The Analysis of Electric Differential Drive Technology and Characteristics on Overhead Crane

Transcription

1 06 International Conference on Materials, Information, Mechanical, Electronic and Computer Engineering (MIMECE 06) IBN: The Analsis of Electric Differential Drive Technolog and Characteristics on Overhead Crane Jian-Ming Yuan and Jing-Feng Zhang ABTRACT Using electrical differential drive to reduce the weight of the trolle on bridge crane. The analsis of rotational speed of reel on both sides of the crane girder in different conditions show that when the trolle and the hook make joint motion rotational speed of reel is uniquel determined b the condition that the middle pulle of the hook does not rotate. tuding the forces of the rope under joint motion and the conditions that the middle pulle does not rotate in the view of mechanics, then, calculating the minimum of hoist that makes the trolle run normall. tuding the power of the reel drive motor under the joint motion, calculating minimum power required for a single motor. INTRODUCTION Overhead Crane is widel used in iron and steel, metallurg, transportation, energ, chemicals, machiner, light industr, environmental protection, water conservanc and other industries of the national econom and plaed an important role in the national econom. With the rapid development of China's econom and the urbanization process, the market demand of large-scale machiner and equipment which make overhead crane as representative is huge. In recent ears, our crane manufacturing industr have been doing a lot of useful work around environmental protection and lightweight, among which mechanical differential technolog has been used in grab ship unloader [-], b reducing weight of the trolle, which achieve lightweight; the ke components to achieve mechanical differential 354

2 technolog mechanical differential gearbo is bulk and production costs is high, so in recent ears researchers have proposed using the electric differential technolog in grab ship instead of mechanical differential technolog [3-5], and analzes the requirements of electrical control of electrical differential and the main similarities and differences between electrical and mechanical differential. For the overhead crane, present research is focused on the optimization of the trolle, running mechanism, bridge structure and other aspects [6-8] to achieve lightweight. This paper puts forward electric differential drive technolog to achieve significant weight loss of overhead crane, and stud driving speed, power distribution and other characteristics. PRINCIPLE OF ELECTRICAL DIFFERENTIAL DRIE TECHNOLOGY ON OERHEAD CRANE Overhead crane b electrical differential driving through removing lifting mechanism on the trolle and driving mechanism of self-driving trolle and placed them on both ends of the main beam, greatl reducing the weight of the trolle and the load on the beam, which can greatl reduce the weight of the beam and combining lifting and trolle drive to reduce the weight of the drive to achieve significant weight loss of overhead crane driving drum -trolle 3- movable pulle group on the hook 4-hoisting 5- fied pulle group 6-beam Figure. implified model of Overhead crane b electrical differential driving. Overhead crane b electrical differential driving is shown in Figure, leading to a rope from one side of the reel, let it pass through the side of the fied pulle group, the movable pulle group on the hook, and then through the fied pulle group on the other side, finall twine on the reel on the other side. Electrical differential overhead crane works b controlling the speed and direction of the reel to achieve trolle, lifting and their joint motion. When both sides of the reel turn in the opposite direction and the speed is the same, the hook lifts; when both sides of the reel turn in the same direction and speed, the trolle moves; otherwise, the trolle and hook achieve joint motion. 355

3 MOTION ANALYI OF TROLLEY AND HOOK As shown in figure, and, respectivel represent linear velocit of the drum on both sides,, respectivel represent walking speed of the trolle and lifting speed of the hook,, respectivel represent the linear velocit of wire rope between the fied pulle group and movable pulle group. When the trolle and the hook move at a certain speed, b analsis of the change of the length of wire rope, the relationship between moving speed of the trolle as well as the hook and rotating speed of the drum on both sides is as follows: m () In formula: m is the ratio of pulle group. 3 -driving drum -fied pulle group 3-trolle 4-hoisting 5-movable pulle group on the hook Figure. Motion model of trolle and hook. 5 4 According to the formula (), rotating speed of the drum on both sides is not certain when the trolle and the hook move at a certain speed. It is because lifting speed is certain b rotation of middle pulle to make the change of the length of wire rope same when rotating speed to make hook lift of the drum is different. In fact, rotating speed of the drum on both sides is decided b work speed of the trolle and the hook and it must be uniquel identified. Therefore, the middle pulle can not rotate. Assuming the middle pulle does not turn, then =.According to the formula () the relationship between moving speed of the trolle as well as the hook and rotating speed of the drum on both sides is as follows: () 356

4 According to the formula (), when =, namel the drum collect or release rope, =0, =/m=/m, namel the hook lift but the trolle does not move; when =-, namel one drum collect rope but another drum release rope, ==, =0, namel the trolle move but the hook does not lift. THE CONDITION TO MAKE THE PEED OF TROLLEY AND HOOK CERTAIN F G driving drum -fied pulle group 3-trolle 4-hoisting 5-movable pulle group on the hook Figure 3. Mechanics model of trolle and hook. Q As shown in figure,, respectivel represent tension of rope on both sides, G is weight of the trolle, F is running resistance of the trolle, Q is weight of hoisting. F (Q G) (3) In formula: ω is running resistance coefficient. ΔF d d 0.33( ) (4) D In formula: ΔF is stiff resistance of rope; d is diameter of rope; D is diameter of pulle. Q d Δf μ (5) m D In formula: Δf is rolling resistance of pulle; d is inner diameter of pulle bearing; μ is rolling friction coefficient. 357

5 When the trolle and hook make joint motion, according to load balance the relationship is as follows: F m m η η (6) ηd η Q m m η η η η η d In formula: ηd is efficienc of guiding pulle; η is efficienc of pulle group. Known from the analsis of the above, when work speed of the trolle and the hook is certain, to make rotating speed of the drum on both sides uniquel identified the middle pulle can not rotate. According to load analsis, tension difference of rope on both sides of middle pulle is less than rolling resistance of pulle. m ηd η ΔF m η η d B solving formula (6) and (7), the minimum of hoisting to make rotating speed of the drum on both sides uniquel identified is acquired. CHARACTERITIC ANALYI OF DRIING MOTOR POWER When the hoisting rises, it makes negative work for motor on both sides. When the hoisting drops, it makes positive work for motor on both sides. When the trolle runs, motor consumes energ to overcome running resistance. When work speed of the trolle and the hook is certain, the power that these three work condition need is constant. When the trolle and the hook make joint motion, formula (6) is simplified as follow: Q ( F) m Q ( F) m etting the power of the motor on both sides to P and P, one side that collects rope makes negative work for motor, another side that releases rope makes positive work for motor. P P Q ( m Q ( m F)( F)( The installed capacit of motor for electrical differential driving mechanism is decided b one side whose power is much than other. According to formula (9), P is much than P, so the analsis for P is more important to select the rated power of motor. Δf m m ) ) (7) (8) (9) 358

6 P Q Q ( F)( m ) ( Q F mf) (0) m m From formula (0), Q and m have much influence on the rated power of motor because F is little. The greater the weight of hoisting, the much power that the motor need; the smaller m, the much power that the motor need. When the weight of hoisting is constant, according to average inequalit, the minimum of P is as follow: P min (Q F Q F ) () CONCLUION The structure of electrical differential driving mechanism is simple and manufacturing is eas. Appling it to overhead crane accords with present development tendenc of crane. This page according to the theor of electrical differential driving, analze the relationship between moving speed of the trolle as well as the hook and rotating speed of the drum on both sides. It has practical significance on the control of electrical differential driving. B analsis of work condition that the trolle and the hook make joint motion, calculating the power that the motor need on both sides. It has guiding significance on choice of motor. ACKNOWLEDGMENT upported b National cience and Technolog upport Program Project (Grant No. 05BAF06B05) REFERENCE. u Chao, un Jingong.300t/h mechanical differential bridge-tpe grab ship unloader [J]. Hoisting and Conveing Machiner, 0, (): Liu Chaojie, Huang Xulin. Analsis of planet differential mechanism of overhead grab ship-unloader [J]. Hoisting and Conveing Machiner, 04, (7): Peng Chuansheng. Development and application of four-drum rope trolle [J]. Hoisting and Conveing Machiner, 000, (0): Yang Zhenli. An Electrical Differential Driving Bridge Grab Bucket hip Unloader [J]. Port Loading and Unloading, 04, (5): Wang Junhua. The power and load research of four-drum rope trolle [J]. Hoisting and Conveing Machiner, 008, (4): Xu Xifeng. Coupling mechanism of bridge gantr crane bo girder structure and stiffener [D]. outhwest Jiaotong Universit, hi Xiaofei. tud of particle swarm optimization method and development of software for overhead travelling crane girders [D]. Taiuan Universit of cience and Technolog, Gao Fei, Liu Jinliang. The optimization of crane girder based on the improved genetic algorithm [J]. Hoisting and Conveing Machiner, 0, (8):