In the hydraulic system of the main engineering machinery product, the common oil ports that cooperate with Hose Fittings have the following types:

3.1 O-ring seal with 15° internal chamfered oil port structure with counterbore groove on metric, American and British threaded column ends

The 15° internal chamfered oil port type is more commonly used in the design of the pump (executor) and motor (power unit) oil inlet and outlet ports in the hydraulic pipeline, as shown in Figure 1. The thread form is produced by the pump and the motor. Manufacturers connect according to different standards, metric thread (ISO 6149-1 standard), American unified thread (ISO 11926-1 standard), and inch pipe thread (JIS B2351 standard). The sealing form is O-ring sealing.

3.2 Metric and inch threaded column end elastic sealing ring or metal-to-metal sealing flat oil port structure

This kind of oil port is commonly used in the design of statically sealed oil inlet and outlet ports such as valves, confluence blocks, and pumps in hydraulic pipelines, as shown in Figure 2. The machining process is relatively simple compared to the 15° internal chamfering of the oil port, but after the internal thread is processed, the oil port is flattened with a shallow sink to ensure the verticality requirements between the pipe joint and the oil port sealing surface, so that the pipe joint and the ED The gasket and the countersink plane of the oil port are completely attached to form a seal and reduce the leakage of the connecting surface.

According to different standards, manufacturers of flat oil ports have metric threads (GB/T 19674.1 standard) and inch pipe threads (ISO1179-1 standard) for connection. The sealing form is sealed by ED elastic sealing ring, or with pipe joints and oil. The sharp corners between the mouths are sealed.

3.3 British tapered pipe thread seal, American NPT tapered pipe threaded port structure

(1) Inch 55° threaded cone pipe thread sealing oil port structure: also called threaded oil port, as shown in Figure 3. The limit size and tolerance of this thread meets the requirements of GB/T 7306. When connecting with pipe joints, no packing or sealing medium is required to prevent leakage. The connection of conical internal thread oil and conical external thread joints can be used under high temperature and high pressure. use;

(2) U.S.-made 60° tooth-shaped pyramid pipe threaded NPT seal oil port structure: as shown in Figure 3, the limit size and tolerance comply with GB/T 12716 regulations, which are mainly used for fuel and lubricating oil pipeline joints, and at the same time It is also suitable for high temperature and high pressure systems.

For more product information, please click here: Metric Thread Fittings.