机械设计课后题答案

机械设计课后题 答案 八年级地理上册填图题岩土工程勘察试题省略号的作用及举例应急救援安全知识车间5s试题及答案 3-1答:主要类型有:普通螺纹、管螺纹、矩形螺纹、梯形螺纹和锯齿形螺纹五种。 特点及应用: 普通螺纹 是米制三角螺纹，牙型角 a=60，因牙型角较大，故当量摩擦系数也较大，自锁性能好，主要用于联接。 管螺纹 是英制三角螺纹，牙型角 a=55度。它有圆柱管螺纹和圆锥管螺纹之分，常用圆柱管螺纹。这种螺纹联接常用于高温、高压及紧密性要求较高的管与管的联接中。 矩形螺纹 牙型为正方形，牙型角 a=0度，因牙型角小，当量摩擦系数小，传动效率高，故常用于传动。 梯形螺纹 牙型呈梯形，牙型角 a=30度。因牙型角较小，所以传动效率较高，对中性较好，故为应用较多的传动螺纹。 锯齿形螺纹 牙型呈锯齿形，工作面牙侧角 。传动效率高，牙根强度高。因只有一个工作面，故多用于承受单方向轴向力的场合。 3-2答:螺栓有普通螺栓和铰制孔螺栓两种。 普通螺栓 常用于被联接件比较薄，能够放置螺母及需要经常拆卸的场合。 铰制孔螺栓 在承受横向载荷或(和)转矩以及需精确固定被联接件的相对位置时常采用铰制孔螺栓。 双头螺柱 被联接件之一太厚不宜制成通孔，无法放置螺钉头，材料较软且需经常拆装时宜采用双头螺柱。 螺钉 被联接件之一太厚，无法放置螺母，不需经常拆装的场合。 3-3 答:螺纹联接在冲击、振动、变载荷或高温环境下，将使螺旋副的摩擦力减小或瞬间消失，经多次重复后，最终导致联接松脱。因此，设计时应采取有效的防松 措施 《全国民用建筑工程设计技术措施》规划•建筑•景观全国民用建筑工程设计技术措施》规划•建筑•景观软件质量保证措施下载工地伤害及预防措施下载关于贯彻落实的具体措施 。 防松方法有摩擦防松、机械防松、铆冲防松等。 3-4 答:为提高联接刚性、紧密性和防松能力以及提高螺栓在变载荷下的疲劳强度，因此大多数螺纹联接都要拧紧。 拧紧力矩要克服螺纹副力矩和螺母底面的摩擦阻力矩。 3-5 答:提高螺栓联接强度的措施有: 1 (降低影响螺栓疲劳强度的应力幅; 2 (改善螺纹牙上载荷分布不均匀的现象; 3 (减小应力集中的影响; 4 (避免附加弯曲应力; 5 (采用合理的制造工艺方法。 3-6 由上图可知，在螺母下加弹性元件将使螺栓刚度由 C b1 减小到 C b2 ，可使螺栓承载截面的应力幅值减小，所以螺栓的疲劳强度提高。 an end to volunteer to do illegal things. Comrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable security environment, the economic environment of fair competition, standardized and orderly legal environment, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the county public security organs peace volunteers construction and deepen. The city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the public security team building higher expectations and requirements, we show that there are many does not reach the designated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing an end to volunteer to do illegal things. Comrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable security environment, the economic environment of fair competition, standardized and orderly legal environment, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the county public security organs peace volunteers construction and deepen. The city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the public security team building higher expectations and requirements, we show that there are many does not reach the designated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing an end to volunteer to do illegal things. Comrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable security environment, the economic environment of fair competition, standardized and orderly legal environment, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the county public security organs peace volunteers construction and deepen. The city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the public security team building higher expectations and requirements, we show that there are many does not reach the designated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing 3-10 图示的吊车 跑道托架，用 4 只普通螺栓安装在钢制横梁上。试选择螺栓材料，并确定该螺栓的公称直径。图中长度单 位 mm 。 an end to volunteer to do illegal things. Comrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable security environment, the economic environment of fair competition, standardized and orderly legal environment, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the county public security organs peace volunteers construction and deepen. The city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the public security team building higher expectations and requirements, we show that there are many does not reach the designated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing 4-1答:平键联接的失效形式有:静联接时较弱零件工作面被压溃和键被剪断;动联接时工作面的磨损。 b × h × L (键宽、键高和键长)的确定。 b × h 是根据轴直径 d 查国家 标准 excel标准偏差excel标准偏差函数exl标准差函数国标检验抽样标准表免费下载红头文件格式标准下载 ( GB1095 — 79 )确定。 L 是根据轮毂宽度 B 查国家标准( GB1095 — 79 )确定。 an end to volunteer to do illegal things. Comrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable security environment, the economic environment of fair competition, standardized and orderly legal environment, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the county public security organs peace volunteers construction and deepen. The city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the public security team building higher expectations and requirements, we show that there are many does not reach the designated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing 4-2 4-4答:铆接的特点是工艺设备简单、耐冲击和联接可靠等优点，但被铆件强度削弱较大，铆接时噪声大，劳动条件差。主要应用于桥 梁、建筑、造船等部门中。 4-5 答:焊接具有强度高、紧密性好、工艺简单、重量轻和成本低等优点。 4-6 答:胶接的主要优点是工艺简单、操作方便、劳动条件好;联接的重量轻、外观平整;胶层有绝缘、防腐和密封作用，亦可缓冲和 吸振。主要缺点是耐老化、耐介质性能差;对温度、湿度的变化较敏感等。主要用于机床、汽车、造船、化工、航空等部门中。 an end to volunteer to do illegal things. Comrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable security environment, the economic environment of fair competition, standardized and orderly legal environment, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the county public security organs peace volunteers construction and deepen. The city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the public security team building higher expectations and requirements, we show that there are many does not reach the designated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing 4-7答:过盈联接的优点是结构简单，对中性好，承载能力高，在冲击、振动或变载荷下也能可靠地工作。其缺点是配合面的加工精度要求较高，装配困难，配合 表 关于同志近三年现实表现材料材料类招标技术评分表图表与交易pdf视力表打印pdf用图表说话 pdf 面处的应力集中较大。 过盈联接是利用零件间的过盈量来实现的联接。其工作原理是靠材料的弹性和包容件与被包容件之间的装配过盈而在配合表面间产生的摩擦力或摩擦力矩来传递外载荷。 5-1 答:摩擦型带传动的主要优点是:带有弹性，可以缓冲和吸振，传动平稳;过载打滑，可防止其它零件损坏;传动中心距大;结构简单，制造、安装、维护方便，成本低。主要缺点是带与带轮之间有滑动，不能保证准确的传动比。另外，由于需要施加张紧力，轴系受力较大。 同步带传动是啮合传动，传动比准确，效率高;缺点是制造和安装精度要求较高。 5-2. 5-3.答:由于带传动存在松紧边拉力差、带本身有弹性，造成带与带轮之间的相对滑动即弹性滑动。 弹性滑动不仅使带传动得不到准确的传动比，而且降低了传动效率，引起带的磨损。 5-4. 答:带传动的主要失效形式是打滑和 V 带的疲劳破坏。保证带传动不打滑，并使胶带具有一定的疲劳强度和寿命是带传动的设计准则。 答: an end to volunteer to do illegal things. Comrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable security environment, the economic environment of fair competition, standardized and orderly legal environment, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the county public security organs peace volunteers construction and deepen. The city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the public security team building higher expectations and requirements, we show that there are many does not reach the designated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing 5-7.答: 链传动兼有齿轮传动和带传动的特点。与带传动相比，链传动能保持准确的平均传动比;作用在轴上的压力小;能在高温、低速重载条件下工作。 5-8答:当链节数为偶数时，接头处正好是内外链板相接，可将一侧外链板与销轴做成固定的接头，装配后用开口销或弹性锁片将另一侧链板锁住。当链节数为奇数时，必须采用折曲的过渡链节。由于过渡链节的链板受到附加弯矩作用，其强度仅为正常链节的 80% 左右，所以在一般情况下链节数取偶数为宜。 链轮齿数选用奇数齿，这样，当与偶数链节相啮合时，磨损比较均匀。 5-9. 答: 由于链条围轮后形成多边形，致使链条中心线在运动中交替与链轮分度圆相切和相割，使链速周期性变化。影响链速变化的主要参数是链轮齿数和节距。 答:链传动的主要失效形式: 1 (铰链的磨损 2.链条的疲劳破坏3.铰链的胶合。 铰链的磨损 5-11. 5-12 an end to volunteer to do illegal things. Comrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable security environment, the economic environment of fair competition, standardized and orderly legal environment, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the county public security organs peace volunteers construction and deepen. The city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the public security team building higher expectations and requirements, we show that there are many does not reach the designated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing an end to volunteer to do illegal things. Comrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable security environment, the economic environment of fair competition, standardized and orderly legal environment, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the county public security organs peace volunteers construction and deepen. The city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the public security team building higher expectations and requirements, we show that there are many does not reach the designated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing an end to volunteer to do illegal things. Comrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable security environment, the economic environment of fair competition, standardized and orderly legal environment, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the county public security organs peace volunteers construction and deepen. The city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the public security team building higher expectations and requirements, we show that there are many does not reach the designated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing 解:5-16 6—1 (答:优点 : 齿轮传动效率高;结构紧凑、工作可靠、使用寿命长。 缺点:制造和安装精度要求较高，精度低时振动和噪音大;不适合大中心距传动。 6—2 答:齿轮传动的失效形式有:轮齿折断、齿面磨损、齿面点蚀、齿面胶合、齿面塑性变形。 开式齿轮传动主要失效形式有:齿面磨损、轮齿折断。 3 答 : 齿根危险剖面位置通常用 30 0 切线法确定。作与轮齿对称线成 30 0 夹角的两直线，与齿根过渡曲线相切，连接两切点的6— 截面即为齿根危险剖面。 6—4答:制造齿轮的材料主要是各种钢材，其次是铸铁，还有其它非金属材料。 钢制齿轮常用的热处理有:对于软齿面齿轮经调质或正火处理，对于硬齿面齿轮切齿后经表面淬火、渗碳淬火、氮化等表面硬化处理。 6—5 ( 答:在啮合过程中，小齿轮的啮合次数比大齿轮多。为了使大、小齿轮的寿命接近，应使小齿轮的齿面硬度比大齿轮高 30~50HBS 。 6 ( 答:进行齿顶修缘主要是为了减小动载荷。 6— 6—7答: 1 (影响齿向载荷分布的主要因素有:齿轮螺旋线总偏差(齿向偏差);齿轮的布置型式及轴、轴承、箱体的刚度;齿轮的齿宽;齿面硬度及跑合效果等。 2 (可采取的措施有:提高齿轮制造和安装精度 ( 如减小齿向误差和两轴线平行度误差等 ) ;提高轴、轴承及箱体的支承刚度;选取合理的齿轮位置，悬臂布置时应尽可能减小悬臂长度;适当限制齿轮的宽度等。另外，将轮齿做成鼓形齿可以有效地改善轮齿的载荷分布 ( 图 6—8c) 。 3 ( 齿轮的精度、齿轮传动的重合度、受载后轮齿的变形、齿顶修缘及跑合效果等均影响齿间载荷分配。 an end to volunteer to do illegal things. Comrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable security environment, the economic environment of fair competition, standardized and orderly legal environment, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the county public security organs peace volunteers construction and deepen. The city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the public security team building higher expectations and requirements, we show that there are many does not reach the designated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing 和变位系数 因为斜齿圆柱、直齿锥齿轮的6—8答: Y Fa 是一个无量纲数，只与轮齿的齿廓形状有关， Y Fa 值取决于齿数 z x 。 齿形系数是按当量齿数 Z v 来取值的，所以三者对应的当量齿数不相等，则 Y Fa 值也不相等 6—9 答:采用正变位齿轮，可以提高轮齿的弯曲强度和接触强度。 6—10 (答:相啮合的大、小齿轮齿面接触应力 σH 相等。 许用接触应力一般不相等，许用接触应力 [σ]H 小的齿轮接触强度低。 6-12答:1 (相啮合的大、小齿轮齿面接触应力σH 相等，故两齿轮接触强度相等; 2 (两齿轮齿数不等，系数 YFa YSa 不相等，齿数少，则系数 YFa YSa 大，齿根弯曲应力大，故小齿轮齿根弯曲强度低。 6-13答:对闭式软齿面齿轮传动，一般都希望在保证弯曲强度的条件下，采用较多的齿数即较小的模数。对一般工业用齿轮传动， z1 , 20 , 40 。对于高速或对噪声有严格要求的齿轮传动，建议取 zl ?25 。 闭式硬齿面齿轮、开式齿轮和铸铁齿轮，因齿根弯曲强度往往是薄弱环节，应取较少齿数以保证齿轮具有较大的模数，以提高轮齿抗弯能力。一般取 zl , 17 , 25 。 为避免出现轮齿根切现象，对标准直齿圆柱齿轮，应取 zl ?17 。 6—14 (答:齿宽系数 ψ d 选大些时，可以使齿轮的直径和中心距减小，但是增大了齿宽和轴向尺寸，增加了载荷沿齿宽分布的不均匀性，提高了对轴系支承刚度的要求。另外，对变速器中的齿轮传动，齿宽还受到轴向移动距离的限制。 螺旋角 β 选大些时，可增大重合度，从而提高了传动的平稳性和承载能力。但 β 过大时，导致轴向力剧增。故一般选 β =8度 , 20度 。如 β 角过小，不能显示斜齿轮传动的优越性。从减小齿轮的振动和噪音角度来考虑，目前有采用大螺旋角齿轮的趋势。 6—15 ( 答:齿轮精度的检验项目有齿距、齿形和齿向三个方面 。 an end to volunteer to do illegal things. Comrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable security environment, the economic environment of fair competition, standardized and orderly legal environment, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the county public security organs peace volunteers construction and deepen. The city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the public security team building higher expectations and requirements, we show that there are many does not reach the designated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing 6—19 ( 1 ( 说明 关于失联党员情况说明岗位说明总经理岗位说明书会计岗位说明书行政主管岗位说明书 齿轮 2 齿面接触应力和齿根弯曲应力的循环特性 r 。 2 (如传动功率改由齿轮 2 输入，齿轮 1 和齿轮 3 输出，如图 6—48b 。这种情况下，齿轮 2 的齿面接触应力和齿根弯曲应力的循环特性 r 有何变化 ? 在确定许用接触应力 [σ] H 和许用弯曲应力 [σ] F 时与齿轮 1 主动时有何区别 ? 解: 1 ( 齿面接触应力总是脉动循环( r =0 )。动力由齿轮 1 输入，齿轮 2 为双齿面工作，故齿根弯曲应力为对称循环 ( r = , 1) 。 2 ( 动力由齿轮 2 输入，齿轮 2 为单齿面工作，故齿根弯曲应力为脉动循环(r =0) ;齿轮 2 转一转，接触应力变化 2 次，在确定许用接触应力 [σ]H 时，接触应力循环次数多，寿命系数小，许用接触应力小;齿根弯曲应力对称循环时的许用应力为脉动循环许用应力的 0.7 倍。 an end to volunteer to do illegal things. Comrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable security environment, the economic environment of fair competition, standardized and orderly legal environment, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the county public security organs peace volunteers construction and deepen. The city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the public security team building higher expectations and requirements, we show that there are many does not reach the designated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing 7—1.答:优点:单级传动比大，传动平稳，振动和噪声小。结构紧凑，有自锁性。 缺点:传动效率低，发热量大，蜗轮材料成本高。 为什么大功率连续传动时不宜采用蜗杆传动 ? 答:蜗杆传动效率低，功率损失大，蜗轮齿面易胶合失效。 7—2.答: 1 )蜗杆的轴向模数 mal 等于蜗轮的端面模数 mt2 ; 2 )蜗杆的轴向压力角αa1 等于蜗轮的端面压力角αt2 ; 3 )蜗杆分度圆导程角 γ 等于蜗轮分度圆螺旋角 β 且螺旋线方向相同。 7—3.答:蜗杆头数少，易实现大传动比，但导程角小，效率低，故大功率传动不宜采用单头蜗杆。蜗杆头数过多，导程角过大，蜗杆制造困难。另外，当传动比 i 较大时， z 1 过多会使蜗轮齿数 z 2 增多，导致蜗杆跨度加大，影响蜗杆刚度和啮合精度。常用的蜗杆头数 z 1 =1 、 2 、 4 、 6 ，可根据传动比 i 选取。当传动比 i , 5 , 8 、 7 , 16 、 15 , 32 、 30 , 83 时，对应蜗杆头数 z 1 , 6 、 4 、 2 、 1 。 蜗轮齿数 z 2 根据传动比及蜗杆头数确定。传递动力时，为增加传动的平稳性，蜗轮齿数应大于 28 。an end to volunteer to do illegal things. Comrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable security environment, the economic environment of fair competition, standardized and orderly legal environment, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the county public security organs peace volunteers construction and deepen. The city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the public security team building higher expectations and requirements, we show that there are many does not reach the designated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing 2 过多，蜗轮直径增大，相应的蜗杆越长，导至刚度下降。因此，在动力传动中，蜗轮齿数一般不超 80 ;用于传递运动，如若齿数 z 分度机构，可以不受此限制。 7—4.答: 1 (滚铣蜗轮的刀具，其直径和齿形参数必须和相应的蜗杆相同。从式 (7—1) 可知，蜗杆分度圆直径不仅与模数有关，还随 z 1 , tg γ 值不同而变化。在同一模数下，也会有很多直径不同的蜗杆，即要求配有相应数目的蜗轮滚刀。 为有利于刀具标准 化，减少滚刀数目， 因此制定了蜗杆分度圆直径的标准系列。 2 (直径 d 1 越小，啮合效率越大;直径越大，刚度越大。 7—5 (答: 1. 蜗杆传动的变位方式与齿轮传动相同，也是依靠刀具的移位实现变位。但由于刀具尺寸不变，即蜗杆尺寸不能变动，因而只能对蜗轮进行变位。 2. 蜗杆传动的变位主要目的是凑中心距或改变传动比。 7—6 (答: 1. 失效常发生在蜗轮上。在闭式传动中，容易发生磨损、胶合或点蚀。在开式传动中，蜗轮轮齿的主要失效形式是磨损。 2. 蜗轮材料通常采用青铜(锡青铜、铝青铜)或铸铁(灰铸铁)。 3. 当采用锡青铜时，由于材料的减摩性和抗胶合性好，主要失效形式是点蚀。蜗轮材料的许用接触应力为 [σ]H = ZN[σ]0H ;当蜗轮材料为铝青铜时，传动的承载能力往往受胶合失效的限制，在确定蜗轮齿面许用接触应力时，要考虑滑动速度 vs 的影响，由于胶合不属于疲劳失效，所以 [σ]H 与应力循环次数无关 。 7—7 (答: 1. 功率损耗一般包括三部分，即啮合时摩擦损耗、轴承摩擦损耗及浸入油池中的零件搅油时溅油损耗。 2. 影响啮合效率的因素:导程角 γ 和当量摩擦角 φv 。增加 γ 可以提高啮合效率，而 φv 愈小效率愈高。 7—8 (答: 1. 蜗杆传动效率低，发热量大。对闭式蜗杆传动，如果散热条件较差，使油温不断升高而使润滑失效，从而加剧了磨损，甚至导致胶合。热平衡计算的目的是使工作时减速箱内的油温稳定地处在所规定的使用范围内。 2. 应采取措施:增加散热片;在蜗杆轴端装风扇;在箱体中设置循环冷却水管。 7—9解: an end to volunteer to do illegal things. Comrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable security environment, the economic environment of fair competition, standardized and orderly legal environment, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the county public security organs peace volunteers construction and deepen. The city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the public security team building higher expectations and requirements, we show that there are many does not reach the designated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing , 5mm ， 1 =90mm ， 1 , 1 ，蜗轮齿数 2 =62 ，蜗杆副当量摩7—11 (图 7—16 为手动蜗杆传动起重器。已知蜗杆模数 m d z z 擦系数 f v , 0.13 ，鼓轮直径 D , 200mm ，起重量 G , 1500N ，试: 1 (画出升起重物时蜗杆转向; 2 (判定机构是否具有自锁性; 3 (求出起重时蜗杆受各分力的大小，画出其方向。 ( 只计啮合效率 η1 ) an end to volunteer to do illegal things. Comrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable security environment, the economic environment of fair competition, standardized and orderly legal environment, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the county public security organs peace volunteers construction and deepen. The city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the public security team building higher expectations and requirements, we show that there are many does not reach the designated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing 7—12 ( 图 7—17 所示单级圆柱蜗杆传动(已知 m =8mm ， d 1 =80mm ， z 1 =2 ， i =20 ，蜗杆转速 n =1450r , min ，由电动 机直接驱动，单向转动，载荷平稳，间歇工作，预期寿命为 10000h (蜗杆采用 45 钢，表面淬火，齿面硬度 >45HRC ，蜗轮采用 ZcuSn10Pb1 ，砂模铸造。试:计算蜗杆传动所能传递的功率 P 1 ;计算蜗杆轴上各分力大小;画出蜗杆、蜗轮受力方向。 an end to volunteer to do illegal things. Comrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable security environment, the economic environment of fair competition, standardized and orderly legal environment, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the county public security organs peace volunteers construction and deepen. The city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the public security team building higher expectations and requirements, we show that there are many does not reach the designated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing 8—1 答:不合适。在一般温度下(低于 200度 )，各种碳素钢和合金钢的弹性模量没有多少差别，因此选用合金钢，只能提高轴的强 度和耐磨性，对轴的刚度影响不大。 an end to volunteer to do illegal things. Comrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable security environment, the economic environment of fair competition, standardized and orderly legal environment, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the county public security organs peace volunteers construction and deepen. The city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the public security team building higher expectations and requirements, we show that there are many does not reach the designated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing 8—3 答:影响机械零件疲劳强度的主要因素有应力集中、尺寸效应、表面状态、腐蚀介质、加载顺序和频率等，其中以前三项比较重要。提高轴的疲劳强度可采取措施:合理布置轴上零件位置、改进轴上零件结构，减小轴的载荷;减小应力集中对轴疲劳强度的影响;改进轴的表面质量等。 8—4 答:校核轴的疲劳强度时，需要在已知轴的外形、尺寸及载荷的基础上，通过分析确定出一个或几个危险截面(确定危险截面不仅要考虑弯曲应力和扭转剪应力的大小，还要考虑应力集中和绝对尺寸等因素影响的程度)，然后求出计算安全系数。如果同一截面有多种产生应力集中的结构，应分别求出其有效应力集中系数，然后从中取最大值进行计算。 8—5 解 :参见例题 an end to volunteer to do illegal things. Comrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable security environment, the economic environment of fair competition, standardized and orderly legal environment, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the county public security organs peace volunteers construction and deepen. The city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the public security team building higher expectations and requirements, we show that there are many does not reach the designated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing an end to volunteer to do illegal things. Comrades, build "restful Juxian", and strive to create a harmonious unity of political environment, stability and stable security environment, the economic environment of fair competition, standardized and orderly legal environment, living environment for people to live and work, is the common aspiration of the people, people are willing to hope, public opinion, glorious and arduous task. Hope everyone in the meeting as an opportunity, hearten spirit, do solid work, forge ahead, to the county public security organs peace volunteers construction and deepen. The city people a sense of security and satisfaction in recent years has been ranked the forefront of the province, behind the achievement, condensed the majority of police effort and sweat, should be fully affirmed. But from the telephone survey carried out recently in the Council, in the first half of this year the city people a sense of security and satisfaction and to year declined compared. People a sense of security and satisfaction is the maximum price of our existenceTo further improve work style sense of values and the highest pursuit, otherwise we do everything meaningless. People a sense of security and satisfaction decreased, indicating that the masses of social security, the public security team building higher expectations and requirements, we show that there are many does not reach the designated position place. This gave us sounded the alarm bell, this should cause our high attention, effectively enhance the sense of crisis, responsibility, closely combined with the area, the actual unit, carefully and find out the existing