JPH01220717A - Bearing device for hydraulic machine - Google Patents

Abstract

PURPOSE:To prevent a bearing from wearing in early stages by fitting a plurality of ceramics pieces divided segmently to the sliding face of the outer circumference of a main shaft via an elastic material and forming a cemented carbide liner inside an opposite bearing. CONSTITUTION:A plurality of ceramics 1 made of silicon carbide etc., divided segmently are adhered to the outer circumference of a main shaft 2 via an elastic material 2 such as hard rubber joined thereto. A high hard cemented carbide liner 5 such as tungsten carbide etc., is fitted to the inner circumference of a bearing 4. Accordingly, the main shaft side sliding face is much harder than the bearing side sliding member so that wear after operation for a long term does not occur at the main shaft 3 side but it occurs only at the bearing 4 side.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a bearing device for a hydraulic machine such as a water wheel or a pump.

(Prior art) Generally, hydraulic machines such as water turbines and pump water turbines are equipped with a bearing device to prevent shaft vibration due to rotation of the runner or main shaft, and also to prevent sand and water from flowing in from the gap between the rotating shaft and the stationary part. Equipped with a shaft sealing device to prevent this.

FIG. 6 shows a bearing device and a shaft sealing device of a Kabran water wheel in a hydraulic machine. In the figure, the pressurized water in the spiral casing 11 flows toward the runner 6 through the guide vane 12, rotates the runner 6, and then is discharged into the discharge channel through a suction pipe (not shown). On the outer periphery of the main shaft 3 directly connected to the runner 6, a resin-based underwater bearing 13 is installed as a bearing device B.

In this submersible bearing 13, fresh water is supplied to the sliding surface to prevent the main shaft 3 from slipping. However, this underwater bearing 13 is made of rubber, which is much softer than metal.

Since it is made of resin-based materials such as 4-fluoride ethylene and phenolic resin, it cannot bear high loads, and if foreign matter such as dirt gets between the main shaft 3 and the underwater bearing 13, it will rapidly wear out. It is accelerated, causing an increase in shaft runout.

In addition, it was necessary to constantly supply fresh water for lubrication and to prevent dirt and sand from entering.

Further, a plurality of backings 14 that slide on the main shaft 3 are arranged in multiple stages as a shaft sealing device S directly below the bearing device B.
Fresh water is also supplied to each stage of the backing 14 to prevent dirt and water from getting mixed in.

However, no matter how much fresh water is supplied, dirt cannot be avoided during normal operation, which often causes backing and early abnormal wear of submerged bearings, increases shaft wear, and frequent damage to bearings and shaft seals. Replacement was essential. Furthermore, since it is necessary to constantly supply fresh water, a huge amount of equipment for securing fresh water or a water supply and drainage system such as complicated piping for supplying fresh water is required.

In addition, the shaft sealing device had to be placed under the bearing, which caused the bearing to be separated from the runner, weakening the effect of suppressing shaft vibration.

Recently, as a means to solve the above problem, a bearing device has been developed in which the bearing housing side is made of ceramic and the main shaft sliding surface is made of cemented carbide such as WC (tungsten carbide). Publication, JP-A-60
-73123 publication, JP-A-60-81517 publication,
JP-A-60-84423 and JP-A-60-88
It has become well known in Publication No. 215. An example of such a bearing device is shown in FIG. 7, and in this structure, since both the main shaft side and the bearing side have high hardness, abnormal wear due to earth and sand etc. can be reduced. However, since the ceramic piece 1a is used on the bearing side, the cemented carbide 5 on the main shaft 3 side
The hardness is higher than that of b, and the spindle side will inevitably wear out.

On the other hand, in bearings of large structures such as water turbines and pump turbines, the main shaft is also large, and it is practically impossible to disassemble or replace the main shaft, so soft materials are usually used on the bearing side. , wear occurs mostly on the bearing side, and wear on the main shaft side is avoided.

However, when the bearing side is harder than the main shaft side, as in the case of the above-mentioned ceramic bearing, the main shaft needs to be replaced due to abrasion of the main shaft. Generally speaking, ceramic pieces are extremely brittle, so if they are directly attached to a rigid body such as metal, there is a risk of the ceramic pieces breaking. was.

(Problems to be Solved by the Invention) As described above, the following problems are latent in bearing devices for conventional hydraulic machines such as water turbines and pump water turbines.

(1) For resin-based water turbine bearings, shaft runout occurs due to 9-stage wear of the resin, a constant supply of fresh water is required, and a shaft sealing device to prevent dirt and sand from entering is essential.

(2) In conventional ceramic bearings, wear occurs on the main shaft side.
There is a need to periodically replace the main shaft of large hydraulic machines, etc., which is difficult to disassemble.

It had many problems such as.

The objects of the present invention are to prevent early wear on the bearing side, to eliminate the need for fresh water supply to the bearing, to eliminate the need for a shaft seal device to prevent dirt and sand from entering, and to prevent wear of the main shaft over a long period of time. Another object of the present invention is to provide a bearing device for a hydraulic machine that can effectively reduce shaft deviation of the bearing.

[Structure of the Invention] (Means for Solving the Problems) A bearing device for a hydraulic machine of the present invention is a bearing device that suppresses shaft runout of a rotating main shaft, in which a sliding surface on the outer periphery of the main shaft is provided with a segment shape. A plurality of divided ceramic pieces are attached via an elastic material such as hard rubber or Teflon, and a cemented carbide liner such as tungsten carbide is formed on the inner surface of the mating bearing.

(Function) In the present invention, the sliding surface is made of ceramic pieces and cemented carbide and is harder than earth and sand, so even if earth and sand enter the bearing sliding surface, no wear occurs.

In addition, ceramic pieces are fragile materials that are weak against impact forces, but even if earth and sand collide with them, the ceramic pieces will absorb the impact with hard rubber, Teflon, etc., so there is no risk of damage. There isn't.

The present invention will be described below with reference to embodiments shown in FIGS. 1 and 2. In both figures, 1 is divided into segments gl [
silicon carbide (SiC), silicon nitride (S+ 3
It is a ceramic piece such as N4).

2 is an elastic material such as hard rubber or Teflon fixed to the inside of the ceramic piece 1 with an adhesive or the like.

It is. The ceramic piece 1 is joined to the outer periphery of the main shaft 3 via the elastic material 2. Reference numeral 4 denotes a bearing that suppresses the radial vibration of the main shaft 3, and a cemented carbide liner 5 made of tungsten carbide (WC) or the like is attached to the inner surface of this bearing.

Therefore, in the bearing device according to the present invention, the sliding movement of the bearing on the main shaft side is made of extremely hard ceramic piece 1, and the sliding movement of the bearing side is made of cemented carbide, which is less hard than ceramic but has a harder hardness than earth and sand. The structure is such that the ceramic piece 1 is attached to the main shaft through an elastic material.

In the bearing device of the present invention constructed in this manner, both the main shaft and the bearing side are harder than earth and sand, so even if earth and water enter the sliding part, the sliding part will not be worn away by the earth and sand. Increase in shaft runout can be prevented over a long period of time. Furthermore, since the ceramic piece 1 is relatively fragile, there is a risk of it being damaged when an impact force is applied to it, but in the present invention, it is supported by an elastic material 2 such as hard rubber or Teflon. , which absorbs impact force and prevents damage to the ceramics.

In general, since the sliding surface on the main shaft side is harder than the sliding surface on the bearing side, the wear that occurs after long-term operation due to sliding between the two does not occur on the main shaft side, but is mostly on the bearing side. It will only wear out. Therefore, there is no longer any need for repair work, which is actually extremely difficult for large water turbines and pump water turbines, where the main shaft side wears out before the bearing side and the main shaft side wears out before the bearing side, unlike conventional ceramic bearings.

Next, an embodiment of the present invention applied to a Kabran water turbine will be described with reference to FIG. In FIG. 3, a bearing device according to the present invention is installed at the lower end of a main shaft 3 that is directly connected to a runner 6 and transmits rotation. 1 is a ceramic piece supported on the outer periphery of a main shaft 3 by an elastic material 2 such as hard rubber or Teflon;
Tungsten carbide (WC) is used inside the mating bearing side.
A cemented carbide liner 5 such as the above is attached to the bearing base metal 4.

In conventional resin-based submersible bearings, fresh water is supplied to the bearing portion, which requires a complicated water supply and drainage system and passage device to supply fresh water, but this is no longer necessary.

Additionally, in the past, a shaft sealing device was installed under the bearing device to prevent dirt and water from entering the sliding parts of the bearing.
In the present invention, there is no abnormal wear even if dirt gets mixed in, and there is no need for a shaft sealing device to prevent dirt getting in. The bearing device is installed directly above the runner 6, and the shaft sealing action is performed on the upper part of the bearing. It is located in the labyrinth 7.

In the Kaburan turbine of FIG. 3 constructed in this manner, river sediment water enters as shown by arrow A in FIG. 3, and the bearing sliding movement is filled with sediment water. On the other hand, bearing base metal 4
Since there is a labyrinth 7 at the top of the labyrinth 7, the earth and sand water is sealed. Some of the sediment water that has passed through the water seal is drained outside using pumps, etc.

When dirt and water enter the sliding movement of a bearing, abnormal wear immediately occurs in conventional resin underwater bearings, but in the bearing device of the present invention, the sliding surface is made of ceramics and cemented carbide, which are harder than dirt and sand, so wear is reduced. will not occur. Furthermore, although the ceramic piece 1 is a brittle material that is weak against impact forces, even if earth and sand are to come into contact with the ceramic piece 1, the impact is absorbed by hard rubber, Teflon, etc. , there will be no damage.

On the other hand, in ceramic bearings used in conventional small pumps, etc., the bearing side is made of ceramic, so
With long-term use, the main shaft would wear out, making it difficult to replace the main shaft in large water turbines, so it was actually impossible to apply it. However, according to the present invention, the main shaft side is made of ceramic piece 1, so long-term use is possible. However, the spindle 3 will not wear out.

In addition to the roughness, the bearing device of the present invention can be installed closer to the runner 6, which is the correction source, than conventional resin-based underwater bearings, so the bearing restraint effect is enhanced and shaft runout is reduced. It also becomes possible.

Therefore, according to the present invention, it is possible to prevent premature wear on the bearing side compared to conventional resin bearings, eliminate the need for a shaft sealing device for supplying fresh water to the bearing and preventing dirt and sand from entering the bearing, and prevent shaft runout. It is also possible to effectively keep it low.

Also, unlike conventional ceramic bearings, it is possible to prevent wear on the main shaft side.

(Embodiment) Next, another embodiment of the bearing device according to the present invention will be described with reference to FIG. Instead of attaching a cemented carbide liner to the inner surface of the bearing base metal 4, the inner surface of the bearing is coated with a cemented carbide 5a by thermal spraying or overlay welding. Compared to cemented carbide liners, this liner can be lined more strongly and easily on the inner surface of the bearing base metal.

Further, another embodiment of the present invention is shown in FIG. In FIG. 5, in order to attach the ceramic piece 1 to the main shaft 3 through an elastic material 2 such as hard rubber or Teflon, the ceramic piece 1 is
Rubber sheets on the top and bottom edges.

Metal holder 8 interposed with an elastic material 2a such as Teflon
This metal holder 8 is fastened to the main shaft 3 with bolts 9 or the like. Normally, if the ceramic piece 1 becomes too large a block, its brittleness increases, so even when used in a large structure such as a water wheel, the ceramic piece 1 must be divided into small segments. If the ceramic pieces 1 are simply attached to the main shaft by adhesive or the like, the number of ceramic pieces will be too large, and there will be a problem that the ceramic pieces will fall off due to deterioration of the adhesive. In order to solve these problems, in the embodiment shown in FIG. 5, the upper and lower ends are mechanically fixed with metal holders 8, and an elastic material 2a such as a rubber sheet or Teflon is placed between the metal and the ceramic as a cushioning material. It is inserted. According to this embodiment, it is possible to completely prevent the ceramic pieces 1 from falling off even when the bearings are used in large water turbine bearings.

[Effects of the Invention] As explained above, in the present invention, by attaching a plurality of ceramic pieces to the outer circumferential surface of the main shaft via a generating substance and forming a cemented carbide liner on the bearing side, (1) Prevents premature wear of bearings.

(ii) There is no need to supply fresh water to the bearing, and a complicated water supply and drainage system is no longer necessary, reducing the number of sources of accidents.

(iii > A shaft seal device to prevent dirt and sand from entering is no longer required,
V) The bearing can be moved closer to the correction source to effectively reduce axis deviation.

←V) The spindle side will not wear out over a long period of time.

It has many effects such as.

[Brief explanation of the drawing]

1 and 2 are a cross-sectional view showing a bearing device for a hydraulic machine according to the present invention, a cross-sectional plan view taken along the line ■-■ in FIG. 1, and FIG.
The figure is a cross-sectional view of a vertical axis Kablan water turbine showing one embodiment of the present invention.
FIGS. 4 and 5 are cross-sectional views showing other embodiments of the present invention, FIG. 6 is a cross-sectional view of a vertical shaft Kabran water turbine equipped with a conventional resin-based submerged bearing, and FIG. 7 is a cross-sectional view of a conventional ceramic bearing. FIG. 2 is a sectional view showing the device. 1.1a... Ceramic piece 2... Elastic material such as hard rubber 3... Main shaft 4... Bearing base metal 5.5b... Cemented carbide liner 5a... Cemented carbide coating 6. ...Runner 7...Labyrinth 8...Metal holder 9...Bolts, etc. 2a...Elastic materials such as rubber sheets (8733) Agent: Yoshiaki Inomata, patent attorney (and others)
1 person) Figure 1 Figure 20 Figure 3

Claims (1)

[Claims] (1) In a bearing device designed to suppress axial runout of a rotating main shaft, a plurality of ceramic pieces divided into segments are attached to the sliding surface of the outer periphery of the main shaft via an elastic material such as hard rubber or Teflon, A bearing device for a hydraulic machine, characterized in that a cemented carbide liner made of tungsten carbide or the like is formed on the inner surface of the mating bearing.