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來源:http://www.phkcgc.live/ 日期:2019-03-26 發布人:admin


Effective protection of linear guides plays an important role in prolonging the life of the guides. To this end, we summarize the following eight characteristics of lubricating oil for linear guides:
1. Viscosity of linear guideway: Linear guideway grease is usually expressed by apparent viscosity or similar viscosity. Temperature and shear speed must be specified when describing the viscosity of grease. Similar viscosity index can be used to control its low temperature fluidity and pumpability.
Strength Limit of Linear Guide: Strength Limit of Linear Guide Grease refers to the minimum shear stress, also known as the ultimate shear stress, which causes the sample to start flowing. The strength limit of grease is a function of temperature. The higher the temperature, the smaller the strength limit of grease, the lower the temperature, and the greater the strength limit of grease. The size of grease depends on the type and content of thickener, and also has a certain relationship with the technological conditions of grease making.
3. Dropping point of linear guideway: The lowest temperature of linear guideway grease when it reaches a certain fluidity under specified conditions is called dropping point. The dropping point of grease is helpful to distinguish the type of grease and roughly estimate the maximum operating temperature of grease. Generally speaking, for soap grease, the higher the dropping point is, the better the heat resistance is.
4. Colloidal Stability of Linear Guideway: Colloidal Stability of Linear Guideway Grease refers to the ability of lubricating grease to keep colloidal structure stable at a certain temperature and pressure and to prevent lubricating oil from precipitating from grease, that is, the ability of lubricating grease to resist oil separation. Usually the amount of oil released from grease is converted to the mass fraction. Colloidal stability of grease reflects the trend of oil in long-term storage and practical application. If the colloidal stability of grease is poor, serious oil distribution will occur under the action of heat, pressure and centrifugal force, which will lead to a rapid decrease in life and make grease thicker and drier, thus losing lubrication.
Fifth, oxidation stability of linear guideway: oxidation stability refers to the ability of grease to resist heat and oxygen during long-term storage or long-term high temperature use, and to maintain its properties without permanent change. Owing to oxidation, the content of free alkali decreases or the content of free organic acid increases, dropping point decreases, appearance color becomes darker, odor, consistency, strength limit, similar viscosity decreases, corrosive products and substances destroying the structure of grease are formed, resulting in the separation of soap oil. Therefore, in the long-term storage of grease, it should be stored in a dry and ventilated environment to prevent sunlight exposure, and periodically check the changes of free alkali or free organic acid, corrosion and other items to ensure its quality and performance.
6. Thixotropy of linear guideway: Thixotropy is the most basic characteristic of linear guideway grease. When an external force is applied, the flow of grease gradually softens and the apparent viscosity decreases, but once at rest, after a period of time (very short), the consistency increases again (recovery), which is called thixotropy. This characteristic of grease determines that it can be lubricated in parts that are not suitable for lubricating oil and show its excellent performance.
Seventh: The basic function of the fixed elements (guideways) of the linear guideway system is like bearing rings, and the support with steel balls is in the shape of "v". The bracket covers the top and sides of the guide rail. In order to support the working parts of the machine tool, a set of linear guides has at least four supports. For supporting large working parts, the number of supports can be more than four.
Eighth: The design of linear guideway system strives to maximize the contact area between fixed and mobile components, which can not only improve the bearing capacity of the system, but also withstand the impact force produced by intermittent cutting or gravity cutting, so that the force can be widely spread and the bearing area can be enlarged. In order to achieve this, the groove shape of the guideway system has many kinds, there are two representative types, one is called Gothic (pointed arch), the shape is the extension of the semi-circle, the contact point is the vertex; the other is circular arc, which can also play the same role. No matter which type of structure, there is only one purpose to make more contact between rolling ball radius and guide rail (fixed element). The key factor to determine the system performance characteristics is how the rolling element contacts the guide rail, which is the key to the problem.
Linear guides have such a large area of use: 1. Linear guides are mainly used in automation machinery, such as German imported machines, paper bowl machines, laser welding machines and so on. Of course, linear guides and straight axis are matched.
2. Linear guideways are mainly used in mechanical structures with high precision requirements. Rolling steel balls are used instead of intermediate medium between moving and fixed components of linear guides. Because rolling steel ball is suitable for high-speed movement, small friction coefficient and high sensitivity, it meets the working requirements of moving parts, such as tool holder, trailer, etc. If the force acting on the steel ball is too large, the steel ball will endure the preload for too long, which will lead to the increase of the bracket resistance.