JPH04171370A - Noncontact type shaft seal device - Google Patents

Abstract

PURPOSE:To improve the sealing performance and prevent the breakage of an air feeding groove by forming the shape of the sectional surface of the air feeding groove formed on the seal surface of a static seal ring thinner toward a groove bottom side. CONSTITUTION:As for an air feeding groove 12 which is formed on the seal surface of a static seal ring 5 and has a groove depth of (h), the shape of the sectional surface is formed thinner toward the groove bottom, for example, into a triangular form. With this constitution, the seal gas G supplied frown outside is drawn by an orifice 15, and supplied into the air feeding groove 12, and the gap between a seal ring and the static seal ring 5 is sealed. Since, in this case, the shape of the section of the air feeding groove 12 is triangular, the capacity of the air feeding groove 12 is reduced, even if the groove width is not reduced, and all the mass of the seal gas G is reduced, and the generation of self-excited vibration is suppressed, and the damping faculty of the seal is improved, and the eccentric pressure excitation on a turning seal ring is eliminated, and the stable revolution of a rotary shaft is secured. Further, since also the angle for the seal surface 5a at the opened port edge of the air feeding groove 12 is over 90 deg., the trouble of the breakage of the opened port edge due to the careless handling in assembly can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a non-contact type shaft sealing device that is applied to a shaft seal between a rotating shaft and a casing of a pump device or the like.

[Conventional technology]

As a shaft sealing device of this type, one shown in FIG. 5 has been known. In the same figure, ■ is the casing;
The rotating shaft 2 provided through the casing l has
A rotary sealing ring 3 is fitted. 4 is an O-ring.

Reference numeral 5 denotes a stationary sealing ring disposed between the casing 1 and the rotating shaft 2, and a surface 5a facing the one side 3a of the rotating sealing ring 3 is configured as a sealing surface. Between the recess 6 formed on the other side surface 5b of the stationary seal ring 5 and the spring bearing member 8 fixed to the casing 1 with bolts 7, etc. A spring member 9 is interposed to provide an elastic force (spring force).

1O111 is an O-ring interposed between the inner circumferential surface of the casing l and the outer circumferential surface of the stationary sealing ring 5.

On the sealing surface 5a of the stationary sealing ring 5, a plurality of, for example, four arcuate air supply grooves 50 having a rectangular (concave) cross-sectional shape are arranged at equal intervals in the circumferential direction as shown in FIG. It is formed. Reference numeral 13 indicates an input port formed in the casing 1 to take in the seal gas G from the outside; The above air supply groove 12
It is an introduction route that leads to.

In such a configuration, as the rotating shaft 2 rotates, the sealing surface 5a of the stationary sealing ring 5 is brought into elastic sliding contact with the side surface 3a of the rotating sealing ring 3. On the other hand, after the seal gas G taken into the input port 13 is narrowed down by the orifice 15,
The air is supplied to each air supply groove 50 through the introduction path 14, and flows out from the air supply groove 50 toward the inner circumferential side and the outer circumferential side through the gap between the rotating seal ring 3 and the stationary seal ring 5. As a result, both of the above 3
．． The gap between the shafts 5 and 5 is automatically adjusted, and the seal gas becomes a seal lubricating film to achieve shaft sealing.

[Problem to be solved by the invention]

By the way, in the case of the conventional non-contact type shaft seal device mentioned above,
Self-excited vibration called pneumatic hammer is likely to occur. One of the causes of such self-excited vibration is the air supply groove 5.
There is a mass of seal gas within 0.

That is, when the volume of the air supply groove 5 is large, self-excited vibration is likely to occur. Therefore, it is conceivable to reduce the width of the air supply groove 50, for example, but in this case, the pressure distribution against the rotary sealing ring will be biased, which will impede smooth rotation of the rotary shaft 2.

Further, when the cross section of the air supply groove 50 is rectangular as described above,
There is also a risk that the opening edge of the air supply groove 50 may be damaged during assembly or the like.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a non-contact type shaft sealing device that can improve sealing performance and prevent damage to the air supply groove.

[Means to solve the problem]

In order to achieve the above object, the non-contact type shaft sealing device according to the present invention has the following features: The cross-sectional shape of the air supply groove formed on the sealing surface of the stationary sealing ring is tapered toward the groove bottom side. It is.

[Effect]

According to the non-contact type shaft sealing device of the present invention, the groove width of the air supply groove can be reduced (or even the volume can be reduced, so self-excited vibrations are suppressed and the seal damping characteristics are improved, and the air supply groove Since the groove is tapered toward the bottom side, it is possible to prevent the opening edge from being damaged during handling.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

Figures 1 and 2 show an example in which an embodiment of the present invention is applied to a static pressure type non-contact sealing device, and the same parts as in the conventional one are given the same reference numerals and explained. Omitted.

In the figure, reference numeral 12 denotes an air supply groove with a groove depth h formed in the sealing surface of the stationary sealing ring 5, and its cross-sectional shape is tapered toward the bottom of the groove, for example, triangular. There is.

In such a configuration, the seal gas G from the outside is narrowed down by the orifice 15 and then supplied to the air supply groove 12, thereby increasing the gap between the rotating stationary ring 3 and the stationary sealing ring 5 as in the conventional case. Gaps are sealed.

In this case, since the cross-sectional shape of the air supply groove 12 is triangular, the volume of the air supply groove 12 can be reduced without reducing the groove width. Therefore, the air supply groove 12
The total mass of the seal gas G inside is reduced, suppressing the occurrence of self-excited vibrations, improving the damping performance of the seal, and eliminating uneven pressure on the rotating seal ring 3, making the rotating shaft 2 more stable. Rotation is guaranteed.

Furthermore, since the angle of the opening edge of the air supply groove 12 with respect to the sealing surface 5a is 90 degrees or more, there is no risk of the opening edge being accidentally damaged such as being broken during assembly or other handling.

In addition, if the air supply groove 12 is selected from a range in which the groove depth h is from 0.3 to 1.5 mm and the angle θ between the groove walls is from 60° to 120°, the above effects will be effectively exhibited. Ru.

By the way, in the above example, the cross-sectional shape of the air supply groove 12 was explained as being triangular, but even if the cross-sectional shape of the air supply hole 22 is trapezoidal as shown in FIGS. 3 and 4, the above-mentioned The same effects as in the embodiment are achieved.

In each of the above embodiments, the static pressure type was explained, but
It is also applicable to a dynamic pressure type in which a spiral group is provided on the side surface 3a of the rotary sealing ring 3 and a hybrid type such as a helical bone type.

〔Effect of the invention〕

As described above, according to the present invention, since the cross-sectional shape of the air supply groove formed on the sealing surface of the stationary sealing ring is tapered toward the groove bottom, the volume can be increased without reducing the groove width. Therefore, the seal damping performance can be improved, and the opening edge of the air supply groove can be prevented from being damaged.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the main parts of a static pressure type non-contact type shaft sealing device which is an embodiment of the present invention, FIG. 2 is a front view showing half of a stationary sealing ring in the same device, FIG. Fig. 4 is a sectional view of a main part and a half front view of a stationary sealing ring showing another embodiment of the present invention, Fig. 5 is a sectional view showing a conventional non-contact type shaft sealing device, and Fig. 6 is a sectional view of a conventional non-contact type shaft sealing device. FIG. DESCRIPTION OF SYMBOLS 1... Casing, 2... Rotating shaft, 3... Rotating sealing ring, 3a... Side surface, 5... Stationary sealing ring, 5a...
・Seal surface, 12.22... Air supply groove, G... Seal gas. Patent Applicant Nippon Biller Industry Co., Ltd. Agent Patent Attorney Takashi Suzue - (stupid name) No. 1!21 G, Shizureka's No. 2 [Fig. 3]

Claims (1)

[Claims] (1) A stationary sealing ring disposed between the rotating shaft passing through the casing and the casing is brought into elastic contact with a side surface of the rotating sealing ring fitted to the rotating shaft, and the rotating sealing ring In a non-contact type shaft sealing device, seal gas is supplied from the outside to a plurality of air supply grooves arranged at equal intervals in the circumferential direction on the sealing surface of the stationary sealing ring side facing the side surface of the shaft. A non-contact type shaft sealing device, characterized in that the cross-sectional shape of the air supply groove is tapered toward the bottom of the groove.