Application du guidage linéaire dans la machine-outil
Le système de rail de guidage permet à la machine-outil d'obtenir une vitesse d'avance rapide. Dans le cas d'une même vitesse de broche, l'avance rapide est une caractéristique des guides linéaires. Les guides linéaires, comme les guides plats, ont deux éléments de base ; l'un comme guide est un élément fixe, et l'autre est un élément mobile. Le guide linéaire étant un composant standard, il est destiné aux fabricants de machines-outils. La seule chose à faire est de traiter le plan d'un rail de montage et d'ajuster le parallélisme du rail. Bien entendu, afin d'assurer la précision de la machine-outil, un léger raclage du banc ou de la colonne est indispensable. Dans la plupart des cas, l'installation est relativement simple.
Compared with flat guide rails, the cross-sectional geometry of linear guide rails is more complicated than that of flat guide rails. The reason for the complexity is that grooves need to be machined on the guide rails to facilitate the movement of sliding elements. The shape and number of grooves depend on the machine tool to complete. Function. For example: a guide rail system that bears both linear force and subversive moment is compared with a guide rail that only bears linear force. The design is very different.
There is no intermediate medium between the moving element and the fixed element of the linear guide, but a rolling steel ball. Because the rolling steel ball is suitable for high-speed motion, has a small friction coefficient and high sensitivity, it can meet the working requirements of moving parts, such as the tool holder and carriage of the machine tool. The basic function of the fixed element (guide rail) of the linear guide system is like a bearing ring, and the bracket for mounting the steel ball is shaped like a "v". The bracket wraps the top and both sides of the rail. In order to support the working parts of the machine tool, a set of linear guide has at least four supports. Used to support large working parts, the number of brackets can be more than four.
When the working parts of the machine tool move, the steel balls circulate in the groove 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 guide rail, the preload can improve the stability of the guide rail system and the preload can be obtained. It is to install an oversized steel ball between the guide 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.
If the working time is too long, the steel ball starts to wear out, and the preload on the steel ball starts to weaken, resulting in a decrease in the movement accuracy of the working parts of the machine tool. If you want to maintain the initial accuracy, you must replace the rail bracket, or even replace the rail. If the rail system has a preload effect. The accuracy of the system has been lost, and the only way is to replace the rolling elements.
La conception du système de rail de guidage s'efforce d'avoir la plus grande surface de contact entre l'élément fixe et l'élément mobile. Cela améliore non seulement la capacité de charge du système, mais également le système peut résister à la force d'impact générée par la coupe intermittente ou la coupe par gravité, répartir largement la force et augmenter la capacité portante. Le domaine de la force. Pour ce faire, il existe différentes formes de rainures du système de rail de guidage, et il y en a deux représentatives, l'une est appelée le type Gedai (type arc pointu), la forme est une extension semi-circulaire, et le point de contact est le sommet ; l'autre est One est en forme d'arc de cercle, qui peut également jouer le même rôle. Quel que soit le type de structure, il n'y a qu'un seul but, et s'efforcer d'avoir plus de contact de rayon de billes d'acier roulant avec le rail de guidage (élément fixe). Le facteur qui détermine les caractéristiques de performance du système est : la manière dont les éléments roulants entrent en contact avec le rail de guidage, qui est la clé du problème.