Sliding component

Abstract

In the present invention, movement of a fluid from an upstream cavitation region to a downstream positive pressure generation region is smoothened, a negative pressure generation origin is enlarged, and cavitation regions are disposed over almost the whole circumference of a low-pressure fluid side. The present invention is characterized in that: dimples (10) are formed along a circumferential direction at an approximately constant width from an upstream cavitation formation region (10a) to a downstream positive pressure generation region (10b); an upstream starting end (10e) of the cavitation formation region (10a) forms a tapered shape inclined along the rotational direction of an opposing sliding surface from the low-pressure fluid side toward a high-pressure fluid side, and is disposed so as to overlap in the radial direction with the positive pressure generation region (10b) of the dimple (10) that is disposed upstream; and the low-pressure fluid-side end (10f) of the positive pressure generation region (10b) forms a tapered shape inclined along the rotational direction of the opposing sliding surface from the low-pressure fluid side toward the high-pressure fluid side, and is smoothly connected to the low-pressure fluid-side end (10c) of the cavitation formation region (10a).

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, due to environmental protection and the like, in order to prevent leakage of the sealed fluid and reduce mechanical loss, the demand for lower friction has been further increased. 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 rotation an...

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 action of the pressure, and the fluid cannot be pushed 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.

[0006] In addition, the above-mentioned prior art 2 is an epoch-making invention in that it has two functions of leakage prevention and lubrication regardless of the magnitude of the pressure difference between the inner and outer peripheries of the sliding surface, but there is the following problem: the basic shape of each dimple 50 is crank shape, thus slightly lacking smoothness in the movement of the fluid from the cavitation forming region 50a on the upstream side to the positive pressure generating region 50b on the downstream side, so the dynamic pressure generation at the low-pressure fluid side X of the positive pressure generating region 50b changes. If it is too large, it may cause leakage, and in addition, the distance from the pressure peak position of the dynamic pressure generating area to the low-pressure fluid side is not so large, so it may cause leakage

In addition, there is a problem that the radial width of the cavitation formation region cannot be increased due to the arrangement of the cavitation formation region on the upstream side close to the low-pressure fluid side, and the starting point of negative pressure generation cannot be increased.

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