JPS62207395A - Method or imparting metal-to-metal extreme pressure lubrication - Google Patents

Abstract

PURPOSE:To effectively decrease the sliding friction between metals and to prevent the seizing between the metals for a long period of time, by multicost coating of the surface of contact between metals with particular two kinds of lubricating coatings contg. finely divided tetrafluoroethylene resin. CONSTITUTION:Molybdenum disulfide and (or) graphite are mixed with finely divided tetrafluoroethylene resin to obtain a lubricating coating. The lubricating coating is applied on the surface of a contact between metals. At least one surface of the contact is further multicoated with a lubricating coating obtd. by dispersing a finely divided tetrafluoroethylene resin in a volatile solvent (e.g., methyl ethyl ketone) to form an extreme-pressure lubricating surface between the metals which can withstand leng-term use. This method enables favorable adoption of e.g. the sleeve and wedge in non-blasting rock breaking- crushing works, where the sliding friction between the wedge and sleeve is reduced thereby preventing seizure between the surfaces of the metals, to afford the aimed lubricant.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is a method for reducing the sliding friction between metals due to impact loads as much as possible and preventing seizure between metal surfaces.
This invention relates to a method for providing extreme pressure lubrication between metals.

Fields of application of the above method include all technical fields where extreme pressure between metals is expected, such as non-blasting rock crushing methods using sleeves and rods. Japanese Patent Publication No. 59-47
In rock excavation using the non-blasting bench cut method (hereinafter referred to as method B) described in No. 96, by dropping a weight and applying an impact load to the wedge, the sliding friction that occurs between the wedge and the sleeve, that is, between the metal members, is reduced. This means reducing the amount of heat as much as possible and preventing seizures between metal surfaces.

(Prior art) Rock excavation work has been increasing more and more in recent years, but on the other hand, restrictions on vibration, noise, etc. associated with this excavation work have become stricter from the perspective of environmental conservation, and hazardous materials are being removed in urban areas, areas with large numbers of private houses, etc. It became difficult to use explosives for blasting. Under these circumstances, a rock excavation method without blasting was required, and the non-blasting bench cutting method disclosed in the above-mentioned publication was invented as one of these methods. However, one difficulty with this method is that the shaft and sleeve used are subjected to a large impact force, and at the same time an extremely large impact frictional force is generated between them, which causes excessive wear. Otherwise, a seizure phenomenon will occur due to the impactful friction on the contact surfaces between the two.
The disadvantage is that they have to be replaced prematurely.

However, the above is just an example, and such a phenomenon is commonly observed in metal surfaces where metals in contact with each other are subjected to excessive loads and extreme pressures are generated.

For this reason, various techniques are known to solve this drawback. The simplest method is to apply a lubricant between the two surfaces, and a petroleum-based lubricant with a high boiling point and high viscosity is generally used. This lubricant has almost no problems in practical use, but when used between sliding metals under high pressure, it wears out rapidly and the lubricant is no longer useful, and new lubrication occurs within a short period of time. There is a disadvantage that the lubricant must be replenished, and when such a lubricant is applied to the construction method disclosed in the above-mentioned publication, for example, it must be applied every - times when the rock is cracked. ,
If this lubricant is a highly viscous oil, it is easily soiled and is difficult to handle.In particular, when crushed rock is dumped for landfill, oil may float and cause water pollution. .

For this reason, there has been a need to create extreme pressure lubricated surfaces that can withstand long-term use on multiple metal surfaces that are subjected to extremely strong pressures.

(Problems to be Solved by the Invention) The present invention provides a method for forming a lubricated surface that does not have the above-mentioned drawbacks and can withstand long-term use. The object of the present invention is to provide a method for providing extreme pressure lubrication between metals to reduce dynamic friction as much as possible and prevent seizure of metal surfaces.

(Means for Solving the Problem) The above problem is solved by the present invention, in which at least one of molybdenum disulfide, graphite, or a mixture thereof and fine powder of ethylene tetrafluoride resin are mixed on both contact surfaces. This problem can be solved by applying a lubricating paint, and then overcoating at least one of the contact surfaces with a lubricating paint in which fine powder of tetrafluoroethylene resin is dispersed in a volatile solvent.

(Embodiments) The present invention will be described in detail below with reference to embodiments illustrated in the accompanying drawings. This embodiment will be explained by taking as an example the non-blasting pincer cut construction method described in Japanese Patent Publication No. 59-4796, but the present invention is not limited to this embodiment.

A lubricating coating film 4.5 was formed according to the present invention on the mutually contacting surfaces of the wedge 2 and the sleeve 1 used in Method B described in this publication. The lubricant used in this case was manufactured as follows.

The lubricant forming the four layers is molybdenum disulfide (hereinafter referred to as Mo
A first lubricant mixture (hereinafter referred to as PTFE) is mixed with either one of graphite or a mixture thereof and tetrafluoroethylene (hereinafter referred to as PTFE).
) was created. As a result of various experiments, the ratio of the amount of this mixture was determined to be 1 to 1 part by weight of PTFE per 100 parts by weight (hereinafter simply referred to as part) of either MoS2 or graphite or a mixture thereof. was found to be appropriate.

The above mixture was then uniformly dispersed in a volatile solvent. The volatile solvent is not particularly limited, but organic solvents that easily evaporate at room temperature, such as methyl ethyl keto/toluene, chlorinated solvents, etc. alone or in mixtures thereof are suitable.

In relation to the above ratio, if the mixing amount of PTFE is less than 1, it will not be able to withstand the instantaneous impact force when applied to metals that are exposed to extremely high impact forces, such as method B. Moreover, it was confirmed that if the amount is 10 parts or more, sufficient adhesion of the paint to the metal surface cannot be obtained, and the paint peels off easily, making it unsuitable for multiple rock splittings.

The lubricant forming the five layers was made by uniformly dispersing PTFE fine powder in a volatile solvent similar to Py.

The thickness of the py layer 4 and PTFE layer 5 to be formed does not need to be particularly limited, but from an economical point of view, the solid content coating amount is 10
g/m to 50 g/m is suitable.

The means for forming the coating layers 4 and 5 may be any known means, such as brush coating or spray coating.

When the method of the present invention was actually carried out, it was found that the average particle diameter of PTFE was preferably in the range of 0.1 to 3 μm in the method B described above. This range is economically advantageous and also provides good dispersibility in solvents. If the PTFE particles are larger than 3 μm, the introduction of the PTFE particles into the delicate gap between the pattern and the sleeve will not work.

(Effects of the Invention) As mentioned above, the present inventors have discovered that the use of a generally known lubricant alone can easily cause a seizing phenomenon due to an extremely strong and instantaneous impact force as in Method B, for example. Recognizing that it is not suitable for sleeve lubrication and does not provide a satisfactory effect, as a result of many years of research, we have mixed and used PTFE fine powder, which has very good slipperiness and extremely high heat resistance. It has been found that these have an excellent synergistic effect in reducing the coefficient of friction. Furthermore, any one of MoS2 and graphite or a mixture thereof and PTFE
Although the mixture py alone has a friction-reducing effect on friction caused by falling weight impact, it is insufficient for static friction as shown in Fig. 4, so PTFE is added on top of the PV layer 4. It has been found that by overcoating the fine powder layer 5, a significant friction reduction effect is exhibited against instantaneous impact friction and static friction. This effect is due to the fact that the PTFE applied to the sleeve,
Fine powder melts due to the high temperature and high load that occurs when struck by a weight,
This is because a composite resin film containing one or a mixture of MoS2 and graphite is formed, providing smooth lubricity. Such a combinatorial effect is surprising, and it should be said that it is a discovery that is far removed from predictions based on expert knowledge in the art.

Below, a series of tests were conducted to evaluate the performance of a lubricant coating formed when the method according to the present invention was applied to the surface of a sleeve and a sleeve according to Method B, and detailed data thereof will be described.

The test method applied in the following tests was the wedge 2 shown in the drawing.
The lubricant coating film formed on the sleeve 1 was subjected to a falling weight impact test, a repeated falling weight impact test, and a sliding friction test defined below.

Test Method B Performance evaluation of the lubricant as shown in FIGS. 3 and 4 was carried out as a mock test method for the construction method. The method will be described below.

As shown in Fig. 3, as a method for evaluating the penetration state of cracks due to falling weight impact in method B, special steel metal pieces 1' (4 x 4... x iQ cm) and 2' (
4cm Comparatively evaluate the lubrication performance by observing the length and the condition of the contact surface of both metal pieces. This is called a falling weight impact test.

After the above test, only the relative positions of the special steel metal pieces 1' and 2' are restored, and the weight 3' is dropped from the above height three times again, and the sliding distance is determined in exactly the same manner as in the above test. Observe state changes. This is a test to check the repeatability of the lubricant, and is called a repeated falling weight impact test.

The third method is to evaluate the pull-out resistance of the wedge 2, as shown in Fig. 4, while applying a lateral pressure P1 (280 kg/cm2) to special steel metal pieces 1' and 2' coated with lubricant. Press P on the metal piece 2' with a hydraulic jack. Measure the pressure Po necessary to slide the metal piece 2',
Find the friction coefficient μ from Po=2μP1. This is called a sliding friction test.

Test A A conventionally used oil-based lubricant (Daphne Mustard 0-CD-10 manufactured by Idemitsu Kosan) was used using the above-mentioned mock test method.
), the performance of the following non-oil-based lubricants was evaluated.

Lubricant A-a...3230 parts of Mo uniformly dispersed in a mixed solvent of 50 parts of methyl ethyl ketone and 20 parts of toluene, ttA-1)...Lubricant A-8100 parts with an average particle size of 0.4 0.5 parts of PTFE fine powder of pm is added and mixed, ttA-C...3 parts of PTFE fine powder with an average particle size of 0.4 μm is added and mixed to lubricant A-aloo part, ttA -dam・8 parts of PTFE fine powder with an average particle size of 0.4 μm is added and mixed to the lubricant A-aloO part, ttA-e...The average particle size is 0, 4 to the lubricant A-aloO part Addition and mixing of 12 parts of PTFE fine powder of pm, // A-f *mm PTF with average particle size of 0.4 pm
30 parts of E fine powder is uniformly dispersed in a mixed solvent of 50 parts of methyl ethyl ketone and 20 parts of toluene, and the above lubricant is applied with a brush wheel on metal pieces 1' and 2' so that the amount of solid content is 50 g/m2. It was coated like this.

The falling weight impact test results, repeated falling weight impact test results, and sliding friction test results are shown in Tables A-I, A-II, and A-, respectively.
Shown in m.

Table A-II Repeated falling weight impact test results Table A-III Sliding friction test results From the results of Tables A-I, A-I[, and A-III, the implementation of the present invention clearly produced better results than the conventional system. ing. In particular, the fact that the repetition effect is clear makes it suitable for today's demands.

Test B An evaluation test was conducted under the same conditions except that MoS2 in Test A was replaced with graphite, and the following Tables B-I and B-
n, B-I [[ results were obtained.

Table B-m Repeated falling weight impact test results Table B-III Sliding friction test results Test C Same as Test B except that MoS2 in Test A was replaced with an equal mixture of MO82 and graphite, except that the lubricant composition was used. An evaluation test was conducted under the following conditions and the following results were obtained.

Table C-■ Repeated falling weight impact test results Table c-m Sliding friction test results As is clear from the above various test results, the implementation of the present invention more accurately meets modern requirements than conventional methods, and is more suitable for rock excavation work. This shows some progress in this area.

[Brief explanation of drawings]

Figure 1 is a diagram showing the principle of the non-blasting bench cut method (Method B) described in Japanese Patent Publication No. 59-4796, and Figure 2 is a diagram showing the method for providing metal-to-metal extreme pressure lubrication according to the present invention. A diagram of the structure of the lubricant coating formed on the wedge and the IJ-b when the method is applied. A diagram showing a simulation test device for estimating behavior. FIG. 4 is a diagram of a simulation test device for estimating the pull-out resistance of the owl in the method B. The symbols in the figure are 1... Sleeve 2... Sleeve 4... py lubricant coating 5... PTFE lubricant coating IC 2'... Special steel metal piece 3'... Weight Po... ...Pushing force Pl r P2...Side pressure

Claims (1)

[Claims] In a metal-to-metal extreme pressure lubrication method for reducing sliding friction between metals due to impact loads, etc. and preventing seizure between metal surfaces, at least one of molybdenum disulfide, graphite, or these materials is applied to both contact surfaces. Applying a lubricating paint containing a mixture of the above mixture and fine tetrafluoroethylene resin powder, and overcoating at least one of the contact surfaces with a lubricating paint containing fine tetrafluoroethylene resin powder dispersed in a volatile solvent. A method for providing metal-to-metal extreme pressure lubrication, characterized by: