JP2017072192A - Sliding bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sliding bearing device capable of avoiding the degradation in radiation performance due to the rust of a heat radiation part while the frictional heat generated in a sliding portion on the rotary shaft side is dissipated to ambient air through a rotary shaft in a rotary fluid machine.SOLUTION: A sliding bearing device for use to support a rotary shaft 10 in a dry condition in which a bearing slide surface is exposed to ambient air that comprises: a sleeve 11 fixed on the circumference of the rotary shaft 10; and a sliding bearing 1 having the bearing slide surface on which the sleeve 11 slidably contacts, in which a material forming the outer peripheral surface of the rotary shaft 10 is provided to hermetically seal a heat transfer material 15 having a heat transfer performance better than that of the rotary shaft 10 on the center side of the rotary shaft 10 with an antirust material; the coefficient of thermal conductivity of the material of the sleeve 11 contacting the rotary shaft 10 is larger than that of the material of the rotary shaft 10; and the coefficient of thermal conductivity of the heat transfer material 15 on the center side of the rotary shaft 10 is larger than that of the material of the rotary shaft 10.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a sliding bearing device that is preferably used as a bearing of a rotary fluid machine such as a pump or a compressor. For example, a pump that performs operation management under dry conditions such as a preceding standby operation pump, and the like, The present invention relates to a sliding bearing device corresponding to high speed.

An example of the background art will be described based on the situation of the preceding standby operation pump in recent years.
In recent years, with the progress of urbanization, the heat island phenomenon has occurred due to the reduction of green spaces, the road surface becoming concrete, and the expansion of asphalt, and so-called guerrilla heavy rains frequently occur in urban areas. A large amount of local rainfall is introduced into the waterway without being absorbed into the ground on concrete and asphalt road surfaces. As a result, a large amount of rainwater flows into the drainage station in a short time.

  In order to prepare for the rapid drainage of a large amount of rainwater caused by such frequent torrential rains, drainage pumps installed in the drainage pump station should have rainwater before reaching the drainage pump station in order to prevent inundation damage due to delays in starting. Pre-standby operation to be started is performed.

  FIG. 1 is a partial schematic diagram of a vertical shaft pump that performs a prior standby operation. The water tank 100 of the drainage station is provided with an impeller 22 at the tip of the rotary shaft 10 arranged in the vertical direction, and the water level of the water tank 100 is lower than the minimum operating water level LWL by causing the impeller 22 to suck air together with water. Also, a vertical shaft pump 3 capable of continuing the operation (preceding standby operation) is arranged. This vertical shaft pump 3 is provided with a through hole 5 in the side surface of the suction bell 27 on the inlet side of the impeller 22, and an air pipe 6 having an opening 6 a in contact with outside air is attached to the through hole 5. ing. Thereby, in this vertical shaft pump 3, the supply amount of the air supplied into the vertical shaft pump 3 through the through hole 5 is changed according to the water level, and the drainage amount of the vertical pump 3 is controlled below the minimum operating water level LWL.

  FIG. 2 is a diagram for explaining the operating state of the preceding standby operation. For example, for large city rainwater drainage, a vertical shaft pump is started in advance according to rainfall information or the like regardless of the suction water level (A: air operation). As the water level rises from the low water level, the water level reaches the impeller position, and the vertical shaft pump is operated from the idling operation (air operation) to the agitating operation with the impeller (B: air / water agitation operation), and further through the through hole. Then, the operation proceeds to a full operation (D: steady operation) in which 100% water is discharged through an operation of gradually increasing the amount of water (C: air / water mixing operation) while sucking in air supplied through the water. When the water level drops from the high water level, the operation shifts from the full operation to the operation of gradually reducing the water amount while sucking in the air supplied through the through holes together with the water (C: air-water mixing operation). When the water level reaches near LLWL, the operation shifts to an operation (E: air lock operation) in which water is not sucked and drained. These five characteristic operations are collectively referred to as advance standby operation. The pump start is started from the water level LLLWL lower than the lower end of the casing.

FIG. 3 is a cross-sectional view showing the entire vertical shaft pump 3 that performs the preceding standby operation shown in FIG. The through hole 5 and the air pipe 6 shown in FIG. 2 are not shown.
As shown in FIG. 3, the vertical shaft pump 3 includes a discharge elbow 30 installed and fixed on the pump installation floor, a casing 29 connected to the lower end of the discharge elbow 30, and a lower end of the casing 29 and an impeller 22. And a suction bell 27 that is connected to the lower end of the discharge bowl 28 and sucks water.

A single rotating shaft 10 formed by connecting two upper and lower shafts to each other by a shaft coupling 26 is provided at substantially the center in the radial direction of the casing 29, the discharge bowl 28, and the suction bell 27 of the vertical shaft pump 3. Has been placed.
The rotary shaft 10 is supported by an upper bearing 32 fixed to the casing 29 via a support member and a lower bearing 33 fixed to the discharge bowl 28 via a support member. An impeller 22 for sucking water into the pump is connected to one end side (suction bell 27 side) of the rotating shaft 10. The other end side of the rotating shaft 10 extends to the outside of the vertical shaft pump 3 through a hole provided in the discharge elbow 30 and is connected to a driving machine such as an engine or a motor (not shown) that rotates the impeller 22.
A shaft seal 34 such as a floating seal, a gland packing, or a mechanical seal is provided between the rotary shaft 10 and a hole provided in the discharge elbow 30, and the water handled by the vertical pump 3 by the shaft seal 34 is supplied to the vertical pump. 3 is prevented from flowing out.

  The driving machine is installed on land so that maintenance and inspection can be easily performed. The rotation of the driving machine is transmitted to the rotary shaft 10 and the impeller 22 can be rotated. The water is sucked from the suction bell 27 by the rotation of the impeller 22, passes through the discharge bowl 28 and the casing 29, and is discharged from the discharge elbow 30.

  FIG. 4 is an enlarged view of a conventional bearing device applied to the bearings 32 and 33 shown in FIG. FIG. 5 is a perspective view of a plain bearing installed in the bearing device shown in FIG. As shown in FIG. 4, the conventional bearing device has a sleeve 11 made of stainless steel, ceramics, sintered metal, or surface-modified metal on the outer periphery of the rotating shaft 10. A slide bearing 1 made of a hollow cylindrical resin material, ceramics, sintered metal, or surface-modified metal is provided on the outer peripheral side of the sleeve 11. The outer peripheral surface of the sleeve 11 faces the inner peripheral surface (slide surface) of the slide bearing 1 through a very narrow clearance, and is configured to slide with respect to the slide bearing 1. The slide bearing 1 is fixed to a support member 13 connected to a pump casing 29 (see FIG. 3) or the like via a collar portion 12a by a bearing case 12 made of metal or resin. As shown in FIG. 5, the plain bearing 1 has a hollow cylindrical shape, the inner peripheral surface 1 a faces the outer peripheral surface of the sleeve 11, and the outer peripheral surface 1 b is fitted in the bearing case 12.

The vertical shaft pump 3 shown in FIG. 3 is operated in the atmosphere when the pump is activated. That is, the bearings 32 and 33 are operated under dry conditions without liquid lubrication. Here, the dry condition refers to a condition in which the atmosphere of the bearings 32 and 33 during pump operation is in the air without liquid lubrication, and the dry operation refers to operation under that condition. Further, the bearings 32 and 33 shown in FIG. 4 are also operated under drainage conditions in which water has passed through the bearings. Here, the drainage condition refers to a condition in which the atmosphere of the bearings 32 and 33 during the pump operation is in water mixed with foreign matter (slurry) such as earth and sand. Water mixing operation, full operation, air lock operation, etc. Bearings 32 and 33 are used under such conditions.
In the vertical shaft pump 3 shown in FIG. 3, the bearings 32 and 33 are arranged at two locations on the rotary shaft 10. However, if the length of the rotary shaft 10 is increased, more bearings are arranged accordingly. .

By the way, in recent years, the capacity of the pump has been further increased, and accordingly, the shaft diameter has been increased. Therefore, the speed of the sliding surface of the bearing has been increased.
In addition, the pumping station has been placed deeper underground, and the preceding standby pump corresponding to the pump station has been required to have a longer shaft and a higher head. In order to cope with higher heads, it is necessary to increase the number of revolutions, and it has become necessary to increase the shaft diameter and increase the rigidity in accordance with the increase in the length of the shaft.
However, increasing the shaft diameter and increasing the rotational speed may cause new technical problems. 6A and 6B are schematic cross-sectional views showing the state of the rotary shaft 10, the sleeve 11, and the slide bearing 1 during pump operation. In the dry operation, the rotating shaft rotates at a higher speed than in the prior art. Therefore, when the sliding bearing 1 in the bearings 32 and 33 and the sleeve 11 attached to the rotating shaft 10 slide, a great amount of frictional heat is generated at the contact portion. Is likely to occur, and there is a risk of locally high temperatures. 6 (a) and 6 (b), the hatched portion is a portion where the temperature is locally high.

Such a local high temperature of the sleeve attached to the rotary shaft may cause a high temperature and expansion of the bearing 1, but the rotary shaft 10 of the pump has a thick shaft diameter or a long shaft. Rather, as shown in FIG. 6 (a), there is a risk that the rotating shaft may bend slightly due to local expansion of the rotating shaft 10, thereby causing vibrations due to interference between the rotating portion and the fixed portion of the pump, and bearing load. Increase is likely to occur. That is, it contacts in the unbalance direction as a rotating body, and since this contact part generates heat, a temperature distribution is generated in the shaft cross section, and the shaft is bent due to thermal expansion. At this time, since the center of gravity of the rotating body is shifted due to bending, the unbalance of the entire rotating body gradually increases. Also, the bearing contact method may change due to the bending, and the temperature gradient of each bearing may change.
Further, when the displacement due to the shaft bending becomes larger than the bearing clearance, as shown in FIG. 6B, a two-point contact state with opposite phases is obtained, and the bending displacement is restrained. In addition, the pressing load increases due to continued thermal expansion, but the bearing temperature rises at an accelerated rate due to a vicious cycle of load increase ⇒ heat generation increase ⇒ thermal bending acceleration ⇒ load increase.

  Therefore, there is a demand for an apparatus or a structure having a function of reducing the bending of the rotating shaft or cooling the contact portion where the rotating shaft is heated. These are not large-scale and complicated devices, but simple devices that overcome various effects such as influence on pump efficiency and assembly / separation / adjustment of the cooling equipment and the pump are required.

By the way, the technical proposal of the countermeasure about such a phenomenon has been made conventionally.
In Japanese Utility Model Laid-Open No. 58-61920 (Patent Document 1), as a countermeasure against seizure due to frictional heat of the sliding bearing at the time of start-up or dry operation, a part of the metal sliding portion on the rotating shaft side is thermally expanded from the metal. The resin on the fixed side is used by embedding a resin such as ethylene tetrafluoride with a high rate and when the temperature rises due to frictional heat, the tetrafluoroethylene extends to the outer periphery of the rotating shaft before the metal sliding part. Proposals have been made to prevent generation of frictional heat between the metal sliding portions by preventing the sliding surface and the metal sliding portion on the rotating shaft side from directly contacting each other.

  However, in Japanese Utility Model Publication No. 58-61920 (Patent Document 1), the degree of sliding load that ethylene tetrafluoride is responsible for is one of the problems. In the case of a small amount, it was difficult to withstand the sliding load, and eventually the entire metal sliding portion on the rotating shaft side had to be replaced with ethylene tetrafluoride.

  Japanese Patent Laying-Open No. 2005-36692 (Patent Document 2) proposes a technique for preventing seizure due to a local high load due to a single contact of a slide bearing that supports a rotating shaft of a vertical drainage pump. According to this, the sliding member on the rotating shaft side is made of a high hardness material such as tungsten carbide, and the sliding member on the fixed side is made of tetrafluoroethylene resin, phenol resin, graphite and their composition, and fixed. In the sliding member on the side, a heat transfer material having a higher thermal conductivity than the sliding member on the fixed side is vertically and horizontally inserted, and local heat in the sliding portion on the fixed side is transferred to the heat transfer material. A technique for avoiding burn-in by transferring heat to dissipate heat is disclosed.

  Similarly to Japanese Patent Application Laid-Open No. 2009-203933 (Patent Document 3), as in Japanese Patent Application Laid-Open No. 2005-36692 (Patent Document 2), the inside of the resin-side sliding member on the fixed side is radially inserted. By providing a heat member, a technique is disclosed in which local heat in the sliding portion on the fixed side is transferred to the heat transfer material to dissipate heat.

  However, in these techniques, since the sliding member on the fixed side is a resin material, the thermal conductivity is very small, and the temperature of the heat generation point is low until the frictional heat due to local friction is passed through the heat transfer material. It had to be quite hot. In addition, since the sliding member on the fixed side is a resin material, the coefficient of thermal expansion is very large, so thermal expansion occurs mainly at the heating point where the temperature is locally high. In the meantime, as described above, since the thermal conductivity is very small, the temperature remains low, so that it is not thermally expanded. For this reason, the resin material has an unpredictable shape at the heat generation point.

  Japanese Patent Application Laid-Open No. 2006-170239 (Patent Document 4) and Japanese Patent Application Laid-Open No. 2012-132548 (Patent Document 5) describe a combination in which the thermal expansion coefficient of the sliding member on the rotating side is an order of magnitude smaller than the thermal expansion coefficient on the fixed side. Specifically, a technique is disclosed in which a rotating sliding member is a carbon fiber reinforced composite material, and a cemented carbide or the like is used for a stationary sliding member. In this way, even if the sliding part is heated to a high temperature due to frictional heat, the coefficient of thermal expansion of the sliding member on the outer peripheral side is higher than that of the sliding member on the rotating side. Since the coefficient of expansion is larger than the expansion coefficient, the phenomenon that the clearance between the rotating member and the sliding member on the fixed side becomes narrow and can be avoided is avoided.

Japanese Patent Laid-Open No. 2015-52273 (Patent Document 6) is disclosed in Japanese Patent Laid-Open No. 2006-170239 (Patent Document 4) and Japanese Patent Laid-Open No. 2012-132548 (Patent Document 5). As the sliding members are limited to carbon fiber reinforced composite materials, and there is no design freedom in the materials used, the structure of the sliding part on the fixed side has been devised to allow for a wider range of materials. Yes.
That is, the rotation-side sliding member is made of a resin material such as PEEK, the stationary-side sliding member is made of a metal having higher thermal conductivity and thermal expansion coefficient than the rotation-side sliding member, and the stationary-side sliding member A structure is provided in which a space is provided so as to easily expand on the outer periphery.

The method of increasing the coefficient of thermal expansion of the sliding member on the fixed side as described above is larger than the coefficient of thermal expansion on the rotating side, because the thermal conductivity of the sliding member on the rotating side is small. The temperature tends to be higher than the sliding part on the fixed side. On the other hand, since the sliding member on the fixed side has a higher thermal conductivity than the sliding member on the rotating side and can dissipate heat toward the outer periphery, the sliding portion on the fixed side is not easily heated.
As a result, the sliding member on the fixed side does not thermally expand because the temperature rise is small, and the sliding member on the rotating side continuously repeats friction while it is difficult to cool the local high temperature. It will be. Therefore, the difference between the surface temperature of the sliding portion on the rotating side and the surface temperature of the sliding portion on the fixed side continues to increase.

  In Japanese Patent Laying-Open No. 2015-52273 (Patent Document 6), since the thermal conductivity of the resin of the sliding material on the rotating side is smaller than the thermal conductivity of the metal of the sliding material on the fixed side, both slide. There is a statement that even if heat is generated sometimes, heat is quickly transferred to the fixed side, but the contact resistance of heat during sliding is very large, so the heat generated on the fixed side escapes to the fixed side and the rotation side Heat cannot be transferred well to the fixed side. Therefore, the temperature of the resin on the rotating side rises, while the resin material has a coefficient of thermal expansion greater than that of the metal, so that the clearance with the sliding portion on the fixed side is narrowed and the rotating side may be constrained to the fixed side. .

In view of such problems, the present inventors have heretofore provided that the rotating shaft as shown in FIG. 7 is generally dissipated rather than dissipating the frictional heat generated in the sliding portion on the rotating shaft side to the fixed side. A method has been proposed in which a heat dissipating part having a heat dissipating function and a heat capacity is provided in the axial direction of the sliding part and the heat is dissipated to the outside air through the heat dissipating part.
By the way, a metal that is not economically expensive is used for the heat radiation part. However, in the conventional structure, it has been difficult for such a metal to gradually rust over time, resulting in a decrease in heat dissipation performance.

Japanese Utility Model Publication No. 58-61920 JP 2005-36692 A JP 2009-203933 A JP 2006-170239 A JP 2012-132548 A Japanese Patent Laying-Open No. 2015-52273

  The present invention has been made in view of the above problems, and in a rotating fluid machine, the heat of friction generated in the sliding portion of the rotating shaft on the rotating shaft side is radiated to the outside air through the rotating shaft, and the heat radiating portion. An object of the present invention is to provide a plain bearing device capable of avoiding deterioration of heat dissipation performance due to rust.

  In order to achieve the above object, a sliding bearing device of the present invention is a sliding bearing device that is used for supporting a rotating shaft of a rotary fluid machine and is used under dry conditions in which a bearing sliding surface is exposed to the atmosphere. A sleeve fixed to the outer periphery of the rotating shaft; and a slide bearing having a bearing sliding surface with which the sleeve is slidably contacted. The material forming the outer peripheral surface of the rotating shaft is a rust-proof material, and the center of the rotating shaft A heat transfer material having better heat transfer than the rotary shaft is sealed on the side, and the thermal conductivity of the material in contact with the rotary shaft of the sleeve is larger than the thermal conductivity of the material of the rotary shaft, The heat conductivity of the heat transfer material on the center side is larger than the heat conductivity of the material of the rotating shaft.

  A sliding bearing device according to another aspect of the present invention is a sliding bearing device that is used for supporting a rotating shaft of a rotary fluid machine and is used under dry conditions in which a bearing sliding surface is exposed to the atmosphere. A sleeve fixed to the outer periphery of the shaft, and a slide bearing having a bearing sliding surface with which the sleeve is in sliding contact, and the material forming the outer peripheral surface of the rotating shaft is a rust-proof material on the center side of the rotating shaft. A heat transfer material having better heat transfer than the rotating shaft is hermetically sealed, and the inner periphery of the rotating shaft and the outer periphery of the heat transfer material on the center side of the rotating shaft are in contact with each other.

According to a preferred aspect of the present invention, the material forming the outer peripheral surface of the rotating shaft is stainless steel.
According to a preferred aspect of the present invention, the heat transfer material on the center side of the rotating shaft is a copper material or aluminum.

According to a preferred aspect of the present invention, the sleeve includes a sliding member that is in sliding contact with the slide bearing, and a heat transfer layer that is provided inside the sliding member and has a higher heat transfer property than the sliding member. Features.
According to a preferred aspect of the present invention, the sliding member covers both ends in the axial direction of the heat transfer layer and is fixed in close contact with the rotating shaft.

According to a preferred aspect of the present invention, the sliding member is made of stainless steel, ceramics, or tungsten carbide.
According to a preferred aspect of the present invention, the heat transfer layer is made of a copper material or aluminum.

According to a preferred aspect of the present invention, the sleeve is entirely made of a carbon fiber reinforced composite material.
According to a preferred aspect of the present invention, the slide bearing is made of a metal material or a carbon fiber reinforced composite material.
According to a preferred aspect of the present invention, another rotary shaft is connected to the end of the rotary shaft via a flange to form one rotary shaft, and water enters the heat transfer material into the flange. It is characterized in that a sealing member is provided to prevent this.

According to a preferred aspect of the present invention, one end of the rotating shaft is connected to the end of the rotating shaft by an interference fit to form one rotating shaft, and the interference fit is applied to the heat transfer material. It is characterized by preventing intrusion.
According to a preferred aspect of the present invention, a clearance is provided between an end portion of the heat transfer material and an end portion of the other rotating shaft.
According to a preferred aspect of the present invention, an end portion on the opposite side of the end portion of the heat transfer material is in contact with a solid portion of the rotating shaft.

The rotary fluid machine of the present invention is characterized by using the above-described slide bearing device.
The pump of the present invention is characterized by using the above-mentioned plain bearing device.

The present invention has the following effects.
(1) The structure of the present invention is provided with a heat transfer material having better heat transfer than the rotation shaft on the center side of the rotation shaft, and a sleeve that slides on the slide bearing and the outer periphery of the rotation shaft are brought into contact with each other. By contacting the outer periphery of the heat transfer material with better heat transfer than the inner periphery and the rotation shaft provided on the center side of the rotating shaft, the heat generated on the surface of the sliding material of the rotating shaft is transferred to the center side of the rotating shaft. The material is quickly diffused in the axial direction by a good material, and at the same time, the heat transfer material on the center side of the rotating shaft transmits heat to the entire outer periphery of the rotating shaft and dissipates it to the outside air in contact with the rotating shaft. Temperature rise can be mitigated.
(2) Since the heat transfer material with better heat transfer than the rotation shaft is sealed on the center side of the rotation shaft, the surface of the heat transfer material with better heat transfer does not rust and the heat transfer performance does not deteriorate. Moreover, since the rotating shaft is made of a rust-proof material such as stainless steel, the outer peripheral surface of the rotating shaft does not rust, and the heat dissipation performance to the outside air does not deteriorate.

FIG. 1 is a partial schematic diagram of a vertical shaft pump that performs a prior standby operation. FIG. 2 is a diagram for explaining the operating state of the preceding standby operation. FIG. 3 is a cross-sectional view showing the entire vertical shaft pump that performs the preceding standby operation shown in FIG. 1. FIG. 4 is an enlarged view of a conventional bearing device applied to the bearing shown in FIG. FIG. 5 is a perspective view of a plain bearing installed in the bearing device shown in FIG. 6A and 6B are schematic cross-sectional views showing the state of the rotary shaft and the slide bearing during the pump operation. FIG. 7 is a cross-sectional view showing a basic configuration of a bearing device according to the background art. FIG. 8 is a schematic view of a bearing device according to the present invention. FIG. 9 is a longitudinal sectional view showing an end portion of the bearing device according to the present invention. FIG. 10 is a view showing another modification of the end portion of the bearing device according to the present invention. FIG. 11 is an example of the end portion of the heat transfer column. FIG. 12 shows a modification of the embodiment shown in FIGS.

  Hereinafter, in order to describe an embodiment of a sliding bearing device and a rotary fluid machine according to the present invention, the background art will be introduced with reference to FIG. 7, and then the sliding bearing device according to the present invention will be described with reference to FIGS. And an embodiment of a rotating fluid machine will be described. 7 to 12, the same or corresponding components are denoted by the same reference numerals, and redundant description is omitted.

FIG. 7 is a cross-sectional view showing the basic configuration of a plain bearing device according to the background art of the present invention, which is a technique proposed by the inventors so far. The slide bearing device is applied to, for example, the bearings 32 and 33 shown in FIG.
As shown in FIG. 7, the plain bearing device has a sleeve 11 on the outer periphery of the rotary shaft 10 having a diameter D1. The sleeve 11 is for protecting the rotary shaft 10 from sliding wear, and is made of resin and its composite material, stainless steel, ceramics, sintered metal, surface-modified metal, carbon and its composite material, It is fixed to the rotating shaft 10 with a thickness. The sleeve 11 rotates with the rotation of the rotating shaft 10. For the rotating shaft, stainless steel is selected from the viewpoint of strength.

  A plain bearing 1 is disposed so as to surround the sleeve 11 so as to face the outer periphery of the sleeve 11. The plain bearing 1 supports the rotating shaft in order to keep the shaft at a fixed position even when the rotating shaft 10 is rotating, and the support member 13 connected to a pump casing or the like is provided with a bearing case 12 therebetween. Is fixed. Therefore, although the rotation shaft 10 is allowed to rotate, there is only a small clearance between the slide bearing 1 and the sleeve 11 to the extent that the rotation shaft 10 cannot be translated. Therefore, since the slide bearing 1 and the sleeve 11 slide, the slide bearing 1 is made of PTFE (polytetrafluoroethylene), PA (polyamide), PC (polycarbonate), EP (epoxy resin) to reduce the friction coefficient. And PEEK (polyether ether ketone).

At both ends in the axial direction of the sleeve 11, there are provided heat radiating portions 14 and 14 ′ for receiving frictional heat generated by sliding in the sleeve 11 during atmospheric operation and quickly radiating it to the outer atmosphere. The inner peripheral diameter of the heat radiating portions 14 and 14 'is D1, and the outer peripheral diameter is D0.
One of the roles of the heat radiating portions 14 and 14 'is to receive the frictional heat generated by sliding on the sleeve 11, so it is necessary to have an appropriate heat capacity. If the heat capacity is small compared to the frictional heat that flows in, the temperature of the heat radiating portions 14 and 14 'rises immediately, and the temperature difference between the sleeve 11 and the heat radiating portions 14 and 14' becomes small, and the frictional heat of the sleeve moves. It becomes difficult.

  Another role of the heat dissipating parts 14, 14 'is to release heat to the atmosphere around the heat dissipating part, so that the surface area of the outer periphery needs to be appropriately wide. If the surface area of the outer periphery of the heat dissipating parts 14, 14 'is small, the amount of heat dissipating is smaller than the inflowing frictional heat, and the temperature of the heat dissipating parts 14, 14' gradually increases.

  The last one of the roles of the heat radiating portions 14 and 14 ′ has a role of a heat flow path that diffuses the received heat to the entire area of the heat radiating portions 14 and 14 ′. Therefore, it is necessary to make the flow cross-sectional area of the heat flow appropriately wide and uniform. Otherwise, when the flow path is narrow, the inflowing frictional heat cannot be properly transmitted to the heat radiating portion.

  In order to function as described above, the heat radiating portions 14 and 14 ′ are made of a metal having a high thermal conductivity such as copper, gold, silver, and aluminum and alloys thereof, or carbon and a composite material thereof, and the heat radiating portions 14 and 14 ′. The outer diameter D0 of the heat radiating portions 14 and 14 'is determined with respect to the axial length, thickness, and outer diameter D1 of the rotating shaft 10. Note that the heat radiating portions 14, 14 ′ can receive the frictional heat in the sleeve 11 more easily by a structure such as a part extending between the rotating shaft 10 and the sleeve 11.

  With the structure shown in FIG. 7, even when the sleeve 11 becomes high temperature due to frictional heat, the frictional heat is quickly transferred to the heat radiating portions 14 and 14 ′, and the heat is transferred to the entire heat radiating portions 14 and 14 ′. Heat can be dissipated to the outer atmosphere, and further increase in temperature due to frictional heat of the sleeve 11 is suppressed.

By the way, in reality, from the economical viewpoint, the heat radiating portions 14 and 14 ′ are expensive in gold, silver and alloys thereof, carbon and composite materials thereof, and aluminum is a stainless steel whose rotating shaft is a natural potential. Because it is far away from the other, it is necessary to take measures against corrosion, and eventually copper is used.
However, since the heat radiating portions 14 and 14 ′ are used in the environment inside the pump, even with copper, patina is generated on the outer peripheral surface over time, and there is a concern that the heat radiating effect may be reduced.

Therefore, the present inventor proposes a structure of a plain bearing device and a rotating shaft as shown in FIGS.
FIG. 8 is a longitudinal sectional view of a plain bearing device and a rotating shaft according to the present invention.
The plain bearing device according to the present invention is also applied to the bearings 32 and 33 shown in FIG. 3, for example. As shown in FIG. 8, the sliding bearing device is provided on the outer periphery of the rotating shaft 10 having a diameter D4, on the inner side of the cylindrical sliding member 11 ′ having an outer diameter D3 and the sliding member 11 ′. The sleeve 11 is formed of a cylindrical heat transfer layer 16 having better heat transfer. However, the sleeve 11 covers both ends of the heat transfer layer 16 in the axial direction and is fixed in close contact with the rotating shaft 10. Therefore, the pump water is sealed by the sleeve 11 and does not penetrate the heat transfer layer 16.

The sleeve 11 is made of a high-hardness alloy such as stainless steel, ceramics, tungsten carbide or the like in order to protect the rotating shaft 10 from sliding wear. These thermal expansion coefficients are 17 to 18 (× 10 ⁻⁶ / ° C.) for stainless steel, but 2 to 10 (× 10 ⁻⁶ / ° C.) otherwise. The thermal conductivity of these materials is 17 to 21 (W / m · K) for stainless steel, 3 to 150 (W / m · K) for ceramics, and 60 to 80 (W / m · K) for high-hardness alloys. It is.

The heat transfer layer 16 is made of a copper material and fixed in contact with the inner surface of the sleeve 11 and the rotary shaft 10 on average. Copper has a thermal expansion coefficient of 16 to 17 (× 10 ⁻⁶ / ° C.) and a thermal conductivity of 400 (W / m · K).

The rotating shaft 10 is stainless steel from the viewpoint of strength. Inside the rotary shaft 10, there is a heat transfer column 15 having a diameter D5 that communicates with both sides in the axial direction from the position of the bearing device. The heat transfer column 15 is made of a copper material like the heat transfer layer 16 and is in average contact with the inner wall of the rotating shaft 10.
When the rotary shaft 10 rotates, the sleeve 11, the heat transfer layer 16, and the heat transfer column 15 rotate along with the rotation.

  The inner peripheral surface of the slide bearing 1 is disposed opposite to the outer peripheral surface of the sleeve 11. The plain bearing 1 is fixed to a support member 13 connected to a pump casing or the like via a bearing case 12. Even when the rotary shaft 10 is rotating, in order to support the rotary shaft in order to keep the shaft in a fixed position, the rotary shaft is allowed to rotate, but the sliding bearing 1 and the sleeve are not allowed to move in parallel. A small clearance is maintained between 11.

When the sliding portion of the sleeve 11 reaches a high temperature, heat is transferred to the heat transfer layer 16 inside the sleeve 11. Since the heat transfer layer 16 has a higher thermal conductivity than the sleeve 11, heat is quickly transferred to the heat transfer layer 16, and the entire temperature of the heat transfer layer 16 rises evenly. Therefore, since the heat transfer layer 16 is in average contact with the rotating shaft 10, the temperature of the rotating shaft 10 is also increased uniformly from the portion where the heat transfer layer 16 is in contact. As a result, since the temperature distribution does not occur in the shaft cross section of the rotating shaft 10, the shaft does not bend due to thermal expansion.
Since the heat transfer layer 16 is placed in a watertight seal with the sleeve 11 as described above, no patina is generated on the surface of the heat transfer layer 16, so the heat transfer performance at the material boundary is reduced. Not maintained.

The frictional heat transmitted to the entire area of the heat transfer layer 16 penetrates uniformly into the rotary shaft 10 from the outer periphery of the rotary shaft 10 that is in average contact with the inner periphery of the heat transfer layer 16, and averages with the inner periphery of the rotary shaft 10. Flow into the heat transfer column 15 that comes into contact with the heat.
When the sleeve 11 is made of stainless steel, the sleeve 11 is made of a stainless steel material if the heat transfer layer 16 and the heat transfer column 15 are made of a copper material. The thermal expansion coefficients of the heat transfer layer 16, the rotating shaft 10 and the heat transfer column 15 can be made substantially equal. When the material of the sleeve 11 is a high-hardness alloy such as ceramics or tungsten carbide, heat transfer If the material of the layer 16 and the heat transfer column 15 is a copper material, since the rotary shaft 10 is a stainless steel material, the thermal expansion coefficient of the sleeve 11 is that of each of the heat transfer layer 16, the rotary shaft 10 and the heat transfer column 15. Smaller than the coefficient. In this way, the thermal expansion in the radial direction of the heat transfer layer 16, the rotary shaft 10 and the heat transfer column 15 is limited by the thermal expansion of the sleeve 11, so that the close contact between these materials is maintained, and the heat The flow is also maintained.

The heat transferred to the heat transfer column 15 is transferred to the end of the heat transfer column 15 that extends through the rotary shaft 10 from the position of the bearing device to both sides in the axial direction. In this process, heat flows from the heat transfer column 15 toward the rotating shaft 10 that is in average contact with the outer periphery of the heat transfer column 15, and heat is radiated from the outer periphery of the rotating shaft 10 toward the atmosphere.
Since the heat transfer column 15 can be dimensioned in the axial direction of the rotating shaft 10 in this way, the outer periphery of the rotating shaft 10 can be abundant heat dissipation surfaces. As a result, the frictional heat on the sliding surface of the sleeve 11 is radiated smoothly, so that the surface temperature of the sleeve 11 does not increase as compared with the conventional case.

  Since the thermal expansion coefficient of the sleeve 11 is relatively small and the surface temperature of the sleeve 11 is not increased as compared with the conventional one, the plain bearing 1 is made of PTFE (polytetrafluoroethylene), It may be a resin such as PA (polyamide), PC (polycarbonate), EP (epoxy resin), PEEK (polyetheretherketone).

However, if the sliding member on the fixed side is a resin material, the resin material has a very low thermal conductivity (1 W / m · K or less), and the bearing case 12 holds the resin material against frictional heat due to local friction. In addition, there is a possibility that the temperature of the heat generation point becomes considerably high before passing through the support member 13. Further, since the sliding member on the fixed side is made of a resin material, the coefficient of thermal expansion is very large (60 to 150 × 10 ⁻⁶ / ° C.). Although expansion has occurred, at a distance from it, the thermal conductivity is very small as described above, and the temperature remains low, so that it is not thermally expanded. Therefore, there is a possibility that the resin material becomes an unpredictable shape at the heat generation point.

From the above viewpoint, the fixed-side sliding material is preferably a metal material such as stainless steel or a carbon fiber reinforced composite material. The carbon fiber reinforced composite material has a thermal conductivity of around 100 (W / m · K) and a thermal expansion coefficient of around 1 × 10 ⁻⁶ / ° C.
If these materials are used, the frictional heat of the sliding bearing 1 generated by the sliding of the sleeve 11 and the sliding bearing 1 is quickly transmitted to the bearing case 12 that supports the sliding bearing 1. The temperature is difficult to increase.

FIG. 9 shows an example of the end portion of the heat transfer column 15, and it is assumed that the bearing device of FIG. 8 is arranged below and is connected to the bottom of FIG. The shaft coupling 26 in FIG. 3 is employed. The upper side of FIG. 9 is a normal rotating shaft 10 ′ having a solid axis with a diameter D0. A flange 17 is provided at the lower part of the rotating shaft 10 ', and can be fastened to a flange 18 provided on the end surface of the rotating shaft 10 according to the present invention on the lower side.
Further below the flange 17, an axis having a substantially diameter D0 extends on the outer periphery on which splines and the like are formed.

  At the upper end of the rotary shaft 10 according to the present invention on the lower side of FIG. 9, a portion that engages with the spline portion of the rotary shaft 10 ′ described above is provided in the vicinity of the joint surface of the flange 18. The rotating shaft 10 is a hollow shaft having an outer diameter D4 and an inner diameter D5 as described above, and D4 is larger than D0. A heat transfer column 15 having an outer diameter D5 is fitted in a hollow portion having an inner diameter D5.

  An O-ring groove 20 is provided on the joint surface with the flange 17, and an O-ring 21 is provided there. The flange 17 and the flange 18 are fastened by a fastening member 19 such as a bolt and sealed by an O-ring. In consideration of the axial extension of the heat transfer column 15, the flange 17 and the flange 18 are joined between the upper end portion of the heat transfer column 15 and the lower end portion of the rotating shaft 10 ′ of the solid shaft. However, the clearance is adequately provided. In this way, the heat transfer column 15 is O-ring sealed so that water does not permeate the heat transfer column 15 even during drainage operation. Heat transfer performance is not impaired.

By adopting a hollow shaft, the outer diameter has to be larger than the diameter of the solid shaft, but conventionally, since the heat dissipation part was attached to the rotating shaft, the overall outer diameter was eventually larger than the diameter of the rotating shaft. Therefore, the use of a hollow shaft is not necessarily a drawback as compared with the conventional technology.
Note that FIG. 9 shows the vertical direction for convenience of explanation, but the direction is not particularly limited. Further, when the end portion of the rotating shaft is the end portion of the pump impeller or the like, this can be dealt with by using the flange 17 as a closing flange.

  10 is another example of the end portion of the heat transfer column 15 employed in the shaft coupling 26 portion in FIG. 3, and the bearing device of FIG. 8 is arranged below and connected to the end portion as in FIG. Assumes that. The upper side of FIG. 10 is a normal rotation axis 10 ′ having a solid axis with a diameter D 0. There is no flange below the rotating shaft 10 ', and the rotating shaft 10' extends as it is.

The rotating shaft 10 according to the present invention at the lower side of FIG. 10 is a hollow shaft having an outer diameter D4 and an inner diameter D5 as described above, but the inner diameter is D0 at the joint portion with the rotating shaft 10 ′ at the upper end. Yes. D4 is greater than D0. A heat transfer column 15 having an outer diameter D5 is fitted in a hollow portion having an inner diameter D5.
The rotary shaft 10 ′ and the rotary shaft 10 are inserted into and coupled to the rotary shaft 10 by shrink fitting or cold fitting.

  In consideration of the axial extension of the heat transfer column 15, the rotary shaft 10 and the rotary shaft 10 'are joined between the upper end of the heat transfer column 15 and the lower end of the solid rotary shaft 10'. Even in the case of clearance, clearance is properly provided. In this way, because of shrink fitting, water is prevented from permeating the heat transfer column 15 even during drainage operation, so that the heat transfer column 15 generates patina on the surface over a long period of time and has heat transfer performance. There is no loss.

  In FIG. 10, as in FIG. 9, the vertical direction is shown for convenience of explanation, but the direction is not particularly limited. Further, when the end of the rotating shaft is the end of a pump impeller or the like, it can be dealt with by closing the end of the rotating shaft 10 by shrink-fitting a closing lid having a diameter D0.

FIG. 11 is an example of the end portion of the heat transfer column 15, and it is assumed that the bearing device of FIG. 8 is disposed above and connected to the upper portion of FIG. It is adopted in the middle of the rotating shaft in FIG. In FIG. 11, for convenience of explanation, a case where the heat transfer column 15 extends downward from the upper side of the rotating shaft 10 according to the present invention and an end portion thereof is in the middle of the rotating shaft 10 is shown.
In this case, the rotating shaft 10 according to the present invention may be a hollow shaft having an outer diameter D4 and an inner diameter D5 up to the lower end portion of the heat transfer column 15, and a lower shaft may be a solid shaft having a diameter D4. Although it is possible to make the outer diameter of the heat transfer column 15 downward from the end of the heat transfer column 15 with a gentle taper, the D0 diameter can be made a solid axis, but this is disadvantageous in terms of processing cost.

As described above, since the heat transfer layer 16 and the heat transfer column 15 are in a water-sealed environment, patina is not generated on their surfaces, and the heat transfer performance from these surfaces is maintained without deterioration. The On the other hand, since the place where the heat is finally transmitted is the rotating shaft 10 made of stainless steel, the surface of the stainless steel does not rust, so that a constant heat radiation performance can always be maintained. Further, since the length of the heat transfer column 15 in the axial direction can be increased as necessary, the surface of the rotating shaft 10 can be sufficiently utilized as a heat radiating portion.
Since the heat transfer layer 16 and the heat transfer column 15 are in a water-sealed environment, not only copper but also aluminum (thermal conductivity: 230 to 240 W / m · K thermal expansion coefficient: 23 to 24 × 10 ^−6). / ° C.) can also be used, and this makes it possible to reduce the weight.

FIG. 12 shows a modification of the embodiment shown in FIGS. In FIG. 11, a carbon fiber reinforced composite material is used for the sleeve 11. In this case, the carbon fiber reinforced composite material has a high thermal conductivity and a low thermal expansion coefficient. Since the carbon fiber reinforced composite material already has heat conduction performance close to that of copper and does not rust, the sleeve 11 can be formed of this material alone.
Furthermore, it is also possible to use a carbon fiber reinforced composite material for the heat transfer column 15. However, it may not be a little economical at this time.

The bearing device according to the present invention shown in FIGS. 8 to 12 is applied to the bearings 32 and 33 shown in FIG.
The vertical shaft pump 3 shown in FIG. 3 is operated in the atmosphere when the pump is activated. That is, the bearings 32 and 33 are operated under dry conditions without liquid lubrication. Here, the dry condition refers to a condition in which the atmosphere of the bearings 32 and 33 during pump operation is in the air without liquid lubrication, and the dry operation refers to operation under that condition. Further, the bearings 32 and 33 shown in FIG. 4 are also operated under drainage conditions in which water has passed through the bearings. Here, the drainage condition refers to a condition in which the atmosphere of the bearings 32 and 33 during the pump operation is in water mixed with foreign matter (slurry) such as earth and sand. It refers to water-mixing operation, full-volume operation, air lock operation, etc. Bearings 32 and 33 are used under such conditions.

According to the present invention, in the vertical shaft pump 3, the rotary shaft 10 that slides with the slide bearing 1 is provided with a heat transfer material having better heat transfer than the rotary shaft on the center side of the rotary shaft, and slides with the slide bearing. The outer periphery of the rotating shaft is in contact with the outer periphery of the rotating shaft, and the inner periphery of the rotating shaft is in contact with the outer periphery of the heat transfer material having better heat transfer than the rotating shaft provided on the center side of the rotating shaft.
According to the above configuration, the heat generated on the surface of the sliding material of the rotating shaft is quickly diffused in the axial direction by the heat conductive material on the center side of the rotating shaft, and at the same time, the heat conductivity on the center side of the rotating shaft is good. Since the material transmits heat to the entire outer periphery of the rotating shaft and dissipates heat to the outside air in contact with the rotating shaft, temperature rise due to heat generation of the sliding material can be mitigated.
In addition, since the heat transfer material having better heat transfer than the rotation shaft is sealed on the center side of the rotation shaft, the surface of the heat transfer material having better heat transfer does not rust and the heat transfer performance does not deteriorate. Moreover, since the rotating shaft is made of a rust-proof material such as stainless steel, the outer peripheral surface of the rotating shaft does not rust, and the heat dissipation performance to the outside air does not deteriorate.

As described above, the specific embodiment according to the present invention has been described by taking the preceding standby pump as an example.
By the way, the sleeve of the three-layer structure according to the present invention, or the sleeve of the structure in which the sliding layer and the heat transfer layer surround the rotation shaft in a state where the end portions of the sliding layer and the heat transfer layer are in contact with each other, It can be used not only for a bearing but also for a labyrinth seal part by being mounted on a rotating shaft of a rotating fluid machine that operates under conditions without liquid lubrication, such as a compressor or a steam turbine. Moreover, it is used not only for a vertical axis but also for a horizontal axis rotary machine.

  Although the embodiment of the present invention has been described so far, the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention may be implemented in various different forms within the scope of the technical idea.

DESCRIPTION OF SYMBOLS 1 Sliding bearing 1a Inner peripheral surface 1b Outer peripheral surface 3 Vertical shaft pump 5 Through-hole 6 Air pipe 6a Opening 10 ', 10 Rotating shaft 11 Sleeve 11' Sliding member 12 Bearing case 13 Support member 14, 14 'Radiating part 15 Heat transfer column 16 Heat transfer layers 17 and 18 Flange 20 O-ring groove 21 O-ring 22 Impeller 26 Shaft coupling 27 Suction bell 28 Discharge bowl 29 Casing 30 Discharge elbow 32 Upper bearing 33 Lower bearing 34 Shaft seal 100 Water tank

Claims (16)

A sliding bearing device used for supporting a rotating shaft of a rotating fluid machine and used in dry conditions in which a bearing sliding surface is exposed to the atmosphere,
A sleeve fixed to the outer periphery of the rotating shaft;
A slide bearing having a bearing sliding surface with which the sleeve slides,
The material that forms the outer peripheral surface of the rotating shaft is a rust-proof material, and a heat transfer material having better heat transfer than the rotating shaft is provided on the center side of the rotating shaft,
The thermal conductivity of the material in contact with the rotating shaft of the sleeve is greater than the thermal conductivity of the material of the rotating shaft,
The slide bearing device according to claim 1, wherein the heat conductivity of the heat transfer material on the center side of the rotating shaft is larger than the heat conductivity of the material of the rotating shaft. A sliding bearing device used for supporting a rotating shaft of a rotating fluid machine and used in dry conditions in which a bearing sliding surface is exposed to the atmosphere,
A sleeve fixed to the outer periphery of the rotating shaft;
A slide bearing having a bearing sliding surface with which the sleeve slides,
The material that forms the outer peripheral surface of the rotating shaft is a rust-proof material, and a heat transfer material having better heat transfer than the rotating shaft is provided on the center side of the rotating shaft,
A sliding bearing device, wherein an inner periphery of the rotating shaft is in contact with an outer periphery of a heat transfer material on a center side of the rotating shaft.   The material which forms the outer peripheral surface of the said rotating shaft is stainless steel, The slide bearing apparatus of Claim 1 or 2 characterized by the above-mentioned.   The slide bearing device according to claim 1, wherein the heat transfer material on the center side of the rotating shaft is a copper material or aluminum.   3. The sleeve according to claim 1, wherein the sleeve includes a sliding member that is in sliding contact with the sliding bearing, and a heat transfer layer that is provided inside the sliding member and has a higher heat transfer property than the sliding member. The plain bearing device described.   The slide bearing device according to claim 5, wherein the sliding member covers both ends of the heat transfer layer in the axial direction and is fixed in close contact with the rotating shaft.   The sliding bearing device according to claim 5, wherein the sliding member is made of stainless steel, ceramics, or tungsten carbide.   The sliding bearing device according to claim 5, wherein the heat transfer layer is made of a copper material or aluminum.   The plain bearing device according to claim 1 or 2, wherein the sleeve is entirely made of a carbon fiber reinforced composite material.   The slide bearing device according to any one of claims 1 to 9, wherein the slide bearing is made of a metal material or a carbon fiber reinforced composite material.   Another rotary shaft is connected to the end of the rotary shaft via a flange to form a single rotary shaft, and the flange is provided with a seal member that prevents water from entering the heat transfer material. The sliding bearing device according to claim 1, wherein the sliding bearing device is provided.   An end of another rotating shaft is connected to the end of the rotating shaft by an interference fit to form a single rotating shaft, and the interference fitting prevents water from entering the heat transfer material. The plain bearing device according to any one of claims 1 to 10, wherein the slide bearing device is characterized.   The plain bearing device according to claim 11 or 12, wherein a clearance is provided between an end portion of the heat transfer material and an end portion of the other rotating shaft.   The sliding bearing device according to claim 13, wherein an end portion on an opposite side of the end portion of the heat transfer material is in contact with a solid portion of the rotating shaft.   A rotary fluid machine using the plain bearing device according to any one of claims 1 to 14.   A pump using the plain bearing device according to any one of claims 1 to 14.

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