Fix the problem of dimension chain

Equipment maintenance, the use of dimension chain principle to analyze problems, to help resolve the correlation between surface position size precision and position accuracy problem, is helpful to choose the suitable method to repair. A, the definition of the dimension chain of mechanical equipment in the process of assembly and parts processing, parts surface or between axis lined the size of a set of a closed form, one dimension tolerance and limit deviation determined by other size tolerance and limit deviation, such a set of size is called the dimension chain. If all dimensions on the same parts, called parts dimension chain. If all the dimension is not the same parts, is composed of several parts in parts size, is called the assembly dimension chain. All sizes are called ring of dimension chain. Can independently existing ring form a ring. Controlled by the other dimension, the natural end of processing or assembling ring call end ring, or closed loop. Assembly dimension chain end ring tend to represent the size of the assembly accuracy requirement. Parts dimension chain end ring for the lowest accuracy requirement, often do not make dimension. In the composition of ring, all its size increases, end ring also increase is called ring. And increase the size of itself, instead of a closed ring is less called minus ring. Assembly, through the size change to meet the requirements of the closed loop form a loop is called compensation loop. Compensation loops and replacement and adjustment. 2. The connection between the dimension chain form equipment parts, often at the same time, there are several dimension chain between them together, each other to form three types of form. ( 1) Parallel dimension chain: a few dimension chain, by one or more public ring form called parallel dimension chain is linked to each other. ( 2) Series: dimension chain series dimension chain is each subsequent dimension chain, before a dimension chain as a baseline base or contact form. ( 3) Composite group size chain: mixed dimension chain, is at the same time has a parallel and series two kinds of connection form of dimension chain. Second, common the calculation of the dimension chain calculating dimension chain, is according to the equipment parts and components in the process of machining and assembly accuracy requirement, to determine the basic size of each ring dimension chain and its limit deviation. The calculation process of dimension chain, usually known as the dimension chain. In solving the dimension chain, often need to solve the problem is: ( 1) According to the basic size of each ring, limit deviation and tolerance, and calculate the end ring of basic dimensions, tolerances and tolerances. In the dimension chain principle is called positive problem solution. ( 2) According to the basic size of end ring, extreme deviation and tolerance, the basic size of ring is calculated, the limit deviation and tolerance. In the dimension chain principle is known as the opposite problem. ( 3) According to put an end to the ring ring and other components of basic dimensions, tolerances and tolerances, calculation of a ring of basic dimensions, tolerances and tolerances, in the middle of the dimension chain principle is known as the solution of the problem. Common calculation methods of dimension chain are as follows: 1. 2 positive problem calculation method. 3 opposite problem calculation method. In the middle of the solution to problems