JP2568459B2 - Non-contact type shaft sealing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact type shaft sealing device applied to shaft sealing between a rotary shaft of a pump device or the like and a casing.

[Conventional technology]

FIG. 5 shows a known shaft sealing device of this type. In the figure, reference numeral 1 denotes a casing, and a rotary seal ring 3 is fitted on a rotary shaft 2 provided through the casing 1. 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 one side surface 3a of the rotating sealing ring 3 is configured as a sealing surface. The recess 6 formed on the other side face 5b of the stationary sealing ring 5 and the casing 1
A spring member 9 for applying an elastic force (spring force) to the stationary sealing ring 5 toward the rotating sealing ring 3 is interposed between the spring sealing member 8 and the spring receiving member 8 fixed by bolts 7 or the like. . 1
Reference numerals 0 and 11 denote the inner peripheral surface of the casing 1 and the stationary sealing ring 5.
O-ring interposed between the outer ring and the outer peripheral surface.

The sealing surface 5a of the stationary sealing ring 5 has a plurality of rectangular (concave) cross-sectional shapes, for example, four long grooves in an arc-shaped air supply groove.
50 are formed at equal intervals in the circumferential direction as shown in FIG. Reference numeral 13 denotes an input port formed in the casing 1 to take in a seal gas G from outside, and reference numeral 14 denotes a supply port formed in the stationary sealing ring 5 to supply the seal gas G taken into the input port 13 through the orifice 15. This is an introduction path leading to the air groove 12.

In such a configuration, the sealing surface 5a of the stationary sealing ring 5 is elastically brought into sliding contact with the side surface 3a of the rotating sealing ring 3 as the rotating shaft 2 rotates. 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 14, and flows out from the air supply groove 50 toward the inner peripheral side and the outer peripheral side through the gap between the rotary seal ring 3 and the stationary seal ring 5. As a result, the gap between the above 3 and 5 is automatically adjusted, and the seal gas becomes a seal lubricating film to achieve shaft sealing.

[Problems to be solved by the invention]

By the way, in the case of the above-mentioned conventional non-contact type shaft sealing device, self-excited vibration called pneumatic hammer is likely to occur. One of the causes of such self-excited vibration is the mass of the seal gas in the air supply groove 50.

In other words, self-excited vibration is more likely to occur as the volume of the air supply groove 50 increases. Therefore, for example, by reducing the groove width (radial width) of the arc-shaped supply groove 50 of the long groove as a whole to reduce the volume thereof, the mass of the seal gas in the supply groove 50 is reduced. In this case, it is conceivable to suppress the generation of self-excited vibration. In this case, the supply amount of the sealing gas to the sealing surface between the opposing surfaces 3a and 5a of the rotating sealing ring 3 and the stationary sealing ring 5 is small. The pressure distribution on the rotary seal ring 3 due to the seal gas is biased, so that the predetermined sealing performance cannot be maintained, and the rotation of the rotary shaft 2, that is, the smooth operation of the entire shaft sealing device cannot be performed. is there.

Further, when the cross-sectional shape of the air supply groove 50 is rectangular as described above, there is a problem that the opening edge of the air supply groove 50 is easily lost at the time of assembly or the like.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and always stably secures the supply of the seal gas while keeping the mass of the seal gas in the air supply groove sufficiently small to suppress occurrence of self-excited vibration. In addition, it is an object of the present invention to provide a non-contact type shaft sealing device capable of maintaining stable sealing performance and smooth operation without deviation in pressure distribution, and preventing loss of an air supply groove.

[Means for Solving the Problems] In order to achieve the above object, a non-contact type shaft sealing device according to the present invention is formed on a stationary sealing ring so that a sealing gas is applied to a sealing surface on the stationary sealing ring side in a circumferential direction. An orifice is formed in the middle of the seal gas introduction path for supplying to the arc-shaped air supply grooves of a plurality of long grooves formed at equal intervals, and the cross-sectional shape of the arc-shaped air supply grooves of the plurality of long grooves Is formed in a substantially V-shape tapered toward the groove bottom side.

[Operation] According to the non-contact type shaft sealing device of the present invention, while the seal gas is always sufficiently fed into the introduction passage, the throttle gas is adjusted by the orifice formed in the introduction passage, and the arc-shaped supply groove of the long groove is formed. The supply of the seal gas to the air supply groove can always be stably ensured.
However, by making the cross-sectional shape of the arc-shaped air supply groove of the long groove into a substantially V-shape tapered toward the groove bottom side, the opening of the air supply groove can be formed without reducing the groove width as a whole. While the area is kept sufficiently large, the volume of the air supply groove, and thus the mass of the seal gas in the air supply groove, can be reduced to such an extent that the generation of self-excited vibration is sufficiently suppressed. Therefore, a stable pressure distribution with respect to the rotary seal ring can be obtained by a stable supply operation of the seal gas even if the supply amount is not large, and a stable seal performance and a smooth operation can be maintained. Further, since the air supply groove has a substantially V-shape tapered toward the groove bottom side, it is possible to effectively prevent the opening edge of the groove from being damaged during assembly or handling.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

FIGS. 1 and 2 show an example in which an embodiment of the present invention is applied to a static pressure type non-contact type sealing device. Omitted.

In the drawing, reference numeral 12 denotes an air supply groove formed in the sealing surface of the stationary sealing ring 5 and having a groove depth of h and a long groove arc shape, and has a substantially V-shaped cross section tapered toward the groove bottom. The shape is, for example, triangular.

In such a configuration, the seal gas G sent from the outside to the introduction path 14 is
After the aperture is adjusted to a predetermined amount by 15 in advance, the introduction path 14
Will always be supplied to the air supply groove 12 in a stable manner,
As in the prior art, the gap between the rotating stationary ring 3 and the stationary sealing ring 5 is 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. Accordingly, the total mass of the seal gas G in the air supply groove 12 is reduced, the occurrence of self-excited vibration is suppressed, the damping performance of the seal can be increased, and the open end area of the air supply groove 12 can be kept large. In addition, there is no bias in the biasing of the pressure on the rotary seal ring 3, and the stability of the shaft sealing performance on the sealing surface and the stable rotation of the rotary shaft 2 are guaranteed.

Further, since the angle of the opening edge of the air supply groove 12 with respect to the sealing surface 5a is 90 ° or more, there is no danger of the opening edge being accidentally dropped or damaged during handling such as assembly.

The above-mentioned effects can be effectively exerted if the air supply groove 12 is selected from the respective ranges of the groove depth h of 0.3 to 1.5 mm and the angle θ between the groove walls of 60 ° to 120 °.

By the way, in the above example, the cross-sectional shape of the air supply groove 12 is described as having a triangular shape. However, as shown in FIG. 3 and FIG. An effect similar to that of the embodiment is obtained.

In each of the above embodiments, the static pressure type is described. However, the present invention may be applied to a dynamic pressure type in which a spiral groove is provided on the side surface 3a of the rotary seal ring 3 or a hybrid type such as a helical bone type. Is also possible.

[Effects of the Invention] As described above, according to the present invention, while the seal gas is always sufficiently fed into the introduction passage, the throttle gas is adjusted by the orifice formed in the middle of the introduction passage, and the arc-shaped supply groove of the long groove is formed. , The supply of the sealing gas to the air supply groove can always be stably secured,
By making the cross-sectional shape of the arc-shaped air supply groove of the long groove into a substantially V-shaped tapering toward the groove bottom side, the opening area of the air supply groove can be sufficiently reduced without reducing the groove width as a whole. The volume of the air supply groove, and thus the mass of the seal gas in the air supply groove, can be reduced as much as possible. Therefore, the synergistic effect of always ensuring stable supply of the sealing gas into the air supply groove and obtaining a stable pressure distribution with respect to the rotary seal ring even when the supply amount of the sealing gas is not large. Thus, stable sealing performance and smooth operation can be maintained while suppressing the generation of self-excited vibration and improving the seal damping characteristic. In addition, since the air supply groove has a substantially V-shape tapering toward the groove bottom side, it is possible to effectively prevent the opening edge of the groove from being damaged at the time of assembly and handling, and to prevent the entire shaft sealing device from being damaged. It is possible to achieve a longer life and a long-term stabilization of the shaft sealing performance.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing a hydrostatic type non-contact type shaft sealing device according to an embodiment of the present invention, FIG. 2 is a front view showing a half of a stationary sealing ring in the device, FIG. 4 is a sectional view of a main part and a front view of a half 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. 5 is a front view showing a half of the stationary sealing ring of FIG. 1 ... casing, 2 ... rotating shaft, 3 ... rotating sealing ring,
3a ... side surface, 5 ... stationary sealing ring, 5a ... sealing surface, 12,
22 ... air supply groove, G ... seal gas.

Claims (1)

(57) [Claims] A stationary sealing ring disposed between the rotating shaft penetrating the casing and the casing and elastically abutting against a side surface of the rotating sealing ring fitted to the rotating shaft; A non-contact type in which a seal gas is supplied from the outside to an arc-shaped air supply groove of a plurality of long grooves formed at regular intervals in a circumferential direction on a sealing surface on a stationary sealing ring side opposed to a side surface of the sealing ring. In the shaft sealing device, an orifice is formed in the middle of a seal gas introduction path formed in the stationary sealing ring to supply a seal gas to the arc-shaped air supply groove of the long groove, and the arc-shaped air supply groove of the long groove is formed. A non-contact type shaft sealing device characterized in that a cross-sectional shape of the shaft is formed in a substantially V-shape tapered toward a groove bottom side.