JPH01159470A - U-shape packing for bearing of hydraulic turbine guide vane - Google Patents

Abstract

PURPOSE:To improve durability against the rough surface of a sliding section caused by aged deterioration by making a U-shaped packing of nitride rubber, which seals pressure water passing through the outer circumferential surface of a guide vane shaft, and forming it in such a way that a gap in a triangular form between the guide vane shaft and a bearing may be eliminated. CONSTITUTION:A packing 1a with a cross section of U-shaped configuration is incorporated in a packing chamber formed by those such as a hydraulic turbine guide vane shaft 2, a lower cover 3 and a bearing 5 so that both leaks in the direction of the guide vane shaft 2 and leaks from a casing 6 to a runner 9 when the guide vane is fully closed, are sealed. The afore-said packing 1 is supported by an adapter 8 formed by a rubber ring so that an effect in preventing water from leaking from the casing 6 to the runner 7 is improved when the guide vane is fully closed. In this case, the packing 1a in U-shape is made of nitrile rubber so as to be concurrently formed in such a way that a gap in a triangular form formed between the guide vane shaft 2 and a bearing 5 may be eliminated. This constitution thereby improves durability against the rough surface of the sliding section of the guide vane shaft 2 caused by aging deterioration.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a U-shaped packing for a water wheel guide vane bearing.

[Conventional technology]

4 and 5 show a cross section of a water turbine and a conventional example of a U-shaped packing for a water turbine guide vane bearing. As shown in the figure, conventionally, a U-shaped packing 1 made of medium leather is composed of a water wheel guide vane shaft (hereinafter referred to as guide vane shaft) 2, a lower cover 3 (or upper cover 4), and a bearing 5. The guide vane is installed in a packing chamber to seal water leakage in the two directions of the guide vane shaft and water leakage from the casing 6 to the runner 7 when the guide vane is fully open. In FIG. 5, reference numeral 8 denotes a rubber ring of the adapter of the U-shaped gasket 1, which is provided to reduce water leakage from the casing 6 to the runner 7 side when the guide vane is fully closed. Regarding this, JP-A-56
There is a publication No.-104166.

[Problem that the invention seeks to solve]

As shown in FIG. 5, the above-mentioned prior art uses the U-shaped packing 1 made of cow skin, so there is a triangle between the guide vane shaft 2 and the bearing 5 and the U-shaped packing 1. A shaped void is formed. Therefore, as shown in FIG. 6, during operation, the U-shaped packing 1 is deformed by the water pressure P acting on its upper part so as to fill the triangular gap.

When deformed like this, the rubber ring 8 and the U-shaped gasket 1
A water pressure P is generated between the rubber ring 8 and
Due to the water pressure P generated between the U-shaped packing 1 and
The letter-shaped gasket 1 is excessively pressed against the guide vane shaft 2 and slides, causing wear.

In particular, if the surface of the guide vane shaft 2 becomes rough due to aging, the U-shaped gasket 1 will eventually break as shown in FIG.

The present invention has been made in view of the above points, and provides a U-shaped water turbine guide vane bearing that improves durability against surface roughening due to aged deterioration of the sliding part of the guide vane shaft and improves water sealing performance. The purpose is to provide packaging.

[Means for solving problems]

The above object is achieved by forming the U-shaped packing from nitrile rubber and by forming it so as to eliminate the triangular gap formed between the guide vane shaft and the bearing.

[Effect]

The U-shaped packing is made of nitrile rubber, and is formed to eliminate the triangular gap formed between the guide vane shaft and the bearing. Water pressure is no longer generated between the mold seal and the rubber ring. Therefore, the U-shaped gasket is not pressed excessively against the guide vane shaft, and
Nitrile rubber has superior abrasion resistance compared to cowhide, so it has a long lifespan and can improve water sealing performance even on the sliding parts of the guide vane shaft that have become rough due to aging.

In other words, U-shaped packing made of cowhide layer and U made of nitrile rubber.
I compared the characteristics with the character-shaped patch skin.

The results of the study are shown in Figure 8. The figure shows the amount of water leakage on the vertical axis and the number of operations of the guide vane shaft on the horizontal axis. This is a study of quantitative characteristics. As is clear from the figure, the nitrile rubber gasket is superior to the cowhide layer gasket, as the number of operations of the guide vane shaft, which causes a rapid increase in water leakage, is about 10 times greater. In other words, a packing made of nitrile rubber has a lifespan approximately 10 times longer than a packing made of cowhide.

〔Example〕

The present invention will be explained below based on the illustrated embodiments. FIG. 1 shows an embodiment of the invention. Note that parts that are the same as those in the conventional system are given the same reference numerals, and therefore their explanations will be omitted. In this embodiment, the U-shaped packing 1a is made of nitrile rubber, and is formed so as to eliminate the triangular gap formed between the guide vane shaft 2 and the bearing 5. By doing this, the U-shaped packing 1a does not deform and has improved wear resistance, improving durability against surface roughness due to aging of the sliding part of the guide vane shaft 2, It is possible to obtain a U-shaped water wheel guide vane bearing U-shaped packing 1a that can improve water sealing performance.

That is, the U-shaped packing 1a is formed of nitrile rubber (spring hardness 90°) so that no gap is generated between the guide vane shaft 2 and the bearing 5.

By doing this, there is no triangular gap that existed conventionally, so even if water pressure acts on the upper part of the U-shaped packing 1a, the U-shaped packing 1a does not deform. In addition, even if the guide vane shaft 2 deteriorates over time and the sliding surface with the U-shaped seal 1a becomes rough, the U-shaped seal 1a is made of nitrile rubber (spring hardness 9o°) as mentioned above. , it has improved durability and water sealing properties compared to the conventional U-shaped packing made of cowhide layer. Incidentally, in the case of cowhide layer packing, since the material is cowhide, it was not possible to change the thickness so as not to create a gap between the guide vane shaft 2 and the bearing 5, but in the case of nitrile rubber, It is easy to change the thickness and make it free of voids.

Another embodiment of the invention is shown in FIG.

In this embodiment, a deep groove 9 is provided in the bearing 5a to accommodate the head side of the U-shaped packing 1b. By doing this, U
Even if the letter-shaped packing 1b is made with a different thickness, the guide vane shaft 2
Also, it is possible to prevent a gap from being generated between the bearing 5a and the bearing 5a, so that the same effects as in the case described above can be achieved.

A comparative study was conducted between each of these embodiments and the conventional example, and the results of the study are shown in FIG. In this figure, the amount of water leaked is plotted on the vertical axis, and the number of operations of the guide vane shaft is plotted on the horizontal axis, and the characteristics of the amount of water leaked according to the number of operations of the guide vane shaft are investigated. As is clear from the figure, the present invention is superior in that the number of operations of the guide vane shaft, at which the amount of water leakage increases rapidly, is ten times greater than that of the conventional example using the U-shaped 'packet'.

As described above, according to this embodiment, the U-shaped packing can be formed so as to eliminate the triangular gap formed between the guide vane shaft and the bearing.

Further, even if a bearing with deep grooves is combined with a U-shaped packing, the triangular gap can be similarly eliminated, so the durability is improved by more than 10 times compared to the conventional U-shaped packing. In addition, compared to cowhide, benidryl rubber is a synthetic material, which improves dimensional accuracy, and 20 φ400 U-shaped gaskets (for one water turbine) can reduce the cost by 70% compared to cowhide (cowhide:
1000 yen/20 pieces → Nitrile rubber: 300 yen
/20 pieces). Furthermore, the leakage of bearing lubricating grease due to damage to the U-shaped packing is eliminated, and environmental pollution can be prevented.

〔Effect of the invention〕

As described above, the present invention improves durability against surface roughening due to aging of the sliding portion of the guide vane shaft, improves water sealing properties, and improves durability against surface roughening due to aging of the sliding portion of the guide vane shaft. It is possible to obtain a U-shaped seal for a water turbine guide vane bearing that has improved durability against roughness and improved water sealing performance.

[Brief explanation of the drawing]

FIG. 1 is an enlarged vertical sectional side view of the A-frame portion in FIG. 4 of an embodiment of the U-shaped packing for the water turbine guide vane bearing of the present invention, and FIG. An enlarged longitudinal sectional side view of the A-frame part in Fig. 4 of another embodiment, and Fig. 3 shows the amount of water leakage depending on the number of operations of the guide vane shaft between this embodiment and the conventional example of the U-shaped packing for the guide vane bearing for a water turbine. Change characteristic diagram, 4th
The figure is a longitudinal cross-sectional side view of a water turbine with a conventional U-shaped seal for a guide vane bearing, and Fig. 5 is an enlarged vertical view of the A-frame part in Fig. 4. A cross-sectional side view, FIG. 6 is a vertical cross-sectional side view showing the state in which the U-shaped packing for the water turbine guide vane bearing shown in FIG. 5 has been deformed by water pressure, and FIG. Figure 8 is a longitudinal side view showing the damaged state of the cowhide layer U.
It is a characteristic diagram of the change in the amount of water leakage depending on the number of operations of the guide vane shaft of a U-shaped packing made of nitrile rubber and a letter-shaped packing. la, lb...U-shaped packing, 2...Water wheel guide vane shaft, 3...Lower cover, 4...Upper cover, 5, 5a
...Bearing, 9...Deep groove. Era 1 Figure 3 Lower cover now Eka 1 (- 5 side receiver Figure 2 γ I or -U; Type backing 5 threads - Bearing 9 - Clear nose Figure 3 Conventional 41'J A et al. Id service section 2σ
Hupubishi 4tashi 0 / 2 3 4! ; 6
7 8 q10 guide line [#'t i'Fti] number < x
tO'riiiJ') version 6 figure

Claims (1)

[Claims] 1. Provided in a packing chamber consisting of a water wheel guide vane shaft of a hydraulic machine, a lower or upper cover, and a bearing, and sealing off pressure water passing through the outer peripheral surface of the guide vane shaft. In the U-shaped packing for a water turbine guide vane bearing having a U-shaped cross-section, the U-shaped packing is made of nitrile rubber, and a triangular gap formed between the guide vane shaft and the bearing is eliminated. A U-shaped packing for a water turbine guide vane bearing. 2. The U-shaped packing for a water turbine guide vane bearing according to claim 1, wherein the bearing is provided with a deep groove for accommodating the head side of the U-shaped packing. 3. The U-shaped packing for a water turbine guide vane bearing according to claim 1, wherein the nitrile rubber has a spring hardness of 90 degrees.