What is Crankshaft?

1. Development

According to “Chinese crank industry market analysis report forecast forward-looking and forward-looking investment.” data show that in recent years, the domestic auto demand, the global automotive market center transfer in developing countries, the increasing globalization of the auto parts procurement, among other factors contributed to China’s overall auto market position in China as the increasingly industrial development of pillar industries. From 2007-2010, China crankshaft production were 4.77 million, 6.42 million, 26.33 million and 31 million, which excluded such as single-cylinder motorcycle engine crankshaft, still reached 4.5 million, 5.75 million, 10.32 million and 14 million.
rapid growth of China’s auto industry for the car to provide a broad market space with the crankshaft. In 2010, China’s automobile production and sales were 18,264,700 and 18,061,900, an increase of 32.44 percentage and 32.37 percentage. Where: passenger car sales 13,897,100 and 13,757,800, an increase of 33.83 percentage and 33.17 percentage; commercial vehicle sales 4.3676 million and 4.3041 million, an increase of 28.19 percentage and 29.90 percentage.
At the same time, the year 2010, a total of 16,909,500 units and engine sales 17,025,900 units, up 27.44 percentage and 29.73 percentage respectively over the previous year. Among them, the diesel engine sales totaled 3.9355 million units and 3.9927 million units, up 25.03 percentage and 30.36 percentage respectively, compared with last year, gasoline engines totaled 12,965,900 units and 13,025,200 units, respectively, the cumulative increase of 28.19 percentage and 29.55 percentage than last year. Preview 2011 net sales of engine market will reach about 19.34 million, an increase of about 13.63 percentage. As the core member of the engine, it is closely related to sales of the crankshaft of the engine production and sales. Changes in engine production and sales reflected the movement of the crankshaft market demand.

2 Overview

Crankshaft In the 21st century, the engine crankshaft in the manufacturing process, tools, etc. are great changes. Led multi-tool turning technology and hand-grinding process nearly half a century, due to low precision and flexibility was poor, is gradually withdraw from the stage of history. High speed, high efficiency composite processing technology and equipment quickly into motor vehicles and parts manufacturing, high-speed high-performance composite processing technology has been a considerable degree of crankshaft machining applications in production, and it is an inevitable trend. Status processing technology equipment crankshaft At present, the older of the crankshaft production line by a majority of general machine tools and special machine components, the relatively low productivity and automation. Much worse rough processing facilities commonly used tool lathe crankshaft main journal and the journal, the link process quality stability, prone to large machining stress is difficult to achieve a reasonable allowance. And other commonly used finish ordinary MQ8260 crankshaft grinder for rough grinding, semi-fine grinding, fine grinding, polishing, normally by manual operation, the quality of processing unstable, the size of poor consistency. Vintage line is a major feature of many common devices, calculated according to ductile iron crankshaft, there is a production line 35 to device 40. Roughing milling ordinary outer main and pin neck, and then NC fine owners journal rod neck, and then through the ground side of the multiple processes into a finishing step. So this line more than 60 sets of equipment, resulting in a long line of product turnover, fields occupy a large area, its productivity is completely on multiple devices decomposition process and to increase the margin.

3. The process of progress

Crankshaft 1, ductile iron crankshaft Foundry Technology
(1) Melting
to obtain a high temperature is to produce molten iron of low sulfur pure high quality ductile iron key. China mainly domestic-based production facilities cupola hot metal desulphurization not pre-processing; followed by less high-purity pig iron, coke poor quality. It has been applied using the double pre-smelting process for desulfurizing molten iron melting cupola, the desulfurization furnace, and then heated in an induction furnace, adjusting elements. Currently, the detection of the hot metal in the domestic vacuum has been widely used to carry out direct reading spectrometer.
(2) Modeling
Impact of air much better than clay sand molding process technology, can be obtained with high accuracy crankshaft casting, the sand mold production process having no rebound deformation characteristics, which is particularly important for multi-throw crankshaft. At present, there are some crank manufacturers from Germany, Italy, Spain and other countries air impact modeling process, however, the introduction of the entire production line of only a handful of manufacturers, such as text prohibitively run Crankshaft Co., Ltd. introduced the German KW casting production lines.

2, steel crankshaft forging technology
In recent years, China has introduced a number of advanced forging equipment, but because of the small number, combined with mold manufacturing technology and a number of other facilities can not keep up, so part of advanced equipment not play its due role. From Generally speaking, the old general forging equipment to be modified and updated and more, at the same time, backward technology and equipment is still dominant, advanced technology has been applied but not widespread.

3, machining technology
Currently most lines from a common crankshaft machine tools and special machine components, the relatively low production efficiency and automation. Multi-tool equipment to use rough lathing and turn the crank journal neck, poor quality of the process stability, prone to large internal stress, it is difficult to achieve a reasonable allowance. Usually finished using coarse MQ8260 crankshaft grinder, etc. – semi-fine grinding – grinding – polishing, normally by manual operation, the quality of processing unstable.

With the advent of globalization of trade, the manufacturers have been aware of the gravity of the situation, have technological innovation, to enhance the competitiveness of enterprises, in recent years introduced a number of advanced equipment and technology, progress very fast . On the current situation is concerned, these devices and technologies essential to rely on imports. Here for the introduction on the situation of Harbin Dongan, FAW big diesel, Wen impossible Run crank, crank Binzhou Hyderabad and other companies.

Group Harbin Dongan crankshaft flexible production line for the automatic production line, the production line by the German rough automatic line plane (Lindenmaier), NC – broaching, milling speed CNC outer follower (BOEHRINGER), fillet rolling machine (HEGENSCHEIDT-MFD) and the car roller thrust face plane, hardening machine (EMA), etc; CNC finishing line of the Japanese high-speed CBN grinding machine (TOYODA), balancing machine, polishing machine (IMPCO-NACHI), detector , washing machine and so on. linkCNC machining spindle is used high speed servo processing technology, high-speed line technology CBN grinding wheel, the grinding line speed of 120m / s.

Wen impossible Run crankshaft through the introduction of advanced equipment Germany, United States, Italy and other developed countries, set up with the current international advanced level of large-scale production base crankshaft, grinding machines by the CBN, HAAS vertical and horizontal machining centers, Italy SAIMP grinders, milling machines, and the German HELLER crankshaft SA-FINA polishing machine and other equipment machining has started mass production line.

FAW diesel crankshaft rough production line, located at different plant finishing step, thus ensuring a clean finishing shop. Roughing crank quality centering machine, CNC milling machines and other equipment inside, finishing equipment by the British LANDIS, Japan TOYADA CNC crankshaft grinding machine and other imported advanced equipment.

After transformation Binzhou sea crankshaft, crank set NC machining line, by the rough processing facilities CNC lathes, milling machines and other equipment of the crankshaft, by a CNC grinding roll finishing equipment, CNC belt sander, polishing machine and other equipment, had recently purchased Japanese TOYADA Koki CNC grinding machines and other key equipment, testing equipment the United States ADCOLE crank coordinate measuring machines, roughness and other components. It is worth mentioning that the crankshaft in the company in the country specializing in crankshaft manufacturers in the first application of ductile iron crankshaft fillet rolling and barrel finishing new technology, and achieved good economic and social benefits.

Liaoning hongfa crankshaft production line after transformation, mainly consists of three CNC lathe (inlet VT36, CAK6163, CAK6150), the two CNC milling (S1-305B) based rough processing facilities; seven CNC crankshaft grinding machine (1 3L1,2 imported CBN wheel sets H197B, 4 sets of H229B) fluorescent magnetic particle inspection, and other finishing equipment; stress-relief using 8 wells furnace, nitriding treatment station 7 using ion nitriding furnace, quenching imported from France EFD produced CIHM12 quenching machine and automatic pusher back to the stove. While imports from the United States of crank integrated measuring instrument may be made to the crankshaft layout inspection, product quality has been a reliable guarantee, along with the three production lines at the same processing capacity.

Crankshaft can be seenThe crankshaft of the engine manufacturing technology is the most rapid progress of machining equipment, processing technology is more typical milling and grinding. The following briefly describes GF70M-T crankshaft grinding machine and VDF 315 OM-4 High-speed follower milling machines, but its advanced evident:
GF70M-T crankshaft grinding machine is developed in Japan production TOYADA Koki special crankshaft grinding machine, to meet multiple variety, low cost, high precision, mass production needs and design CNC crankshaft grinder. Application of the grinder wheel feed and workpiece rotation servo control linkage, a fixture can be changed without the rotational center of the crankshaft to complete the grinding of all the journal, including the crankpin grinding track follower; hydrostatic spindle, hydrostatic guideway, hydrostatic feed screw (wheelhead) and linear gratings closed-loop control, produced using TOYADA Koki GC50 CNC control system, the grinding accuracy can be achieved journal roundness 0.002mm; using CBN grinding wheel, grinding line speeds up to 120m / s, with double wheelhead, high grinding efficiency.

VDF 315 OM-4 High-speed milling machine is an outer follower BOEHRINGER company for the German automobile engine crankshaft design and manufacture of flexible CNC milling machine, the work rotating device application and milling feed servo control linkage, one can clamping of the crankshaft rotational center without changing the milling track follower crankshaft connecting rod journal. VDF 315 OM-4 High-speed milling with integrated outer follower composite bed structure, both ends of the electronic drive synchronized rotation of the workpiece, having a dry cutting, high precision, and high cutting efficiency; using SIEMENS 840D CNC control system, device operation instructions on the display unit, automatic generation of the basic machining program to the parameter input part, the processing length can be 450 ~ 700mm, a diameter turning at various crankshaft, connecting rod journal diameter of 380mm was an error within ± 0.02mm.

4, heat treatment and surface hardening techniques
Heat Treatment of the crankshaft is the key technology of surface hardening treatment. Ductile iron crankshaft normalizing generally used, good organization prepared for surface treatment, surface hardening or induction hardening is generally employed nitridation process. Forged steel crankshaft journal fillet is used quenching process. The introduction of equipment AEG fully automatic crankshaft hardening machine, EMA quenching machine tools.

According to foreign materials, ductile iron songFillet rolling-axis ion nitriding process and the use of reinforced composite in combination, the fatigue strength can increase the whole crankshaft 130% or more. Domestic manufacturers in recent years have also been the practice in this area, and achieved good results.

Crankshaft fillet rolling processing, Germany Hogan Seth (HEGENSCHEIDT-MFD AUTOMATIC) produced a variation of the pressure rolling machine tool applications and patents correction, fillet rolling apparatus is relatively good, but expensive. At present the domestic research in this area has also been some achievements, Dongfeng Motor Co., Ltd. Technology Research Institute’s “research and development and application of technology to strengthen Crankshaft fillet rolling and rolling straightening” to solve the domestic enterprise heavily in the introduction of foreign technology issue, the subject of access to the former State Administration of Machinery industry Science and Technology progress Award.

4, face the problem of

and today’s automotive engine crankshaft manufacturing industry is facing the following questions:
more than one variety, small batch production;
2 delivery. greatly reduced;.
3 reduce production costs;.
4 appears difficult to cut material so that the processing difficulty significantly increases processing presents many needs problem, such as a hard cutting;
5 to protect the environment. require less or no cutting fluid, that is, to achieve quasi-dry cutting or dry cutting; based on the above circumstances, the 21st century, high-speed, high-precision, high efficiency composite processing technology and equipment has been in the automotive crankshaft manufacturing rapid application, production efficiency is greatly improved, so that the engine crankshaft production line equipment number is reduced.

Crankshaft line equipment (including heat treatment, surface hardening) only about 13 devices, short turnaround product line, high efficiency, easy quality control management. Development of the crankshaft composite processing technology in the late 1980s, the German BOEHRINGER company and HELLER has developed a comprehensive Crankshaft – broaching machine, the process is the crankshaft turning process with the crankshaft broaching perfect combination of technology, high production efficiency, processing good accuracy, flexibility, high degree of automation, short tool change time, particularly suitable forUndercut groove machining the crankshaft, the crankshaft may be performed directly after the refining process, the rough grinding step is omitted. Therefore, Crankshaft – broaching process is one of the current international process crankshaft roughing popular. The mid-1990s appeared the new high-speed CNC milling outside the crankshaft so that the crankshaft roughing process and on a new level. CNC milling the crankshaft and the outer CNC milling high speed crank contrast, the mill has the following disadvantages: the knife is not easy, low cutting speed (typically no greater than 160m / min), non-cutting time is longer, more investment in machine tools, the step cycle time longer. High speed CNC milling outside the crankshaft has the following advantages: high cutting speeds (up to 350m / min), shorter cutting time, process cycle time is shorter, the cutting force is small, the workpiece temperature is low, high tool life, number of tool changes less, higher precision, better flexibility. Thus, CNC milling high speed crank the crankshaft rough outer direction of development. Jiangsu automatic car in South Asia Limited Fiat car crankshaft production line to see the German company BOEHRINGER two devices, one of which Taiwan several holes Crankshaft – broaching machine, in addition to a Taiwan high-speed CNC milling outside the crankshaft, to experience a “cut iron drunk “feeling. According to experts, Crankshaft – broaching machine is particularly suited to journal has undercut, the counterweight side without processing the crank shaft; outer high speed milling machining can not have an axial undercut crankshaft. The milling machine is a German company BOEHRINGER VDF 315 OM-4 High-speed milling machine the outer follower, which is the German company BOEHRINGER for automotive engine crankshaft design and manufacture of flexible CNC milling machine, the work rotating device application and milling feed servo control linkage , a fixture can not change the center of rotation of the crankshaft, and with the tracking crankpins of a crankshaft milling. VDF 315 OM-4 High-speed milling with integrated outer follower structural composite bed, both ends of the drive electronics synchronized rotation of the workpiece, having a dry cutting, high precision, and high cutting efficiency; the use SIEMENS 840D CNC milling machine control system, automatically generating a machining program input through the basic parameters of the part to be processed in the length of 450 700mm, turning diameter various crankshaft, connecting rod journal diameter less than 380mm ~ error of ± 0.02mm.

As can be seen from the above, the crankshaft roughing process is more popular: the main journal broaching process using an outer milling and high speed, evenHosel outer high-speed milling, and high speed tends to follow the outer milling, all dry cutting. Because these foreign equipment is expensive, product processing costs are high, some domestic machine tool manufacturers (such as Qinghai second machine tool manufacturers limited liability company) have developed a CNC crankshaft lathe, CNC high-speed crankshaft milling machine, CNC machine tools and other special crankshaft broaching machine tool. CNC Crankshaft Grinding finishing using domestic situation is quite common, improve product processing accuracy has been considerable degree. To meet the increasing processing requirements crankshaft, crankshaft grinding machine made high demands. Modern except crankshaft grinder have a high static and dynamic stiffness and high machining accuracy, but also requires a high grinding efficiency and more flexible. In recent years, the crankshaft grinding machine also requires stable machining accuracy, therefore, process capability coefficient of the crankshaft grinding machine provides Cp≥1.67, which means that half of the crankshaft grinding machine requires little actual crankshaft machining tolerances than a given tolerance.

With the application of modern drive and control technology, measurement control, the CBN (cubic boron nitride) grinding wheel and advanced machine components, to create the conditions for high-precision, high efficiency grinding of a crankshaft grinding machine. A technique called link follower neck grinding process. It reflects the results of these new technologies specific integrated applications. This follower grinding efficiency grinding process can significantly improve the crankpin, machining precision and flexibility.

When the follower rod neck for grinding as the crankshaft main journal axis of rotation, and a clamping all the grinding rod neck. In the grinding process, the grinding head swing Reciprocating feed track the eccentric rotation of the rod neck grinding process. To achieve follower grinding, X-axis must have in addition to the high dynamic performance, also must have sufficient tracking precision, to ensure rod neck shape tolerances required. CBN grinding wheel applications is an important condition for the follower rod neck grinding. Because of the high wear resistance of CBN grinding wheel, the grinding wheel diameter is almost the same, one can grind the dressing 600 to crankshaft 800. CBN grinding wheels may also be employed high grinding speed, the crankshaft grinding machine grinding speed may generally be up to 120 ~ 140m / s, the high grinding efficiency. Machine tool for complex machining of the crankshaft mentioned composite processing technology, we have to mention complex machine tools, the definition of multitasking machines is also changing with the times. Past the processing center called compound machine tools, but the varieties of exchange processing tool is limitedSystem, but also get out of the field of cutting machining, now no longer be a general call processing center of the compound machine. Composite tool should have integration step, more processing integration. From the environment in which the watch manufacturing, machine tool will always be one of the key developers of machine tools, functionality continues to expand, will move toward “a machine into a small factory” direction. Crankshaft machine tool, the Austrian company WFL horizontal milling machining center has a representative.

Crankshaft WFL company put forward the concept of “one clamping, fully completed,” the. M40G car milling centers integrated dual-spindle turning center axis machining center, deep boring, milling, drilling, and coordinate functions in one, crankshaft can fully processed on a milling machining center having two spindles the crankshaft can be processed directly into a finishing step. Currently also launched a similar complex machine, during CIMT2005, Shenyang CNC Machine Tool Co., Ltd. exhibited CKZ80-5 milling machining center is a complex machine, represents the highest level of similar machine tools in China. In the machine axis X, Y, Z, B-axis linear scale or grating detected roundness, closed loop control can be achieved. The machining center equipped with 48-96 stations can realize automatic tool changing magazine, a chucking process can be turning, milling, drilling, boring, tapping or the like. In terms of the finishing of the crankshaft, there have been integrated CBN CNC grinding step, i.e., once all the clamping grinding crankshaft main journal and the journal, such ships with double grinder wheelhead. Japan TOYADA Koki, Germany Junker (JUNKER), Germany NAXOS CNC grinding machines and other production of such devices are relatively mature. Here a brief overview of the development and production Japanese Koki TOYADA performance GF70M-T crankshaft grinding machine: the machine in order to meet the variety, low cost, high precision, mass production needs and design CNC crankshaft grinder, the grinding wheel and workpiece swing application linkage to the servo control technology, a fixture without changing the rotational center of the crankshaft to complete the grinding of all the journal, including the crankpin grinding track follower; hydrostatic spindle, hydrostatic guideway, hydrostatic feed screw (wheelhead) and linear gratings closed-loop control, produced using TOYADA Koki GC50 CNC control system, the grinding accuracy can be achieved journal roundness 0.002mm; miningCBN grinding wheel with a grinding line speeds up to 120m / s, with double wheelhead, high grinding efficiency. Improve tool performance diversification crankshaft machining cutting tool material for the efficient, high-speed processing offers the possibility of development, in addition to high-speed steel, cemented carbide, the development of superhard material plays an important role. PCD, PCBN cutting difficult machining, dry machining, hard cutting and other processing materials to create the conditions.

To meet the processing speed of the crankshaft, high efficiency, the demand for dry cutting, use is currently a large number of coated tools. TiN coating material from the development of A12O3, TiC, ZrO2, etc., in accordance with processing requirements, in order to improve high temperature performance, and the development of TiCN, TiAlN, TiSiN, CrSiN like. Now PVD (physical vapor deposition), the CVD (Chemical Vapor Deposition) technology innovation, the development of a single-layer multilayered, Melaleuca, composite coating, now developed into a nano-coating; deep hole machining process using a drill gun HSS drills instead of normal extended, drilling and tapping carbide material instead of high-speed steel material of the past. Currently finishing crankshaft gradually began to use CBN Wheel, CBN grinding wheel is expensive, but because of processing efficiency and high durability, cost-sharing to the tool on each workpiece but lower than the use of affordable generic wheel. According to the German NAXOS grinding machine factory data show that the use of CBN grinding wheel machining time can usually be reduced by 50 percentage, and processing cost savings of 50% or more. The main conclusion from the above crankshaft machining aspects discussed progress in crankshaft machining, whereby the following conclusions: multi-knife crank turning technology will gradually withdraw from the stage of history, in spite of this long period of time; high-speed machining has been quite effective in the crankshaft manufacturing degree of application; suitable for multi-species, small quantities of composite processing technology is a future direction of the crankshaft machining; improve cutting tool performance for the efficient high-speed, complex processing development to provide technical support.