Sliding part

Abstract

Provided is a sliding part providing functionality for both leak prevention and lubrication with no relation to the magnitude of the pressure difference between the inner and outer circumference of a sliding face by drawing in a fluid with a cavitation region on the upstream side of a depressed portion, such as a dimple formed on the sliding face, and generating positive pressure between the sliding faces on the downstream side of the dimple. A sliding part is characterized in that: dimples are provided on the sliding face on one of a pair of sliding parts that slide relative to each other; a cavitation forming region on the upstream side of each dimple is disposed near a low pressure fluid side and a positive pressure generating region on the downstream side is disposed near a high pressure fluid side; and the fluid drawn in with the cavitation forming region of the dimple is returned to the high pressure fluid side from the positive pressure generating region by passing through the inside of the dimple.

Description

technical field [0001] The present invention relates to sliding parts suitable for use in, for example, mechanical seals, bearings, and other sliding parts. In particular, it relates to sliding parts such as seal rings and bearings that require fluid to intervene on sliding surfaces to reduce friction and prevent fluid leakage from the sliding surfaces. Background technique [0002] In a mechanical seal as an example of a sliding member, in order to maintain the sealing performance for a long period of time, it is necessary to balance the contradictory conditions of "sealing" and "lubrication". In particular, in recent years, in order to cope with environmental issues and the like, there has been an increased demand for low friction in order to reduce mechanical loss while preventing leakage of sealed fluid. As a method of reducing friction, it is possible to achieve a so-called fluid lubrication state in which dynamic pressure is generated between sliding surfaces by rotat...

AI Technical Summary

Problems solved by technology

[0005] However, in the invention described in the above-mentioned Patent Document 1, when there is a pressure difference between the inner and outer peripheries of the sliding surface of the seal, etc., it is necessary to overcome the suction effect of the pressure, and there is a problem that the fluid cannot be drawn back due to the magnitude of the pressure. in the case of

Therefore, when the pressure difference is small, leakage can be prevented, but there is a problem that the leakage amount increases when the pressure difference is large.

In addition, in the invention described in the above-mentioned Patent Document 2, if the suction effect of the dimple portion on the side of the sealed fluid is too strong, the amount of leakage increases. Conversely, if the suction effect of the dimple portion on the air side is too strong , the fluid to be sealed disappears from the sealing surface, and the following phenomenon occurs: These dimples formed on the sealing surface directly contact the sliding surface on the other side, resulting in an increase in torque

In prior art 2, there is a problem that in order to prevent an increase in leakage and an increase in torque, it is necessary to balance the suction effects of the respective dimples, but this is actually quite difficult

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