JPH025960B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a new method of lubrication.
Grease lubrication has many advantages over lubricating oils and is widely used. The advantages of grease include: (1) Less scattering, spillage, and dripping, prevents contamination of peripheral equipment, and can lubricate without replenishing for a long period of time. (2) Since the grease itself acts as a seal,
It prevents foreign matter from entering, and the sealing device for the lubricating part is simple and easy to design. (3) Can be used over a wider range of temperatures than oil alone. (4) It has better water resistance than oil and can be used in areas where water is present. (5) Withstands harsh conditions such as high pressure loads, low speeds, shock loads, sliding, and intermittent operation. (6) It can be stored for a long time and retains an oil film even in lubricated parts that are not operated for a long time, preventing rust and corrosion. However, lubrication with grease has the following disadvantages compared to lubricating oil. (1) Replacement, oiling, cleaning, and filling require experience. (2) If foreign matter such as water or dirt gets mixed in, it is difficult to clean. (3) The cooling effect is small and heat generation due to stirring resistance is large. (4) Not suitable for ultra-high speeds. In addition, grease lubrication is performed in a wide range of locations, and the conditions at the locations are various and miscellaneous, such as operating temperatures, loads, speeds, environments, etc. Many greases with different compositions have been developed. In recent years, as part of efforts to conserve resources, energy, and labor, demands have been made for greases to have longer lifespans, lower torque, and be maintenance-free, as well as requests to use lubricating oil to lubricate parts. Conventional greases cannot satisfy all of these requirements and demands. In order to satisfy these demands and desires, the inventors of the present invention have conducted research aimed at correcting the drawbacks that conventional greases should have, but which are insufficient and have not been solved. In response to this request, the drawbacks of grease are a problem, but in some cases the benefits of grease are halved in order to solve the drawbacks, and we have confirmed that it is difficult to solve the problem with a single grease. Many types of seals are used in lubricating equipment, but since the lubricating oil is a liquid, it must come into direct contact with the rotating body, and the seals are made of rubber or similar material. Whether it is a soft polymeric material or a soft metal, friction due to contact with the surface of the rotating body cannot be avoided, and there are problems such as energy loss and deterioration of sealing performance due to wear. The biggest reason why grease is so widely used is that it can simplify the sealing mechanism when used in various types of lubricating equipment. That is, there is almost no need to use a contact seal used with lubricating oil, and with grease lubrication, a simple non-contact seal may be used. Furthermore, an ideal grease would soften due to shearing when it is in a rotating state, and harden again (recover to its original hardness) when it is stopped; in that case, a seal would not be necessary. However, in reality, depending on the conditions of use or long-term use, even simple grease seals often leak. Therefore, in such a case, it would be better to use a lubricating oil seal, but in that case, the lubricant is lubricated with grease. The advantage of being able to simplify the seal mechanism is lost, and the disadvantages are that the friction between the seal and rotating parts and the agitation resistance of grease is greater than that of lubricating oil, and the resulting energy loss is increased. Become. if,
This problem should be solved if the sealing properties of the grease can be improved. Hard grease may be used for this purpose, but it is not always easy to do so because it lacks the ability to intervene in lubricated parts and may cause poor lubrication. Regarding this, it is easy to think that it would be sufficient to use two types of grease together, or a combination of grease and oil, but it is difficult to do so in practice. For combinations of hard grease and soft grease, or combinations of hard grease and oil, etc., when a machine works and rotation or sliding is applied to the lubricant, the lubricant with a similar composition or similar properties will be used for a relatively short period of time. The initial purpose cannot be achieved because the mixture becomes homogeneous and there is no difference from the mixture supplied in advance. Therefore, these methods have not been put to practical use. If we consider that they are not mixed, and there is hard grease surrounding soft grease in the actual lubricated part, the heat generated by agitation, which is a disadvantage of grease, will be minimized, and the deterioration caused by heat generation will be less and the life will be extended. Torque can be reduced, and the sealing properties, which are an advantage of grease, can be maintained or strengthened. However, in reality, this is more impossible than the above. The present inventors have conducted various studies in order to maintain the advantages of the lubrication method using a two-layer lubricant,
The present invention has now been achieved. To explain in more detail, the feature of the present invention is that grease and gel semi-solidified by a gelling agent are used together to supply lubrication as two layers. It consists in using two different substances. Conventionally, grease is defined as a semi-solid or solid lubricant made by dispersing a thickening agent in a liquid lubricant, including those with other ingredients added to improve specific performance. In the lubricating oil, thickeners (various types ranging from spherical particles to fibrous particles with length and width) are dispersed as micelles, creating a structure in which the oil is retained by the thickener. It's on. For this reason, greases used for ball bearings, roller bearings, and greases used in areas without anti-scattering devices can lubricate the parts where they are used, so when the grease itself is mixed, Hardness (hardness)
In other words, it is necessary to stabilize the mixture, and it is desirable that the torque is low.In some cases, on the race surface of the bearing, due to so-called channeling, grease is removed from the outside of the lubricated part of the bearing during use. It is necessary to form a protective film over the entire grease. Since the oil in grease is retained by a thickening agent, the oil that overflows from the thickening agent due to shearing etc. does not have the hardness of grease and does not have the original performance of grease. When strong shear is applied, the micellar structure created by the thickening agent is destroyed, and the thickening agent itself is also destroyed, and even after the shear is removed, the grease does not return to its original properties. . The lubricity of grease is due to its thixotropic property (thixotropy), which softens the entire surface and lubricates it.
It is said that once the grease stops moving, it returns to its original hardness, but in reality, such an ideal phenomenon is unlikely to occur. Therefore, it is better to use a gelling agent with strong thixotropy, but unlike grease hardened with a thickening agent, a grease hardened with a gelling agent is easily softened by heat or shear, and cannot be used continuously. cannot be used. The thickening agent referred to in the present invention has a micellar structure that increases the amount of liquid (lubricating oil in the case of the present invention), and most of them have a network structure of fibers to hold oil. It requires relatively more thickening agent to maintain its structure and is relatively resistant to shear. Furthermore, it is not necessarily necessary to dissolve or uniformly disperse in the liquid. On the other hand, a gelling agent is almost the same as a thickening agent in its action of solidifying a liquid (non-aqueous liquid in the present invention), but it thickens a liquid in a smaller amount compared to a thickening agent. Although it exhibits high static hardness, it is easily softened by heat and/or shearing. Also, unlike thickening agents, gelling agents can solidify liquids by solubilizing or stably dispersing them in liquids. Therefore, it is difficult or insufficient to prepare and use greases with gelling agents alone. As mentioned above, grease and gel have completely different compositional and rheological properties, so even if a machine is operated and shear is applied to the lubricant, their behavior in response to shear is different and they do not mix at the interface. They discovered this and effectively utilized this phenomenon to establish the lubrication method of the present invention. The lubrication method of the present invention was achieved for the first time by discovering the above, and is a novel lubrication method that cannot be easily achieved using conventional techniques. The feature of the present invention is that it combines two types of grease and gel with different flow characteristics, each has a different role, lubrication and sealing performance, and is supplied in two stages.In other words, lubrication is required. The idea is to first supply an oil that acts as a lubricant to the part, and then supply an oil that acts as a seal around it. The method of the present invention includes (1) applying soft grease to the part to be lubricated to form a lubricating layer, and applying hard gel around it to form a sealing layer; (2) There are two methods: applying soft gel to the area to be lubricated to form a lubricating layer, and applying hard grease around it to form a sealing layer. The grease used in the present invention may be any conventionally used grease, but since the lubrication locations to which this lubrication method is applied often have severe conditions such as high loads, high speeds, and high temperatures, it is preferable to use Multi-purpose grease with high dropping point, such as lithium grease, urea-based grease, aluminum complex grease, and lithium complex grease. The gelling agent needs to have the ability to solidify non-aqueous liquids. The present invention also includes those that have no gelling effect when used as one component, but exhibit the ability to work with a gelling agent when used as two or more components. For example, xanthan polymers, low density polyethylene, isotactic polypropylene, polycarboxylic acid esters, polycarboxylic acid derivatives and their salts, esters of carboxylic acid and hydroxypropyl hydrocarbons, unsaturated higher fatty acid esters, aluminum octate, aluminum alcoholates. , alkoxides of group IA of the periodic table and A
Group I and A alkoxides, N
-Acylglutamic acid diamide, N,N',N''-
trialkylhydroxyaspartic acid amide,
Examples include amides having a tetrahydrofuran group, alkylated derivatives of glucose, heterocyclic compounds having -C(OR)-N-, and dibenzylidene sorbitol. N-acylglutamic acid diamide, N, which preferably dissolves in lubricating oil at elevated temperatures;
N′,N″-trialkylhydroxyaspartic acid amide, dibenzylidene sorbitol.
-Acylglutamic acid diamide and N,N',N''-
Trialkylhydroxyaspartic acid amides exhibit similar gelling ability. In method (2), N-acylglutamic acid diamide and N,N',N''-trialkylhydroxyaspartic acid amide, which have excellent lubricating properties, are preferred.As the lubricating oil,
Mineral oil, ester synthetic oil, PAO oil, synthetic hydrocarbon, etc., preferably mineral oil, ester synthetic oil,
It is PAO. The grease in the above method (1) has a hardness grade of No. 000 to No. 1, preferably No. 00 to No. 0. No. 1 or higher is too hard and requires a lot of torque;
If it is less than 000, the two-layer structure cannot be maintained and it is unsuitable.
The hardness of the gel needs to be harder than that of the grease, and the 0W (zero work) stiffness of the grease is applied, and No. 2 to No. 5 is appropriate. If it is No. 2 or less, the sealing function is insufficient, and if it is No. 5 or more, it is inconvenient and inappropriate for greasing. The hardness of the gel in method (2) needs to be softer than that of the grease described below, and applying the 0W hardness of the grease, No. 0 to No. 2 is appropriate. If it is No. 2 or more, the torque to start lubrication becomes large, and if it is No. 0 or less, the two-layer structure cannot be maintained, which is inappropriate. Grease is No. 2 to No.
5 is appropriate. If it is No. 2 or less, the sealing function is insufficient, and if it is No. 5 or more, greasing is inconvenient and unsuitable. The scope of application of the lubrication method of the present invention is not particularly limited, but it is suitable for various open bearings, various sealed bearings, various joints, etc. The method of filling grease and gel according to the present invention in an open type roller bearing is explained with reference to FIG. Fill (part a) with soft grease. Thereafter, a hard gel is filled in the part (part b) between the outside of the grease and the housing 5 where sealing is mainly required. In method (2), part a is filled with soft gel and part b is filled with hard grease. In FIG. 1, although there is no space between the grease and the gel, there may actually be a space therebetween. Figure 2 also shows a shielded ball bearing.
FIG. 3 shows a method for filling a constant velocity joint with grease and gel in the same manner as the above method shown in FIG. 1. Advantages of the present invention are as described above, but the method
(1) and (2) are common and can be listed as follows: (1) There is little heat generation due to stirring. (2) The lubricant is less likely to deteriorate due to heat generation and has a long life. (3) The lubricant that comes into contact with the outside is hard and has a long life. Almost no foreign matter gets mixed in (4) The lubricant on the outside is hard, so there is almost no leakage or dripping of the lubricant (5) The lubricant in the lubricated parts has high fluidity during rotation, and there is no interference with the lubricated surface. This means that the lubricity is good. The invention will be illustrated by the following examples and comparative examples. Example 1 No.0 lithium grease as grease, and paraffin mineral oil as gel (Vis100.3cst@40℃)
Using No. 3 (0W) gel prepared by adding 5% by weight of dibenzylidene sorbitol and 0.5% by weight of PAN to 94.5% by weight, heating and dissolving it and cooling it, the following test was conducted and the obtained results were reported. It is shown in Table 1. (a) Life test according to ASTMD1741 Fill the ball, retainer, and race parts of 6306 open bearing with 3 g of grease using a grease dispenser, and add 3 g of gel on the outside (part b in Figure 1).
The grease life and grease leakage amount were investigated according to ASTMD1741. (b) Temperature rise test due to rotation Similar to (a), a 6306 open bearing was filled with grease and gel, and a thermocouple was placed in contact with the outside of the outer race of the bearing, and set in the ASTMD1741 test machine to measure temperature rise. However, the machine was operated without the heating heater turned on, and the temperature rise due to rotation was measured using a thermocouple on the outside of the outer race, and its steady-state value was measured. Examples 2 to 4 Tests were conducted in the same manner as in Example 1, but with different types of grease and gel. The filling method is the method in Example 2.
(1), and in Examples 3 and 4, method (2). Please check the grease, gel and test results first.
Shown in the table. Example 5 Using a syringe, apply 0.7 g of the same grease used in Example 1 to the bearings of a motor equipped with 6202VV sealed bearings.
The race surface was filled with 0.2 g of gel, which was uniformly applied to the shield plate, and a rotation test was performed.
Its operating conditions were compared with conventional grease lubrication.
The results were as follows. The temperature of the outer cover under no load was 35°C. In contrast, with conventional grease lubrication, the temperature was 40°C. Even under various conditions where the radial load was changed, a 5 to 10°C decrease in temperature was observed compared to conventional grease lubrication. Further, no unusual noises, lubricant leakage, or other abnormalities were observed. Example 6 Using a syringe, fill the ball, retainer, and race surface with 0.7 g of the same gel used in Example 4 for the bearing of a motor equipped with a 6202VV shield bearing, and apply 0.2 g of lubricating grease evenly to the shield plate. A rotation test was performed by replacing it with the one previously applied. Its operating conditions were compared with conventional grease lubrication. The results were as follows. The temperature of the outer cover under no load was 33°C. In contrast, with conventional grease lubrication, the temperature was 40°C.
Even under various conditions where the radial load was changed, a 5 to 10°C decrease in temperature was observed compared to conventional grease lubrication. Further, no abnormal sounds, lubricant leakage, or other abnormalities were observed. Comparative Example 1 The same test as in Example 1 was conducted using conventional grease lubrication by filling the entire bearing with grease as used in Examples. Table 1 shows the greases used and the test results. Comparative Examples 2 and 3 The same test as in Example 1 was conducted using the same conventional grease as used in Example 1, with soft grease being filled in part a and hard grease in part b. Table 1 shows the greases used and the test results.

【table】

[Table] As a result of the above test, the amount of grease leaked gradually increased over time in the case of the comparative example, whereas in the case of the example, almost no leakage was observed until just before the end of life. In addition, the temperature rise due to rotation is almost the same even after a temporary stop and restart in the case of the example, and because the temperature rise was kept low compared to the comparative example, there was less deterioration of the lubricant. It was found that the length had become significantly longer.

[Brief explanation of drawings]

Figure 1A is an explanatory diagram showing the state in which an open-type roller bearing is installed in a machine, Figure 1B is an enlarged view of the bearing part circled in Figure 1A, and Figure 2 is an illustration of a shielded ball bearing. FIG. 3 is an explanatory diagram showing the lubrication state near the ball, and FIG. 3 is an explanatory diagram of the constant velocity joint lubrication state. 1...Roller, 2...Retainer, 3...Inner race, 4...Outer race, 5...Housing, 6
... Ball, 7... Shield plate, 8... Gauge, 9... Inner ring, 10... Outer ring.

Claims (1)

[Claims] 1. When applying lubricant to lubricated parts, first, JIS
A lubricating layer consisting of grease is formed by applying a grease having a hardness ranging from No. 000 to No. 1. A lubrication method comprising: lubricating a gel having a high degree of stiffness to form a sealing layer made of the gel on the outside of the lubricating layer. 2. When applying a lubricant to a lubricated location, first apply a gel that has been made semi-solid or solid using a gelling agent and has a softer stiffness than the grease described below to form a lubricating layer made of gel. , then JIS
A lubrication method characterized by supplying grease having a hardness in the range of hardness No. 2 to No. 5 to form a sealing layer made of grease on the outside of the lubricating layer.