【導讀】第一節(jié)云臺設計方案的提出…第四章機械部分的設計………第七章參考資料………………………球型外殼能減少灰塵及各種干擾，日常維護方便，可達到隱蔽監(jiān)視的。目的，云臺在水平方向可連續(xù)350無級變速掃描，并設有設置攝像點的功能。隨著科學技術的不斷發(fā)展，人們已經不滿足于電話通信，對信息傳輸?shù)囊?，監(jiān)控電視主要是對機要部門、商場、貨場、生產等部門的監(jiān)視、控制和報警。輸管理、醫(yī)療衛(wèi)生、水下作業(yè)、鐵路現(xiàn)場、公安系統(tǒng)等國民經濟的各個部門。為適應安裝不同的攝象機及防護罩，云臺的承重應是不同的。因而應根據選用的攝象機及防。云臺的轉動是通過在控制室操作控制器，將。在電源供電電壓方面，目前常見的有交流24V和220v兩種。目前，還有直流6V供電的室內用小型云臺，可在其。內部安裝電池，并用紅外遙控器進行遙控。目前大多數(shù)云臺仍采用有線遙控方式。裝位置距控制中心較近，且數(shù)量不多時，一般采用從控制臺直接輸出控制信號進行控制。

　　

【正文】 low as possible to avoid the impact. On the one hand, velocity during forming must be sufficient for lubrication. On the other hand, we have to consider the rise in the yield stress corresponding to an increase in the strain rate which creates greater forces and which may cause fractures at the transition from the punch radius to the side wall of the part. In fing, short pressure dwell time is desirable. As the pressure dwell time drops the die surface temperature goes down and as a result the thermal wear This is counteracted by the enhanced mechanical wear due to the greater forming force, but the increase due to the strain rate is pensated by lower yield stress because of the lower cooling of the part. The optimal short pressure dwell can nowadays be determined quantitatively using the finite element method [3]. In addition to cost avoidance due to reduction in wear, short pressure dwell time is also an important technological requirement for the precision fing of near shape parts, which has a promising future. The requirements of high part quality and high output will only be met by a machine technology which takes into account the demands of the metal forming process in equal measure to the goal of decreasing work production costs. Previous press designs have not simultaneously met these technological and economical requirements to a sufficient extent, or they are very costly to design and manufacture, such as presses with link drives [6]. This makes it necessary to look for innovative solutions for the design of the press. Its design should be largely standardized and modularized in order to reduce costs [6]. Fig 1. Prototype press 3 Press Drive with Noncircular Gears Principle The use of noncircular gears in the drive of mechanical crank presses offers a new way of meeting the technological and economic demands on the kinematics of the press ram. A pair of noncircular gears with a constant center distance is thus powered by the electric motor, or by the fly wheel, and drives the crank mechanism uniform drive speed is transmitted cyclically and nonuniformly to the eccentric shaft by the pair of noncircular gears. If the noncircular gear wheels are suitably designed, the nonuniform drive of the driven gear leads to the desired stroketime behaviour of the ram. Investigations at the Institute for Metal Forming and Metal Forming Machine Tools (IFUM) of Hanover University have shown that in this simple manner all the relevant uninterrupted motions of the ram can be achieved for various forming processes [2]. Apart from, the advantages of the new drive, which result from the kinematics and the shortened cycle time, the drive concept is distinguished by the following favorable Propertius. Because it is a mechanical press, high reliability and low maintenance may be expected. In panion to linkage presses the number of parts and bearings is clearly reduced. Above all, a basic press type can be varied without further design changes by installing different pairs of gears, designed according to the demands of the customer. Unlike link drives, bearing locations and installations do not change within one load class as a result of different kinematics. Thus the above mentioned requirement of popularization and standardization is taken into account Reductions in time and costs are possible for the design and press manufacture. Prototype At the Institute for Metal Forming and Metal Forming Machine Tools (IFUM) a Cframe press has been remodeled and a pair of noncircular gears was installed. The previous back gears were replaced by a plaary gear set for this purpose. The work carried out shows that remodeling of existing presses for the new drive is possible. The state of the press at the end of the modelli is shown in figure 1. The press is designed for a nominal ram force of 1,000 N and 200 N of the die cushion. The center distance of the noncircular gears is 600 mm. The pair of noncircular gears has an average transmission ratio of gear wheel has 59 gear teeth, straighttoothed,module 10 mm (fiacre 2). The face width is 150 mm. The gears have involute gear teeth. We assume a noncircular base curve for the design of the flank geometry. As a result the tooth geometry of a noncircular gear varies along the circumference. In spite of this, it can be derived from the wellknown trapezium rack, however [4, 51. An algorithm for the putation, which takes the addendum and addendum into account exactly, has been developed. Fig. 2 View of the gears from the rear The press is designed for deep drawing of flat parts in single stroke operation mode. The maximum ram stroke is 180 mm, the number of strokes 32/min. At a stroke of 140 mm the ram velocity almost remains constant 71 mammals from 60 mm before lower dead center until lower dead center, see figure 3. Thus the velocity corresponds to the working velocity of hydraulic presses. The velocity of incidence of a crank mechanism with the same number of strokes would be 220 mammals, in parison. In order to keep the same average velocity with a crank press, the number of strokes would have to be halved. The short cycle time of the jodelled machine results from the fast upward motion. Because the press is run in single stroke operation mode, no particular requirements were made concerning handling time during design. The drive mechanism of the prototype with noncircular gears has in addition a favorable effect on the ram forces and the driving torques (failure 4). For a crank press the nominal force is normally available at 30 rotation of the crank shaft before the lower dead center. This corresponds to a section under nominal force of only 7 5% relative to the stroke. To reach the nominal force of 1,000 N, the drive has to supply a torque of 45