斯特封简介 Introduction to Step Seal SS85*6.3 oil seal

2026年5月14日

一、斯特封简介

1. 定义与结构

斯特封（Step Seal）是一种阶梯组合式轴用/孔用双向/单向密封圈，属于高性能往复运动密封件，由聚四氟乙烯（PTFE）滑环+弹性橡胶O形圈组合而成：

• 外层/主密封：PTFE阶梯滑环（低摩擦、耐磨、耐介质、自润滑）；

• 内层/预紧元件：O形橡胶圈（提供径向预紧力，补偿间隙、磨损，保证PTFE滑环紧贴密封面）。

按用途分两类：

• 轴用斯特封：用于活塞杆、轴类外圆密封；

• 孔用斯特封：用于缸筒、内孔密封。

2. 工作原理

O形圈受介质压力和装配压缩产生弹性变形，对PTFE滑环施加持续径向预紧力，使滑环紧贴金属密封面；压力越高，O形圈挤压越紧，密封效果越强，实现低压预紧、高压自紧密封，同时PTFE材质大幅降低摩擦、避免爬行、耐磨寿命长。

3. 核心特点

✅ 低摩擦、无爬行、启动阻力小；
✅ 耐高压、耐磨损、寿命长；
✅ 耐油、耐酸碱、耐液压介质、耐高低温；
✅ 适配往复运动工况（液压油缸、气缸、工程机械、液压系统）；
✅ 可补偿间隙、偏心、轻微磨损，密封可靠性高；
❌ 不适合高速旋转密封，主打往复直线运动。

4. 常用材质组合

• PTFE滑环：纯PTFE、填充玻纤/碳纤/铜粉/二硫化钼PTFE（提升耐磨、抗压）；

• O形圈：NBR（丁腈橡胶，液压油通用）、FKM（氟橡胶，高温/特种介质）、HNBR（氢化丁腈，耐磨耐温）。

二、斯特封常用标准

斯特封无单一专属国标，多参考液压密封件通用标准、行业标准、国际标准，国内生产企业多按GB/T国标、ISO国际标准、行业厂标执行：

1. 国内标准

1. GB/T 15242系列

◦ GB/T 15242.1～4《液压气动用O形橡胶密封圈尺寸系列及公差》：规范O形圈尺寸、公差、沟槽基础；

◦ 斯特封O形预紧圈尺寸优先遵循此标准。

2. GB/T 3452.1
《液压气动用O形橡胶密封圈第1部分：尺寸系列和公差》：国内O形圈核心尺寸标准，斯特封配套O形圈必用。

3. JB/T 6657
《液压缸活塞和活塞杆密封件沟槽尺寸》：工程机械、液压油缸专用，规定斯特封安装沟槽的槽径、槽宽、槽深、公差、表面粗糙度，是国内油缸厂家最常用的斯特封沟槽设计标准。

4. HG/T 2579
《O形橡胶密封圈用沟槽尺寸》：化工、通用机械密封沟槽参考标准。

2. 国际标准

1. ISO 6194
《Sealing devices - O‑rings》：国际O形圈尺寸、公差、材料基础标准，进口斯特封常用参考。

2. ISO 5597
《Hydraulic fluid power - Cylinders - Housings and rod glands for single‑acting rod seals》：液压油缸活塞杆/活塞密封沟槽国际标准，高端液压系统斯特封设计依据。

3. DIN 3869（德国标准）
欧洲常用斯特封/格来圈组合密封尺寸标准，国内很多高端密封件厂按DIN标准生产替代件。

3. 行业/企业标准

• 工程机械（三一、徐工、中联）、液压件厂多有企业厂标，基于GB/T、JB/T优化，适配自身油缸缸径/杆径；

• 进口品牌（如Hallite、Trelleborg、SKF）有自家企业产品标准，包含斯特封规格、材质、压力温度范围、沟槽推荐。

三、斯特封关键参数与选型要点

1. 压力范围：常规 0～40MPa，高压型可达60MPa以上；

2. 温度范围：NBR O形圈 -40～+100℃，FKM O形圈 -20～+200℃；

3. 速度：往复运动≤1m/s（低速中载最优）；

4. 介质：液压油、水乙二醇、乳化液、部分酸碱介质；

5. 选型：确定缸径/杆径、沟槽尺寸、压力、温度、介质，再匹配对应标准尺寸斯特封。

四、斯特封与格来圈区别（快速区分）

• 斯特封：PTFE滑环为阶梯型，单向密封，结构更紧凑，多用于活塞杆；

• 格来圈：PTFE滑环为平环/双台阶，双向密封，多用于活塞密封。

需要我给你一份常用轴用/孔用斯特封尺寸选型表（沟槽+规格）吗？可以直接对照GB/T、JB/T标准选型。

1. Introduction to St. John's Wort

1. Definition and structure

The Step Seal is a high-performance reciprocating seal with a stepped and combined design, suitable for both axial and bore applications, featuring both bi-directional and unidirectional sealing capabilities. It is composed of a polytetrafluoroethylene (PTFE) sliding ring combined with an elastic rubber O-ring:

• Outer layer/main seal: PTFE stepped slip ring (low friction, wear-resistant, medium-resistant, self-lubricating);

• Inner layer/pre-tightening component: O-shaped rubber ring (provides radial pre-tightening force, compensates for clearance and wear, and ensures the PTFE sliding ring adheres closely to the sealing surface).

It can be divided into two categories based on its purpose:

• Shaft seals: used for sealing the outer circumference of piston rods and shafts;

• Hole sealing: used for cylinder barrel and inner hole sealing.

2. Working principle

The O-ring undergoes elastic deformation due to medium pressure and assembly compression, exerting a continuous radial pre-tightening force on the PTFE sliding ring, ensuring it adheres closely to the metal sealing surface. The higher the pressure, the tighter the O-ring is squeezed, resulting in a stronger sealing effect. This achieves low-pressure pre-tightening and high-pressure self-sealing. Additionally, the PTFE material significantly reduces friction, prevents creeping, and ensures long wear resistance.

3. Core characteristics

✅ Low friction, no creeping, and low starting resistance;
✅ High pressure resistance, wear resistance, and long service life;
✅ Resistant to oil, acids and alkalis, hydraulic pressure medium, high and low temperatures;
✅ Suitable for reciprocating motion conditions (hydraulic cylinders, pneumatic cylinders, construction machinery, hydraulic systems);
✅ It can compensate for gaps, eccentricities, and minor wear, ensuring high sealing reliability;
❌ Not suitable for high-speed rotary sealing, primarily designed for reciprocating linear motion.

4. Common material combinations

• PTFE slip ring: pure PTFE, filled with glass fiber/carbon fiber/copper powder/molybdenum disulfide PTFE (to enhance wear resistance and compressive strength);

• O-ring: NBR (nitrile rubber, commonly used in hydraulic oil), FKM (fluoroelastomer, suitable for high temperatures/special media), HNBR (hydrogenated nitrile rubber, resistant to wear and temperature).

II. Standard for commonly used Sturgeons

Stelfon does not have a single exclusive national standard. It mainly refers to general standards for hydraulic seals, industry standards, and international standards. Domestic manufacturing enterprises mostly follow GB/T national standards, ISO international standards, and industry factory standards:

1. Domestic standards

1. GB/T 15242 series

◦ GB/T 15242.1~4 "O-rings for hydraulic and pneumatic applications - Dimensions and tolerances": specifies the dimensions, tolerances, and groove basis of O-rings;

◦ The dimensions of the O-ring pre-tightening seal for the Stahl seal should preferably follow this standard.

2. GB/T 3452.1
"O-Rings for Hydraulic and Pneumatic Applications - Part 1: Dimensions and Tolerances": This is the core dimensional standard for O-rings in China, and it is mandatory for the O-rings used in conjunction with Stet seal products.

3. JB/T 6657
"Groove Dimensions for Seals of Hydraulic Cylinder Pistons and Rods": Specifically designed for construction machinery and hydraulic cylinders, it stipulates the groove diameter, groove width, groove depth, tolerance, and surface roughness for the installation of O-rings. It is the most commonly used O-ring groove design standard among domestic cylinder manufacturers.

4. HG/T 2579
"O-Ring Groove Dimensions": a reference standard for chemical and general mechanical seal grooves.

2. International standards

1. ISO 6194
"Sealing devices - O-rings": International basic standard for O-ring dimensions, tolerances, and materials, commonly used as a reference for imported stet seal products.

2. ISO 5597
"Hydraulic fluid power - Cylinders - Housings and rod glands for single‑acting rod seals": This is an international standard for the grooves of hydraulic cylinder piston rods/piston seals, serving as the design basis for the Starr seal in high-end hydraulic systems.

3. DIN 3869 (German Standard)
The combination seal of Stromberg/Gland ring is commonly used in Europe, and many high-end seal parts manufacturers in China produce replacement parts according to DIN standards.

3. Industry/corporate standards

• Many enterprises in the construction machinery (SANY, XCMG, Zoomlion) and hydraulic component industries have their own corporate logos, optimized based on GB/T and JB/T standards, and adapted to their own cylinder bore/rod diameters;

• Imported brands (such as Hallite, Trelleborg, SKF) have their own corporate product standards, including specifications, materials, pressure and temperature ranges, and groove recommendations for seals.

III. Key parameters and selection points of Stirling seals

1. Pressure range: Conventional 0~40MPa, high-pressure type up to 60MPa or more;

2. Temperature range: NBR O-ring -40~+100℃, FKM O-ring -20~+200℃;

3. Speed: Reciprocating motion ≤1m/s (optimal for low speed and medium load);

4. Medium: hydraulic oil, water-glycol, emulsion, and some acid-base media;

5. Selection: Determine the cylinder diameter/rod diameter, groove size, pressure, temperature, and medium, and then match the corresponding standard size of the Stromberg seal.

IV. Difference between Stet seal and gland ring (quick distinction)

• Stet seal: PTFE sliding rings are of a stepped design, featuring one-way sealing and a more compact structure, and are commonly used in piston rods;

• Gland ring: PTFE sliding ring is a flat ring/double-step design, featuring bidirectional sealing, and is commonly used for piston sealing.

Do you need me to provide you with a selection table for commonly used shaft/bore seals (groove + specification)? You can directly refer to the GB/T and JB/T standards for selection.