JPH0339616Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Field of industrial application) The present invention relates to a bearing device for hydraulic machinery, and is particularly suitable for hydraulic bearings suitable for suppressing shaft vibration of the main shaft of hydraulic machinery such as water turbines and pumps. Concerning bearing devices for machines.

(Prior Art) In general, hydraulic machines such as water turbines and pumps are equipped with bearing devices to prevent shaft vibration due to rotation of the runner, main shaft, etc., and to provide a water seal between the rotating shaft and fixed members such as the casing. Equipped with a shaft sealing device.

Figure 10 shows the bearing device and shaft sealing device of a pump-turbine.
After rotating the runner 3, it is discharged into the waterway through a suction pipe (not shown). On the outer periphery of the main shaft 4 directly connected to the runner 3, a bearing device B includes a bearing metal 6 that slides on a skirt-shaped rotary support portion 5 formed integrally with the main shaft 4, and supports this bearing metal 6. A bearing stand 7 is arranged at the lower end of the rotation support part 5, and a bearing metal 6
The bearing stand 7 is immersed in lubricating oil 9 stored in an oil tank 8. The rigidity created by the oil film of the lubricating oil 9 prevents the spindle 4 from wobbling. A cooling device 10 consisting of a plurality of cooling pipes is disposed within the oil tank 8, and the lubricating oil 9 is cooled by passing water through the cooling pipes. However, if the water supply system of the cooling device 10 breaks down during operation of the pump-turbine, it may lead to a serious accident such as seizing of the bearing metal 6. Furthermore, as will be described later, the shaft sealing device S is disposed below the bearing device B. As a result, the fulcrum position of the main shaft 4 by the bearing device B becomes far from the runner 3, and the swing of the runner 3 around the bearing device B increases, which is disadvantageous in suppressing the shaft runout of the entire shaft system. It was hot. In addition, if the lubricating oil 9 leaks to the outside for some reason, it may cause pollution problems, and furthermore, a considerable amount of lubricating oil is required to suppress the temperature rise of the lubricating oil 9, and the entire bearing device B There was a problem that the size of the

On the other hand, below the bearing device B, a shaft sealing device S
As shown in FIG.
The flow flows above the runner 3 through the main shaft 4 and the upper cover 1.
It seals the pressure water that tries to flow out between the two. However, in order to prevent the sliding surface of the packing 11 from seizing and to prevent dirt from entering the packing sliding surface from the runner 3 side, it is necessary to supply fresh water through the water supply hole 13 between the packings 11. Also, since the shaft sealing device S is disposed below the bearing device B, if the packing 11 becomes worn due to long-term use, the bearing device B must be disassembled or the bearing device B must be installed. The packing had to be replaced in a very narrow space,
There was a problem that the workability was very poor.

In addition, Fig. 11 shows the bearing device and shaft sealing device of the Kaplan water turbine.Since the Kaplan water turbine has relatively small shaft runout, the bearing device B
The structure is simple, and the submersible metal 14 that slides on the main shaft 4 is simply disposed on the inner circumferential surface of the bearing housing 15. However, since the underwater metal 14 is made of phenolic resin, it cannot bear a high load, and if foreign matter such as dirt gets between the main shaft 4 and the underwater metal 14, wear will be rapidly accelerated. Therefore, it was necessary to supply fresh water, and there was a problem that maintenance and management for supplying this fresh water was complicated.

Further, a plurality of packings 16 that slide on the main shaft 4 are arranged in multiple stages as a shaft sealing device S directly below the bearing device B, and between the packings 16 a water supply hole 17 is provided.
Fresh water is supplied through the In this case as well, the above-mentioned fresh water supply is essential for the same reason as in the shaft sealing device S of the pump-turbine described above.

(Problems to be solved by the invention) As described above, in conventional hydraulic machines such as water turbines and pumps, the bearing device B requires water supply for cooling or lubrication, and the shaft seal device S also requires water supply for lubrication. A water supply is required, and this water supply system causes the problem that the structures of the bearing device B and the shaft seal device S become complicated. Furthermore, since the bearing device B and the shaft sealing device S are disposed at different positions on the main shaft, and the shaft sealing device S is disposed below the bearing device B, the bearing section is placed at a position distant from the runner. This structure is undesirable in view of the original purpose of the bearing device, which is to prevent shaft runout.

Therefore, the present invention solves the problems of the conventional technology mentioned above, integrates the bearing device and the shaft seal device, simplifies the structure by omitting the fresh water supply system, and installs it near the runner. Therefore, an object of the present invention is to provide a bearing device for a hydraulic machine that suppresses shaft runout of a main shaft.

(Means for solving the problem) In order to achieve the above object, segment-shaped inner ceramic pieces are fixed to the outer circumferential surface of the main shaft in a plurality of stages in an annular shape in close contact with the main shaft and in the axial direction. A segment-shaped outer ceramic piece that is in sliding contact with the inner ceramic piece is fixed to the inner peripheral surface of the bearing housing in an annular shape and in the same number of steps as the inner ceramic piece, and a rib formed on the outer peripheral surface of the inner ceramic piece and the outer ceramic piece The segment-shaped seal member is formed so as to be in sliding contact with the protrusions formed on the inner circumferential surface, and the protrusions are alternately inserted into the segment-shaped seal member having the protrusions formed on the inner circumferential surface, facing the ribs of the inner ceramic piece. It is characterized in that it is fixed in an annular shape between each stage of the outer ceramic pieces.

(Function) To explain the function based on the above configuration, fluctuating loads such as shaft vibration generated during rotation of the main shaft are supported by the contact between the inner ceramic piece and the outer ceramic piece. In addition, the sealing member incorporated between each stage of the outer ceramic piece acts as a labyrinth seal, so the bearing part and the shaft sealing part can be integrated, making the bearing device compact and installed near the runner. This makes it possible to effectively suppress the axial runout of the main spindle.

(Embodiment) Hereinafter, an embodiment of a bearing device for a hydraulic machine according to the present invention will be described with reference to FIGS. 1 to 9. In addition, the same symbols are used for parts that are the same as before,
The explanation will be omitted.

In FIG. 1, the bearing device, which is designated as a whole by reference numeral 21, consists of an inner ring 22 of the upper cover 12 and a main shaft 4.
The bearing housing 23 of the bearing device 21 is fixed onto the inner ring 22 with fixing bolts 24. Above bearing housing 2
A bearing device 21 is provided on the outer circumferential surface of the main shaft 4 surrounded by 3.
As shown in FIG. 2, on the rotation side of the rotor, at least two segment-shaped inner ceramic pieces 25 are arranged in an annular shape, and these annular segment pieces are arranged in at least three stages in the axial direction to fasten members such as countersunk screws. 2
It is fixed at 6. Each of the inner ceramic pieces 25 is made of silicon nitride (Si ₃ N ₄ ) ceramic or tungsten carbide (WC) cemented carbide, and as shown in FIG. It is formed as a rectangular section curved so that it comes in close contact with the A seat 27 in which the head of the fastening member 26 is accommodated is formed at the corner of the section, and a rib 28 extending in the longitudinal direction of the section, that is, in the circumferential direction of the main shaft 4, is formed on the outer peripheral surface of the section. There is. By fixing the inner ceramic piece 25 to the outer circumferential surface of the main shaft 4, at least two rows of ribs 28 made of ceramic or cemented carbide are formed on the outer circumference of the main shaft.

Further, on the outside of the main shaft 4 on which the inner ceramic piece 25 is fixedly installed, there is provided a segment-shaped outer ceramic piece 29 that is in sliding contact with the inner ceramic piece 25 as the stationary side of the bearing device 21. As shown in FIG. 4, at least two annular ceramic pieces are formed on the inner circumferential surface of the bearing housing 23, and these annular ceramic pieces are attached to fastening members such as countersunk screws in the same number of stages as the inner ceramic pieces 25 in the axial direction. It is fixed at 26. Each of the outer ceramic pieces 29 is made of a silicon (Si) compound ceramic having lower mechanical strength than the inner ceramic piece 25, and has the same curved shape as the inner ceramic piece 25, as shown in FIG. It is formed as a rectangular section. As shown in FIG. 5, the inner circumferential surface of this section is formed with a protrusion 30 approximately in the center that makes sliding contact with the rib 28 of the inner ceramic piece 25, and the outer circumferential surface of the section is formed at the upper end of the section. A notch 31 is formed along the edge and the lower edge in the longitudinal direction, that is, in the circumferential direction of the main shaft 4, and a seat 27 in which the fastening member 26 is accommodated is formed at the corner of the cut piece. . Thus, the main shaft 4, on which the inner ceramic piece 25 is fixed on the outer circumferential surface, slides inside the bearing housing 23, on which the outer ceramic piece 29 is fixed on the inner circumferential surface, so that the main shaft 4 is rotatably supported. , fluctuating loads such as shaft vibration during rotation of the main shaft 4 are applied to the protrusion 30 of the outer ceramic piece 29 and the rib 2 of the inner ceramic piece 25.
It is effectively supported by sliding contact with 8.

Furthermore, at least two segment-shaped seal members 32 are arranged in an annular manner between each stage of the annular outer ceramic pieces 29 arranged in multiple stages in the axial direction, and these seal members 32 The bearing housing 23 is secured together with the outer ceramic piece 29 by the same fastening member 26 that secures the ceramic piece 29.
is fixed to the inner circumferential surface of the Each of the above seal members 3
As shown in Fig. 6, 2 is a curved rectangular section made of a high molecular compound such as rubber or a non-rusting metal, and the inner circumferential surface of this section has a main axis in the longitudinal direction of the section. A protrusion 33 extends in the circumferential direction of the outer ceramic piece 29, and the upper and lower sections of the protrusion 33 are formed as a flange 34 to be incorporated into the notch 31 of the outer ceramic piece 29. This flange portion 34 is formed with a receiving hole 35 through which the fastening member 26 is inserted, and the protruding portion 33 has a triangular cross section with an upper surface 33a, that is, the generator side, being inclined, and a lower surface 33b, that is, the runner side, being horizontal. It is formed. As shown in FIG. 4, the sealing member 32 is installed between each stage of the annular outer ceramic piece 29, and the sealing member 32 is installed above the uppermost outer ceramic piece 29. By fixing the flange portion 34 to the bearing housing 23 with the presser plate 36, an effective labyrinth seal is formed by the seal member 32 on the inner peripheral surface of the bearing housing 23.

Further, as described above, the bearing device 21 is composed of the inner ceramic piece 25 whose rotating side is fixed to the outer circumferential surface of the main shaft 4, the outer ceramic piece 29 whose stationary side is fixed to the inner circumferential surface of the bearing housing 23, and the seal member 32. As shown in FIGS. 2 and 7, the dimensions of each part are: D ₁ is the outer diameter of the rib 28 formed on the outer peripheral surface of the inner ceramic piece 25; D ₃ is the outer diameter of the outer peripheral surface of the inner ceramic piece 25; The inner diameter of the protrusion 30 formed on the inner peripheral surface of the outer ceramic piece 29 is D ₂ ,
A protrusion 33 formed on the inner peripheral surface of the seal member 32
If the inner diameter of the main shaft ₄ is D4, then the size relationship is determined as _D3 < _D4 < _D1 < _D2 , and the difference in these dimensions is D, if the diameter of the main shaft 4 is D. The values are determined to be small, such as ₂ −D ₁ =2/1000×D and D ₄ −D ₃ =3/1000×D.

As shown in FIG. 7, the bearing housing 23 has a structure in which it is divided into at least two parts, and can be assembled into one piece by tightening the flange part 23a formed on the mating surfaces with a fastening member such as a bolt. It's getting old. Furthermore, reinforcing rib plates 37 are arranged radially around the outer circumference of the bearing housing 23, and as shown in FIG. 38 is attached to seal pressure water that flows between the runner 3 and the upper cover 12 and tries to flow out between the main shaft 4 and the bearing device 21.

Next, the operation of the bearing device 21 configured as described above will be explained.

Variable loads such as shaft runout that occur during rotation of the main shaft 4 are absorbed by the outer peripheral end of the rib 28 of the inner ceramic piece 25 fixed to the main shaft 4 and the protrusion of the outer ceramic piece 29 fixed to the bearing housing 23. It is supported by contact with the inner circumferential end of 30. That is, the load applied to the rib 28 is distributed over the entire outer circumference of the main shaft 4 because the inner ceramic piece 25 on which the rib 28 is formed has a segment shape that closely contacts the main shaft 4. The load applied to the protrusion 30 is distributed and transmitted to the entire bearing housing 23 via the outer ceramic piece 29,
Furthermore, the load transmitted to the bearing housing 23 is transmitted to the rigid portion of the upper cover 12 via the fixing bolts 24. In this case, the inner ceramic piece 25 and the outer ceramic piece 29 are arranged in multiple stages in the axial direction of the main shaft 4.
are provided, so that the rib 28 of the specific inner ceramic piece 25 and the protrusion 3 of the outer ceramic piece 29
This prevents excessive stress from being concentrated at zero. Moreover, the material is ceramic, which has a large load capacity and high wear resistance, and the ribs 28 and the protrusions 30 can sufficiently withstand the load during sliding contact. Overall, the combination of the inner ceramic piece 25 and the outer ceramic piece 29 therefore makes it possible to keep the load share on both the rotating side and the stationary side of the bearing device 21 low. 8 and 9 show modifications of the inner ceramic piece, and the shape of the ribs of the inner ceramic piece may be selected as follows depending on the load. In this case, the inner ceramic piece 39 shown in FIG. 8 has a rib 40 formed on its outer peripheral surface with a trapezoidal cross section, and the inner ceramic piece 41 shown in FIG. 9 has a rib 42 formed with a semielliptical cross section. There is. By forming ribs having such a shape, concentration of stress can be suppressed.

Further, the ribs 28 of the inner ceramic piece 25 and the protrusions 33 of the sealing member 32 assembled between the outer ceramic piece 29 are arranged so as to face each other and enter alternately, and the inner diameter of the protrusions 33 is
Since the dimensional difference between D ₄ and the outer diameter D ₃ of the outer peripheral surface of the inner ceramic piece 25 is determined to be approximately 3/1000 times the diameter of the main shaft, the seal member 32 functions as a very effective labyrinth seal. However, pressure water flowing between the runner 3 and the upper cover 12 and flowing between the main shaft 4 and the bearing device 21 can be sealed. This eliminates the need for a conventional shaft sealing device. Further, since the bearing device 21 is constructed compactly by coaxially combining the inner ceramic piece 25 and the outer ceramic piece 29, which are the bearing parts, and the seal member 32, which is the shaft seal part,
The bearing device can be installed near the runner 3, and the whirling of the runner 3 can be suppressed. Further, it is possible to stabilize the shaft system vibration mode of the entire main shaft 4 including the bearing device on the generator side (not shown).

Furthermore, as mentioned above, since the bearing device 21 is installed near the runner 3, the area around the rotating side and the stationary side of the bearing device is filled with river water, and the inner ceramic piece 25 and the outer ceramic piece 29 are Frictional heat from contact is cooled by river water. This eliminates the need for conventional water supply systems for lubrication and cooling, simplifying the overall structure of the bearing device.
In addition, since both the inner ceramic piece 25 and the outer ceramic piece 29 are made of a high-hardness material, there is little wear due to foreign matter such as earth and sand, and it can be used for a long period of time. Even if foreign matter gets mixed in, since the upper surface 33a of the protrusion 33 of the seal member 32 is formed to be inclined toward the runner 3, the foreign matter will slide down into the runner 3 due to the inclined surface and settle in the bearing device 21. There's nothing to do.

Furthermore, since both the inner ceramic piece 25 and the outer ceramic piece 29 are fixed with fastening members 26 such as countersunk screws, they can be attached and detached, and each component can be easily replaced by simply removing the bearing housing 23. can. In addition, since the inner ceramic piece 25 that constitutes the rotating side of the bearing device is formed in the shape of a segment, all the segments can be molded with one mold, and the accuracy is much higher than that of an integrally molded piece that is not shaped like a segment. This improves the dimensional tolerance and improves the stability of the bearing.

[Effect of idea]

As is clear from the above description, according to the present invention, a plurality of segment-shaped inner ceramic pieces are fixed in the axial direction on the outer peripheral surface of the main shaft as the rotating side of the bearing device, and the bearing is mounted on the outside of the inner ceramic pieces. As the stationary side of the device is provided with a bearing housing in which a segment-shaped outer ceramic piece and a sealing member are fixed in multiple stages in the axial direction, the sealing member functions as a conventional shaft sealing device, and the bearing part and shaft sealing By coaxially integrating the bearing and shaft sealing parts, the bearing can be installed close to the runner, effectively reducing the axial runout of the main shaft. It can be suppressed. Furthermore, since the bearing device is installed near the runner, the area around the bearing device is filled with river water, and this river water cools the bearing device, eliminating the need for a water supply system for lubrication and cooling, which improves the overall structure of the bearing device. This has the effect of simplifying the process.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of a bearing device for a hydraulic machine according to the present invention, FIG. 2 is a front view showing the state in which the inner ceramic piece constituting the rotating side of the bearing device is installed, and FIG. 1 of the inner ceramic pieces above
FIG. 4 is a perspective view showing a segment; FIG. 4 is a front view showing the mounting state of the outer ceramic piece and seal member constituting the stationary side of the bearing device; FIG. 5 is a perspective view showing one segment of the outer ceramic piece; 6 is a perspective view showing one segment of the sealing member, FIG. 7 is a plan view showing the stationary side of the bearing device, FIGS. 8 and 9 are perspective views showing modified examples of the inner ceramic piece, and FIG. 10 and 11 are longitudinal sectional views showing a conventional bearing device for a hydraulic machine. 3...Runner, 4...Main shaft, 12...Top cover, 21...Bearing device, 23...Bearing housing, 25, 39, 41...Inner ceramic piece, 2
8, 40, 42,... Rib, 29... Outer ceramic, 32... Seal member, 33... Protrusion.

Claims (1)

[Claims for Utility Model Registration] 1. In a bearing device for a hydraulic machine designed to suppress shaft runout of a rotating main shaft, a segment-shaped inner ceramic piece is arranged on the outer peripheral surface of the main shaft in an annular shape so as to be in close contact with the main shaft. Segment-shaped outer ceramic pieces are fixed in multiple stages in the axial direction and are in sliding contact with the inner ceramic pieces in an annular shape on the inner peripheral surface of the bearing housing in the same number of stages as the inner ceramic pieces. The rib formed on the surface and the protrusion formed on the inner peripheral surface of the outer ceramic piece are formed so as to come into sliding contact,
A segment-shaped sealing member having protrusions formed on the inner circumferential surface is fixed in an annular manner between each stage of the outer ceramic piece so that the protrusions face the ribs of the inner ceramic piece and alternately enter therein. A bearing device for hydraulic machinery characterized by: 2. The bearing device for a hydraulic machine according to claim 1, wherein the inner ceramic piece, the outer ceramic piece, and the sealing member are detachably attached by fastening members. 3. The bearing device for a hydraulic machine according to claim 1, wherein the bearing housing is formed so that it can be divided into at least two parts.