The seal tolerance refers to the difference between the processing size and the standard size. In order to ensure that the seal can be installed correctly and perform as expected, the allowable deviation range of the seal size, shape, and position parameters is specified.
There is a set of tolerance standards internationally or in each country, which is essential to ensure the normal operation of the hydraulic system.
To ensure the sealing of the seal, it is necessary to select the appropriate seal type, material, and processing technology according to the specific situation and control the tolerance within the allowable range.
Definition and classification of seal tolerance
Seal tolerance refers to the difference between the processing and standard sizes, generally including upper deviation, lower deviation, and reference sizes. According to the size and position of the tolerance, it can be divided into the following types:
1. Radial tolerance: the difference between the diameter of the seal ring and the diameter of the shaft hole. The radial tolerance is divided into zero tolerance, quantitative tolerance, and interval tolerance, among which zero tolerance means that the diameter of the seal ring is exactly equal to the diameter of the shaft hole.
2. Axial tolerance: the difference between the axial thickness of the seal ring and the axial length of the corresponding shaft hole.
3. Roundness tolerance: Roundness tolerance refers to the deviation between the cross-section and the axis of the sealing ring.
4. Tilt tolerance: Tilt tolerance refers to the deviation of the sealing ring during assembly, which is divided into angle tilt and distance tilt.
The function of tolerance standards
1. Improve sealing performance: Reasonable tolerance standards can ensure the matching accuracy between the seal and the sealing groove, thereby reducing leakage and oil seepage and improving the sealing performance of the hydraulic system.
2. Enhance reliability: By strictly controlling the tolerance of the seal, the risk of system failure caused by poor sealing can be reduced, and the overall reliability of the hydraulic system can be improved.
3. Easy installation and maintenance: Clear tolerance standards help guide installers to correctly install hydraulic seals and also help maintenance personnel to quickly and accurately replace hydraulic seals during maintenance.
What are the hydraulic seal tolerance standards?
The standards for the tolerance range of hydraulic parts mainly include national standards, international standards, and industry standards. Among them, international standards have global guiding significance, while industry standards are more practical and adaptable. By meeting the standard requirements of the tolerance range of hydraulic parts, the stability and reliability of hydraulic parts during use can be guaranteed while improving their production efficiency and economic benefits.
International standards
International standards are very important for the tolerance range of hydraulic seals, and they have guiding significance worldwide. The tolerance range standards of seals mainly include standards issued by the International Organization for Standardization (ISO), and different grades correspond to different tolerance ranges.
Industry standards
Industry standards mainly refer to standards formulated by various industries. For example, the China Hydraulic Parts Industry Association has formulated standards for the tolerance range of hydraulic cylinders, including the calculation method of the tolerance range and the setting of tolerance grades. These industry standards are usually more practical and adaptable and can better reflect the characteristics and requirements of hydraulic seals in actual applications.
National standards
National standards specify the specific values and calculation methods of the tolerance range of hydraulic seals. For example, the tolerance of hydraulic cylinders generally adopts the national standard GB/T 1800-2009, and its tolerance range is divided into multiple grades, such as IT1, IT2, IT3, IT4, IT5, and IT6, according to different tolerance grades. In addition, the national standard also includes the tolerance standards for hydraulic parts such as hydraulic cylinders, hydraulic pumps, and hydraulic valves.
How does the tolerance standard affect sealing effectiveness?
The tolerance standard of the sealing ring has an important impact on the sealing effect. If the tolerance is too large or too small, it will affect the sealing effect of the sealing ring, resulting in leakage or poor sealing.
Too large tolerance
Tolerance is too large, which will cause the gap between the sealing ring and the piston and cylinder to be too large, resulting in oil leakage and failure to achieve the expected sealing effect.
Too small tolerance
Tolerance is too small, which will cause the gap between the sealing ring and the piston and cylinder to be too small, and the sealing ring will be compressed and deformed, resulting in a poor sealing effect, easy to burn under high-temperature and high-pressure environments, and a shortened service life.
How to ensure the sealing of the seal?
The sealing of hydraulic seals plays an important role in the operation of industrial equipment. Therefore, how to ensure the sealing of seals is an important issue in industrial design. Specifically, the following aspects need to be considered:
Material selection
The hydraulic seal material should have good wear resistance, corrosion resistance, high-temperature resistance, low-temperature resistance, and chemical corrosion resistance.
Processing technology
The processing technology of the seal should use high-precision equipment and advanced processing methods, and the appropriate material should be selected for processing according to the specific situation.
Tolerance control
The tolerance of the seal should be controlled within the allowable range.
Regular maintenance and care
Regular maintenance and care of the seal also have a great impact on the sealing performance. If necessary, the seal can be replaced regularly.
Testing method
After the seal is processed and assembled, it needs to be strictly tested to ensure that its sealing meets the requirements. The testing method generally includes visual inspection, installation test, etc.
When purchasing and selecting hydraulic seals, you also need to pay attention to the following points:
1. Choose a manufacturer and brand with reliable quality.
2. Manufacture or purchase according to the tolerance standard of the seal ring;
3. When installing the seal ring, strictly follow the requirements of the operating manual to avoid leakage due to improper installation.
The tolerance standard of hydraulic seals is a key factor in ensuring the sealing performance and reliability of hydraulic systems.
By deeply understanding and rationally applying these standards, we can provide strong support for the optimized design, installation and commissioning, and daily maintenance of hydraulic systems, thereby extending the service life of the system and reducing operating costs.
This article introduces the tolerance standards of hydraulic seals and their impact on the sealing effect in detail and gives suggestions for the correct selection of hydraulic seals. I hope it can help you better understand hydraulic seal tolerance, thereby improving the stability and reliability of the system.
