When the working parts of the machine tool using miniature linear guides move, the steel balls circulate in the grooves of the bracket, and the wear of the bracket is distributed to each steel ball, thereby prolonging the service life of the linear guide. In order to eliminate the gap between the bracket and the rail, the preload can improve the stability of the rail system. The preload is obtained by installing an oversized steel ball between the rail and the bracket. The diameter tolerance of the steel ball is ±20 microns, with 0.5 micron increments. The steel balls are screened and classified and installed on the guide rails respectively. The size of the preload depends on the force acting on the steel balls. If the force acting on the steel ball is too large, the steel ball will withstand the preload for too long, which will increase the movement resistance of the bracket. There is a balance problem here; in order to improve the sensitivity of the system and reduce the movement resistance, the preload must be reduced accordingly, and in order to improve the movement accuracy and the retention of precision, it is required to have sufficient preload negative numbers, which are contradictory two. aspect. The design of the guide rail system strives to have the largest contact area between the fixed element and the moving element. This not only improves the carrying capacity of the system, but also the system can withstand the impact force generated by intermittent cutting or gravity cutting, spread the force widely, and expand the bearing capacity. The area of force. In order to achieve this, the groove shape of the guide rail system has various shapes, and there are two representative ones, one is called the Gedai type (pointed arch type), the shape is a semi-circular extension, and the contact point is the apex; One is circular arc shape, which can also play the same role. No matter what kind of structure, there is only one purpose, and strive to have more rolling steel ball radius contact with the guide rail (fixed element).
The factor that determines the performance characteristics of the system is: how the rolling elements contact the guide rail, which is the key to the problem. Strive to have the largest contact area between the fixed element and the moving element, which can not only improve the load-bearing capacity of the system, but also the system can withstand the impact force generated by intermittent cutting or gravity cutting, spread the force widely, and expand the force-bearing area. In order to achieve this, there are various groove shapes for the guide rail system. There are two representative ones. One is called the Gedai type (pointed arch type), the shape is a semicircular extension, and the contact point is the vertex; the other The species is arc-shaped and can also play the same role.
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