JPH06265026A - Slide ring for shaft sealing device - Google Patents

Abstract

PURPOSE:To provide a slide ring which is constituted to provide proper lubrication and pumping operation of a slide surface by means of grooves despite of a rotation speed and the temperature of sealing fluid and prevent the occurrence of leakage during a stop and low speed rotation. CONSTITUTION:A plurality of embedding materials 3 embedded in a direction crossing the rotation direction of a slide ring matrix 2 and formed of a slide material having the coefficient of thermal expansion lower than that of the slide ring matrix 2 are provided. A smooth slide surface 1a comprises an end face 2a in an axial direction of the slide ring matrix 2; and the end face 3a of the embedding material 3 exposed to one end face 2a. A groove is formed in the end face 3a of the embedding material 3 by means of a difference in thermal expansion between the slide ring matrix 2 and the embedding material 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slide ring of a shaft sealing device such as a mechanical seal mounted on a shaft sealing portion of a rotating machine, and more particularly to a slide ring suitable for high temperature sealed fluid or high speed rotation. .

[0002]

2. Description of the Related Art Conventionally, a carbon material or a ceramic material such as SiC has been widely used as a sliding ring of a shaft sealing device such as a mechanical seal. This is because the carbon material is excellent in self-lubricating property and wear resistance, and the ceramic material is excellent in wear resistance, chemical resistance and heat resistance.

However, even with such a sliding material, the sliding surface temperature is insufficiently lubricated when it is used under severe conditions such as high speed rotation and high temperature sealing fluid. Abnormally rises, causing surface damage such as seizure, cracking due to thermal strain, chipping, and abnormal wear. In order to prevent the occurrence of such a problem, the sliding surface is processed by shot blasting or the like to form a large number of fine grooves having a spiral or radial direction with a depth of several μm. Is extremely effective.
It is also known that this groove is effective in improving the sealing performance by utilizing the pumping action by rotation.

[0004]

However, the proper groove depth for effective lubrication and pumping varies depending on the rotation speed and the temperature of the sealed fluid. Therefore, if the groove depth is too deep, It is unavoidable that leakage through the groove increases when stopped or at low speed rotation, and when it is too shallow, sufficient lubrication and pumping effects during high speed rotation and when the sealed fluid is hot. There is a problem that is not obtained.

The present invention has been made under the above circumstances, and its technical problem is to appropriately lubricate the sliding surface by the groove regardless of the rotation speed and the temperature of the sealing fluid. Another object of the present invention is to provide a sliding ring that can obtain a pumping action and that does not leak when stopped or at low speed rotation.

[0006]

The above-mentioned technical problems are as follows.
The present invention can effectively solve the problem. That is, the sliding ring of the shaft sealing device according to the present invention includes a sliding ring base material formed in an annular shape, the sliding ring base material embedded in the sliding ring base material in a direction intersecting the rotation direction, and the sliding ring base material. A plurality of embedding materials made of a sliding material having a coefficient of thermal expansion lower than that of the sliding ring base material, and a smooth sliding surface is formed on the one end surface in the axial direction of the sliding ring base material and the surface of the embedding material exposed on this surface. It was done.

[0007]

According to the sliding ring having the above structure, when stopped, the entire sliding surface forms a smooth flat surface, but the rotation speed increases and the sliding ring temperature rises due to the frictional heat generated on the sliding surface. If the temperature of the sealed fluid is high or the temperature of the sealed fluid is high, the difference in the amount of thermal expansion between the sliding ring base material and the embedding material made of a sliding material with a coefficient of thermal expansion relatively lower than that of the sliding ring base material By this, a groove having a minute depth extending along the surface of the embedding material in a direction intersecting the rotation direction is formed on the sliding surface, and a lubricating film is formed on the sliding surface by a part of the sealing fluid introduced into the groove. Is formed. Further, the leakage of the sealing fluid through the groove is suppressed by the pumping action accompanying the rotation of the groove.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to the drawings. FIG. 1 is a perspective view schematically showing a sliding ring 1 according to this embodiment. This sliding ring 1 has an inner diameter of 45 mm, an outer diameter of 64 mm, and an axial width 22 in which a smooth sliding surface 1a extending in a direction substantially orthogonal to the axis is formed at one axial end.
It is an annular body of mm and has a sliding ring base material 2 and a width 2 radially embedded in the sliding ring base material 2 in 8 equal parts centered on the axis.
mm, and a plate-shaped embedding material 3 having an axial length of 12 mm. The surface 3a of the embedding material 3 is exposed on the same plane as the sliding surface 1a, that is, a smooth sliding surface 1a which is continuous by the end surface 2a of the sliding ring base material 2 and the surface 3a of the embedding material 3.
Are formed. The sliding ring base material 2 is a sliding material having a high thermal expansion coefficient, for example, SiC-2 having a thermal expansion coefficient of 4.8 × 10 ^−6.
The embedding material 3 is made of 5% TiB ₂ , and the embedding material 3 is made of a sliding material having a low thermal expansion coefficient, for example, SiC having a thermal expansion coefficient of 3.5 × 10 ⁻⁶ .

In FIG. 2, the sliding ring 1 having the above-mentioned structure is incorporated into a mechanical seal, and the sliding surface 1a is fitted to the mating sliding ring 1.
It shows a change in the shape of the sliding surface 1a depending on the sliding speed (rotational speed) when it is brought into sliding contact with the sliding surface 10a of No. 0. One of the sliding rings 1 and 10 is fixed to the housing side to hold the non-rotating state, and the other is mounted to the rotating shaft side, and the sliding surface 1 is rotated by the rotation of the rotating shaft.
a and 10a slide in a sealed manner, and the sliding surfaces 1a and 1a
It is configured to prevent leakage of the sealing fluid on the outer peripheral side between 0a.

When the rotary shaft is stopped and the sliding surfaces 1a and 10a are in a non-sliding state or the sealed fluid is at room temperature,
As shown in FIG. 2A, the sliding surface 1a of the sliding ring 1 forms a smooth flat surface, and the entire surface thereof is in close contact with the mating sliding surface 10a. In addition, the sliding surface 1 rotates with the rotation of the rotary shaft.
When friction heat is generated due to sliding of a and 10a, or when the sealed fluid is at a high temperature, thermal expansion of the sliding material occurs, but the expansion amount is larger than that of the sliding ring base material 2. Since the embedding material 3 is smaller, as shown in FIG. 2 (B), the sliding surface 1a is such that the surface 3a portion of the embedding material 3 is relatively relative to the surrounding end surface 2a portion of the sliding ring base material 2. It is depressed, and as a result, the radial grooves 4 along the surface 3a of the embedding material 3 are formed.
Is formed. Further, the higher the temperature of the sliding ring 1 is, the larger the difference in thermal expansion between the sliding ring base material 2 and the embedding material 3 is.
As shown in (C), the depth of the groove 4 becomes deep. In the case of the above embodiment, for example, when the average temperature in the range of 5 mm from the sliding surface 1a is 600 ° C., the groove 4 having a depth of 3.9 μm is used.
Is formed.

Generally, in the mechanical seal, the higher the sliding speed and the temperature, the lower the viscosity of the lubricating liquid film between the sliding surfaces and the more easily the lubrication is impaired. However, according to this embodiment,
Since the groove 4 formed on the sliding surface 1a becomes deeper as the sliding speed and the temperature increase, a thick lubricating film is introduced to maintain a good lubrication state, and the sliding surfaces 1a and 10a due to insufficient lubrication.
It is possible to effectively prevent the occurrence of surface burn-in, cracks due to thermal strain, surface damage such as chipping, and abnormal wear. Further, at low speed rotation, the pumping force that pushes back the sealed fluid to the outer peripheral side decreases due to the rotation of the groove 4, but the depth of the groove 4 becomes shallow due to the decrease in the sliding heat generation amount.
Moreover, since the viscosity of the lubricating liquid film increases due to the decrease in the sliding surface temperature, the amount of leakage from between the sliding surfaces 1a and 10a does not increase. Further, when stopped, as described above, the groove 4 disappears and the sliding surface 1a returns to a smooth original shape as shown in FIG. 2 (A), and the entire surface thereof is mated with the sliding surface 10a.
The leak is completely blocked because it is in close contact with. In this case, if the sealed fluid is at a high temperature even when stopped, the groove 4
Does not disappear, but in general, the ambient temperature also drops when the equipment is stopped, so the above effect is effectively realized.

The present invention is not limited to the illustrated embodiment. The sliding ring base material 2 and the embedding material 3 may be a combination of a sliding material having a high coefficient of thermal expansion and a material having a low coefficient of thermal expansion other than the exemplified SiC-25% TiB ₂ and SiC. The arrangement of the material 2 is not limited to the radial arrangement, and for example, a tangential direction with respect to the inner diameter or a spiral arrangement is extremely effective in enhancing the lubrication of the sliding surface or the leakage prevention effect by the formed groove 4.

[0013]

According to the sliding ring of the shaft sealing device of the present invention, a deep groove is formed on the sliding surface as the amount of sliding heat generated by high-speed rotation increases and the ambient temperature of the sealing fluid increases. Therefore, regardless of the rotation speed and temperature conditions, it is possible to maintain a good lubrication state to prevent damage and abnormal wear of the sliding surface, and when stopping, the sliding surface returns to a smooth original shape and the groove is Since it disappears, there is an excellent effect that leakage at the time of stop can be prevented.

[Brief description of drawings]

FIG. 1 is a perspective view schematically showing a sliding ring 1 according to an embodiment of the present invention.

FIG. 2 shows changes in the shape of the sliding surface 1a when the sliding surface 1a of the sliding ring 1 of the above embodiment is brought into sliding contact with the mating sliding surface 10a, and (A) shows the sliding surface. 1A is an explanatory view showing the original state of the sliding ring 1, FIG. 1B is an explanatory view showing a state in which the shallow groove 4 is formed by the temperature rise of the sliding ring 1, and FIG. 1C is a deep groove by the further temperature rise of the sliding ring 1. It is explanatory drawing which shows the state in which 4 was formed.

[Explanation of symbols]

 1 Sliding Ring 1a Sliding Surface 2 Sliding Ring Base Material 3 Embedded Material 4 Groove

Claims (1)

[Claims] 1. A slide ring base material formed in an annular shape, and a slide embedded in the slide ring base material in a direction intersecting with a rotation direction and having a thermal expansion coefficient lower than that of the slide ring base material. A plurality of embedding materials made of a material, wherein a smooth sliding surface is formed on one end surface in the axial direction of the sliding ring base material and the surface of the embedding material exposed on this surface. Sliding ring of sealing device.