCHADEYAOQIU。

 

4、目前到底有哪些测量方法可以解决大半径小圆弧的相对准确测量?

 

(1) 通过参考零件基准坐标系,偏移间隔相等的点,定点测量;

 

7.png

优点:

KEYIBAOZHENGMEIGEDIANDOUYOUGUDINGDEZUOBIAO,QUEBAOCELIANGDEYIZHIXING;

 

缺点:

DANGJIZHUNZUOBIAOBUWENDING、HUOXIANGDUIYUJIZHUNZUOBIAODEZONGHENGXIANGJULICHICUNGONGCHABIJIAODASHI,HUIDAOZHISUODINGDEDIANTUOLILEYUANHUDESHIJIFANWEI,HUOZHESUODINGDEDIANBINGFEIFUGAIDAOYUANHUDE80%SHIJIYUANHUSHANG,ZHEIYANGJIUHUICHANSHENGJUDAPIANCHA。

 

(2)在影像测量仪中,参考基准坐标系,把基准原点平移到圆弧所在的理论圆心,再把直角坐标XYZ切换为极坐标RθZ,接着在圆弧任意位置取多个点,选取半径偏离理论半径最差的值作为最终测量值;

 

8.png

 

9.png

优点:

            BUYONGKAOLVJIZHUNDEPIANCHALEIJI,GAIFANGFAKEYIZHUNQUEDECELIANGYUANHUDEBANJINGPIANCHA;          

缺点:

            该方法需要频繁切换坐标系,并且需要目视手动或半自动取点,效率低下,只适合于做工程开发检测验证,不适合制程检测。

 

(3)如果与圆弧相切的边缘都是直边,可以直接运用该两条直边的交点作为坐标原点,再偏移间隔相等的点,定点测量;定点的同时,要始终确保所有点的X或Y坐标一定不是0,这样就能最大限度的确保点落在圆弧范围内。

 

10.png

优点:

该方法消除了基准坐标系、相对于基准坐标系的线性距离公差的累积误差。 


缺点:

大电竞DANGYUYUANHUXIANGJIEDELIANGZHIBIANZHIXIANDUJIAOCHA,BINGQIEDUANBUFASHENGBIANXINGSHI,QUXIANDEZHANGDUANZHIJIEYINGXIANGYUANHUDEZHUNQUECELIANG。

大电竞JIEJUEFANGANJIUSHITONGGUOJIZHUNZUOBIAOXI,DINGYIXIANDEQISHIWEIZHI,QUEBAOCELIANGXIANDUANDEYIZHIXING,ZUIDAXIANDUDEKONGZHIYUANHUSHANGDECESHIDIANDEWENDINGXING。

 

(4)通过KEYENCE一键式测量设备的直线和直线自动构造切点圆弧功能,直接读取圆弧半径;

 

11.png

 

优点:

BIKAILEZHIJIEQUYUANHUDAILAIDEBUQUEDINGXINGPIANCHA,ZHONGFUXINGHAO;

 

缺点:

WU(ZHISHIYONGYUYUYUANHUXIANGQIEDEZHIXIANBIANYUANFEICHANGGUIZEDECHANPIN)

 

 

(5)参考基准坐标系,把基准原点平移到圆弧所在的理论圆心,再以理论圆弧中心为原点,等分固定角度旋转坐标系,在圆弧上相对于坐标系的X或Y的零点上取点测量。

 

12.png

优点:

KEYIQUEBAOSUOYOUDIANDEFANGXIANGYIDINGSHIZAIMEIGEXUANZHUANZUOBIAOXIDE0DIANWEIZHI,ZHONGFUXINGHAO;

 

缺点:

DANGSHIJIYUANHUFANWEIYUANBILILUNYUANHUFANWEIDAHUOXIAOHENDUODESHIHOU(JIASHEYUANHUBANJINGOK),GAIFANGFAWUFAZHUNQUECELIANG,GAIFANGFASHIYONGYUCNCJINGJIAGONGLINGJIANDEJIANCE。

 

 

总结


DUIYUDABANJINGXIAOYUANHUDECELIANG,QICELIANGFANGFAHAIYOUHENDUOZHONGLEI,BUGUANSHIYONGRENHEFANGFA,DOUYOUYIDINGDEJUXIANXING,XUYAOZUODAOJUTIWENTIJUTIFENXIHOU,ZAIXUANZEZUIJIACELIANGFANGAN。

 

大电竞ZAISHIJIDEGONGCHENGTUZHIPINGGUZHONG,WOMENTICHUGENGGAIWEIXIANLUNKUODUGUANKONGDETONGSHI,YAODONGDEYUNYONGGD&TJICHUZHISHI,JIEHESHIJIZHUANGPEIXUQIU,DINGYICHUJUTIDEXIANLUNKUODUGONGCHA。

 

RUGUOXIANGSHENCENGCIDELIJIEDABANJINGXIAOYUANHUCELIANGWENTI,KEYIZAIMOUDUSHURU“DABANJINGXIAOYUANHUCELIANGFANGFAJIWUCHAFENXI”,YOUXINGQUDEPENGYOUKEYIXIAZAIYANJIUYIXIA。TONGSHI,RUGUONIYOUGENGHAODECELIANGFANGFA,KEYIZAILIUYANQUFABIAONIDEJIANJIE。

 

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