JPH071062B2 - Shaft seal device - Google Patents

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-divided first sealing ring and a circumferentially divided second sealing ring made of a material having a higher degree of wear than the sealing end face constituent material of the sealing ring. The so-called outward flow type shaft sealing device configured to shield and seal the sealed fluid region, which is the inner peripheral side region, and the atmospheric region, which is the outer peripheral side region, by the relative rotational sliding contact action of It is a thing.

[Prior art]

As a conventional shaft seal device of this type, as shown in FIGS. 3 and 4, a non-divided first seal ring 3 is fixed to a rotary shaft 2 and a retainer 4 is slid in an axial direction on a seal casing 1. The retainer 4 is held so as to be freely and relatively non-rotatable, and the retainer 4 is internally fitted and held with the second sealing ring 5 divided in two in the circumferential direction.
The second sealing ring 5 is pressed into contact with the first sealing ring 3 by the spring 11 inserted between the seal casing 1 and the retainer 4, and the sliding contact is caused by the relative rotational sliding contact action of both sealing rings 3, 5. It is well known that the portions 3a and 5a are configured so as to be able to shield and seal the sealed area A which is the inner peripheral side area and the atmospheric area B which is the outer peripheral side area. The retainer 4 is constructed so that it can be disassembled by a retainer body 6 held by the seal casing 1 so as to be slidable in the axial direction and relatively non-rotatable, and a holding body 7 attached to the retainer body 6. Further, the second sealing ring 5 is a soft material (inorganic fiber such as asbestos solidified with phenol resin) having a higher degree of wear than the sealing end face constituent material (hard material such as ceramics) of the first sealing ring 3. ), It is devised so that the second sealing ring 5 is always worn by the sliding contact action of both sealing rings 3, 5. In such a shaft seal device (hereinafter referred to as "conventional device"), if the shaft seal function is deteriorated due to wear of the seal ring, only the second seal ring 5 needs to be replaced. Moreover, since the second sealing ring 5 is of a split type, it is not necessary to disassemble and assemble the entire apparatus, and the second sealing ring 5 can be easily replaced by attaching and detaching the holding body 7 to the retainer body 6. .

[Problems to be Solved by the Invention]

Although the conventional device is extremely easy to maintain in this way, there is a problem that it cannot be used under high pressure conditions because the second sealing ring 5 is a divided structure made of a soft material. That is, in the conventional device, the second sealing ring 5 is internally retained in the retainer 4, and the entire inner peripheral portion 5b is exposed to the sealed fluid region A, so that the pressure of the sealed fluid acts. The pressure receiving area is extremely large. Therefore, under high pressure conditions, the inner peripheral portion 5b of the second sealing ring 5 is
The fluid pressure acting on the second sealing ring 5 becomes extremely large.
In combination with that made of soft material as described above,
The second sealing ring 5 is distorted, or the second sealing ring 5 is expanded in diameter to form a gap in the abutting surfaces 5'a, 5'a of the divided portions 5 ', 5', and the gap is sealed from the gap. There is a risk of fluid leakage, and a good shaft sealing function cannot be expected. In order to prevent leakage from the split surfaces 5'a, 5'a of the second sealing ring 5, it is necessary to increase the binding force of the second sealing ring 5 by the retainer 4 more than necessary. As a result, the second sealing ring 5 is further distorted and cannot be used at all. The present invention has been made in view of the above circumstances, and an object thereof is to provide a shaft sealing device that can exhibit a good shaft sealing function even under high pressure conditions.

[Means for Solving the Problems]

In the shaft sealing device of the present invention, which solves this problem, in particular, the second sealing ring is made of a soft material such as carbon, and the retainer that holds the second sealing ring in a detachable manner holds the second sealing ring of the second sealing ring. An inner peripheral holding portion for externally fitting and holding the inner peripheral portion is provided except for a sealing end surface portion slidingly contacting the first sealing ring, and the fitting portion is fitted to the inner peripheral portion of the second sealing ring. A secondary seal is provided to prevent the sealed fluid from entering the part.

[Action]

The inner peripheral portion of the second sealing ring is not exposed to the sealed fluid region except for a very small sealing end surface portion by the inner peripheral holding portion provided on the retainer. Moreover, the sealed fluid does not enter the fitting portion between the inner peripheral portion of the second sealing ring and the inner peripheral holding portion due to the secondary seal provided in the portion. That is, the fluid pressure does not act on the inner peripheral portion of the second sealed end surface except for the sealed end surface portion, and the fluid pressure receiving area becomes extremely small. Therefore, even under a high pressure condition, a relatively large fluid pressure does not act on the inner peripheral portion of the second sealing ring, and in combination with the fact that the second sealing ring is made of a hard material such as carbon,
A good shaft-sealing function is exhibited without causing a strain in the second sealing ring or leaking the sealed fluid from the divided surface thereof.

【Example】

Hereinafter, the structure of the present invention will be specifically described based on the embodiments shown in FIGS. 1 and 2. In the shaft sealing device shown in FIG. 1, 1 is a seal casing, 2 is a rotary shaft that penetrates the seal casing 1, 3 is a rotary seal ring which is a first seal ring fixed to the rotary shaft 2, and 4 is a seal casing 1. The retainer 5, which is held so as to be slidable in the axial direction and non-rotatable in the axial direction, is a stationary seal ring which is a second seal ring fitted and retained in the retainer 4. The rotary seal ring 3 is of a non-divided type, and at least the seal end surface 3a that is in sliding contact with the stationary seal ring 5 is made of a ceramic material such as SiC, WC, chromium oxide, which is a superhard material. The retainer 4 includes a retainer body 6 and a pressing body 7. The retainer body 6 is held in the seal casing 1 via a drive pin 8 so as to be relatively non-rotatable and axially movable, and is retained in the seal casing 1 via an O-ring 9 so as to be slidable in the axial direction. And the sliding portion 6b is formed. The pressing body 7 is composed of a flange portion 7a attached to the flange portion 6a of the retainer body 6 with a bolt 10 and an outer peripheral holding portion 7b for holding the stationary seal ring 5 in an inward fit. The stationary seal ring 5 is formed of a hard material such as carbon having a higher degree of wear than the seal end face constituent material of the rotary seal ring 3, and is divided into two in the circumferential direction as shown in FIG. As shown in FIGS. 1 and 2, the stationary seal ring 5 is formed by the flange portion 6a of the retainer body 6 and the outer peripheral holding portion 7b of the retainer body 7 in the circumferential end surfaces 5'of both divided portions 5 ', 5'. The a and 5'a are internally fitted and retained in the retainer 4 in a state of abutting against each other. The sealing end surface 5a, which is the front end surface of the stationary sealing ring 5, is pressed against the sealing end surface 3a of the rotary sealing ring 3 by the spring 11 inserted between the seal casing 1 and the retainer 4.
By the relative rotational sliding contact action of both sealing end faces 3a, 5a accompanying the rotation of the rotary shaft 2, the sealed fluid region A which is the inner peripheral side region and the atmospheric region B which is the outer peripheral side region of the sliding contact portions 3a, 5a are shielded. It is designed to be sealed. Further, the retainer body 6 has an outer peripheral holding portion 7b of the pressing body 7.
An inner circumference holding portion 6c is provided to face the inner circumference holding portion 6c, and the inner circumference portion 5b of the stationary seal ring 5 is fitted and held by the outer circumference. That is, by providing the inner circumference holding portion 6c, the inner circumference portion of the stationary seal ring 5 is
Most of 5b is shielded from the sealed fluid region A, and only a very small inner peripheral portion 5c on the sealed end face 3a side is exposed in the sealed fluid region A. The axial width l of the exposed portion 5c is an inner peripheral holding portion even when the wear amount of the stationary seal ring 5 due to the sliding contact with the rotary seal ring 3 reaches the allowable limit.
6c is set as small as possible, provided that 6c does not interfere with the rotary seal ring 3. An O-ring 12, which is a secondary seal that prevents the fluid to be sealed from entering the fitting portion, is provided at the fitting portion between the stationary sealing ring 5 and the inner circumference holding portion 6c. It is devised that the fluid pressure of the sealed fluid region A does not act on the inner peripheral portion 5b of the ring 5 except the sealed end surface portion 5c. The O-ring 12 is held on the inner circumference holding portion 6c side. An O-ring 13 is also arranged between the outer peripheral portion of the stationary seal ring 5 and the outer peripheral holding portion 7b of the pressing body 7. In the shaft sealing device configured as described above, the fluid pressure does not act on the inner peripheral portion 5b of the second sealing ring 5 except the sealing end surface portion 5c, that is, the pressure receiving area is extremely small. Therefore, coupled with the fact that the second sealing ring 5 is made of a hard material, the second sealing ring 5 is not distorted even under a high pressure condition, and a good shaft sealing function is exhibited. The shaft sealing device according to the present invention is not limited to the above embodiment, and may be appropriately modified within a range not departing from the basic principle of the present invention.
Can be improved. For example, the rotary seal ring 3 may be a split second seal ring and the stationary seal ring 5 may be a non-split first seal ring.

【The invention's effect】

As is clear from the above description, the shaft sealing device of the present invention,
Since the split type second sealing ring is made of a hard material and the pressure receiving area on which the fluid to be sealed acts is suppressed to a necessary minimum, it is possible to obtain a good shaft not only under low pressure conditions but also under high pressure conditions. It can exhibit a sealing function and can be suitably used for high-load rotating equipment such as high-lift pumps installed in high-rise buildings while ensuring ease of maintenance.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing an embodiment of a shaft sealing device according to the present invention, FIG. 2 is a vertical sectional front view taken along line II-II of FIG. 1, and FIG. 3 shows a conventional device. 4 is a vertical sectional side view, and FIG. 4 is a vertical sectional front view taken along the line IV-IV in FIG. 1 ... Seal casing, 2 ... Rotating shaft, 3 ... Rotating sealing ring that is the first sealing ring, 3a ... Sealing end face of rotating sealing ring, 4
...... Retainer, 5 ...... Static seal ring as second seal ring, 5 '
...... Divided part, 5a ...... Sealing end face of stationary seal ring, 5b ...... Inner part of stationary seal ring, 5c …… Sealing end face part, 6 …… Retainer body, 6c …… Inner circumference holding part, 7 …… Presser body, 7b ... Perimeter holding part, 12 ... O-ring as secondary seal.

Claims (1)

[Claims] 1. A relative rotational sliding contact action between a non-divided first sealing ring and a circumferentially divided second sealing ring made of a material having a higher degree of wear than the sealing end face constituent material of the sealing ring. In the shaft sealing device configured so as to shield and seal the sealed fluid region that is the inner peripheral side region and the atmospheric region that is the outer peripheral side region of the sliding contact portion, the second sealing ring is made of a hard material such as carbon. The retainer that holds the second sealing ring in a detachable manner is provided with an inner circumferential holding portion that holds the inner circumferential portion of the second sealing ring by external fitting except for a sealing end surface portion that slidably contacts the first sealing ring. A shaft seal device, characterized in that a secondary seal is provided in a fitting portion between the holding portion and the inner peripheral portion of the second sealing ring to prevent the sealed fluid from entering the fitting portion. .