【正文】 y may be cut either circumferentially, so that they engage by cylindrical mating, or on the faces of the mating elements. Devices such as linear drives or motoroperated screw drivers must run to definite limit and then e to a stop. An overloadrelease type of clutch is required for these applications. These clutches are usually springloaded so as to release at a predetermined toque. The clicking sound which is heard when the overload point is reached is considered to be a desirable signal. Magic fluid clutch or brake is a relatively new development which has two parallel magic plates. Between these plates is a lubricated magic powder mixture. An electromagic coil is inserted somewhere in the magic circuit. By varying the excitation to this coil, the shearing strength of the magic fluid mixture may be accurately controlled. Thus any condition from a full slip to a frozen lockup may be obtained. 齒輪和軸的介紹 司徒忠 摘 要 :在傳統(tǒng)機(jī)械和現(xiàn)代機(jī)械中齒輪和軸的重要地位是不可動(dòng)搖的。 that is ,a righthand driver goes with a righthand driven. In the design of crossedhelical gears, the minimum sliding velocity is obtained when the helix angle are equal. However, when the helix angle are not equal, the gear with the larger helix angle should be used as the driver if both gears have the same hand. Worm gears are similar to crossed helical gears. The pinion or worm has a small number of teeth, usually one to four, and since they pletely wrap around the pitch cylinder they are called threads. Its mating gear is called a worm gear, which is not a true helical gear. A worm and worm gear are used to provide a high angularvelocity reduction between nonintersecting shafts which are usually at right angle. The worm gear is not a helical gear because its face is made concave to fit the curvature of the worm in order to provide line contact instead of point contact. However, a disadvantage of worm gearing is the high sliding velocities across the teeth, the same as with crossed helical gears. Worm gearing are either single or double enveloping. A singleenveloping gearing is one in which the gear wraps around or partially encloses the worm.. A gearing in which each element partially encloses the other is, of course, a doubleenveloping worm gearing. The important difference between the two is that area contact exists between the teeth of doubleenveloping gears while only line contact between those of singleenveloping gears. The worm and worm gear of a set have the same hand of helix as for crossed helical gears, but the helix angles are usually quite different. The helix angle on the worm is generally quite large, and that on the gear very small. Because of this, it is usual to specify the lead angle on the worm, which is the plement of the worm helix angle, and the helix angle on the gear。Shaft In the force analysis of spur gears, the forces are assumed to act in a single plane. We shall study gears in which the forces have three dimensions. The reason for this, in the case of helical gears, is that the teeth are not parallel to the axis of rotation. And in the case of bevel gears, the rotational axes are not parallel to each other. There are also other reasons, as we shall learn. Helical gears are used to transmit motion between parallel shafts. The helix angle is the same on each gear, but one gear must have a righthand helix and the other a lefthand helix. The shape of the tooth is an involute helicoid. If a piece of paper cut in the shape of a parallelogram is wrapped around a cylinder, the angular edge of the paper bees a helix. If we unwind this paper, each point on the angular edge generates an involute curve. The surface obtained when every point on the edge generates an involute is called an involute helicoid. The initial contact of spurgear teeth is a line extending all the way across the face of the tooth. The initial contact of helical gear teeth is a point, which changes into a line as the teeth e into more engagement. In spur gears the line of contact is parallel to the axis of the rotation。 30(6)： 2～ 8 [11].Gang Feng． A Compensating Scheme for Robot Tracking Based Oil Neural Networks． Robotics and Autonomous Systems． 1 995： 1 99206 [12].Yang Simon X， Meng Max． An Effcient Neural Network Method for Realtime Motion Planning with Safety Consideration． Robot and Autonomous Systems． 20xx [13].張穎，吳成東，原寶龍．機(jī)器人路徑規(guī)劃方法綜述．控制工程． 20xx， 10(50)： 1～2 [14].李玲，鄒 大勇，謝維達(dá)．基于自適應(yīng)模糊人工勢(shì)場(chǎng)法的自動(dòng)引導(dǎo)小車路徑規(guī)劃．長沙電力 學(xué)院學(xué)報(bào)． 20xx． 20(3)： 13 。 61 參考文獻(xiàn) [1] J. P. Hong, H. MSh im, S. B. J ung, et al. 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