Distinguish between domestic and foreign harmonic reducer innovation technology key to see these three points


Release time:

2021-05-06

摘要作为二十世纪中期机械传动领域的又一重大突破,谐波齿轮传动是一种出现在弹性薄壳理论基础上的新型的传动技术。其传动原理与普通齿轮传动相比有本质的区别,它属于柔性传动方式,通过利用机械波控制柔性齿轮的弹性变形来传递运动和动力。          作为二十世纪中期机械传动领域的又一重大突破,谐波齿轮传动是一种出现在弹性薄壳理论基础上的新型的传动技术。其传动原理与普通齿轮传动相比有本质的区别,它属于柔性传动方式,通过利用机械波控制柔性齿轮的弹性变形来传递运动和动力。    与普通减速机相比,谐波减速机具有如下优点:相同传动比的减速机,谐波减速机的零件减少50%,体积和重量也均减少1/3左右;传动比范围比普通减速机大,由于同时啮合的齿数较多,可达30-50%,故大大提高了其承载能力及传动平稳性;功率范围从几瓦至几十千瓦不等,无冲击且噪声小;同轴性好,运动精度也较高,具有较高的传动效率,约为65%—96%;谐波减速机可实现向密闭空间,如密封谐波传动减速装置传递运动及动力,驱动那些工作在真空、含腐蚀性及其它有害介质的空间机构,这一独特优点是其它传动机构难以比拟的优势;除此之外,谐波传动还可用于实现诸如手摇发电机、风力发电机等高增速运动,以及方便的实现差速传动。    在减速机市场,哈默纳科占据了国际市场的大部分份额,而哈默纳科的谐波减速机系列,不仅畅销欧美市场,在中国市场更是拥有广泛的拥趸,在用户中颇具口碑,尤其是在对可靠性要求极高的工业机器人领域应用甚广,并在半导体液晶生产设备、医疗器械、光学仪器、印刷机械等诸多行业尽显优势。   当然,国产机器人企业也在奋力追赶中,涌现出了像绿的谐波、北京中技克美、北京谐波传动、浙江来福谐波等企业,其中,绿的谐波的谐波减速机在国内机器人谐波减速机市场的渗透率超过80%,市场占有率超过50%。   那么在技术创新上面,和哈默纳科相比较,国产谐波减速机都有哪些技术上的不同?国内外减速机都有哪些各自的特点?   在此之前我们先来了解一下谐波减速机的工作原理:谐波减速机仅由3个基本部件构成:柔轮、波发生器和刚轮。柔轮的外径略小于刚轮的内径,通常柔轮比刚轮少2个齿,波发生器的椭圆型形状决定了柔轮和刚轮的齿接触点分布在介于椭圆中心的两个对立面,波发生器转动的过程中,柔轮和刚轮齿接触部分开始啮合,波发生器每正时针旋转180°,柔轮就相当于钢轮逆时针旋转1个齿数差,在180°对称的两处,全部齿数的30%以上同时啮合,这也造就了其高转矩传送。   创新技术关键词一: 齿形的设计   通过对比我们发现,国产的减速器包括绿的和来福谐波都强调了齿形的设计,据来福谐波董事长张杰介绍齿形是各家都不一样,这也是谐波减速器的差异化所在。   在微型谐波传动领域,哈默纳科于2005年向市场推出了“P”齿形,目前开发出了MHD8和MHD10两个系列的产品,外径最小为8mm,采用行星齿轮传动式波发生器,传动比为160、500和1000,质量最小为2.2g,重复精度可达10弧秒。   在谐波齿轮传动中采用双圆弧齿廓,可以有效改善柔轮齿根的应力状况和传动啮合质量,提高承载能力、扭转刚度和柔轮疲劳寿命,并可降低最小传动比。哈默纳科的IH齿形是基于余弦凸轮波发生器开发的双圆弧齿形,由于采用近似方法设计,应用初期出现了齿廓干涉等问题,但是到1990年代初期已经基本完善。目前,哈默纳科的谐波产品有十几个类型,二十多个系列,最小传动比为30,型号中带有字母“S”的,其齿形为双圆弧齿形,产品垄断了主要国际市场。   在齿形的设计上面,绿的谐波跳出了传统以 Willis 定理为基础的渐开线齿轮设计,应用全新的齿形设计理论,设计出非共轭的谐波啮合齿形,可以在大幅提高谐波减速机使用寿命的前提下,提高其输出效率和扭矩承受能力。与国外同类产品齿形比较,全新的谐波啮合齿形“P 型齿”克服了以往谐波啮合齿形的缺点,通过一系列创新性的改进措施,能极大提高柔轮的使用寿命。   而浙江来福谐波谐波减速机采用的是δ齿形,该齿形是根据谐波的啮合传动特点,运用特殊的数学工具,在双圆弧齿形的基础上,结合国内外其它产品的相关齿形设计而成的。它具有接触应力小、寿命长、啮合性能好、噪音低、工作平稳的特点。同时,根据特定的工作要求,可很方便地设计出具有针对性应用的齿形。   创新关键词二:柔轮的设计和处理工艺   柔轮的成型工艺是整个谐波减速器的中技术难点最大的,也是很多企业攥在手上的技术机密;而柔轮和钢轮的材料、材质和热处理是也是减速机需要突破的技术难关。   据悉,北京中技克美XB1系列(GB/T14118-93) XBI系列是谐波传动减速器中是最常见,也是使用最广泛的一类,其主要结构特点是采用杯状柔轮,刚轮比柔轮多两个齿。   根据不同的应用需求,北京中技克美还研制出了一系列的谐波减速机,XB3系列 XB3系列为扁平式,采用齿环柔轮,和两个刚轮,其中输入刚轮比柔轮多两个齿,输出刚轮的齿数与柔轮的相同,整体轴向尺寸较短,适用于轴向尺寸较受限制的场合;XBF系列 XBF系列中包括XBF2和XBF3系列,均为相位调节器用谐波传动减速器系列,多用于印刷包装机械之中,其结构是采用齿环柔轮、双排柔轮轴承;XB2系列 XB2系列即速比在2000——100000范围内的内啮复波谐传动减速器,其主要特点是传动比特别大,采用双排齿环形柔轮,双排柔性轴承结构;R系列 R系列谐波传动减速器是高精度谐波传动产品,其外形及安装与XB1系列相同,但精度较高(空回及运动误差均小于3′ )。   除了形状之外,柔轮的材料和处理工艺也是影响波发生器性能的因素,日本哈默纳科来谐波减速机在柔轮材料上使用疲劳强度大的特殊钢,与普通的传动装置不同,同时啮合的齿数占总齿数的约30%,而且是面接触,因此使得每个齿轮所承受的压力变小,可获得很高的转矩容量。其超短杯型号CSD和SHD,柔轮长度仅有常规谐波传动柔轮的1/3,既增加传动刚度,又大幅度减轻了谐波减速器重量。   此外,哈默纳科采用铝等轻合金材料制造波发生器与减速器壳体等方式,减薄刚轮外缘以及改进连接结构等形式,使整机重量大幅度减轻,其轻量化谐波传动产品系列在航空航天和机器人领域的应用日益广泛。   而浙江来福谐波根据柔轮的工作特点,研制了特殊的柔轮材料,经过特殊的光整强化处理,处理后的柔轮具有很高的疲劳强度和疲劳寿命。   创新技术关键词三:波发生器的疲劳性能   由谐波齿轮减速机工作原理及组成可知,波发生器是谐波齿轮减速机中的关键部件之一,其主要元件包括柔性薄壁轴承和波发生器凸轮。柔性轴承是波发生器的核心部件,在工作中,柔性轴承通过其弹性变形使减速机达到高减速比的性能要求,在循环交变载荷作用下极易发生疲劳失效,其疲劳寿命决定着波发生器的寿命,进而决定着整个减速机的使用寿命。   影响零部件疲劳性能的因素有很多,主要包括尺寸、表面形状、平均应力等。通常可通过选择合适的材料、结构的改进、尺寸大小的优化、表面强化处理、表面防护措施的添加、改进加工方式等方法提高零部件的疲劳性能。   据悉,凸轮式柔性波发生器能全面控制柔轮变形,承载能力大,刚度好,适于标准化批量生产,日本哈默纳科就是采用IH齿形谐波减速机就是采用了余弦凸轮波发生器;而双滚轮式波发生器结构简单,但承载能力低,适于单件生产。   柔性轴承作为波发生器的核心部件,其使用寿命决定了减速机的使用寿命,因此柔性轴承的润滑技术的创新显得尤为重要,谐波减速机是油脂润滑,不像使用油润滑的RV减速机,只要油换的勤一点,寿命就长,谐波减速机可以说是一次性产品,使用了之后坏了就是坏了,这也是谐波减速机相比较其它类型的减速机的劣势所在。   来福谐波根据谐波减速器的工作特点,研制开发了特种润滑油脂,它具有优异的润滑性和抗极压性。   而北京中技克美研制成功了世界领先技术的全固体润滑谐波传动减速机,在低速轻载传动的固体固体润滑谐波传动取得了成功,解决了在真空环境下普通的谐波减速机发热引起柔轮断裂的问题。

AbstractAs another major breakthrough in the field of mechanical transmission in the middle of the twentieth century, harmonic gear drive is a new type of transmission technology based on the theory of elastic thin shell. Its transmission principle is essentially different from ordinary gear transmission. It belongs to the flexible transmission mode, which transmits motion and power by using mechanical waves to control the elastic deformation of flexible gears.
 

As another major breakthrough in the field of mechanical transmission in the middle of the twentieth century, harmonic gear drive is a new type of transmission technology based on the theory of elastic thin shell. Its transmission principle is essentially different from ordinary gear transmission. It belongs to the flexible transmission mode, which transmits motion and power by using mechanical waves to control the elastic deformation of flexible gears.

Compared with ordinary reducers, harmonic reducers have the following advantages: for reducers with the same transmission ratio, the parts of harmonic reducers are reduced by 50%, and the volume and weight are also reduced by about 1/3; The transmission ratio range is larger than that of ordinary reducers, and due to the large number of teeth meshing at the same time, it can reach 30-50%, thus greatly improving its carrying capacity and transmission stability. The power range ranges from a few watts to tens of kilowatts, no impact and low noise; Good coaxiality, high motion accuracy, and high transmission efficiency, about 65%-96%; Harmonic reducer can transmit motion and power to confined spaces, such as sealed harmonic transmission reducer, and drive space mechanisms that work in vacuum, corrosive and other harmful media. This unique advantage is incomparable to other transmission mechanisms; in addition, the harmonic drive can also be used to achieve such as hand-cranked generators, wind turbines and other high-speed movement, as well as convenient to achieve differential transmission.

In the reducer market, Hamernak occupies most of the international market share, and Hamernak's harmonic reducer series not only sells well in the European and American markets, but also has a wide range of fans in the Chinese market, and is quite popular among users. It is widely used in the field of industrial robots with extremely high reliability requirements, and shows its advantages in semiconductor liquid crystal production equipment, medical equipment, optical instruments, printing machinery and many other industries.

Of course, domestic robot enterprises are also struggling to catch up, with the emergence of enterprises such as Green Harmonic, Beijing Zhongji Kemei, Beijing Harmonic Drive and Zhejiang Laifu Harmonic. Among them, the penetration rate of Green Harmonic Reducer in the domestic robot harmonic reducer market exceeds 80%, and the market share exceeds 50%.

So in the technological innovation above, and compared to the Hamernake, domestic harmonic reducer have what technical differences?

Before that, let's first understand the working principle of harmonic reducer: harmonic reducer is composed of only three basic components: flexible wheel, wave generator and rigid wheel. The outer diameter of the flexible wheel is slightly smaller than the inner diameter of the rigid wheel. Usually, the flexible wheel has 2 teeth less than the rigid wheel. The elliptical shape of the wave generator determines that the tooth contact points of the flexible wheel and the rigid wheel are distributed on two opposite surfaces between the center of the ellipse. During the rotation of the wave generator, the tooth contact parts of the flexible wheel and the rigid wheel begin to mesh, and the wave generator rotates 180 degrees at each timing, the flexible wheel is equivalent to a steel wheel rotating counterclockwise by one tooth number difference. At two symmetrical places of 180 °, more than 30% of all teeth are meshed at the same time, which also creates its high torque transmission.

 Key words one of innovative technology: design of tooth profile

Through comparison, we find that domestic reducers, including green and Laifu harmonic, emphasize the design of tooth profile. According to Zhang Jie, chairman of Laifu harmonic, the tooth profile is different from one company to another, which is also the difference of harmonic reducers.

In the field of micro harmonic transmission, Hamernak introduced the "P" tooth profile to the market in 2005. At present, it has developed two series of products, MHD8 and MHD10, with a minimum outer diameter of 8mm. It adopts a planetary gear transmission wave generator with transmission ratios of 160, 500 and 1000, a minimum mass of 2.2g, and a repetition accuracy of 10 arc seconds.

Adopting double circular arc tooth profile in harmonic gear drive can effectively improve the stress condition of flexspline tooth root and transmission meshing quality, improve the bearing capacity, torsional stiffness and flexspline fatigue life, and reduce the minimum transmission ratio. Hamernaco's IH tooth profile is based on the development of cosine cam wave generator double arc tooth profile, due to the use of approximate method design, the initial application of tooth profile interference and other issues, but to the early 1990 s has been basically perfected. At present, Hamernaco's harmonic products have more than a dozen types, more than 20 series, the minimum transmission ratio is 30, the model with the letter "S", its tooth shape is double arc tooth shape, the product monopolizes the main international market.

In the design of the tooth profile above, the green harmonic out of the traditional Willis theorem based on the involute gear design, the application of new tooth design theory, design a non conjugate harmonic meshing tooth profile, can greatly improve the harmonic reducer under the premise of life, improve its output efficiency and torque bearing capacity. Compared with similar foreign products, the new harmonic meshing tooth profile "P-type tooth" overcomes the shortcomings of the previous harmonic meshing tooth profile. Through a series of innovative improvement measures, the service life of the flexspline can be greatly improved.

The Zhejiang Laifu harmonic harmonic reducer uses delta tooth profile, which is designed according to the characteristics of harmonic meshing transmission, using special mathematical tools, on the basis of double arc tooth profile, combined with other products at home and abroad. It has the characteristics of small contact stress, long life, good meshing performance, low noise and stable operation. At the same time, according to the specific work requirements, it is easy to design a tooth profile with targeted applications.

Innovation keyword two: design and processing technology of flexible wheel

The forming process of the flexible wheel is the most difficult technical difficulty in the whole harmonic reducer, and it is also a technical secret that many enterprises hold in their hands. The material, material and heat treatment of the flexible wheel and the steel wheel are also the technical difficulties that the reducer needs to break through.

It is reported that Beijing Zhongji Kemei XB1 series (GB/T14118-93) XBI series is the most common and widely used type of harmonic drive reducer. Its main structural feature is the use of cup-shaped flexspline, which has two more teeth than flexspline.

According to different application requirements, Beijing Zhongjiekemei has also developed a series of harmonic reducers. The XB3 series XB3 series is flat and adopts a gear ring flexspline and two rigid wheels. The input rigid wheel has two more teeth than the flexspline. The number of teeth of the output rigid wheel is the same as that of the flexspline. The overall axial dimension is shorter and is suitable for occasions with limited axial dimension. The XBF series XBF series includes XBF2 and XBF3 series, they are all harmonic drive reducer series for phase regulators, which are mostly used in printing and packaging machinery. Their structure is to adopt ring flexspline and double-row flexspline bearings. XB2 series XB2 series internal meshing compound harmonic drive reducer with speed ratio in the range of 2000-100000, its main feature is that the transmission ratio is extremely large, and it adopts double-row tooth ring flexspline and double-row flexible bearing structure; R series R series harmonic drive reducer is a high-precision harmonic drive products, its shape and installation and XB1 series the same, but the accuracy is higher (air back and motion error are less than 3 ').

In addition to the shape, the material and treatment process of the flexspline are also factors that affect the performance of the wave generator. Japan's Hamernakolai harmonic reducer uses special steel with high fatigue strength on the flexspline material, which is different from ordinary transmission devices. At the same time, the number of meshing teeth accounts for about 30% of the total number of teeth, and it is in surface contact, thus reducing the pressure on each gear and obtaining a high torque capacity. Its ultra-short cup models CSD and SHD, the length of the flexible wheel is only 1/3 of that of the conventional harmonic drive flexible wheel, which not only increases the transmission stiffness, but also greatly reduces the weight of the harmonic reducer.

In addition, Hamernako uses light alloy materials such as aluminum to manufacture wave generators and reducer housings, thinning the outer edge of the rigid wheel and improving the connection structure, so that the weight of the whole machine is greatly reduced, and its lightweight harmonic drive product series is increasingly widely used in aerospace and robotics.

According to the working characteristics of the flexible wheel, Zhejiang Laifu harmonic has developed a special flexible wheel material, which has been treated with special finishing and strengthening, and the treated flexible wheel has high fatigue strength and fatigue life.

Innovative technology Keywords three: wave generator fatigue performance

According to the working principle and composition of the harmonic gear reducer, the wave generator is one of the key components in the harmonic gear reducer, and its main components include flexible thin-walled bearings and wave generator cams. The flexible bearing is the core component of the wave generator. In work, the flexible bearing makes the reducer meet the performance requirements of high reduction ratio through its elastic deformation. It is prone to fatigue failure under the action of cyclic alternating load, and its fatigue life determines The life of the wave generator, which in turn determines the service life of the entire reducer.

There are many factors that affect the fatigue performance of parts, including size, surface shape, average stress and so on. The fatigue performance of parts can usually be improved by selecting suitable materials, improving the structure, optimizing the size, strengthening the surface, adding surface protection measures, and improving the processing methods.

It is reported that the cam-type flexible wave generator can fully control the deformation of the flexible wheel, has large bearing capacity and good rigidity, and is suitable for standardized mass production. Japan's Hamernaco uses IH tooth-shaped harmonic reducer and cosine cam wave generator. The double-roller wave generator has simple structure, but low bearing capacity and is suitable for single-piece production.

As the core component of the wave generator, the service life of the flexible bearing determines the service life of the reducer. Therefore, the innovation of the lubrication technology of the flexible bearing is particularly important. The harmonic reducer is grease lubricated, unlike the RV reducer that uses oil lubrication. As long as the oil is changed frequently, the service life will be long. The harmonic reducer can be said to be a one-time product, and it is broken after use, this is also the disadvantage of harmonic reducer compared to other types of reducer.

According to the working characteristics of harmonic reducer, Laifu harmonic has developed special lubricating grease, which has excellent lubricity and extreme pressure resistance.

However, Beijing Zhongji Kemei has successfully developed the world's leading technology of all-solid lubrication harmonic drive reducer, and has achieved success in the solid solid lubrication harmonic drive of low speed and light load drive, which solves the problem of flexible wheel fracture caused by the heating of ordinary harmonic reducer in vacuum environment.

Key words:


Previous Page

Next Page

Previous Page:

Next page: