Research of lubricants in cutting connections of cardan shafts of autotesovoz

Bykov V.V., Kapustin R.P. (BGITA, Bryansk, RF)

Research of Greasings In Connections of Shaft Of AutoTimber Carrying Vessels.

Cardan transmission of autotesovozos consists of two shafts connected by a slotted joint and hinges. The slotted connection provides a change in length cardan shafts When deflection is sprinkling. The shaft offset in the slotted sleeve reaches 40 ... 50 mm, which causes intensive wear of the conjugation when the tightness of the compound and due to large loads (torque and axial forces). It is possible to bend and twisting the pipe of the cardan shaft.

The Department of Mechanization of the Forest Industry and Forestry (now the Department of Technical Services) BGITA is conducted studies of wear of handbrips of forest-carriage vehicles using various lubricants. For this purpose, poster studies were conducted. Due to the emergence of new lubricants, poster studies are continued, and also monitored the technical condition of the shlot joints of the cardan shafts of auto hikes in the conditions of their operation in the leshozes of the Bryansk region. Observations have been carried out behind forestry cars MAROK ZIL-131, URAL-4320, MAZ-509A and KAMAZ-5312 in a coupling with the dissolution of TMZ-802 and GKB-9383.

The factory operating instructions are given overestimated standards of periodicity of replacement of lubricants in cardan transmissions (up to 20,000 miles). The specificity of the operation of auto hikes: large load modes, road off-road movement and water, gully storage, etc. require reducing standards for the frequency of lubricating operations up to 10,000 km of mileage.

The use of new plastic lubricants will contribute to the reduction of wear of the cutting connections of cardan transmission and increase their service life.

For lubrication of slotted connections of cardan shafts, plastic lubricants are used. As an oil base lubricants are used various oils Oil and synthetic origin. Thickeners can be soap fatty acids, paraffin, soot, etc. The content of the thickener in plastic lubricants is 10-20%. The dimensions of the particles of the dispersed phase of the thickener fluctuate from 0.1 μm to 10 microns. To improve anti-wear, anti-mailing and conservatory properties, additives are added to plastic lubricants (up to 5%).

The main operational characteristics of plastic lubricants include: strength limit, viscosity, colloidal stability, dripping temperature, mechanical stability and water resistance.

The strength limit characterizes the ability of lubricants to be held in friction nodes under the influence of inertial forces. It depends on temperature, with an increase in which its decrease is noted.

The viscosity of plastic lubricants with an increase in the temperature of the node is reduced, thereby worsering its anti-wear properties. It is determined at 10 s -1.

The temperature at which the first drop of lubricant falls is called the capplement temperature. For this characteristic, lubricants are divided into low melting (t KP \u003d up to 60 0 s), medium permanent (t KP \u003d from 60 to 100 0 s) and refractory (t KP\u003e 100 0 s).

Lubrication with poor mechanical stability quickly collapsing, diluted and follows from friction nodes.

By type of thickener, lubricants are divided into soap lubricants on organic and inorganic thickeners and hydrocarbon lubricants.

To study the performance of plastic lubricants recommended by automobiles for lubricating the slot compounds of cardan shafts, lubricant 158, Litol-24 and Fiol-2, the main physico-chemical and operational properties of which are shown in Table 1.

Table 1- Physico-chemical and operational properties of the lubricants under study.

Lubrication No. 158, recommended for lubrication of cardan shafts, has no full-fledged replacement, it prevents the jams and jackets of rubber surfaces at high loads, has good water resistance, which corresponds to the operational conditions for the operation of the drive shafts of forest car. However, the conditions for the operation of auto hikes contribute to the disruption of the tightness of the lubrication washing and its leakage from the slotted shaft connection, which limits its service life and requires frequent replacement. The rate of consumption of plastic lubricants is 0.25 - 0.30 kg per 100 liters of total fuel consumption. The substitute may be Lithol-24.

Lithol-24 is a unified lubricant, has good water resistance, withstands a wide range of temperatures and has good mechanical resistance, it does not work up when heated. For a long time, it retains performance at +130 0 C. (operating temperatures of slotted joints of cardan shafts are within +60 0 s). The substitute is plastic lubricant of improved quality Fiol-2.

Fiol-2 is a multipurpose lubricant containing antioxidant, viscous, anti-corrosion and antisosal additives. It is waterproof and efficient in a wide range of speeds and loads. This lubricant has good conservation properties.

Table 2 shows the results of friction forces in a slotted connection with tested lubricants.

Table 2 - dependence of friction forces in the slotted connection cardanian Vala During the coupling time of the shaft operation and the type of lubricant under the torque Mr Q \u003d 500 nm, KN

From Table 2, it can be seen that in the initial moment (the period of development), the friction force is quite high, then decrease or remain constant (for example, for Fiol-2 lubrication) until the appearance of the bulk. The appearance of the bulk causes a sharp increase in the forces of friction and wear. If the shaft with the bully continues to test, then the zone zone is rapidly expanding, causing heating zone of friction, which leads to an increase in the friction forces and the intensive wear of the slots. Lubrication diluted and loses antifriction properties.

Tables 3 and 4 present data on the wear of the shaft slots and the coupling sleeves.

Table 3 - Dynamics of wear of the shaft slots depending on the type of lubricant used under the torque Mr. Mr \u003d 400 nm, mm

Table 4 - Dynamics of wear of the slots of the sleeve, depending on the type of lubricant used under the torque Mr CR \u003d 400 nm, mm

The nature of the wear of the splines indicates the presence of the so-called hot jamming, since the destruction of the fine oil film occurs under the influence of the load and elevated temperatures in the contact zone of bodies, where the segments of the seal are formed. This process is characterized by intensive wear, as evidenced by the data of the table.

The quality of lubricant is the most important factor affecting the process of jamming and wear of the slots. top scores When testing, Fiol-2 lubricant showed, with which the slotted connection was working without noticeable wear before the appearance of the bulk, i.e. As long as the lubricant retained its functional properties. Lubricant №158 occupies an intermediate position between Little-24 lubricants and Fiol-2. The operating time of the slotted compound before the appearance of the loop with lubrication lithol-24 was 20 hours, with lubricant No. 158 - 60 hours, with Lubrication Fiol-2 - 140 hours.

Conducted studies of the working capacity of lubricants in the slot connection of the drives of cars ZIL and KAMAZ have shown that the smallest resource has a slotted connection with the current lithol-24 lubricant, the greatest - with Fiol-2 lubrication.

The frequency of replacement of lubricants to reduce to 10,000 miles of mileage in order to exclude the occurrence of scaling in the slotted connection of the cardan shafts of forestry road trains.

Literature

Bykov, V.F., Kapustin, R.P., Shuvalov, A.V. Study of the operability of cardan shafts of autolysovozozov / V.F. Beskov, R.P. Kapustin, A.V. Shuvalov. // Operation of forest-free rolling stock. Interuniversity Sat.-Sverdlovsk: Publishing House of UPI. S.M. Kirova, ultimate them. Leninsky Komsomol, 1987.- S. 11-14.

Vasilyeva, L.S. Automobile operating materials: studies. For universities / L.S.Vasilyeva - M.: Science-Press, 2003.- 421c.

Balteneas, R, Safonov, A.S., Ushakov, A.I., Sheregalis, c. Transmission oils. Plastic lubricants / R. Baltenas, A.S. Safonov, V.Shergalis - SPb.: LLC "Publishing House DNA", 2001.- 209c.

© Michael Ozherevyev

There are many nodes in the car, where for separation rubbing surfaces Used thick massea products, called plastic lubricants. About them and will be discussed.

Plastic lubricants are used to reduce friction and wear of nodes in which the forced circulation of oil is inappropriate or impossible. For example, wheeled and pivot bearings, steering and suspension hinges, cardan and slotted connections, etc. Previously, this list was quite extensive, and today we see that in the car the share of plastic lubricants is reduced among other operational materials. The reason for this is the use of non-listed nodes based on innovative structural materials (for example, replacement of the friction pair "sleeve" on a hinge of high molecular rubber). However, where there is no alternative to the use of masculine products, today the most stringent requirements are presented, including an environmental nature. It often happens that for each specific node, whether it is a saddle-coupling device or a cabin chain hinge, only a certain brand of operational material is recommended. How to choose the right product? In this we have to figure out.

And solid and liquid

© Michael Ozherevyev

Plastic consistency lubricants occupy an intermediate position between liquid oils and solid lubricants (graphites, for example). With a low temperature and the absence of a load, the lubricant retains the shape given to it earlier, and when heated and under the load begins weakly leaking - so weakly that the friction zones do not leave and does not seal through the seals.

© Michael Ozherevyev

The main functions of plastic lubricants do not differ from those that are imposed on liquid oils. All the same: reduced wear, preventing scaling, corrosion protection. Specifications only in the field of application: suitability for lubrication of highly worn friction pairs; the ability to use in leakage and even in open nodes, where there is a forced contact with moisture, dust or aggressive media; The ability to firmly hold onto the lubricated surfaces. A very important feature of plastic lubricants is a long service life. Some modern products practically do not change their quality indicators for the entire period of operation in the friction assembly and therefore can be laid a one-time when assembling.

If we talk about the general disadvantages of the magazine substances, first of all, attention should be paid to the lack of cooling (heat removal) and the removal of wear products from the friction zone. By the way, maybe therefore some automakers, developing such nodes, such as wheeled hubs, often prefer transmission oils.

© Michael Ozherevyev

The simplest plastic lubrication consists of two components: oil basics (mineral or synthetic) and thickener, under the action of which the oil becomes low-lifted. Thickener - Lubricant frame. It can be easily compared with the foam rubber holding the liquid with its cells. Most often as a thickener, the content of which can be from 5 to 30% of the mass of the product, calcium, lithium or sodium soaps are used (salts of higher fatty acids). The cheapest calcium lubricants obtained by the industrial thickening mineral oils Calcium soaps, - solidol. Once they were so commonly used that the word "solidol" became a good designation of the plastic lubricant in general, although this is not entirely correct. Solidolaes do not dissolve in water and have very high anti-wear actions, but normally function only in nodes with working temperature up to 50-65 ° C, which restricts their use in modern cars. And the most versatile lithols are lubricants obtained by the thickening of oil and synthetic oils with lithium soaps. They have a very high capple temperature (about + 200 ° C), exclusively moisture resistant and are working in almost any load and thermal modes, which allows them to be used almost everywhere where plastic grease is required.

© Michael Ozherevyev

Also, hydrocarbons (paraffin, ceresic, petrolatum) or inorganic compounds (clay, silica gels) can be used as a thickener. Clay thickener, unlike soap, does not soften when high temperaturesTherefore, it can often be found in the composition of refractory lubricants. But the hydrocarbon thickeners are mainly used for the production of conservation materials, since their melting point does not exceed 65 ° C.

In addition to the basis and thickener, the lubricant includes additives, fillers and modifiers of the structure. The additives are practically the same as used in commercial oils (motor and transmission), they are oil-soluble surfactants and make up 0.1-5% of the mass of lubrication. A special place in the additive package is occupied by adhesive, that is, adhesive components - they enhance the effect of the thickener and increase the ability of lubricant to hold onto the metal. To ensure the work of the lubricant in the limiting thermal and load mode, sometimes solid and insoluble fillers are introduced into it - as a rule, disulfite molybdenum and graphite. Such additives usually give lubricant specific color, for example, silver-black (Molybdenum disulfite), blue (copper phthalocyanide), black (carbon graphite).

© Michael Ozherevyev

Properties and standards

The scope of lubrication is determined by a large set of indicators, among which the strength limit for the shift, mechanical stability, the temperature of the capepulation, thermal stability, water resistance, etc. But the role is the most important characteristics The temperature of the dripping and the level of penetration is discharged. In fact, it is this pair that is an output parameter to estimate the lubricant.

The temperature of the dripping shows, to what limits you can heat the lubricant so that it does not turn into a liquid and, therefore, does not lose its properties. It is measured very simply: a piece of lubrication of a certain mass is heated evenly from all sides, smoothly increasing the temperature until the first drop falls from it. The border of the lubrication dropping should be 10-20 degrees above the maximum heating temperature of the node in which it is used.

© Michael Ozherevyev

The term "penetration" (penetration) by its appearance is obliged to measure the measurement method - the indicator of the density of semi-liquid bodies is determined in the device called the penetrometer. For consistency assessment Metal cone standard size And forms under their own weight for 5 ° C are immersed in lubricant heated to a temperature of 25 ° C. The softer the lubricant, the deeper the cone will enter it and the higher its penetration, and on the contrary, more solid lubricants are characterized by a smaller number of penetration. By the way, such tests are used not only in the production of lubricants, but also in the paint business.

© Michael Ozherevyev

Now about standards. According to the generally accepted classification of lubrication, it is customary to distinguish between applications and density. In accordance with the area of \u200b\u200bapplication, lubricants are divided into four groups: antifriction, conservative, sealing and cable cars. The first group is divided into subgroups: lubricants general purpose, multipurpose lubricants, heat-resistant, low-temperature, chemically resistant, dashboard, automotive, aviation. With regard to the transport sphere, antifriction lubricants were most common: Multipurpose (Litol-24, Fiol-2u, Zimol, Lita) and special automotive (LSTS-15, Fiol-2U, SHRUS-4).

© Michael Ozherevyev

To distinguish products on consistency, the American classification of NLGI is used worldwide (National Lubricating Grease Institute), which divides lubricants into 9 classes. The criterion of division is the level of penetration. The higher the class, the thicker product. Plastic lubricants used in cars are more common to the second, less often - to the first class. For semi-liquid products recommended for use in centralized lubrication systems, two separate classes are allocated. They are denoted by codes 00 and 000.

© Michael Ozherevyev

Previously, in our country, the name of lubricants was established arbitrarily. As a result, some lubricants received a verbal name (Solidol-C), the other - number (№158), the third - the designation of the established institution (CIIM-201, VNIIIII-242). In 1979, GOST 23258-78 was introduced, according to which the name of the lubricant should consist of one word and alphanumeric index (for different modifications). Domestic petrochemicals of this rule hold today. As for imported products, it currently does not currently have a single classification for all manufacturers on operational indicators. Most European manufacturers are guided by the German standard DIN-51 502, which sets the designation of plastic lubricants displaying several characteristics immediately: Purpose, Type basic oil, additive set, NLGI class and operating temperature range. For example, the designation K PHC 2 N-40 indicates that this plastic lubricant is designed to lubricate the sliding and rolling bearings (literature), contains in its composition anti-wear and anti-sex additives (P), produced on the basis synthetic oil (NA) and refers to the second consistency class on NLGI (digit 2). The maximum use of such a product is + 140 ° C (n), and the lower operational limit is limited to the -40 ° C bar.

© Michael Ozherevyev

Some world manufacturers use their own designations. Say, the symbol of plastic lubricants Shell has the following structure: Mark - Suffix 1 - Suffix 2 -
NLGI class. For example, the Shell Retinax HDX2 product is decrypted as a lubricant with very high operational characteristics for aggregates working in extremely heavy conditions (HD) containing molybdenum disulfite (X) and related to the second Consistency class NLGI.

Often, two designations are present on foreign product labels: its own labeling and code according to DIN. By analogy with liquid oils, the most complete requirements for operational materials are reflected in the specifications of automakers or component manufacturers (Willy Vogel, British Timken, SKF). The rooms of the corresponding tolerances are also applied to the lubricant label next to the designation of its operational properties, but the basic information on the products recommended for the use and the timing of their replacement is contained in the maintenance manual vehicle.

© Michael Ozherevyev

Lubricants different manufacturers (even the same destination) is impossible to mix, as they may contain different additives on the chemical composition and other components. Also impossible to mix products with various thickeners. For example, when mixing litea lubrication (lithol-24) with calcium (solidol), the mixture gets the worst operational properties. Of the automotive plastic lubricants offered in the market, it is most advisable to choose those recommended by the car manufacturer.

Timely maintenance and lubrication of cardan shafts plays an important role in the work of Kardan. The grease of the cardan shaft must be made according to the maintenance instructions for this car model. The frequency of maintenance of cardan shafts of a truck, passenger and agricultural machinery is different.

It is necessary to lubricate the cardan shafts after each sink in the event that the washing was produced under high pressure water. When cleaning the cardan with water under high pressure, it is not desirable to direct the jet on the dirt protective anthers and sealscross , Slot steam, suspended bearings. Penetration of dirt and water can entail a premature failure of the cardan transmission. It is forbidden to direct water stream for seals Cross and the suspension bearing, if they are maintenance-free. During lubrication, not only water and abrasive particles are removed, but also products of natural wear.

Periodicity of lubrication of cardan shafts

Cardan shafts are equipped with a tapered head press oil according to DIN 71412, with which it is possible to produce additional lubricant with standard lubricant syringes.

Lubrication of the cutting shaft slot

The dots of the lubrication of the cardan shaft arecross Cardanov, suspended bearing and slotted connection. The lubricant is made not only through the press Maslenka. To avoid premature wear Cardan shaft and extend its resource you need to know what together with hinged compound It is also necessary to carry out the lubricant of the slotted connection. In some cases, it is necessary to dismantle the cardan shaft and lubricate the slotted pair in the spread position, on the removed cardan shaft. For servicing the slotted part of the cardan shaft, the same lubricants and tools are used as for lubrication.cross. When the first installation of the cardan shaft is recommended to check the presence of lubrication in the slotted pair. If necessary, to ensure a sufficient reserve of lubricant for the period to the first maintenance, add about 80g lubricant material.

Cardan shaft cross lubrication

It is not recommended to use pneumatic syringes for lubricating the crosses of the cardan shaft. In order to avoid damage to the seals during lubrication, it is not allowed to supply a pressure of over 2 MPa pressure or strong hydraulic blows. In the case of using a pneumatic tool for lubrication, there is a possibility of damage to the dirt protective anther crossing due to a large pressure and uncontrolled dosage. Use mechanical syringes to lubricate the cardan shaft.

To maintain a cardan shaft, you need to use high-quality lubricants recommended by the manufacturer of the car. Mixing lubricants having different bases are not allowed. For example, lithium and natron (bicarbonate) lubricants are incompatible. When mixing such materials with an incompatible chemical composition, a reaction is reacting a disturbing lubricant properties. Lubrication loses its lubricating properties and quality. To maintain a cardan shaft, as a lubricant, it is recommended to use plastic lubricant based on lithium - for example Castrol LMX

Often, drive shafts are designed for operation at temperatures from - 35C to + 60C. In the event that the operating conditions outside the specified temperature are required to take into account the special conditions in the preparation of the technical task on the manufacture of the cardane transmission.

For you:

• Free inspection of the cardan shaft.
• Operative maintenance Cardan shaft in St. Petersburg.

Cardan SPB - will extend the Kardan resource.

Hello, friends!

Today we will talk about lubricants for slotted connections. To do this, analyze the features of this type of compounds and the nature of friction in them.

So, the slotted compound is the connection of the shaft (covered surface) and the holes (covering surface) with the help of slots (grooves) and teeth (protrusions), radially located on the surfaces of the shaft and holes. Provides the possibility of axial movement of parts along the axis.

Fig. 1 Slotches

Of course, a slotted compound is a moving connection that allows the shaft that transmitting rotation to lengthen and shorten during operation. Power transmission The rotation is characterized by a torque that causes the corresponding contact pressures between the side surfaces of the slots.

Thus, the pair of friction slot-tooth by nature of friction is a kind of linear sliding bearing. The features of the operation of slot compounds in the composition of the cardan shafts and the drive spindles are the low speed of sliding and high specific pressure. This creates an unstable elastohydrodynamic friction regime, which goes into boundary friction.

Fig.2 Split connection of the cardan shaft

Lubricants to protect nodes under friction edge mode must contain solid lubricating additives designed to enhance the action non-promotional additives, so little efficient at low slip speeds. This is usually graphite or molybdenum disulfide. If graphite is preferable to high-temperature use, the molybdenum disulfide is more efficient to tribologically.

Tribology - science of friction and phenomena accompanying friction. Tribological properties of lubricant is a combination of anti-wear and anti-promotional properties.

As an example of lubricant based on disulfide molybdenum for slot compounds, I will give a popular lubricant from the Russian company Argo.. Here is its characteristics:

The loading load of 3920 Newtons is a rather high indicator of anti-promotional properties, which allows to use in the highest-loaded spline connections. In low and medium-wide slots, for example, passenger cars It is not necessary to use such a "powerful" lubricant. Completely effective here are universal car lubricants. Here is another example of lubrication from Argo For universal automotive applications – :

Plastic greases are widely used in cases where the working conditions of the mechanism exclude the use of conventional oils. Recently, the role of special lubricants has significantly increased, which allow to provide high-performance work of modern and expensive equipment. There are two main ways to increase the effectiveness of greases to reduce friction and wear. The first path is the use of chemically active additives that increase the ability of lubricant material to withstand heavy loads. The second way is the use of plastic lubricants containing finely dispersed particles of a special substance or compound (in the form of thinnest plate inclusions) - Molybdenum disulfide, graphite or ceramics. When developing modern lubricants with high performance characteristics, specialists Liqui Moly. We successfully apply both of these methods. With a relatively low pressure, plastic lubricant behaves like a solid. But it is worth the pressure to increase, the product in its properties begins to resemble liquid. This is the main difference from ordinary oils.

Wide range of consistant lubricants

• in the passenger trucks;
• in agricultural machines;
• in the equipment applied in paper, food, sewing, textile industry;
• in devices used in household.