The stone crusher machine

Stone crusher features large crushing rate, high yield, equal product size, simple structure, reliable operation and easy maintenance, economic operating costs etc.

Stone crusher is widely used in mining and construction industry, metallurgy industry, building material, highway, railway, water conservancy, chemical materials and many other departments, the SBM stone crusher contains PE jaw crusher, JC jaw crusher, PF impact crusher, PFW impact crusher, cone crusher, VSI crusher and mobile crusher. The stone crushing units can be seen in the vicinity of almost all major cities and towns.

Stone crusher is suitable for crushing materials with particle size more than 3mm. According to the difference between feeding opener and output sizes, they are usually separated: primary stone crusher, secondary stone crusher (medium crusher) and fine stone crusher. SBM stone crusher can used as slag crusher, quartz crusher, lime stone crusher, granite crusher, iron ore crusher, marble crusher and so on.

For example, our Jaw crusher are ideal for primary and secondary crushing. With the increase of production, our jaw crusher can greatly reduce the operating costs. And it is of reliability and flexibility. The large feed opening and force-feeding action from the inward and downward eccentric movement of the swing jaw mean that our jaw crusher can increase the capacity.

our Hydraulic Impact Crusher is the latest kind of impact crusher developed from PF impact crusher based on the SBM's more than 20 years experience and leading technology in impact crusher. The PFW series impact crusher is also called European style impact crusher.

Jaw crusher has been widely applied in mining, metallurgical, construction, road and railway building, water conservancy and chemistry etc. It is mainly applied in the primary crushing in which the compressive strength of original material is under 320Mpa.

Hydraulic impact Crushers have the features of heavy duty rotor design, unique hammer locking system, interchangeable wearing parts, and easy maintenance. This series impact crushers provide customers low capital cost solutions, outstanding performance, good cubical shape, lowest operation cost per ton, and wide materials applications.

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BCaiWa

Micro gear manufacturing method

1. Injection molding plastic gears? Use of plastic injection molding method for processing gear, due to mass production can be achieved in a short time, so much for office machines, home appliances and other gear used in light load. In recent years, rising in the injection molding technology, plastic material properties are improved, the precision injection molding gears with substantial increases in the precision plastic injection molds for the gears and injection molding technology are affecting an important factor in injection molding method. In the production of mold, the main use of wire cutting and EDM. However, as the use of wire, forming electrode discharge gap and other factors limit the improvement of micro-precision gear molds. Electroforming mold also can be used to manufacture. The base used for electroforming gear, using cutting or grinding can improve its accuracy. Pieces of gear can be plated thicker base. By chemical dissolution, by the sun (or convex) of the baseline conditions are overcast (concave) mold. Baseline conditions due to high precision gears, plating will not produce distortion and other reasons, it is possible to produce high precision micro-gear mold. As a result of baseline conditions, using chemical solution method, can be processed out of the mold to the shape of complex, in addition to spur gears, helical gears, the bevel gears, face gears, worm and other types of mold can be manufactured. Using high-precision molds, so that mass production of plastic micro-gear possible. However, the gear is small, easily deformed by the force and other reasons, the large load transmission and drive high precision of the occasion, with great strength of the metal gear is more favorable. ?


2. Hob hobbing process? Usually hob in gear hobbing machine on the cutting system. Micro gear (m0.1 below) hobbing, the hob tooth must be micro-machining. Because small tooth, in addition to hob tooth profile error, the hob aperture beat, end beat, pitch and other error of micro gear will greatly affect accuracy. The processing of the hobbing machine, the workpiece spindle, tool spindle, the workpiece sub-degree institutions and Fixtures, and many other aspects of accuracy, stiffness and hob and the workpiece mounting accuracy, etc., will affect the manufacture of precision micro-gears, so it is necessary to improve accuracy of the total integrated manufacturing system. On this basis, then select the cutting of the material, you can more easily achieve the same volume modulus, the variety of different micro-gear. ?




3. Sintered metal production method? Metal powder in the mold after molding, high pressure, high temperature sintering is made of sintered metal gears curing (powder metallurgy gear), its high mechanical strength than the plastic gears in the middle-load conditions of use. Molding method suitable for mass production. But the die forming, after a high temperature sintering, large deformation, so to achieve the necessary precision, but also in the sintered gear for finishing. As the tooth small, micro gear finishing difficult, combined with a larger metal particles of metal powder, thus limiting the shape precision and surface finish improvement. If mold injection molding plastic gears used in the above mentioned benchmarks Gear electrode electrochemical machining method, the accuracy of their processing out of gear is likely to increase. ?


4. Other manufacturing methods? Using semiconductor manufacturing method, optical or laser etching method can create micro-machining of gear. Optical loss method can trial out of hundreds of tiny micro-sized gears, broaches can be drawn inside the gear. Future demand for more and more micro-gear, new manufacturing methods and mass production technology will also continue. ?




source:http://useascender.com/856988-The-manufacture-of-micro.html

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BCaiWa

How to correct maintenance and repair ball mill

The ball mill common cause of the malfunction and its elimination method are shown in the following table

How to correct maintenance and repair ball mill

Maintenance and repair of the ball mill is a regular work , maintenance work will affect the mill rate and the life of the operation , then the process of how to use the correct maintenance and repair , give the following introduction :
1 , all the oil mill into continuous operation in a month should be all released , thoroughly washed , replaced with new oil . After rounding the combination of oil change once every 6 months .
2 , the wear of steel ball in a timely manner in accordance to add .
3, if found to be normal maintenance should immediately stop grinding .
On the mill 's maintenance of a regular work , maintenance work directly affects the rate and service life of ball mill operation . In order to eliminate hidden dangers to detect deficiency in order to ensure normal operation of its mill , in addition to routine maintenance , but also require regular stop grinding , ( recommended monthly ) on important components such as hollow shaft , main bearings, cylinder, gear , Size of the gear for serious examination , a detailed record . In accordance with the defect of the sub- priorities and arrangements for proper disposal repair and overhaul program .

4 , the lubrication points, lubrication and oil level checked at least every 4 hours .
5, large and small gears smoothly without abnormal noise . Necessary, adjust the gap in time .

6, mill liner is worn 70% or a 70mm long crack should be replaced .
7, liner bolts for damage caused by loose liner should be replaced .
8, mill operation , the main bearing lubricating oil temperature does not exceed 55 .
9, mill normal operation , the drive bearings and gearbox temperature does not exceed 55 , a maximum of 60 .

10, main bearing serious wear and tear should be replaced .
11, lattice -type ball mill Grate Plate Welding can no longer wear to be replaced .
12, large gear gear surface wear to a certain extent continue to use after turning it over .

13, ball mill running smoothly and without a strong vibration .
14, electrical current fluctuations should be no exception .
15, no loose fasteners each connected , combined with surface without leakage , the five tax evasion water , no leak of mine phenomenon .

16, severe wear of the pinion should be replaced .
17 , should be timely access to material wear spiral welding repair , welding repair can not be worn to replace .
18, anchor bolts loose or damaged should be repaired in time .

Failure to eliminate the reasons for the phenomenon method 
Main bearing melting, the bearings smoking or electrical overload power outages
1. Journal of lubricants supply interruption;
1. Cleaning and replacement of bearings lubricants

2. Falling into the sand in the bearings;
2. Bearings and repaired or re-casting Journal

Starting at the ball mill, the electrical overload or prior to the commencement could not be activated no later start-disc mill

Hydraulic too high or too low 
1. Tubing plug, fuel shortage; hydraulicor eliminate the reasons for the lower
2. Non-oil viscosity, the dirt, filter plug

Electrical power supply instability or excessive
1. Spoon the first activities of the ore loose; tight on the first or spoon to the mine, improved lubrication conditions, the replacement liner, adjusting operation, replacement or repair gear, ruled out electrical fault
2. Debris back to eating sand

3. Hollow shaft lubrication bad

4. Pai ore concentration

5. Around the cylinder liner weight imbalance, or uneven Mount Loss

6. Excessive wear gear

7. The electrical fault on the circuit

Bearing fever
1. The volume of ore or more or less; oily failed to stop fouling mine, to identify reasons for the replacement of oil pollution, cleaning bearings, check lubricants ring.

2. Bearing Installation tendencies or loading debris

3. Circuit illogical, lubricants Central does not work

Ball mill vibration
1. Gear meshing well, or wear a substantial adjustment tooth gap and tighten loose screws, repaired or replaced Bearing

2. Bearing pin or screw in screws loosening

3. Large gear connected off screws or loose screws

4. Bearing Wear a very Drive

Suddenly a strong vibration and impact of the acoustic
1. Mix-iron gears meshing space debris to eliminate impurities, tighten the screw, repaired or replaced Bearing
2. Fixed gear shaft small string;
3. Gear bash
4. Bearing or fixed on the basis of screws loose in
Cover connection with the cylinder, screw liner missed the pulp
1. Loose screw connection, the positioning pin-tightening or replacing screws and tighten the positioning pin, and sealing gaskets.
2. Lining screws loose, ring wear, bolts interrupt

Overhaul

Indeed ball mill for the operation and enhance the safety of its equipment intact rate, extend the life span of machinery, must be planned overhaul. Repair work is divided into three types:

Minor repairs: a monthly, including temporary accident repairs, mainly for small, minor. Grindability focused on the replacement parts, such as ball mill liner, the first to mine-spoon, adjusting bearings and gears meshing situation. Throughout the repair of Repair: General takes place once a year, the various components of the equipment for the clean-up and adjustment of larger, easy replacement of a large number of mill components.

Overhaul: In addition to the completion of medium and small repair tasks, focus on the repair and replacement of major components, such as the hollow shaft, the gear, etc.. Overhaul time interval is determined by the extent of the damage these components.

Fragile milling mill parts and the average life span as a minimum reserve of Table 9-3.

Vulnerable parts of the name Life (months) in each machine at least spare capacity
Cylinder Liner Manganese Steel 6-8 2 sets
Cover liner ibid. 8 ~ 10 2 sets
Journal of carbon steel liner or white iron 12 ~ 18 1 kit
Lattice board liner manganese steel or chrome steel 6 ~ 18 2 sets
Mine-to-carbon steel spoon or white iron 8 2 sets
The ore-body shell ibid. 24 1 kit
Main bearing bush bearing alloy 24 1 kit
Drive bearing bush bearing alloy 18 2 sets
Small gear 40Cr 6 ~ 12 2 sets
Gear carbon steel 36 to 48 1 set
Lining screw steel 6-8 semi-sets

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BCaiWa

35hMFA steel composition

35hMFA steel composition

                C    Cr        Mn    Ni        P        S        other
35KhMFA        0.33 1.04     0.40     -         0.023     0.018     0.23mo

35 hMFA. 38KhMA. 38Kh2N2MA. 38Kh2N2MA. 22K. 25KhN3MFA. 15Kh2NMFA. 35L. 35L. 40L. 20L. 12KhGFL. Note. Thermal treatment regime,. °C. Hardening from 880 + annealing at 540. Hardening from 880 + annealing at 600. Hardening from 850 + annealing at 650. Hardening from 850 + annealing at 600 ...
springerlink.com/index/x1n17l6654w28416.pdf

Links of fracture characteristics with structure of cast and deformed structural steels
Journal    Metal Science and Heat Treatment
Publisher    Springer New York
ISSN    0026-0673 (Print) 1573-8973 (Online)
Issue    Volume 33, Number 3 / March, 1991
Category    Strength Properties
DOI    10.1007/BF00769342
Pages    197-202
Subject Collection    Chemistry and Materials Science
SpringerLink Date    Monday, December 13, 2004
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A. V. Vikulin, A. V. Popkov and V. V. Skobkin

Conclusions 
1.      The crack resistance of steel depends on its structural condition and is determined by the average dimensions of the initial or actual austenitic grain or the dimensions of other structural elements, for instance, packets of martensite.
2.      The proposed diagrams which link the characteristics of strength, impact strength, crack resistance, and the average dimension of cleavage facets make possible to carry out a simplified evaluation of the crack resistance of structural steels.
Leningrad Technical Institute of the Refrigeration Industry. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 3, pp. 18–21, March, 1991



Investigation and selection of steels for nitrided crankshafts
Journal    Metal Science and Heat Treatment
Publisher    Springer New York
ISSN    0026-0673 (Print) 1573-8973 (Online)
Issue    Volume 20, Number 3 / March, 1978
Category    Technical Information
DOI    10.1007/BF00777106
Pages    243-245
Subject Collection    Chemistry and Materials Science
SpringerLink Date    Monday, December 13, 2004
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V. V. Skotnikov, V. N. Zikeev and V. V. Krasikov

Without Abstract
Yaroslavl Engine Factory. I. P. Bardin Central Scientific-Research Institute of Ferrous Metallurgy. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 3, pp. 65–67, March, 1978.





from:Steel in the USSR

Steel in the USSR. --
London :Iron and Steel Institute,1971-1991
v. :ill. ;30 cm.
Vols. for 1971-73 issued by the Iron and Steel Institute; 1974- by The Metals Society.
"A selection of translated material from Stal' and Izvestiëiìa vysshikh uchebnykh zavedenii, chernaëiìa metallurgiëiìa."--verso t.p.
1
4:SER 668.14 S813 1971 p.4965-end/Ind. canm v.16:SER 668.14 S813 1972 p.501-end/ind. canm v.28:SER 668.14 S813 1973 p.533-end/ind. canm v.310:SER 668.14 S813 1974 p.517-end/ind. canm v.4
1.Steel--Translations from Russian--Periodicals.
Dynamic Details
#9996929LCCN:72-615597

Holdings
SER 668.14 S813 1971 p.1-495 canm v.1
32329000333836
Circulating from Ottawa (555 Booth)
Located at Stacks
Status is Available
SER 668.14 S813 1971 p.4965-end/Ind. can
32329000333844
Circulating from Ottawa (555 Booth)
Located at Stacks
Status is Available
SER 668.14 S813 1972 p.1-500 canm v.2
32329000333851
Circulating from Ottawa (555 Booth)
Located at Stacks
Status is Available
SER 668.14 S813 1972 p.501-end/ind. canm
32329000333869
Circulating from Ottawa (555 Booth)
Located at Stacks
Status is Available
SER 668.14 S813 1973 p.1-532 canm v.3
32329000333877
Circulating from Ottawa (555 Booth)
Located at Stacks
Status is Available
SER 668.14 S813 1973 p.533-end/ind. canm
32329000333885
Circulating from Ottawa (555 Booth)
Located at Stacks
Status is Available
SER 668.14 S813 1974 p.1-515 canm v.4
32329000333893
Circulating from Ottawa (555 Booth)
Located at Stacks
Status is Available
SER 668.14 S813 1974 p.517-end/ind. canm
32329000333901
Circulating from Ottawa (555 Booth)
Located at Stacks
Status is Available
SER 668.14 S813 1975 canm v.5
32329000333919
Circulating from Ottawa (555 Booth)
Located at Stacks
Status is Available
SER 668.14 S813 1976 canm v.6
32329000333927
Circulating from Ottawa (555 Booth)
Located at Stacks
Status is Available
SER 668.14 S813 1977 canm v.7
32329000333935
Circulating from Ottawa (555 Booth)
Located at Stacks
Status is Available
SER 668.14 S813 1978 canm v.8
32329000319769
Circulating from Ottawa (555 Booth)
Located at Stacks
Status is Available
SER 668.14 S813 1979 canm v.9
32329000333943
Circulating from Ottawa (555 Booth)
Located at Stacks
Status is Available
SER 668.14 S813 1980 canm v.10
32329000333950
Circulating from Ottawa (555 Booth)
Located at Stacks
Status is Available
SER 668.14 S813 1981 canm v.11
32329000333968
Circulating from Ottawa (555 Booth)
Located at Stacks
Status is Available
SER 668.14 S813 1982 canm v.12
32329000333976
Circulating from Ottawa (555 Booth)
Located at Stacks
Status is Available
SER 668.14 S813 1983 canm v.13
32329000333984
Circulating from Ottawa (555 Booth)
Located at Stacks
Status is Available
SER 668.14 S813 1984 canm v.14
32329000333992
Circulating from Ottawa (555 Booth)
Located at Stacks
Status is Available
SER 668.14 S813 1985 canm v.15
32329000334008
Circulating from Ottawa (555 Booth)
Located at Stacks
Status is Available
SER 668.14 S813 1986 canm v.16
32329000334016
Circulating from Ottawa (555 Booth)
Located at Stacks
Status is Available
SER 668.14 S813 1987 canm v.17
32329000144712
Circulating from Ottawa (555 Booth)
Located at Stacks
Status is Available
SER 668.14 S813 1988 canm v.18
32329000334024
Circulating from Ottawa (555 Booth)
Located at Stacks
Status is Available
SER 668.14 S813 1989 canm v.19
32329000334032
Circulating from Ottawa (555 Booth)
Located at Stacks
Status is Available
SER 668.14 S813 1990 canm v.20
32329000334040
Circulating from Ottawa (555 Booth)
Located at Stacks
Status is Available

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BCaiWa

Coal mining methods

The goal of coal mining is to economically remove coal from the ground. Coal is valued for its energy content, and since the 1880s is widely used to generate electricity. Steel and cement industries use coal as a fuel for extraction of iron from iron ore and for cement production. In the United States, United Kingdom, and South Africa, a coal mine and its structures are a "colliery". In Australia, "colliery" generally refers to an underground coal mine.

Mountaintop removal coal mining is the removal of mountains to expose coal seams, and fills the elimination of congestion associated with nearby mining valleys and hollows. This method combines the surface and contour strip mining methods.

Surface mining is used for about 40% of coal production in the world. If coal is near the surface, can be cost-effective to extract coal by this method. The different types of contour strip mining and removing mountains.

Or strip mining is most suitable for areas with flat terrain. It exposes the charcoal for the earth above the coal seam or cut into long strips. If all the earth above the coal seam is removed, the underlyingcoal seam will be exposed. The exposed carbon-block can be drilled and jump. Once this bar is empty of coal, the extraction process is with a new strip next to it repeatedly created.

The contour extraction method is more common in areas with steep rolling terrain. This method involves the removal of earth above the coal seam in a model follows the contours along an edge or a slope. This method can lead to serious landslides and erosion problems. To resolve thisProblems, a variety of methods have been developed for use freshly cut overburden fill worked-out area. There are no restrictions on mining contour. When the process reaches a predetermined value stripping is not profitable to continue.

Modern OpenCast new methods, a greater proportion of the coal deposit than underground methods.

Deep mining is required when coal deposits are too deep to see the world. The main methods of underground mining are long wall, continuous Blast Short Wall Mining and Mining withdrawn.

Continuous mining is used for about 45% of underground coal. It 's like a machine with a large rotating drum with carbide teeth to scrape coal from the seam.

Quick extraction method, the wall is only less than 1% of coal used in depth. This method also uses a continuous mining machine with mobile armor, similar to longwall mining method.

Longwall mining accounts for about 50% of underground production. It uses a sophisticated machine with a rotation that moves back and forth mechanically on a large drum coal seam. Longwall mining helps highThe levels of production with high security standards. The sensors used in the extraction process helps to determine the amount of carbon that remains in the seam while robotic controls by helping to increase process efficiency.

Retreat mining method used in columns or coal to keep ripping up to my roof. This mining method is one of the most dangerous, because it is impossible to predict when crushing collapse of the ceiling or roof and is the case or the miners.

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BCaiWa is Technical support at Luoyang Moheman Heavy-duty Machinery Co.Ltd

ISO6336 标准的一些问题及其哲学方法论根源

ISO6336 标准的一些问题及其哲学方法论根源
（长安大学工程机械学院
陕西西安
710064） 冯守卫
张伟社

ISO6336标准，第六部分，给出了有载荷普的情况下的计算方法。
累计疲劳计算可以理解，附录中还给出了Ka的计算，这时候如果计算出了Ka是应用在额定扭矩上，还是在载荷普各工况的扭矩上？
这时会有比较大的差别，不知道哪位对ISO6336理解，请给予指点。

(附言：该文本应属于个人工科本行的母鸡蛋，而且自感是所下的约30个母鸡蛋中最好的一个，也是其他"蛋"们诞生的基础。但因沾了些公鸡蛋味，故正式的母 鸡窝和公鸡窝内均无处下，只好下在这里。）
摘要
文献[1～10]中论述了ISO6336齿轮承载能力计算标准中的一些问题和矛盾。本文中从哲学方法论角度对这些问题作了进一步的论述。并说明存在问题的 方法论根源，通过具体问题论述了唯物辩证法的一些观点。启发性地显示了如何用辩证法的观点来指导具体研究工作，以及如何通过具体问题的分析来学习唯物辩证 法。形象地说明了养成辩证思维习惯对善于发现分析问题、提高思维能力和创新能力的极端重要性。作者也再次认为，ISO 6336标准在几个核心问题上有进一步研究改进的必要。
关键词
齿轮强度
ISO 6336
唯物辩证法
思维能力
创新能力

0 引言


ISO 6336标准（GB3480与之等效）自发表以来，对齿轮承载能力计算方法的研究起了很大的指导和推动作用。但因为这个问题的复杂性，故该标准尚未完善。 在国际上也并未取得真正统一地位。如美国、苏联、日本等国家可能尚未采用。我国GB3480标准制订和修订组的负责人等也均谈到各国对该标准的争论尚颇 多。在文献[1～9]中，我们曾分析了该标准的一些问题和矛盾。从哲学方法论角度来看，这些问题产生的根源是存在着违背唯物辩证法的现象。而掌握辩证法并 养成辩证思维习惯对善于发现分析问题，提高思维能力和创新能力是极端重要的。故本文中准备从ISO中一些问题及其方法论根源相结合角度加以分析。
1
齿根应力计算中的客观性、主要矛盾、全面性及发展观点

唯物辩证法的一个基本观点是要严格地按照事物的客观本来面目去探索，反对主观性。目前世界上各种齿轮强度计算标准中的齿根应力计算方法，都是以对轮齿的悬 臂梁假设为基础，再用应力修正（集中）系数来修正。由于悬臂梁假设与实际齿形相差极大，而且悬臂梁弯曲应力公式也不适用于这种悬臂长度仅相当于或小于(载 荷作用于单对齿啮合区外侧点时)梁的宽度的情况。因此，在这种悬臂梁应力与齿根最大拉应力之间的规律（即应力修正系数公式）就难以找到或不存在。同时这种 方法在轮齿受载情况、齿根应力状态和应力修正系数中，也还是一个又一个的假设。所以这种方法先天缺陷很大，各标准之间也相当纷纭，且难以统一完善。如 ISO与美国AGMA中公式的分歧很大。ISO中的相对齿根圆角敏感系数，在持久寿命时与悬臂梁长度和重合度无关，在静强度时却与它们有关（包含在YS 中）。ISO中还存在着下述现象：当齿数较多时，正变位时的弯曲强度反小于负变位时，且变位系数的影响反大于齿数较少时。对多种钢材的齿轮，在静强度下的 齿根应力计算仅仅只取决于悬臂梁应力系数（服从悬臂梁应力规律）。详见[4~6]。

此外这种方法也相当复杂。ISO中公式和参数多达20多个，并包含迭代运算。AGMA中则更复杂，它还要通过作图测量来计算。这使人联想起爱因斯坦的话： "上帝不会创造这么复杂的公式"。

造成这种现象的根本原因在于悬臂梁假设的主观牵强性。为此我们在文献[1～6]中提出了新的方法：直接从实际齿形出发，以相似理论为基础，通过引入对应于 真实齿形和实际齿根最大拉应力的应力齿形系数，来直接建立齿根最大拉应力的计算公式。并通过边界元采样计算和回归分析，得到应力齿形系数的回归公式。从哲 学角度来看，应力齿形系数仅与齿数、变位系数和载荷作用高度系数有关，故在它们之间必然存在着精确的客观规律。我们又严格地按照客观内在联系去探索回归模 型，果然得到了精度极高的回归公式[4~6]。我们还发现齿根应力只是与齿数的倒数（1/z）而不是与齿数本身有良好的抛物线关系。这里的客观必然性在 于：因为渐开线齿廓的曲率是曲率半径的倒数，而曲率半径与齿数成正比。仿型法加工的刀具编号基本服从按1/z值的等间距规则。

这种新方法不需要种种假设，理论基础先进，实际准确性好，且计算大为简化。它提供了使齿根应力计算完善化统一化的可能。该方法的关键在于采样数据的准确 性。如果采用应变片测量方法，根据边界元计算可知，应变片应小于0.05mn，且在不同齿形和载荷位置下，应变片的大小和粘贴位置均应不同。而且还要在完 全同等条件下进行大量概率实验，且还不一定精确，故难度和费用是极大的。不知是否有更好的实验方法。

在文献[5,6]中，我们还用同样的方法给出了轮齿挠度和啮合刚度的回归公式。并从多个方面佐证了文中的计算结果，这也使我们感受到边界元法的先进性和可 信性。而且由于回归模型合理、回归精度极高，回归公式相当于多维空间的连续光滑流型，故用文中回归公式计算基本相当于直接用边界元法计算。

辩证法的另一重要观点是要善于抓主要矛盾，抓关键。这一点对发现分析问题是极其重要的。毛泽东讲："万千的学问家和实行家，不懂得这种方法，结果如堕烟 海，找不到中心，也就找不到解决矛盾的方法"。目前国际上的齿轮强度计算标准有约十种，但其齿根应力计算方法都是仅限于对悬臂梁宽度、长度及应力修正系数 的不同假设，以及对悬臂梁弯曲应力公式的不同修改上，而没有突破悬臂梁假设本身这个要害。因此形成了各执一说而又无法统一的不正常局面。又由于齿轮失效的 随机离散性及强度计算的保守处理，故其中的问题也难以判断和容易掩盖。所以这种不正常的局面得以长期延续。这里关于悬臂梁宽度的假设可能还存在着一种错 觉：好像只要通过危险点就是合理的。实际上这个考虑并不应该是出发点。因为一方面要想通过这种方法或对悬臂梁公式的某些改动来逼近齿根最大拉应力是徒劳 的。另一方面这里的出发点应是：要找到这样一种悬臂梁，它的应力与齿形参数和载荷位置的变化规律与齿根最大拉应力的变化规律之间有客观必然的联系规律（修 正公式）。显然这是很难找到的。

辩证法还告诉我们要全面的分析问题，防止片面性和以偏概全。我们在应力齿形系数的边界元采样计算时已注意到了这点，而且所用齿轮样本空间过分密集。根据最 新分析，齿轮样本空间可精简如下表（略），载荷作用高度系数取2.2,1.8,1.4三种即可。在ISO 6336中不同基本齿条标准时也共用同样的公式。但我们见到的资料是，其有限元计算数据仅取了x＝0，z＝14，24，48，3种载荷作用高度，分别为 6、3、2种刀具齿顶圆角的共33个数据。故仅在这个范围内ISO中的悬臂梁齿形系数与应力修正系数的乘积（YFS值）才与我们边界元计算的真实应力齿形 系数相吻合（ISO约高2～5％）。但ISO中YFS值随着变位系数的相对变化很难理解[4~6]。

辩证法还要求我们要有不断发展的观点。W.Lewis的悬臂梁假设方法已经110多年了，它应当已经完成了它的历史贡献。我们没有必要再在这个圈子里钻来 钻去。既然有一步平坦的捷径，为什么还要再走那两步都是泥潭的弯路？即使ISO中计算没有缺陷，似也应改用新的方法。钱学森前辈同温总理的谈话中，谈到全 面和创造型人才的培养问题。爱因斯坦也还说，想象力比知识本身更重要。而传统的惯性和保守的惰性是不利于发展进步和培养创新能力的。一个新的东西总要顶着 石块弯曲的生长似乎也是一种无奈的规律。突破这种规律并敏于发现新的苗头，是有利于发展和创新。

2
重合度系数、端面载荷系数及联系分析的观点
辩证法还强调要互相联系地分析问题。重合度系数是考虑双对齿承载时有利影响的系数，端面载荷系数是又考虑到由齿轮误差等引起双齿对载荷分担不均的抵消作用 的系数。它们是紧密相关的，故必须互相联系起来分析。而且它们的乘积（复合系数）必须满足极值条件——大于等于重合度系数而小于等于1。但在ISO中却把 两者互不相关的弧立分析，因此其复合系数值的相对关系存在着诸多矛盾和混乱。如存在着复合系数大于1的矛盾。在一些情况下复合系数反而随着重合度的增大而 增大。复合系数随着精度等级的相对变化情况及其在直斜齿轮之间的相对关系也是混乱难解的。从定性分析来看，ISO中计算的大前提均是单位齿宽载荷，多对齿 对啮合应是对整个齿宽而言的，故端面重合度应是唯一代表啮合齿对数多少的参数。轴向重合度本质上是代表齿轮宽度的参数，不能认为它也重复地代表了啮合齿对 数的多少。ISO中端面载荷系数公式把二者视为等同，主要与总重合度相关。这是很难解释或明显错误的。ISO中直齿轮的接触强度重合度系数公式也是人为假 设公式。在文献[5,6]中，我们对这两种系数有详细的分析，并从整体联系上给出了具有明确的含义和推导的新的公式 。

3
曲率系数等计算中的深入性

辩证法还教导我们要深入地研究问题，防止表面性。在接触应力中曲率系数（ISO称为区域系数）计算的关键是，应该选取哪一个啮合点的综合曲率半径作为计算 依据。在AGMA中，直齿轮采用小齿轮单齿对啮合区内界点作依据，普通斜齿轮采用过连心线上两轮顶圆间中点的小齿轮半径与啮合线的交点作依据。在 ISO6336——1980中均是以节点作依据。而在1993版中作了较大修改。一是改为以节点和单齿对啮合区内界点中综合曲率半径较小者作依据；二是认 为对小直齿轮和大直齿轮的计算应力也要分别采用不同的点计算。对普通斜齿轮和内齿轮，则仍是按节点算。至于窄斜齿轮，两标准都用插值原则。
在AGMA中直齿轮的重合度系数等于1，即在计算载荷中不考虑重合度的影响。H.Winter（ISO前负责人）曾对此提出批评。而 E.J.Wellauer（AGMA负责人）反驳说因为AGMA中直齿轮曲率系数计算采用了单齿对啮合区内界点，故在此已经考虑了重合度的影响[11]。
在文献[8]中我们对这个系数作了深入分析。首先我们认为重合度的影响不应且也难以与曲率系数混在一起，它只应在计算载荷的重合度系数中去考虑。曲率系数 只应作为一个纯粹代表齿面耐久性的几何系数。其次我们从能正确反映齿面相对强度高低等方面出发，从理论分析和有关实验结合中分析了ISO与AGMA中的一 些疑问和矛盾。提出了以小齿轮齿根部啮合区的平均综合曲率半径作为曲率系数计算依据的商榷意见。
关于深入性的例子还可见对斜齿轮接触线长度变化规律的分析中，对此目前大都只关心固定的接触线长度最小值。AGMA认为接触强度重合度系数计算完全要从这 个最小值甚或瞬时最小值出发（无论直斜齿轮）。ISO中直齿轮和窄斜齿轮是折中的从此出发。在文献[9]中，我们一方面给出了接触线长度计算的改进公式， 分析了其极值大小随端面、轴向重合度的变化规律。而且分析了在不同极值大小时其持续时间长短的动态变化规律。并得出结论：重合度系数计算只能从动态的接触 线长度统计平均值出发。
在文献[10]中有对齿向载荷分布系数的深入分析。文中指出ISO中这个系数存在着当载荷较小时其值无限增大等问题，并提出了改进意见。
在齿轮强度计算中各种相对关系和整体关系的合理性较绝对数值的准确性更为重要，因为后者只是反映在试验齿轮许用应力的相对高低上。而ISO对此点似注意不 够。此外该标准似有过分烦琐倾向（我国GB3480已作了简化），日本专家仙波正庄也曾说，这个标准是很难懂的[11]。

4
要善于从差异矛盾中发现分析问题并敢于创新
善于发现分析问题首先就是要善于发现分析事物的矛盾。目前ISO、AGMA等标准之间的差异很多。"差异就是矛盾"，矛盾就是问题。这种局面本身就说明这 方面值得深入研究的地方尚很多。同时这两种标准各自本身中也存在一些问题和矛盾。我们要善于从这些差异矛盾之中比较分析，揭示矛盾，发现问题并敢于创新。 我们一方面要尊重继承前人的伟大贡献，另一方面也不能只因为是权威标准就不去思索分析或不敢分析触及。我们需要树立这样的信心：无论在实际工作或科学研究 中，一方面总是需要参考借鉴和继承的，另一方面也总是可以有所发现有所前进的。而关键就在于要善于发现分析和解决问题。

5
如何培养辩证思维习惯
善于发现分析问题归根结底就是要善于用唯物辩证法的观点来观察分析问题。毛泽东讲："要学会辩证法，这个用处很大"。如何才能学会辩证法并养成随时随事都 能自觉地用辩证法的观点来分析观察问题的习惯呢？这当然首先需要认真深入的理论学习，但仅仅这样还不够。因为这样的情况是很多的：往往谈起理论条文来，似 乎也还知道和明白，但是一到具体问题的分析应用当中，就忘到九屑云外或陷于糊涂之中。所以最主要的是要通过具体问题的分析从理论与实际应用相结合上来学习 领会。这要求我们一方面要随时注意有意识的用辩证法观点来指导对具体问题的分析研究，另一方面要善于从对具体问题的分析研究当中抽象上升到辩证法的理论 上。本文的目的也是希望对这两方面有所帮助启发。
培养辩证思维习惯是一个要下大力气、不断积累的从必然到自由的过程，决不是可以一蹴而就和一劳永逸的。稍有疏忽或不用气力，"就会滑到唯心论和形而上学方 面去。"在实际生活的许多方面，违背唯物辩证法的现象是很多的
哲学是自然科学与社会科学的概括和总结。所以我们还可以读一些真正从客观实际出发、严格"追踪蹑迹"，真正有人生意义和思想深度的如同血管之血的文学作 品，和一些善于分析的文章。例如鲁迅的小说和杂文。以锻炼思维深度和精度，学习分析方法。

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BCaiWa is Technical support at Luoyang Moheman Heavy-duty Machinery Co.Ltd

ISO6336 ISO1328 DIN3968

DIN 3968 Tolerances for Single-start Hobs for Involute Spur Gears
Deutsches Institut Fur Normung E.V. (German National Standard) / 01-Sep-1960 / 8 pages



ISO 1328-1:1995

Cylindrical gears -- ISO system of accuracy -- Part 1: Definitions and allowable values of deviations relevant to corresponding flanks of gear teeth

Cancels and replaces ISO 1328 (1975). Establishes a system of accuracy relevant to corresponding flanks of individual cylindrical involute gears. Specifies appropriate definitions for gear tooth accuracy terms, the structure of the gear accuracy system and the allowable values of pitch deviations, total profile deviations and total helix deviations. Applies only to each element of a toothed wheel taken individually. Does not cover gear pairs as such.



ISO 1328-2:1997

Cylindrical gears -- ISO system of accuracy -- Part 2: Definitions and allowable values of deviations relevant to radial composite deviations and runout information


ISO 6336-1:2006 Calculation of load capacity of spur and helical gears -- Part 1: Basic principles, introduction and general influence factors

ISO 6336-1:2006 presents the basic principles of, an introduction to, and the general influence factors for, the calculation of the load capacity of spur and helical gears. Together with ISO 6336-2, ISO 6336-3, ISO 6336-5 and ISO 6336-6, it provides a method by which different gear designs can be compared. It is not intended to assure the performance of assembled drive gear systems. It is not intended for use by the general engineering public. Instead, it is intended for use by the experienced gear designer who is capable of selecting reasonable values for the factors in these formulae based on knowledge of similar designs and awareness of the effects of the items discussed.

The formulae in ISO 6336 are intended to establish a uniformly acceptable method for calculating the pitting resistance and bending strength capacity of cylindrical gears with straight or helical involute teeth.


ISO 6336-2:2006  Calculation of load capacity of spur and helical gears -- Part 2: Calculation of surface durability (pitting)

ISO 6336-2:2006 specifies the fundamental formulas for use in the determination of the surface load capacity of cylindrical gears with involute external or internal teeth. It includes formulas for all influences on surface durability for which quantitative assessments can be made. It applies primarily to oil-lubricated transmissions, but can also be used to obtain approximate values for (slow-running) grease-lubricated transmissions, as long as sufficient lubricant is present in the mesh at all times.


ISO 6336-3:1996  Calculation of load capacity of spur and helical gears -- Part 3: Calculation of tooth bending strength

Gives the fundamental formulae for use in tooth bending strength calculations for involute internal and external gears with a minimum rim thickness under the root.

ISO 6336-5:2003 Calculation of load capacity of spur and helical gears -- Part 5: Strength and quality of materials

SO 6336-5:2003 describes contact and tooth-root stresses, and gives numerical values for both limit stress numbers. It specifies requirements for material quality and heat treatment and comments on their influences on both limit stress numbers. Values in accordance with it are suitable for use with the calculation procedures provided in ISO 6336-2 and ISO 6336-3 and in the application standards for industrial, high speed and marine gears. They are also suited to the calculation procedures given in ISO 10300 for rating the load capacity of bevel gears. It is applicable to all gearing, basic rack profiles, profile dimensions, design, etc., covered by those standards. The results are in good agreement with other methods for the range indicated in the scope of ISO 6336-1.



ISO 6336-6:2006 Calculation of load capacity of spur and helical gears -- Part 6: Calculation of service life under variable load


ISO 6336-6:2006 specifies the information and standardized conditions necessary for the calculation of the service life (or safety factors for a required life) of gears subject to variable loading. While the method is presented in the context of ISO 6336 and calculation of the load capacity of spur and helical gears, it is equally applicable to other types of gear stress.

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BCaiWa is Technical support at Luoyang Moheman Heavy-duty Machinery Co.Ltd