Rubber sealing ring, generally made of nitrile rubber, natural rubber, neoprene rubber, ethylene propylene rubber, fluorine rubber, silicone rubber and blend. The sealing ring is mainly used for oil proof, waterproof and anticorrosive sealing gas to prevent leakage.

According to the different materials used in the sealing ring, there are different classifications in nature:
1, high temperature resistance sealing ring, 2, high pressure resistance sealing ring, 3, corrosion resistance sealing ring, 4, wear resistance sealing ring

All kinds of rubber sealing ring material comparison

An annular cover consisting of one or several parts, fixed on one ring or washer of the bearing and in contact with another ring or washer or forming a narrow maze clearance to prevent the leakage of lubricating oil and the invasion of foreign objects. The sealing ring is a rubber ring with a circular section. Because its section is O-type, it is called O-type sealing ring. It is one of the most widely used hydraulic and pneumatic transmission systems. It is usually called O Ring in Taiwan and Japan.

First, NBR nitrile rubber sealing ring: suitable for petroleum hydraulic oil, ethylene glycol hydraulic oil, diester lubricating oil, gasoline, water, silicone grease, silicone oil and other media. It is the most widely used and the lowest cost rubber seal. Do not apply to polar solvents such as ketones, ozone, nitrohydrocarbons, MEKs and chloroform. The general temperature range is -40~120 ℃.

Two, HNBR hydrogenated nitrile butadiene rubber sealing ring: has excellent corrosion resistance, tear resistance and compression deformation characteristics, ozone resistance, sunlight resistance, weather resistance. It has better wear resistance than nitrile butadiene rubber. It is suitable for washing machinery, automobile engine system and refrigeration system using new environmental refrigerant R134a. It is not recommended for use in alcohol, ester, or aromatic solutions. The general temperature range is -40~150 ℃.

Three, SIL silicone rubber sealing ring: has excellent heat resistance, cold resistance, ozone resistance, atmospheric aging resistance. It has good insulation properties. But the tensile strength is worse than the general rubber and does not have oil resistance. Suitable for household appliances such as electric water heater, electric iron, microwave oven, etc. Also suitable for a variety of human body contact supplies, such as kettles, water dispensers and so on. Not recommended for use in most concentrated solvents, oils, concentrated acids and sodium hydroxide. The general temperature range is -55~250 ℃.

Four, VITON fluorine rubber sealing ring: high temperature resistance is better than silicone rubber, has excellent weather resistance, ozone resistance and chemical resistance, cold resistance is poor. It is resistant to most oils and solvents, especially acids, aliphatic hydrocarbons, aromatic hydrocarbons and animal and vegetable oils. Suitable for diesel engine, fuel system and chemical plant sealing requirements. Not recommended for ketones, low molecular weight esters and nitro-containing mixtures. The general temperature range is -20~250 ℃.

Five, F-SIL fluorine silicone rubber sealing ring: its performance has the advantages of fluorine rubber and silicone rubber, oil resistance, solvent resistance, fuel oil resistance and high and low temperature resistance are good. Resist the attack of oxygen - containing compounds, aromatic - containing solvents and chlorine - containing solvents. It is generally used for aviation, aerospace and military purposes. Exposure to ketones and brake fluids is not recommended. The general temperature range is -50~200 ℃.

Six, EPDM three ethylene propylene rubber sealing ring: has good weather resistance, ozone resistance, water resistance and chemical resistance. Can be used for alcohols and ketones, also can be used for high temperature water vapor environment seal. Suitable for sanitary equipment, automobile radiator and automobile brake system. Not recommended for food use or exposure to mineral oils. The general temperature range is -55~150 ℃.

Seven, CR neoprene rubber sealing ring: sun resistance, weather resistance is particularly good. Not afraid of dichlorodifluoromethane and ammonia and other refrigerants, resistant to dilute acid, silicone grease lubricating oil, but in the low aniline point of mineral oil expansion. It is easy to crystallize and harden at low temperature. Suitable for all kinds of contact atmosphere, sunlight, ozone environment and all kinds of fire resistance, chemical corrosion resistance of the seal link. It is not recommended for use in strong acids, nitrohydrocarbons, esters, chloroforms and ketones. The general temperature range is -55~120 ℃.

Eight, IIR butyl rubber sealing ring: air tightness is particularly good, heat resistance, sunlight resistance, ozone resistance, good insulation performance; It has good resistance to polar solvents such as alcohols, ketones and esters, and can be exposed to animal and plant oils or oxides. Suitable for chemical resistance or vacuum equipment. Not recommended for use with petroleum solvents, kerosene, or aromatics. The general temperature range is -50~110 ℃.

Nine, ACM acrylic rubber sealing ring: has excellent resistance to oil, high temperature resistance, weather resistance are good, but the mechanical strength, compression deformation rate and water resistance is slightly poor. Generally used in automotive transmission system and power steering system. Not suitable for hot water, brake oil, phosphate ester. The general temperature range is -25~170 ℃.

NR natural rubber sealing ring: rubber products have good wear resistance, elasticity, tear strength and elongation. But it is easy to age in air, sticky in heat, easy to expand and dissolve in mineral oil or gasoline, alkali resistant but not resistant to strong acid. Suitable for automotive brake oil, ethanol and other liquid with hydroxide ions used. The general temperature range is -20~100 ℃.

Eleven, PU polyurethane rubber sealing ring: polyurethane rubber mechanical properties are very good, wear resistance, high pressure resistance are far better than other rubber. Aging resistance, ozone resistance, oil resistance is also quite good, but high temperature easy hydrolysis. Generally used for high pressure and wear resistance sealing link, such as hydraulic cylinder. The general temperature range is -45~90 ℃.

12, metal rubber sealing ring: made of stainless steel wire, does not contain any rubber components, has a strong use characteristics. For example: in high vacuum, high temperature, strong radiation, and all kinds of corrosion environment to maintain normal work. The sealing ring skin is made of different materials such as stainless steel, copper, polytetrafluoroethylene and other materials according to different uses. The coated metal rubber component is used as the lining core, which has the advantages of high sealing strength, good effect and reusable. The sealing ring lining core is made of different wire diameters and densities, which is suitable for different pressure occasions. The general use range is -80~800℃. This kind of sealing ring is expensive because of its high cost. But good performance, a wide range of use environment, have been recognized by people.

The role of all kinds of sealing rings

V-ring seal

Is an axially acting elastic rubber seal ring, used as a rotary shaft pressure free seal. Sealing lip has better mobility and adaptability, can compensate for large tolerance and Angle deviation, can prevent internal grease or oil leakage, can also prevent the outside of the splash of water or dust intrusion.

O-ring seal

Mainly used for static seal and reciprocating motion seal. For rotary motion seals, only low speed rotary seals.

V-ring seal

Generally installed in the outer circle or the inner circle on the section of the rectangular groove plays a sealing role.

Y-type sealing ring

It is widely used in reciprocating sealing device. In addition, there is a spring tension (spring storage) seal ring, is in PTFE sealing material to add a spring, O spring, V spring, U spring.

Yx-type sealing ring for hole

Application: Used for sealing piston in reciprocating hydraulic cylinder.

Retainer for YX hole

This standard is suitable for use with YX-type seal ring when the working pressure of the cylinder is greater than 16MPa, or when the eccentric pressure of the cylinder is applied, it plays the role of protecting the seal ring

Yx-type sealing ring for shaft

Simple description of product use: Used for reciprocating hydraulic cylinder piston rod seal scope PU: general hydraulic cylinder, general equipment hydraulic cylinder.

YX retaining ring for shaft

This standard is suitable for use with YX-type seal ring when the working pressure of the cylinder is greater than 16MPa, or when the eccentric pressure of the cylinder is applied, it plays the role of protecting the seal ring

Selection and requirement of sealing ring device

Sealing ring is the most important and effective means to solve the leakage problem of hydraulic system. If the sealing ring of the hydraulic system is poor, the sealing ring may not be allowed to leak, the leakage of oil will pollute the environment; It may also make the air into the oil suction chamber, affecting the performance of the hydraulic pump and the stability of the movement of the hydraulic actuator.

Therefore, the reasonable selection and design of the sealing ring device is very important in the design of the hydraulic system, the requirements for the sealing ring device are as follows:

1, the sealing ring in the working pressure and a certain temperature range, should have good sealing performance, and with the increase of pressure can automatically improve the sealing performance.

2, the friction between the sealing ring device and the moving parts should be small, and the friction coefficient should be stable.

3. The sealing ring has strong corrosion resistance, is not easy to aging, long working life, good wear resistance, and can be automatically compensated after wear to a certain extent.

4, simple structure, easy to use and maintenance, so that the sealing ring has a longer life.

Installation precautions

1. Clean the installation position;

2, remove the burr in the process of sealing installation;

3, smear lubricant on the seal;

4, protect the sealing surface from damage;

5. Check and confirm that the size of the seal is correct;

6, for the need to deformation installation of seals using the corresponding tools installation.

Properties and applications of O - shaped rubber seals

< I >Performance and application of O - shaped rubber seals

O-shaped rubber sealing ring is widely used in a variety of mechanical equipment, in different temperature, pressure and media plays a sealing role, to prevent mechanical equipment oil leakage, air leakage, water leakage and the invasion of the external environment media and dust. Compared with other rubber seals, it has the following advantages:

1, simple structure, small volume, compact installation site.

2, with self-sealing effect, no periodic adjustment.

3, good sealing performance, static sealing will not leak.

4, the movement friction resistance is small, suitable for the occasion of alternating pressure.

5, the size and groove has been standardized, the price is cheap, the product is easy to get, easy to use and buy.

6, strong adaptability, very wide range of uses.

< Ⅱ > The deficiency of the O-shaped rubber sealing ring

1, used for compression dynamic seal, starting friction resistance is larger.

2, dynamic sealing is difficult to do not leak, can only control its leakage does not exceed the specified allowable value.

3. In the process of air pressure and water pressure sealing, lubricating oil needs to be added to prevent wear. In some cases often need to add dust-proof, protective ring.

4, matching parts (such as moving surface, groove, clearance, etc.) processing size and precision requirements are strict.

According to the relative motion state of the O-shaped rubber seal ring and the sealed device, it can be divided into O-ring with static seal, O-ring with reciprocating motion seal and O-ring with rotating motion seal. According to the sealing structure, it can be divided into radial seal and axial seal two types of O-ring.

The main material for the manufacture of O-shaped rubber seals is synthetic rubber. According to the working temperature, contact medium, pressure, the selection of rubber is also different.

Formula design of O - shaped rubber sealing ring

< I > Principles of formula design

Rubber formula is generally composed of raw rubber, curing antioxidant reinforcing agent system, protection system, reinforcing system and softening system. The purpose of formula design is to seek the best ratio combination of various matching components, so as to obtain good comprehensive performance. Formulation design should ultimately achieve the following objectives:

1, meet the performance requirements of the sealing ring.

2. Good processing performance of rubber material.

3, under the premise of ensuring product quality, try to choose cheap, rich sources, non-toxic or low toxicity, stable performance of raw materials.

< Ⅱ > Formula design of O-ring sealant

O-shaped rubber seal ring working environment is complex and diverse, it requires that the rubber material has some special properties. In the hydraulic system, it is required to have good oil resistance, temperature resistance, low compression permanent deformation and a certain tensile strength. As a dynamic seal, in addition to the requirements, the rubber material should also have better wear resistance and tear resistance. For the sealing of special media requires small changes in the volume and hardness of the rubber material in the medium. In short, the formula design should be based on the specific working conditions, media type, use temperature, working pressure and application state comprehensive consideration.

< Ⅲ > O sealing ring material processing

At present, the production method of O-shaped rubber sealing ring is mainly produced by over-molding, among which the vulcanization method of molding products mainly includes plate molding, transfer molding and injection molding. Plate molding has the oldest history. Transfer molding began to be used around the 1950s, and injection molding gradually from the plastic industry into the rubber industry since the 1960s. The current development trend is to develop injection pressure method gradually, but due to the different range of adaptation. Coexistence and development of the three is still a reality. O-ring according to its characteristics is still the main forming method of plate molding.

In the process of molding curing, it is necessary to master the temperature, time and pressure of curing strictly and correctly, and pay attention to the change of temperature and other parameters in the curing process at any time, and carry out corresponding treatment, otherwise it will cause the product under-sulfur or over-sulfur. If an automatic control system is used, the whole curing process will be automatically recorded and controlled to ensure that the product reaches a positive curing degree.

Vulcanization temperature is one of the basic conditions of vulcanization of rubber O-ring, which directly affects the vulcanization rate and product quality. High curing temperature, curing speed, high production efficiency; Curing temperature is low, curing speed is slow. The vulcanization temperature depends on the formula, most importantly on the type of rubber and the vulcanization system used. The most suitable vulcanization temperature of natural rubber is generally 143℃- 150℃, synthetic rubber is generally 150℃ ~ 180℃. Curing time is usually determined by the curing temperature, through the test to determine the curing time.

Rubber products in the vulcanization process of pressure, its purpose is to make the rubber material easy to flow, full of cavity, to prevent bubbles in the vulcanization process, improve the density of the product. The vulcanization pressure depends on the hardness of the rubber material and the size of the mold. When the hardness of the rubber material is high and the size of the mold is large, the pressure can be larger, and on the contrary, the pressure should be properly reduced.