Chinese name: linear guide rail, also known as line rail, slide rail, linear guide rail and linear slide rail. Usage: Used for linear reciprocating motion. Classification: introduction, function, characteristics, working principle, application field, precautions, development and introduction of guide rail and screw.
It is divided into square ball linear guide, double-axis core roller linear guide and single-axis core linear guide. function
The function of linear motion guide rail is to support and guide the moving parts to do reciprocating linear motion in a given direction. According to the nature of friction, linear motion guide can be divided into sliding friction guide, rolling friction guide, elastic friction guide and fluid friction guide. Linear bearing is mainly used for automation machinery, such as machine tools, bending machines and laser welding machines imported from Germany. Of course, linear bearing is used with a straight axis. Linear guide rail is mainly used in mechanical structures with high precision requirements, and its characteristics are as follows
Self-alignment ability
The DF _ (45-45) combination from the circular groove can be absorbed by the rail slider even if the installation surface is somewhat deviated due to the elastic deformation of the steel ball and the transfer of the contact point, resulting in self-positioning ability and smooth movement, with high accuracy and stability.
With interchangeability
Due to the strict control of manufacturing accuracy, the size of the linear guide rail can be kept within a certain level, and the slider is designed with a cage to prevent the steel ball from falling off, so the accuracy of some series is interchangeable. Customers can order guide rails or sliders as needed, or store the guide rails and sliders separately to reduce storage space.
All-round high rigidity.
Using four rows of circular grooves and four rows of steel balls with equal contact angle of 45 degrees, the steel balls can achieve an ideal two-point contact structure and can bear loads in the up, down, left and right directions; If necessary, a preload can be applied to improve the stiffness. principle of operation
It can be understood as a rolling guide, in which the steel ball rolls endlessly between the slider and the guide rail, so that the load platform can easily move linearly along the guide rail with high precision, and the friction coefficient can be reduced to one fiftieth of that of the ordinary traditional sliding guide, so that high positioning accuracy can be easily realized. The final unit design between the slider and the guide rail makes the linear guide rail bear loads in all directions at the same time. Patented reflux system and simplified structural design make HIWIN's linear guide rail move more smoothly and with low noise.
Slider-Change the motion from curve to straight line. The new guide rail system enables the machine tool to obtain faster feed speed, which is the characteristic of linear guide rail at the same spindle speed. Like the plane guide rail, the linear guide rail has two basic elements; One is a fixed element as a guide, and the other is a moving element. As the linear guide rail is a standard part, the only thing that the machine tool factory has to do is to process a plane for installing the guide rail and adjust the parallelism of the guide rail. Of course, in order to ensure the accuracy of the machine tool, a small amount of scraping and grinding of the bed or column is essential, and in most cases, the installation is relatively simple. As a guide rail, the guide rail is hardened steel, which is put on the installation plane after fine grinding. Compared with the plane guide rail, the cross-sectional geometry of the linear guide rail is more complicated than the plane guide rail. The complicated reason is that grooves need to be machined on the guide rail to facilitate the movement of the sliding element. The shape and number of grooves depend on the function of the machine tool. For example, the guide rail system bearing both linear force and overturning moment is quite different from the guide rail bearing only linear force in design.
The fixed element (guide rail) of linear guide rail system basically acts like a bearing ring and a bracket for installing steel balls, which is V-shaped. The bracket wraps the top and both sides of the guide rail. In order to support the working parts of the machine tool, a set of linear guide rails has at least four brackets. In order 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, thus prolonging the service life of the linear guide rail. In order to eliminate the gap between the bracket and the guide rail, the preload can improve the stability of the guide rail system. Pre-load is obtained by installing oversized steel balls between the guide rail and the bracket. The diameter tolerance of steel balls is 20 microns, and the steel balls are screened and classified in increments of 0.5 microns, which are installed on the guide rails respectively. The magnitude of preload depends on the force acting on the steel ball. If the force acting on the steel ball is too large and the pre-tightening time is too long, the movement resistance of the support will increase, and the balance problem will occur; In order to improve the sensitivity of the system and reduce the motion resistance, the pre-tightening force should be reduced accordingly, while in order to improve the motion accuracy and maintain the accuracy, it is required to have enough negative pre-tightening force, which are two contradictory aspects.
When the working time is too long, the steel ball begins to wear, and the pre-tightening force acting on the steel ball begins to weaken, which leads to the decline of the motion accuracy of the working parts of the machine tool. If the initial accuracy is to be maintained, the guide bracket or even the guide rail must be replaced. If the guide rail system has been preloaded. The accuracy of the system has been lost, and the only way is to replace the rolling elements.
The design of the guide rail system maximizes the contact area between the fixed element and the moving element, which can not only improve the bearing capacity of the system, but also bear the impact force caused by intermittent cutting or gravity cutting, widely disperse the force and expand the bearing area. In order to achieve this, the groove shape of the guide rail system is varied and there are two kinds of representativeness. One is called Gothic (pointed arch), which is an extension of a semicircle, and the contact point is the vertex; The other is an arc, which can also play the same role. No matter which structural form, there is only one purpose, to strive for more rolling steel ball radius to contact with the guide rail (fixed element). The factors that determine the performance characteristics of the system are: how the rolling body contacts the guide rail, which is the key to the problem. application area
1, linear guide rail is mainly used for automation machinery, such as machine tools, paper bowl machines and laser welding machines imported from Germany. Of course, linear guides and linear shafts are used together.
2. The linear guide rail is mainly used in mechanical structures with high precision requirements. Rolling steel balls are used to replace the intermediate medium between the moving element and the fixed element of the linear guide rail. Because the rolling steel ball is suitable for high-speed movement, it has low friction coefficient and high sensitivity, and meets the working requirements of moving parts, such as tool rest and carriage of machine tools. If the force acting on the steel ball is too large and the steel ball is preloaded for too long, the movement resistance of the support will increase. Pay attention to use
Linear guide rail is a precision part, so it needs to be used with great care. Even if the high-performance linear guide rail is not used properly, it can not achieve the expected performance effect, and it is easy to damage the linear guide rail. Therefore, the following items should be paid attention to when using the linear guide rail:
prevent rust
When holding the linear guide rail directly by hand, it is necessary to fully wash the sweat off your hands and apply high-quality mineral oil before operation, especially in rainy season and summer.
Keep the environment clean
Keep the linear guide rail and its surrounding environment clean. Even if invisible smile dust enters the guide rail, it will increase the wear, vibration and noise of the guide rail.
Be careful in installation.
Be careful when using and installing the linear guide rail. It is not allowed to punch holes forcibly. It is not allowed to hit the guide rail directly with a hammer. It is not allowed to transmit pressure through rollers.
Installation tools should be suitable.
Use suitable and accurate linear guide rail installation tools. Try to use special tools, and try to avoid using cloth, short fibers and the like.
Clean guide rail
As one of the core components of equipment, guide rail and linear shaft play a guiding and supporting role. In order to ensure the high machining accuracy of the machine tool, its guide rail and straight line are required to have high guiding accuracy and good motion stability. During the operation of the equipment, a large amount of corrosive dust and smoke will be produced during the workpiece processing, which will be deposited on the surfaces of the guide rail and the linear shaft for a long time, which will greatly affect the processing accuracy of the equipment, and will form corrosion spots on the surface of the linear shaft of the guide rail, shortening the service life of the equipment. In order to make the machine work normally and stably and ensure the processing quality of products, the daily maintenance of guide rails and linear shafts should be done carefully. Note: Please prepare to clean the guide rail-dry cotton cloth and lubricating oil. The guide rail of engraving machine is divided into linear guide rail and roller guide rail. Cleaning of linear guide rail: First, move the laser head to the far right (or left) to find the linear guide rail, wipe it with dry cotton cloth until it is bright and dust-free, add a little lubricating oil (sewing machine oil can be used, but engine oil is not used), and slowly push the laser head left and right several times to make the lubricating oil evenly distributed. Cleaning of roller guide rail: move the cross beam inward, open the end covers on both sides of the machine, find the guide rail, wipe the contact between the guide rail on both sides and the roller with dry cotton cloth, then move the cross beam and clean the rest. General situation of development
The sustained and rapid economic growth in China provides a huge market space for linear guide products. The strong temptation of China market makes the world focus on China market. In the short decades of reform and opening-up, the huge production capacity of China linear guideway manufacturing industry has made the world sit up and take notice. With the continuous expansion of China's power industry, data communication industry, urban rail transit industry, automobile industry and shipbuilding industry, the demand for linear guide rail will also grow rapidly, and the linear guide rail industry has great potential for future development.