JPH0774352B2 - Fluid lubricated sliding member - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention is used, for example, in mechanical seal parts, packings, rubber bearings, and other parts that come into contact with fluids, and the fluids themselves are used as lubricants. A fluid lubrication sliding member.

(B) Conventional Technology Conventionally, as a method of preventing seizure or wear that occurs in the above-mentioned fluid lubricated sliding member, for example, a fluid lubricated sliding member is used in a structure in which friction acts at a right angle to the processing direction of the sliding surface. There is a method of molding the dynamic member or adding Teflon powder, graphite, mica, molybdenum difluoride or the like into the base material to reduce the friction coefficient of the fluid lubricated sliding member itself.

(C) Problems to be solved by the invention However, when the sliding surface of the above-mentioned fluid lubricated sliding member is processed to be extremely smooth, it becomes difficult to replenish the lubricating oil, and the lubricating action of the lubricating oil decreases, and the sliding surface The coefficient of friction increases due to the relationship between the roughness and the friction direction, and seizure easily occurs on the sliding surface.

Further, when a filler such as Teflon powder, graphite, mica, molybdenum difluoride, etc. is added to the base material, the strength and elastic modulus of the base material itself are lowered because the filler and the base material are not firmly bonded to each other. As a result, the life cannot be extended, and if the elastic modulus decreases, it cannot withstand a high load, and the lubricating film formed on the sliding surface becomes locally thin, resulting in a thin portion of the lubricating film. However, there is a problem that seizure occurs on the surface of the fluid-lubricated sliding member to accelerate the wear of the sliding member.

In view of the above problems, the present invention fibrillated para-aromatic polyamide short fibers in a carbon-blended rubber base material (commercially available as a product of para-aromatic polyamide fibers by DuPont under the trade name of Kevlar fiber). It is an object of the present invention to provide a fluid-lubricated sliding member in which the lubricating action of a lubricating film can be stably obtained and the life of the sliding member can be extended by including and containing the above.

(D) Means for Solving the Problems The present invention is a fluid-lubricating sliding member that is used in a portion that comes into contact with a fluid and that uses the fluid itself as a lubricant. The fluid-lubricated sliding member is characterized in that the para-type aromatic polyamide short fibers are uniformly dispersed and the short fibers are contained in an amount of 3 to 15 Vol% with respect to the base material.

According to the present invention, according to the present invention, fibrillated para-type aromatic folinamide staple fibers in the carbon-blended rubber base material (fibrillated staple fibers are short fibers that are loosened to a fine fiber state that constitutes the yarn). 3) to 15 Vol% is included in the fluid-lubricated sliding member, so that a liquid such as a lubricant is adsorbed and held between the short battle zones protruding to the lubrication surface side of the fluid-lubricated sliding member, and A lubrication film is always formed and maintained on the lubrication surface side of the lubrication sliding member.

(F) Effects of the invention As a result of the above, the strength and elastic modulus of the fluid-lubricated sliding member are increased, and it is resistant to high loads, vibrations, shocks, etc. applied during use, and a lubricating film is constantly provided on the sliding surface side. To maintain formation,
The lubrication effect of the lubricating film is stably obtained, the self-lubricating property of the fluid lubricated sliding member is improved, and it is possible to prevent seizure phenomenon or wear on the sliding surface side. The durability of the moving member itself can be improved and the service life can be extended.

Moreover, since the glass transition point of the para-type aromatic polyamide fiber is higher than the softening temperature of the base material, it is superior in heat resistance to the conventional fluid-lubricated sliding member and is effective in preventing leakage of high-temperature fluid.

The above-mentioned fibrillated para-type aromatic polyamide short fibers mean para-type aromatic polyamide short fibers that have been loosened to a fine fiber state that constitutes the thread. Therefore, when blended into a rubber material, Since a fine fiber network is formed on the above and the fine fibers have a function of retaining the fluid when used in a fluid, there is an effect of exhibiting excellent lubrication sliding characteristics.

Originally, a rubber material has a large coefficient of friction and has a property of being hard to slip, and generally, when it is used as a bearing material, a lubrication sliding characteristic becomes a problem. However, the present invention can solve such a problem.

Further, the above-mentioned fine fibers are further fibrillated during the kneading with the rubber base material, and a weak chemical bond between the active surface of the fibers and the rubber material generated at that time is generated, so that a macroscopic combination of the fibers In addition to the reinforcing effect, a microscopic reinforcing effect can be obtained, and the mechanical strength can be improved.

(G) Embodiment One embodiment of the present invention will be described in detail below with reference to the drawings.

The drawing shows a fluid lubricated sliding member used in a sealing device,
In FIG. 1, the fluid lubricated sliding member 1 is a c-NBR.
Kevlar fiber as a fibrillated para-type aromatic polyamide fiber (Kevlar is a product name of DuPont) fibrillated carbon blended rubber (Nihon Zeon, Nipol, 1072) as a base material (Kevlar # 29, fiber diameter 12 μm , Fiber length 5m
m) is added in an amount of 3 to 15 Vol% and fibrillated. It is integrally molded into a ring shape.

The method for forming the fluid lubricated sliding member 1 described above is, for example, c-
Carbon compound rubber with NBR as the base material and 5 Kevlar fibers
After adding Vol%, first kneading, and then kneading for 25 minutes (1 cycle, 2.5 minutes, intermittent kneading) with a Banbury mixer (capacity: 1.1 L, rotation speed: 91 rpm), Kevlar fiber in rubber base material Fibrillate with.

Next, in the secondary kneading, the vulcanizing agent is dispersed and the fibers are oriented by an open roll, and the Kevlar fibers are uniformly dispersed and kneaded in the carbon compound rubber, and then transfer molding (temperature: 160 ° C., pressure: 40kg / cm ² , time: 30min)
By heating and pressurizing the kneading raw material Is integrally molded into a ring shape.

On the other hand, a sealing device 2 using the above-mentioned fluid lubricated sliding member 1
As shown in FIG. 2, the mountain ring 4 is closely fitted to the atmosphere side of the sealing portion 3 and is tightened and fixed by the bolt 5, and the mountain ring 4 and the plate 6 are tightly fitted and fixed by the bolt 7. The plate 6 and the casing 8 are tightly fitted to each other by tight fitting, and the bolt 9 and the nut 10 are tightened and fixed.

The fluid lubrication sliding member 1 is provided on the inner peripheral surface side of the casing 8 described above.
Is inserted and the drive band 11 is wound around the outer peripheral surface of the fluid lubricated sliding member 1, and the fluid lubricated sliding member 1 is closely fixed to the outer peripheral surface of the rotary shaft 12 inserted through the central portion of the sealing device 2. In addition, both side peripheral portions 1a, 1a of the fluid lubrication sliding member 1 are brought into close contact with the inner peripheral surfaces of the plate 6 and the casing 8 to prevent fluid leakage.

An emergency seal is provided on the inner peripheral surface of the mountain ring 4.
13 is inserted.

As described above, by adding Kevlar short fibers (however, Kevlar is a product name of DuPont) as para-type aromatic polyamide short fibers to the carbon-blended rubber, the strength and elastic modulus of the fluid lubricated sliding member 1 are increased. Therefore, it is resistant to high loads, vibrations, shocks, etc. applied during use.

Moreover, since the Kevlar short fibers have water absorbency, the water absorbency can be enhanced by forming them into a fibrous shape, and the Kevlar short fibers protruding toward the sliding surface side of the fluid lubrication sliding member 1 are lubricated between them. The liquid such as the agent is adsorbed and held, and the lubricating film is constantly formed and maintained on the sliding surface side, so the lubricating action by the lubricating film is stably obtained, and the self-lubricating property of the sliding member is improved, and the lubricating surface side is improved. It is possible to prevent the seizure phenomenon, wear and the like from occurring and to improve the durability of the fluid lubrication sliding member 1 to extend the life thereof.

Moreover, since the Kevlar short fiber has a higher glass transition point than the softening temperature of the base material, it has excellent heat resistance and is effective in preventing leakage of high-temperature fluid.

Also, a test product containing Kevlar short fibers (Example product)
And the additive-free standard product (comparative example product) are mounted in the sealing device 2 and subjected to an operation test. Although the seizure phenomenon and wear of rubber are observed on the sliding surface of, the seizure phenomenon and wear are hardly observed on the sliding surface of the test product (Example product) to which Kevlar short fibers are added.

Furthermore, test products containing Kevlar short fibers (Example products)
To compare the standard product with no additives (comparative example product),
These samples were formed into the same shape and dimensions, and various tests such as tensile strength, tensile stress, elongation (fiber orientation direction), tear strength, hardness, and Akron wear amount were performed.

The basic physical properties of the sample shown below is 5% by volume of Kevlar staple fiber.
It is the result of having tested the added test product (Example product) and the additive-free standard product (Comparative product) under the same conditions.

That is, compared to the standard product, the test product has excellent test results in terms of tensile strength, tensile stress, elongation (fiber orientation direction), tear strength, and hardness, and in the dry wear test (Acron wear amount) Although it is difficult to express the difference, the wear resistance and the stability of the sliding torque are remarkably improved especially in the liquid.

Fig. 3 shows the changes in the operating time and sliding torque of the standard product (comparative example product). The standard product has fluid pressure P = 1 kgf / cm ² and peripheral speed V.
= 6m / s, sliding time is 62Hr.

FIG. 4 shows the changes in the operating time and sliding torque of the test product (example product), the test product being fluid pressure P = 2 kgf / cm ² and peripheral speed V.
= 10m / s, sliding time 67Hr is the result of the test.

That is, even though the test condition of the test product is more severe than that of the standard product, the sliding torque of the test product gradually decreases at about 4 hours after the start of the test, and the time required for stabilization is short, Since the sliding torque of the test product is low and stable compared to the standard product, overload during operation is small and the operating efficiency can be improved.

FIG. 5 shows the limit PV value of each sample, which is the result of the test under the same conditions as the test product (Example product) to which Kevlar short fibers were added and the standard product without addition (Comparative Example product). That is, since the limit range of the test product is wider than the limit range of the standard product and it can withstand high pressure and high-speed rotation, the range of use of the test product can be expanded as compared with the standard product.

FIG. 6 shows the wear state of the other side in contact with the standard product (comparative example product), and FIG. 7 shows the wear state of the other side in contact with the test product (example product). It is the result of the wear test performed by setting the test condition of 1.

That is, even if the test condition of the test product is set higher than that of the standard product, the sliding surface on the mating side in contact with the standard product is 15.0 μm.
On the sliding surface of the mating side that comes into contact with the test product due to wear of 7.
A test result that wear of 5 μm occurs is obtained, and the amount of wear caused by the test product can be reduced as compared with the amount of wear caused by the standard product.

The above test results prove that the test product (Example product) to which Kevlar short fibers are added has higher performance than the standard product (Comparative example product).

In the above-mentioned examples, 5% by volume of Kevlar short fibers was added to the carbon-blended rubber base material to form the fluid-lubricated sliding member 1. However, the amount of Kevlar short fibers added was 3 to 15 Vol depending on the use conditions. It may be increased or decreased within the range of%.

[Brief description of drawings]

The drawings show one embodiment of the present invention. FIG. 1 is an external perspective view of a fluid lubrication sliding member, FIG. 2 is a vertical side view of a sealing device, and FIG. 3 shows the operating time and sliding torque of a standard product. Fig. 4 is a characteristic diagram showing changes in running time and sliding torque of the test product, Fig. 5 is a characteristic diagram showing the limit PV value of each sample, and Fig. 6 is a standard product. FIG. 7 is a surface roughness curve diagram showing the wear state of the contacting partner, and FIG. 7 is a surface roughness curve diagram showing the wear state of the partner contacting the test product. 1 ... Fluid lubrication sliding member, 2 ... Sealing device

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Claims (1)

[Claims] 1. A fluid-lubricating sliding member which is used in a portion which comes into contact with a fluid and which uses the fluid itself as a lubricant, wherein para-aromatic polyamide short fibers fibrillated in a carbon compound rubber base material are uniformly dispersed. And 3 to 15 vol% of short fibers contained in the base material.