【正文】 ft on the reduction of inertia。附錄 附錄 1 英文原文 Rolling Contact Bearings The concern of a machine designer with ball and roller bearings is fivefold as follows:(a) life in relation to load。 as far as possible the elimination of drive space and reduce deadzone inverse error and improve displacement precision. Linear Roller Guides outstanding advantage is seamless, and can impose prepression. By the rail body, the slider, ball, cage, end caps and so on. Also known as linear rolling guide unit. Use a fixed guide body without moving parts, the slider fixed on the moving parts. When the slider moves along the rail body, ball and slider in the guide of the arc between the straight and through the rolling bed cover of Rolling Road, from the work load to nonwork load, and then rolling back work load, constant circulation, so as to guide and move the slider between the rolling into a ball. Bridge Crane Bridge crane is having an elevated track running in a bridgetype crane, also known as the crane. Bridge Crane in the laying of the bridge on both sides along the elevated track on the vertical run, lifting trolley along the bridge laying on the track in the horizontal operation, a scope of work of a rectangle, it can take full advantage of having the space below lifting materials from the ground equipment hindered. Bridge Crane widely used in indoor warehouses, factories, wharves and open storage yard and other places. Able to carry items, stood up, lifting status, and adjust operations, mainly for the workshop, sections and steel production lines yard, etc.. Lifting capacity usually in the 10 to 100 t. Bridge crane itself for horizontal movement, the winch frame for the vertical movement of the winch suspended from the hook for vertical movement, the direction of movement of three of the crane can work. In order to prevent bridge crane driver not clear in the specific hook campaign, on the ground are equipped with lifting the general mand or folder, put hook. If hanging overhead crane hoisted electromagic lifting plate, often operated by the drivers themselves. Bridge cranes can be divided into general overhead crane, simple girder bridge crane for bridge crane and metallurgical three. Ordinary general overhead crane from lifting trolley, having run institutions, having posed of a metal structure. Lifting up from the car and from institutions, agencies and the car running small frame consists of three parts. Lifting bodies, including the motor, brakes, reducer, and the pulley drum group. Motor through the reducer, driven rotating drum so that the wire rope around or down to lifting weights. Small frame is from the brackets and install or run agencies and institutions, such as car parts rack, usually welded structure. Crane running the driving mode can be divided into two categories: one category is the concentrated drive, which uses a motordriven initiatives on both sides of the drive shaft driven wheel。 Some of the clamp punctured ingot mould, with Ingot filed small pair of pliers. Feeding Crane: Charge will be added to the open hearth furnace. Trolley bottom of the column with the pickand inciting material to me and it into the furnace. The main column to bypass the vertical axis rotation, pickand rotary can swing from top to bottom. Deputy car repair furnace for such auxiliary operations. Fing Crane: to meet with hydraulic fing large workpieces. Trolley displayed on the main hook up special feeder to support and flip the workpiece。 (c) friction。s more sophisticated lathes are called machining centers since they are capable of performing, in addition to the normal turning operations, certain milling and drilling operations. Basically, a machining center can be thought of as being a bination turret lathe and milling machine. Additional features are sometimes included by the versatility of their machines. Numerical Control One of the most fundamental concepts in the area of advanced manufacturing technologies is numerical control(NC). Prior to the advent of NC, all machine tools were manually operated and controlled. Among the many limitations associated with manual control machine tools, perhaps none is more prominent than limitation of operator skills. With manual control, the quality of the product is directly related to and limited to the skills of the operator. Numerical control represents the first major step away from human control of machine tools. Numerical control means the control of machine tools and other manufacturing systems through the use of prerecorded, written symbolic instructions. Rather than operating a machine tool, an NC technician tool to be numerically controlled, it must be interfaced with a device for accepting and decoding the programmed instructions, known as a reader. Numerical control was developed to overe the limitation of huma n operators, and it has done so. Numerical control machines are more accurate than manually operated machines, they can produce parts more uniformly, they are faster, and the longrun tooling costs are lower. The development of NC led to the development of several other innovations in manufacturing technology: 1. Electrical discharge machining. 2. Laser cutting. 3. Electron beam welding. Numerical control has also made machines tools more versatile than their manually operated predecessors. An NC machine tool can automatically produce a wide variety of parts, each involving an assortment of widely varied and plex machining processes. Numerical control has allowed manufacturers to undertake the production of products that would not have been feasible from an economic perspective using manually controlled machine tools and processes. Like so many advanced technologies, NC was born in the laboratories of the Masschusetts Institute of Technology. The concept of