A pin assembly for insertion into a pin joint of an aircraft landing gear is disclosed. The pin assembly includes a reservoir for storing a lubricating agent and a piston mounted for reciprocal movement within the reservoir, the piston dividing the reservoir into a first chamber and a second chamber. A bi-directional flow path between the first and second chambers via the surface to be lubricated is provided by means of a first bi-directional flow path between the first chamber and the exterior of the pin assembly and a second bi-directional flow path between the second chamber and the exterior of the pin assembly. A pin assembly including an indicator system, and a pin insert in the form of a replaceable cartridge is also disclosed along with associated methods.

When an annular portion of a thrust collar rotates together with a rotating shaft member, centrifugal force and shear force, or differential pressure caused by difference in flow rate are generated in lubricating oil in a circulation oil chamber. With this, the lubricating oil in the circulation oil chamber is guided from the inner peripheral side to the outer peripheral side of the annular portion, through a circulation hole penetrating the annular portion. The flow of lubricating oil guided by the circulation hole forms a flow of lubricating oil from a lower oil chamber to an upper oil chamber through the circulation oil chamber. As a result, the lubricating oil stored in the lower oil chamber is circulated to the upper oil chamber through the circulation oil chamber, by rotation of the thrust collar.

When an annular portion of a thrust collar rotates together with a rotating shaft member, centrifugal force and shear force, or differential pressure caused by difference in flow rate are generated in lubricating oil in a circulation oil chamber. With this, the lubricating oil in the circulation oil chamber is guided from the inner peripheral side to the outer peripheral side of the annular portion, through a circulation hole penetrating the annular portion. The flow of lubricating oil guided by the circulation hole forms a flow of lubricating oil from a lower oil chamber to an upper oil chamber through the circulation oil chamber. As a result, the lubricating oil stored in the lower oil chamber is circulated to the upper oil chamber through the circulation oil chamber, by rotation of the thrust collar.

When an annular portion of a thrust collar rotates together with a rotating shaft member, centrifugal force and shear force, or differential pressure caused by difference in flow rate, for example, are generated in lubricating oil in a circulation oil chamber. With this, the lubricating oil in the circulation oil chamber is guided from the inner peripheral side to the outer peripheral side of the annular portion, through a circulation hole penetrating the annular portion. The flow of lubricating oil guided by the circulation hole forms a flow of lubricating oil from a lower oil chamber to an upper oil chamber through the circulation oil chamber. As a result, the lubricating oil stored in the lower oil chamber is circulated to the upper oil chamber through the circulation oil chamber, by rotation of the thrust collar.

When an annular portion of a thrust collar rotates together with a rotating shaft member, centrifugal force and shear force, or differential pressure caused by difference in flow rate, for example, are generated in lubricating oil in a circulation oil chamber. With this, the lubricating oil in the circulation oil chamber is guided from the inner peripheral side to the outer peripheral side of the annular portion, through a circulation hole penetrating the annular portion. The flow of lubricating oil guided by the circulation hole forms a flow of lubricating oil from a lower oil chamber to an upper oil chamber through the circulation oil chamber. As a result, the lubricating oil stored in the lower oil chamber is circulated to the upper oil chamber through the circulation oil chamber, by rotation of the thrust collar.