The number of sports, the number of 鬓 鬓 产 产 产 淤 淤 淤 淤 淤 蛇 蛇 蛇 蛇 蛇 蛇 蛇 蛇 The intestines are called the multi-figure current-changing liquid hydraulic suspension throttle rubber current-changing liquid rubber mold air electrode response point vibration to achieve the best damping effect. The active control damping system uses linear real-time optimization adjustment technology and adopts closed-loop control. At present, fluid drive control or servo motor drive control is mostly used. The literature proposes an active control of vibration absorption technology and its successful application in diesel engines. According to the vibration characteristics and laws of internal combustion engine, an electromagnetic active control vibration absorber is developed. A new control system combining active vibration absorber and passive vibration isolation technology is proposed to realize the tracking reduction of the fundamental frequency vibration of internal combustion engine. The test was successful on a diesel engine. In the literature, the active vibration isolation under the engine cycle excitation is studied experimentally. The relative displacement between the upper mass acceleration and the mass absolute velocity is used as the control parameter, and good results are obtained. There are many methods for active control, and the engine mainly adopts the optimal control method and the adaptive control method. Conclusion With the improvement of engineering machinery performance requirements, the traditional vibration reduction technology can not meet the requirements, and it is imperative to adopt new vibration reduction technology. In the future, we should apply modern design methods and methods, and adopt advanced manufacturing technology to improve the design and manufacturing level of the engine, thereby reducing or eliminating the harmful exciting forces and moments generated during engine operation. On the other hand, it is necessary to adopt an engineering machinery engine damping system that controls the effective cost, so as to reduce the impact of engine vibration on the performance of engineering machinery and improve the competitiveness of China's construction machinery products in the market. References Yu Chengbo, He Huaibo, Shi Xiaohui. Vibration control and application of internal combustion engines. Beijing National Defense Industry Press, [Japan] Xiao Linming. Automotive vibration. Beijing Machinery Industry Press, Hao Zhiyong. Research on active control damping device for internal combustion engine. Journal of Internal Combustion Engine, Zhang Hongtian et al. Research on Active Control Vibration Reduction Technology of Internal Combustion Engines. Internal combustion engine engineering, Liu Zhigang and so on. Research on active vibration isolation test under cyclic excitation. Internal Combustion Engine Engineering, (Received date: The third engineering office of the No. 16 Bureau of the Ministry of Railways of the Air Compressor Engine, Liao Shixin, purchased two Shanghai Ingersoll Rand internal combustion air compressors during the construction of the Longdongbao Airport in Guiyang. The internal combustion engine model is the German Deutz air-cooled engine. The engine is better installed on the transport vehicle as the power, but it is installed on the air compressor, especially when it is above the altitude, because the air compressor is not in place during use, the heat dissipation condition is poor, and the engine temperature rise is too high. Faults such as pulling cylinders and even crankshaft deformation and fracture, the consumption of accessories is rising linearly, the downtime is long, the mechanical utilization rate is low, and the economic efficiency is poor. In order to repair the machine, it was decided to change the air-cooled engine to a water-cooled engine. Depending on the original engine rated speed and power, an engine greater than or equal to the rated speed must be selected to match. After investigation, it was decided to select the rated speed of the Dongfeng Cummins engine. The measured air compressor coupling housing size is basically the same as that of the Dongfeng Cummins engine series. According to the size of the engine and its four frame positions and frame beam size, four additional supports are designed, two for the rear support and two for the front support. The four bases on the engine are preferably rectangular. . A suitable cushion must be selected between the base and the support. The maximum intake resistance of the system is Cummins series pressurized water-cooled construction machinery. The moving side of the engine should not exceed the pipeline layout to ensure that the engine intake temperature is not higher than the ambient temperature and the pipeline is in good condition. Due to the high dust content in the working environment of the compressor, a heavy-duty three-stage air filter must be used. The line from the outlet of the air filter to the inlet of the engine is as straight as possible and should be used in the recommended size (pipeline to engine). Because the maximum allowable bending moment at the outlet flange of the exhaust manifold is the outlet of the supercharger, the muffler installed on the engine should be flexibly connected with the exhaust pipe. To reduce the resistance, the pipe should be as straight as possible, and the recommended exhaust pipe should be used. The specifications and capacity of the second muffler within the diameter of the road shall be determined according to the amount of exhaust in the engine parameter table. This machine only configures the elbow and the connection hoop at the outlet of the supercharger, and makes a discharge pipe with an inner length of about the discharge port to prevent rain and snow. According to the pressure speed of the engine on the cooling water volume and the working conditions of the air compressor, the domestic engine radiator and fan were selected, and the windshield was designed. The bending moment of the fan wheel should not be exceeded. 7 The fan is controlled from the engine component between 20 and the spring washer cannot be used when installing the fan. The gap between the windshield (hair dryer) and the fan tip should be as small as possible and should not exceed the diameter of the fan. 2 5 fan in the windshield, the front extension should be one-third of the projection width, the pipe between the engine and the radiator from the radiator is as straight as possible, reducing bending and sufficient flexibility to adapt to the engine Relative movement between the heat sink and the heat sink. The coolant is synthesized by using water and ethylene glycol solution. The purpose of using this solution is to reduce the occurrence of water cavitation and rust, and to increase the boiling point of water during the hot season, and to prevent freezing in winter. According to the technical data of the engine flywheel housing, redesign the coupling pin plate as shown in the figure. The pin screw design pin plate design must ensure that there is no mechanical load on the crankshaft. Keep the crankshaft axial clearance. The engine load can be accelerated from low idle to work. The speed can meet the acceleration requirements at the specified maximum altitude. Any drive attachment mounted on the engine, its size and the manner in which the load is applied to the engine must not detract from the performance and reliability of the engine. The natural frequency must be outside the critical frequency of the engine. Before the outer casing is connected, the clutch should be removed and the machined pin plate mounted. The compressor should be repaired to check and adjust the bearing clearance. Clean the oil and gas separator lubrication line radiators and fan blades. After the transformation of this water-cooled screw compressor, in the construction of Guiyang construction site for more than three months, no previous failures were found, the technical transformation cost was 10,000 yuan, and the purchase of a water-cooled engine of the same power level was 260,000 yuan. station. From the engineering cost calculation, it has good economic benefits and proves that the technical transformation plan is successful. (Received the date of the receipt, page 1 of the entire batch before the entire batch of the front hole of the hole group processing, and then the hole group processing, positioning as shown. Firstly, the processed hole assembly person positioning mandrel positioning mandrel is placed on the type positioning seat to limit the degree of freedom of the front frame. Then, according to the distance from the mast to the plate when the combined machine tool is processed, the distance from the center line of the positioning mandrel to the plate is determined, and then the positioning point of the mandrel point is located. The positioning seat clamps and positions the mandrel by opening and closing, which is convenient for clamping the workpiece, thereby determining the degree of freedom and correctly processing the hole group. Similarly, by increasing the position of the positioning seat and the adjusting positioning seat on the flat plate, 9) hole groups can be machined, thereby completing the machining of the C' hole group one by one, and achieving the use of the reference conversion and processing on the same combined machine tool. The purpose of the front frame of the model. For other large structural parts of the loader, such as the boom and the rear frame, the machining process equipment can also be referred to this method. (Received date one construction machinery, one
A hoist is a device used for lifting or lowering a load by means of a drum or lift-wheel around which rope or chain wraps. It may be manually operated, electrically or pneumatically driven and may use chain, fiber or wire rope as its lifting medium.
The basic hoist has two important characteristics to define it: Lifting medium and power type. The lifting medium is either wire rope, wrapped around a drum, or load-chain, raised by a pulley with a special profile to engage the chain. The power can be provided by different means. Common means are hydraulics, electrical and air driven motors. Both the wire rope hoist and chain hoist have been in common use since the 1800s, however mass production of an Electric Hoist did not start until the early 1900s and was first adapted by Germany. A hoist can be built as one integral-package unit, designed for cost-effective purchasing and moderate use, or it can be built as a built-up custom unit, designed for durability and performance. The built-up hoist will be much more expensive, but will also be easier to repair and more durable. Package units were once regarded as being designed for light to moderate usage, but since the 60s this has changed. Built-up units are designed for heavy to severe service, but over the years that market has decreased in size since the advent of the more durable packaged hoist. A machine shop or fabricating shop will use an integral-package hoist, while a Steel Mill or NASA would use a built-up unit to meet durability, performance, and repairability requirements. NASA has also seen a change in the use of package hoists. The NASA Astronaut training pool, for example, utilizes cranes with packaged hoists.
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