KR101405907B1 - Rubber composition of O-ring for mono tube type shock absorber - Google Patents

Abstract

The present invention provides an o-ring rubber composition for a mono-tube type shock absorber. Accordingly, the rubber composition of the o-ring for a mono-tube type shock absorber of the present invention is an o-ring for a monotube type shock absorber interposed between a separation piston included in a monotube type shock absorber of a vehicle and a tube to seal the oil chamber and the gas chamber. An inorganic filler having 30 to 70 parts by weight based on 100 parts by weight of the polymer, and an inorganic filler having a particle diameter of 20 to 30 nm, And an organic filler having 30 to 70 parts by weight based on 100 parts by weight of the polymer.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a rubber composition for an O-ring for a mono-tube type shock absorber,

The present invention relates to a rubber composition for an o-ring for a monotube shock absorber used in a separating piston in a monotube type shock absorber used in a vehicle.

In general, a shock absorber is a vibration absorber installed between an axle and a vehicle body to absorb a vibration or an impact received from the road surface by an axle when the vehicle is running, thereby enhancing ride comfort. Inside the shock absorber, And fillers such as oil are filled.

According to the structure, the oil storage tube is a double tube type (Twin tube type) and the oil storage tube is a single wall type mono tube type (Mono tube type).

The monotube shock absorber includes a separation piston located in the interior of the tube and positioned midway between the gas chamber and the oil chamber.

The outer peripheral surface of the separating piston is in close contact with the inner peripheral surface of the tube in order to distinguish between the upper oil chamber filled with the oil and the lower gas chamber filled with the gas. An O-ring is disposed on the outer peripheral surface of the separating piston. The O-ring pressurizes the inner circumferential surface of the tube to prevent the oil of the oil chamber and / or the gas in the gas chamber from leaking into the gap between the separation piston and the tube.

The O-ring is made of a material having excellent frictional force in order to satisfy perfect sealing. However, due to the side effect of the high frictional force, a sticking phenomenon occurs in which the separating piston does not move, so that the normal damping force action is not performed, and the external impact is transmitted to the vehicle body as it is.

In addition, when a material having excellent lubricity is applied, the mechanical properties such as tensile strength and modulus deteriorate and durability is weakened.

It is an object of the present invention to provide a rubber composition for an o-ring for a mono-tube which is excellent in lubricity and also in mechanical properties to solve various problems including the above problems.

Accordingly, the rubber composition of the o-ring for a mono-tube type shock absorber of the present invention is an o-ring for a monotube type shock absorber interposed between a separation piston included in a monotube type shock absorber of a vehicle and a tube to seal the oil chamber and the gas chamber. (NBR), an inorganic filler having a talc content, a titanium content and a silica content based on 100 parts by weight of the polymer, and an inorganic filler having a particle diameter of 20 nm to 30 nm, And carbon black having 30 to 70 parts by weight based on 100 parts by weight of the polymer.

 In this case, a silane coupling agent having 1 to 2 parts by weight relative to 100 parts by weight of the polymer may be further included.

Also, it is preferable to use 1 to 5 parts by weight of 2,2,4-trimethyl-1,2-dihydroquinoline, based on 100 parts by weight of the polymer. A crosslinking aid having 5 to 10 parts by weight of dicumyl peroxide, 10 to 15 parts by weight of a crosslinking auxiliary containing stearic acid and zinc oxide, and 5 to 15 parts by weight of a diester-based antioxidant And may further include a plasticizer.

In this case, it is preferable that the zinc oxide contained in the crosslinking aid has 8 to 12 parts by weight based on 100 parts by weight of the polymer.

According to the present invention, lubricity is improved and sticking can be prevented. As a result, the normal damping force action is performed, and the riding comfort is improved. Further, the mechanical properties are excellent, and the durability is improved.

1 is a cross-sectional view illustrating an example of a monotube type shock absorber to which the present invention can be applied.

Hereinafter, preferred embodiments of the present invention will be described in detail.

1 is a cross-sectional view illustrating an example of a monotube type shock absorber to which the present invention can be applied. As shown in Fig. 1, a tube 1, a piston rod 2 which is inserted into the tube 1 and whose other end extends to the outside of the tube 1, and a piston rod 2 which is provided at one end of the piston rod 2 A separating piston 6 positioned in the middle of the tube 1 so as to separate the gas chamber 4 and the oil chamber 5 from each other, And a rod guide (7) installed to support the piston rod (2) at the lower end thereof.

The outer peripheral surface of the separating piston is in close contact with the inner peripheral surface of the tube in order to distinguish between the upper oil chamber filled with the oil and the lower gas chamber filled with the gas. An O-ring 10 for a mono-tube type shock absorber according to a preferred embodiment of the present invention is disposed on the outer circumferential surface of the separation piston.

The o-ring for a mono-tube type shock absorber 10 pressurizes the inner circumferential surface of the tube to prevent the oil of the oil chamber and / or the gas chamber from leaking into the gap between the separation piston and the tube, .

The rubber composition of the O-ring 10 for a monotube type shock absorber includes a polymer, an inorganic filler, and an organic filler.

The polymer is made of nitrile rubber (NBR).

The inorganic filler includes talc, titanium, and silica. The inorganic filler composed of the talc, titanium, and silica series improves lubricity. In particular, when titanium dioxide (TiO2) is used as the titanium-based material, the lubricity can be further improved.

In this case, the inorganic filler preferably has 30 to 70 parts by weight based on 100 parts by weight of the polymer. If the weight part is less than 30 parts by weight, the lubricating property is deteriorated. If the weight part is more than 90 parts by weight, compounding processing becomes difficult and the dispersibility is deteriorated.

Further, the mechanical strength deteriorated by application of the inorganic filler can be complemented by blending the organic filler. In this case, the organic filler includes carbon black having a particle diameter of 20 nm to 30 nm.

The smaller the particle diameter of the carbon black, the more improved the mechanical properties such as tensile strength, abrasion resistance, hardness and modulus. Therefore, by controlling the particle diameter of the carbon black to be as small as 20 nm to 30 nm, the mechanical properties can be prevented from deteriorating.

In this case, the carbon black preferably has 30 to 70 parts by weight based on 100 parts by weight of the polymer. When the weight part is more than 70, the elasticity of the rubber deteriorates to degrade the lubricity. When the weight part is less than 30 This is because there is no effect of improving the mechanical properties.

In order to further improve the mechanical properties, zinc oxide (zinc oxide) is preferably included as a crosslinking aid in an amount of 8 to 12 parts by weight based on 100 parts by weight of the polymer. The crosslinking aid is intended to increase the crosslinking rate of the polymer while preventing side chain reaction to increase the crosslinking density.

When the zinc oxide is blended in an amount of 8 to 12 parts by weight, wear resistance is improved and durability is improved. The crosslinking assistant may further include stearic acid. In this case, the crosslinking assistant preferably has 10 to 15 parts by weight based on 100 parts by weight of the polymer.

In the present invention, a silane coupling agent having 1 to 2 parts by weight relative to 100 parts by weight of the polymer may be further included. The silane coupling agent is bonded to the surface of the inorganic filler in which one of the molecules of the molecule is mixed with the polymer and the other is affinity with the matrix resin to improve the dispersibility and the adhesion between the inorganic filler and the matrix polymer is improved Thereby improving the strength of the rubber.

Meanwhile, the present invention may include a cross-linking agent having 5 to 10 parts by weight and containing dicumyl peroxide. The cross-linking agent functions to cross-link the monomers constituting the polymer. When vulcanized with an organic peroxide, a good compression ratio of the rubber can be obtained.

On the other hand, the present invention provides an antioxidant composition comprising 1 to 5 parts by weight of an antioxidant comprising 2,2,4-trimethyl-1,2-dihydroquinoline, As shown in FIG. Antioxidants prevent aging of organic polymeric materials. Antioxidants are often referred to as antioxidants because they often have the same action as antioxidants. Antioxidants act to stop the chain reaction, which is autoxidized by oxygen, a major factor in the aging process.

Further, the present invention may further include a diester-based plasticizer.

The plasticizer serves to soften the polymer. In general, the plasticizer is an organic material which is added to a thermoplastic such as vinyl chloride and vinyl acetate to increase the thermoplasticity, thereby facilitating molding at a high temperature, and plays a role similar to a softener which gives flexibility.

For example, the action of a plasticizer is briefly explained as follows. Plastics are formed by gathering molecules such as long strings. The stronger the attraction force between molecules becomes, the harder it becomes. In this case, when a plasticizer intercalates between molecules, the direct pulling force between the plastic molecules weakens and bends well. Therefore, it is advantageous that the plasticizer has a property of mixing well with the polymer, that is, a blendability. In the present invention, the plasticizer of the present invention may be a diester-based plasticizer in an amount of 5 to 15 parts by weight based on 100 parts by weight of the polymer.

According to the present invention, the inorganic filler is used to improve the friction property, and the mechanical strength is improved by adjusting the weight ratio of the organic filler, the particle size, the weight ratio of the crosslinking aid, and the like. Accordingly, the sticking phenomenon of the separating piston can be prevented, so that a normal damping force action is achieved.

Hereinafter, a rubber composition of an o-ring for a mono-tube type shock absorber according to an embodiment of the present invention (hereinafter referred to simply as "embodiment ") and a rubber composition of a conventional o- Quot; Yes ").

In this case, as shown in Table 1, an inorganic filler was applied for the examples and N330 having a small particle size for the organic fillers. Further, 10 parts by weight of zinc oxide was added as a crosslinking aid. In contrast, in the comparative example, an inorganic filler was not applied, and in the case of an organic filler, N770 having a large particle diameter was applied. Further, 5 parts by weight of zinc oxide was added as a crosslinking aid.

Components (parts by weight) Comparative Example Example Polymer NBR ^{1 )} 100 100 Filler N774 ^{2 )} 85 - N330 ^{3 )} - 50 Zeosil 155 ⁴⁾ - 10 TiO2 ^{5 )} - 20 Talc MG-400 ⁶⁾ - 30 Antioxidant SUNNOC ^{7 )} One One TMQ ^{8 )} One One Crosslinking auxiliary ZnO ^{9 )} 5 10 Stearic Acid ^{10 )} One One Cross-linking agent Sulfur ^{11 )} 1.2 One DCP ^{12 )} - 2 DM ^{13 )} 2 3 Plasticizer TP-95 ¹⁴⁾ 5 10 1) NBR: B7150, LG Chem
2) N774: Carbon, Dongyang Steel Chemical
3) N330: Carbon, Dongyang Steel Chemical
4) Zeosil 155: SiO2, Rhodia Silica
5) TiO2: Titanium, Dupont
6) Talc MG-400: Mg · SiO 2, Daewon Chemical
7) SUNNOC: Special Wax, Emerging in-house
8) TMQ: 2,2,4-Trimethyl-1,2-dihydroquinoline, Lanxess
9) ZnO KS-2: Zinc oxide, SBC
10) Stearic Acid: Stearic acid, NATOLEO
11) Sulfur: Hwang, Miwon
12) DCP: Dicumyl Peroxide, NOF
13) DM: Dibenzothiazyl Disulfide, Lanxess
14) TP-95: Diester system, ROHM & HAAS

Table 2 is a table showing friction characteristics and lubricity test results of the examples and comparative examples. In this case, the friction characteristics were measured through a heidon friction test. The highdon friction test is carried out by applying pressure to the plate and the sheet-shaped test piece with a ball fixed, and the difference between the test pieces is obtained based on the ball. In this case, the rotation speed of the ball is 1 / sec, the number of rotations is 600, the friction force is 39.23 N · cm, the weight is 100 g, the turning radius is 35 mm, and the material of the friction ball is SUS.

Item Required property Comparative Example Example Friction characteristic
(Psalter) Static friction - 248 197 Dynamic friction - 218 176 Lubricity
(O-ring) Stick phenomenon Not to be Occur none

As shown in Table 2, it can be seen that the friction strength of the example is superior to that of the comparative example. Therefore, it can be seen that the embodiment has better mechanical properties.

In addition, in the case of the lubricity test, the sticking phenomenon does not occur in the Examples, whereas the sticking phenomenon occurs in the Comparative Examples. Accordingly, it can be seen that the lubricating properties of Examples are excellent.

 While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the present invention. Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

1: Tube 2: Piston rod
3: Piston valve 4: Gas chamber
5: Oil chamber 6: Separation piston
7: Rod guide 10: O-ring for monotube shock absorbers

Claims (4)

A rubber composition for an o-ring for a mono-tube type shock absorber interposed between a separating piston and a tube included in a monotube shock absorber of a vehicle to seal between the oil chamber and the gas chamber,
A polymer composed of nitrile rubber (NBR);
Silica-based, talc-based, and titanium-based inorganic fillers having 30 to 70 parts by weight based on 100 parts by weight of the polymer; And
Carbon black having a particle diameter of 20 nm to 30 nm and 30 to 70 parts by weight based on 100 parts by weight of the polymer;
Wherein the rubber composition of the O-ring for a mono-tube type shock absorber is characterized in that it comprises: The method according to claim 1,
And a silane coupling agent having 1 to 2 parts by weight based on 100 parts by weight of the polymer. The method according to claim 1,
An antioxidant having 2,2,4-trimethyl-1,2-dihydroquinoline, which has 1 to 5 parts by weight, relative to 100 parts by weight of the polymer, , 5 to 10 parts by weight of a crosslinking agent containing dicumyl peroxide, 10 to 15 parts by weight of a crosslinking auxiliary containing stearic acid and zinc oxide, and 5 to 15 parts by weight of a diester-type plasticizer Wherein the rubber composition is a rubber composition. The method of claim 3,
The rubber composition for an o-ring for a mono-tube type shock absorber according to claim 1, wherein the zinc oxide contained in the crosslinking aid has 8 to 12 parts by weight based on 100 parts by weight of the polymer.

Images