JP2022124981A - Bearing slide mechanism - Google Patents

Abstract

To solve the problem that for a bearing slide mechanism used for a rotary machine, a slide member is not available which can operate to slide in a liquid, including solid foreign matter and high-viscosity associative substance such as particles, fibrous substance etc., apt to stay in a bearing gap for a long time to high density, and a high-viscosity liquid.SOLUTION: There is provided a bearing slide mechanism that consists of a rotary shaft-side slide member fitted and fixed to a rotary shaft, and a fixed shaft-side slide member fitted to an outer circumference of the rotary shaft-side slide member in a freely rotatable and slidable state, wherein a cooling fluid flow passage where a cooling fluid flows is formed only on an outer circumferential surface of the rotary shaft-side slide member, and the cooling fluid flow passage is formed spirally.SELECTED DRAWING: Figure 3

Description

The present invention relates to a bearing sliding mechanism used in a rotating machine. In order to prevent the bearing from sticking due to the heat generation phenomenon of the sliding part, it has a function to forcibly discharge the stagnant substances in the sliding part, which flow into the bearing gap and cause heat generation, to the outside of the bearing gap. It relates to a sliding bearing mechanism.

The shape of a conventional slide bearing combination sliding portion will be described with reference to FIG. The sliding surface of the sliding bearing is composed of a rotating shaft side sliding member 2 fitted and fixed to the rotating shaft 1 and a fixed shaft side sliding member 3 which is fitted so as to be rotatably slidable. A cooling fluid passage groove 4 is provided in the moving member 3 .

The cooling fluid passage groove 4 on the sliding surface of the fixed-shaft-side sliding member serves to supply lubricating fluid to the sliding surface to prevent heat generation during the sliding operation of the sliding bearing and to cool the sliding member. However, in the conventional sliding bearing combination, the cooling fluid passage groove 4 is formed by processing the sliding surface of the fixed shaft side sliding member 3 integrally formed with a cylinder. In the method of arranging the split-type sliding members 5 on the inner circumference as shown in FIG.

Taking a pump as an example of a rotating machine, in particular, a pump that handles a large amount of gas-liquid mixed fluid containing a large amount of solid particles such as earth and sand, or a large amount of highly viscous foreign matter, requires the sliding member on the fixed shaft side of the slide bearing. Even if the cooling fluid passage grooves are arranged on the sliding surface of the fixed shaft side sliding member, a large amount of foreign matter contained in the fluid fills the cooling fluid passage grooves provided in the fixed shaft side sliding member, and the cooling fluid passes quickly. is hindered, heat generation on the sliding surface becomes excessive, and wear and sticking of the sliding bearing become conspicuous.

Sliding bearings with an extremely smooth sliding surface that are designed for fluid lubrication will have extremely stable sliding characteristics if a continuous fluid film is formed on the sliding surface, but they contain solid particles. When performing sliding operation in a gas-liquid mixed fluid, solid particles in the gas-liquid mixed fluid clog the piping that supplies the cooling and lubricating fluid to the sliding parts of the bearing. Hard solid particles that enter the bearing gap between the sliding surface of the sliding member and the sliding surface of the rotating shaft side sliding member cause the fluid film that governs lubrication on the sliding surface to be lost, and the fixed shaft side sliding. Direct contact between the moving member and the sliding member on the rotating shaft side causes abnormal wear of the sliding surface due to solid particles, and excessive thermal expansion of the rotating shaft due to abnormal heat generation due to insufficient cooling. The bearing gap, which is the gap between the sliding surface of the moving member and the sliding surface of the sliding member on the rotating shaft side, is remarkably reduced, and it is less likely that the two sliding surfaces will eventually stick together and completely lose the bearing function. do not have.

In this way, in the sliding bearing, heat generation on the sliding surface of the bearing, which is a cause of destruction, is suppressed, and the sliding surfaces of the sliding member on the rotating shaft side and the sliding surface on the fixed shaft side in the sliding bearing are solidified. A continuous supply of cooling fluid that forms a fluid lubricating film that prevents direct contact between them is essential.

Cooling fluid passage grooves provided on the sliding surface play a major role in strengthening and improving the lubricating ability and cooling ability of the sliding bearing. The larger the flow passage cross-sectional area of the cooling fluid passage groove, the more cooling fluid can be supplied to the sliding surface and the cooling effect is improved. Foreign inclusions such as solid particles such as earth and sand enter the surface more often, resulting in a defect that severe wear of the sliding surface of the bearing is caused.

In order to remove the heat generated by the lubricating function and sliding on the sliding surface in the cooling fluid passage grooves of conventional sliding bearings, it is a premise that the cooling fluid passage passages are ensured. If foreign matter stays in the fluid passage grooves and the conduction of the cooling fluid is obstructed, the heat generated by the sliding of the sliding bearing stays in the bearing, and eventually the sliding bearing is broken. are not few.
Furthermore, when the sliding bearing is intermittently exposed to air operation, the foreign matter stagnating in the cooling fluid passage dries and solidifies. Due to the heat generated by the motion, the rotation-side sliding member expands, leading to the failure of the bearing.

The number of cooling fluid passage grooves in conventional sliding bearings is often 3 to 5 when the fixed shaft side sliding member 3 has a cylindrical integral structure, and there is a limit to securing the fluid passage cross-sectional area of the cooling fluid passage grooves. It is the actual situation that there is As shown in FIG. 2, in the case of a sliding member divided structure in which a plurality of fixed shaft side sliding members 3 are arranged at equal intervals on the inner circumference of the fixed bearing, which was devised to solve this problem, cooling fluid passage The number of grooves 6 corresponds to the number of divisions of the fixed-shaft-side sliding member 3. However, as the number of divisions increases, the ability to form a fluid lubricating film on the sliding surface decreases. There was a problem that it was difficult to maintain a lubricating state.

In particular, for sliding bearings that are used in a slurry environment where hard particles are expected to enter, both the fixed shaft side sliding member and the rotating shaft side sliding member are made of ultra-hard brittle materials such as cemented carbide and ceramics. It is often used for sliding members, and increasing grooves in the axial direction of a cylindrical brittle material inevitably causes damage due to vibrations and shocks that occur during abnormal operation. When using a split-structure bearing in which split-type sliding members are arranged in a cylindrical shape, the discontinuity of the sliding surface due to the split arrangement of the hard material may It becomes difficult to maintain the roundness and concentricity of Furthermore, the fixed-side bearing having the split-type sliding member has the problem that the longer it is used, the more the out-of-roundness and the concentricity are degraded. Therefore, there is a problem that the fixed shaft side sliding member and the rotating shaft side sliding member are likely to come into local contact, and local damage is unavoidable.

In general, in order to ensure wear resistance and suppress sliding heat generation in a fluid environment containing foreign matter with high stagnation, it is necessary to realize a continuous supply of the fluid necessary for smooth lubrication and cooling on the sliding surface. It is important to note that in the structure in which the cooling fluid passage grooves are arranged in the fixed shaft side sliding member, direct contact between the sliding members is prevented by discharging foreign matter that remains in the cooling fluid passage grooves and by ensuring a fluid lubricating film. However, the problem of sudden breakage of materials due to brittleness, which is a characteristic of high-hardness materials, has not yet been solved.

The problem to be solved is that in a bearing sliding mechanism used in a rotating machine, a liquid containing a high concentration of particles that tend to stay in the bearing gap for a long time, solid foreign matter such as fibrous substances, and highly viscous association substances There is no sliding member that enables sliding operation in medium to high-viscosity liquids, and solid foreign matter and high-viscosity substances accumulate when the bearing slides, causing abnormal temperature rise in the bearing due to heat generated by sliding. However, there is no method for suppressing sudden loss of the function of the sliding bearing due to significant damage of the material forming the sliding bearing due to insufficient supply of the lubricating fluid that governs the sliding of the bearing.
Therefore, even if the fluid contains a large amount of solid foreign matter that tends to stagnate, it is possible to continuously cool the heat generated by sliding in the bearing clearance to delay the clinging due to the temperature rise in the bearing clearance, which is a major factor in breaking the sliding bearing. By stably supplying the fluid that governs the formation of the lubricating film and forcibly discharging the solid foreign matter that remains and adheres in the bearing gap, There is a demand for a bearing sliding mechanism that does not cause significant damage, but there is nothing that satisfies this requirement.

The object of the present invention is to provide a bearing sliding mechanism that is used in liquids containing solid foreign substances such as particles and fibrous substances that tend to stagnate and highly viscous associative substances, as well as in highly viscous liquids. In order to maintain stable sliding characteristics even under conditions containing solid foreign matter, by forcibly discharging the solid foreign matter stagnating in the bearing clearance, the sliding heat generated by the slide bearing is cooled and fluidized. To provide a bearing sliding mechanism that stably supplies a fluid that governs the formation of a lubricating film and does not cause excessive wear or breakage even in a cargo liquid that contains a large amount of solid foreign matter, especially in a vertical shaft pump. It is a submersible bearing that assumes lubrication by cargo liquid, and there is concern that sticky substances may accumulate near the bearing and the bearing part may be buried by sediments. It exhibits good sliding characteristics even with pumps that handle concentrated sewage, and maintains stable sliding characteristics by forcibly discharging solid foreign matter remaining in the bearing gap while the pump is stopped at the same time as the pump is running. An object of the present invention is to provide a bearing sliding mechanism.

In order to achieve the above object, the invention as set forth in claim 1 provides a bearing for use in liquids containing solid foreign matter such as particles and fibrous substances that tend to stagnate, highly viscous associative substances, and in highly viscous liquids. In the sliding mechanism, as shown in FIG. 3, from the lower part of the bearing to the upper part, it spirals on the rotating shaft side sliding surface while maintaining an inclination angle 7 of 20° to 40° with respect to the cross section of the rotating shaft. After securing the cooling fluid flow path 8 of the present invention that is circulated and conducted, liquid containing solid foreign substances such as particles and fibrous substances that tend to stay on the sliding surface of the fixed side sliding member 9 and high viscosity association substances , and a rotating shaft side sliding member 10 which is formed of a completely continuous surface without any passage groove for a highly viscous liquid and is fitted to the fixed shaft side sliding member 9 so as to rotate and slide freely is made of a metal material or A combined sliding member of a slide bearing characterized by using a carbon material occupying a volume ratio of 50% or more.

In conventional slide bearing combination sliding members that are assumed to be used in liquids containing solid foreign matter such as solid particles and fibrous substances and highly viscous associative substances, as well as in highly viscous liquids, the fixed shaft side sliding member as cemented carbide, silicon nitride _{( Si3N4} ), silicon carbide (SiC), tungsten carbide (WC), alumina _{( Al2O3} ) _, chromia ₍ CrO2, _Cr2O3 ), zirconia ₍ ZrO2 ) has high hardness and high corrosion resistance. The flow path for supplying the cooling fluid that governs the cooling of heat generation and the formation of a fluid lubricating film on the sliding surface can only be arranged in the shape of a groove penetrating the fixed shaft side sliding member in the direction of the rotating shaft, and is likely to remain. When used in liquids containing solid foreign matter such as particles and fibrous substances and high-viscosity association substances, or in high-viscosity liquids, foreign matter contained in the fluid accumulates in the cooling fluid passage grooves provided on the fixed bearing side. Stagnation and obstruction of the stable supply of the cooling fluid to the bearing gaps lead to adhesion wear due to strong local contact between hard materials due to the loss of the fluid lubricating film, which causes sliding deterioration due to changes in the sliding surface properties. Significant change in dynamic characteristics and abnormal temperature rise of the sliding part due to heat generated by sliding may cause the bearing clearance loss due to thermal expansion of the sliding member on the rotating shaft side, which may cause a sticking phenomenon, or hold the sliding member on the rotating shaft side. There have been problems such as the occurrence of breakage of the material of the sliding portion of the rotating shaft due to the tensile stress load on the sliding member on the rotating shaft side caused by the thermal expansion of the fixed metal rotating shaft. can be resolved for sure.

Conceptual diagram of conventional slide bearing combination sliding part shape Conceptual diagram of the shape of sliding part combined with slide bearing that adopts split-type sliding member Conceptual diagram of a bearing sliding mechanism that forcibly discharges stagnant substances in the bearing clearance A first conceptual diagram of the cooling fluid flow path on the outer peripheral surface of the sliding member on the rotation side of the plain bearing, developed from a plane. A second conceptual diagram of the cooling fluid flow path on the outer peripheral surface of the sliding member on the rotation side of the sliding bearing, which is developed from a plane. Sectional view of a centrifugal pump to which the bearing sliding mechanism of the present invention is applied Sectional view of a vertical mixed flow pump to which the bearing sliding mechanism of the present invention is applied Partially cut side view of a bearing sliding test device for demonstrating the effectiveness of the present invention.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 4 shows a plan developed view of the outer peripheral surface of the rotation-side sliding member in the bearing sliding mechanism according to the first embodiment of the present invention. In this combination, the sliding surface of the fixed-shaft-side sliding member 9 and the sliding surface of the rotating-shaft-side sliding member are characterized by having no flow path for the cooling fluid. The rotating shaft side sliding member 10 provided with the cooling fluid flow path 8 of the present invention arranged from the lower part to the upper part of the rotating shaft side sliding member while spirally turning around the outer circumference is used. Compared to the combination of the conventional example, the sliding mechanism is capable of rotating the rotating shaft 1 in a liquid containing solid foreign substances such as particles and fibrous substances that tend to stay together, highly viscous association substances, and in a highly viscous liquid. Therefore, even if a large amount of foreign matter enters the cooling fluid flow path 8 of the present invention, the spiral cooling fluid flow path 8 spirally turns the foreign matter remaining in the cooling fluid flow path 8 into the bearing groove. Since it is forcibly transported in the direction 13 where it is scooped up inside and discharged outside the bearing, it leads to a sticking phenomenon due to lack of fluid that controls the cooling of sliding heat generation and the formation of fluid lubricating film in the sliding bearing. It is not.

A major feature of the present invention is that it is necessary for cooling sliding heat generation and forming a fluid lubricating film in liquids containing solid foreign matter such as solid particles and fibrous substances and highly viscous associative substances, as well as in highly viscous liquids. Cooling fluid passage grooves or channels for supplying the essential fluid are not provided on the sliding surface of the fixed-shaft-side sliding member, but the flow-path 8 is spirally provided on the sliding surface of the rotating-shaft-side sliding member. trying to ensure. In general sliding bearings, by providing cooling fluid passage grooves 4 arranged radially in the fixed shaft side sliding member 3, fluid is supplied to cool the heat generated by sliding and to form a fluid lubricating film on the sliding surface. However, it is impossible to eliminate the risk that foreign matter contained in the fluid will stagnate in the cooling fluid passage groove 4 that is fixed on the fixed bearing side and the supply of the fluid will be interrupted. However, in the sliding bearing in which the cooling fluid flow path 8 of the present invention is spirally provided on the surface of the rotating shaft side sliding member 10, the inside of the groove of the cooling fluid flow path 8 acting when the shaft is rotating It utilizes the effect of forcibly discharging the retained substances of the
Furthermore, the forced discharge function of the helical cooling fluid flow passage 8 also prevents cargo liquid containing hard particles that may enter the cooling fluid flow passage 8 and severely wear the sliding surface of the bearing. It suppresses the amount of wear on the sliding surface, prevents viscous fluid from accumulating in the bearing gap when used in high-viscosity fluid, suppresses abnormal heat generation in the sliding part of the bearing, and prevents the sliding bearing from being stuck and broken. It is characterized by not being able to

From the above, it can be concluded that the rotating shaft side as shown in FIG. A combination in which the cooling fluid flow path 8 of the present invention spirally circling the sliding surface of the sliding member 10 from the bottom to the top of the sliding member 10 is provided on the sliding surface of the sliding member 10 is solid particles, fibrous substances, etc. stagnation that blocks the cooling flow path of the bearing in a liquid containing solid foreign matter and highly viscous associative substances, and in a state in which an excessive amount of substances that block the cooling fluid flow path in the bearing, such as in a high-viscosity liquid, is included. It is excellent in that substances are forcibly expelled from the bearing through the cooling fluid channel 8 .

Furthermore, in order to remove the sliding heat generated when the sliding bearing slides in a fluid, stable heat is applied to the bearing gap where the fixed shaft side sliding member 9 and the rotating shaft side sliding member 10 slide. The supply of cooling fluid becomes an important factor. In the fluid passage groove 4 provided in the general fixed shaft side sliding member 3 as shown in FIG. Fluid passage resistance increases. Therefore, when used in a liquid with poor fluidity and containing solid foreign matter such as solid particles and fibrous substances and highly viscous associated substances, or in a highly viscous liquid, there is always a danger of suffocation due to the stagnation of foreign matter in the fluid passage groove. Gender cannot always be ruled out. In the present invention, as shown in FIG. 3, since the spiral cooling fluid channel 8 is provided on the surface of the rotating shaft sleeve side sliding member 10, the cooling fluid channel 8 of the present invention can be blocked. It is extremely effective in expelling foreign matter that has a tendency to be brittle, and the cooling fluid that governs cooling is smoothly supplied to the sliding surface of the bearing clearance. Furthermore, since the sliding surfaces 12 on both sides of the helical groove provided on the surface of the rotating shaft side sliding member 10 secure a very large area, the fluid film formed on the sliding surface may be damaged. It has unusual features.

In other words, it secures a path that allows foreign matter and solid particles to be forcibly discharged outside the bearing, prevents foreign matter and solid particles that cause wear from entering the sliding surface, and controls the lubrication formed on the sliding surface. It has an extremely excellent feature in that it simultaneously prevents the loss of the fluid film and quickly removes the generated sliding heat.

FIG. 5 shows a plan developed view of the outer peripheral surface of the rotating shaft side sliding member in the bearing sliding mechanism according to the second embodiment of the present invention. As shown in FIG. 5, the cooling fluid flow path 8 has a plurality of cooling fluid flow paths 8 of the present invention so as to helically circulate the surface of the sliding surface of the rotating shaft side sliding member 10 manufactured integrally. It can also be configured by arranging. In this case also, when a plurality of the cooling fluid passages 8 are arranged in a spiral shape, the fluid is fed from the bearing end by the rotation of the rotating shaft and is discharged to the other end side, so that the rotating shaft cross section is 20 degrees. The sliding surface on the rotating shaft side is provided in a helical shape at equal intervals while maintaining an inclination angle 7 of .degree. to 40.degree.

The sliding bearing combination according to the second embodiment is particularly effective in rotary machines that are handled in liquids containing a large amount of solid foreign matter such as solid particles and fibrous substances, high-viscosity association substances, and ultra-high-viscosity liquids. be. When a large amount of foreign matter is contained in the cooling fluid, it is of course effective to improve the ability to discharge the foreign matter from the cooling fluid passage groove 8. It is extremely effective when operating sliding bearings in fluids with extremely high viscosity, such as fluids such as asphalt, fluids such as liquid soap, and fluids in which the cooling fluid itself has extremely high viscosity, such as emulsions of water and oil. be.

In determining the bearing clearance in designing a general sliding bearing, in addition to the sliding load and rotational speed during operation of the sliding bearing, the viscosity of the fluid under the operating environment is an extremely important factor. When used in a low-viscosity fluid, the film thickness of the fluid lubricating film that governs lubrication becomes extremely thin, and when used in a high-viscosity fluid, the film thickness of the fluid lubricating film becomes extremely thick. Generally, the bearing clearance of a sliding bearing is determined so that the fluid film thickness is maximized and the eccentric rotation of the rotating shaft in the fixed bearing is minimized. If a sliding bearing with a small bearing clearance intended for use in 1 is used in a high-viscosity fluid, the lack of bearing clearance causes excessive sliding heat generation, causing the sliding bearing to stick and cause damage. On the other hand, if a sliding bearing with a large bearing clearance intended for use in a high-viscosity fluid is used in a low-viscosity fluid, the excessive bearing clearance will cause excessive eccentricity of the rotating shaft, resulting not only in large vibrations, but also in fluid The lubricating film is lost, and direct contact occurs between the solids of the sliding member on the fixed bearing side and the sliding member on the rotating shaft side, and wear of the sliding bearing progresses at an accelerated rate, leading to breakage.

For this reason, when a general sliding bearing is used in an environment with a high concentration of foreign matter or a highly viscous fluid, an attempt has been made to secure a flow path for the fluid by arranging a large number of cooling fluid passage grooves in the sliding member on the fixed bearing side. is common. However, since the carrying force of the high-viscosity fluid in the cooling-fluid passage grooves depends only on the flow velocity of the external fluid, it is difficult to carry out the high-viscosity fluid quickly.

However, if a sliding bearing configured by arranging a plurality of sliding members spirally around the surface of the sliding surface of the rotating shaft side sliding member according to the present invention is used, the cooling flow path itself becomes high in the cooling flow path. It is possible to forcibly discharge the viscous cooling fluid, and the fluidity of the fluid in the cooling channel is enhanced. For this reason, even with sliding bearings used in high-viscosity fluids, it is possible to provide smaller bearing clearances than normal sliding bearings. It is excellent in that it can suppress clinging due to heat generation, vibration due to eccentric rotation, and abnormal wear.

Here, the effect of the sliding test of the bearing sliding member conducted to clarify the practicality of the bearing sliding mechanism of the present invention will be described.

FIG. 8 shows a sliding test device for the bearing sliding member in the bearing sliding mechanism of the present invention. The test conducted with this experimental device was conducted using various existing combinations of sliding members, and sliding was performed under a usage environment in which lubricating fluid was rapidly inflowed repeatedly from fresh water atmosphere, slurry atmosphere, non-lubricating atmosphere, and non-lubricating area. The characteristics and fracture morphology were investigated. As a result, it was found that the bearing slide mechanism of the present invention is very excellent.

That is, in the vertical bearing experimental apparatus, a rotating shaft 24 is rotated by an electric motor 22 on the upper side through a torque detector 23 . The rotating shaft 24 is rotatably held by an upper bearing 25 and a lower test bearing 26 . A test rotating shaft sliding member 27 detachably fixed to the rotating shaft 24 is inserted into the sliding portion of the lower test bearing 26 so as to be slidable and rotatable. An eccentric load generating disk 28 is mounted at an intermediate position between the upper bearing 25 and the lower test bearing 26, and an eccentric weight 29 for generating whirling load is attached to the disk 28 in the radial direction. It is fixed so that it can be freely adjusted and moved. By rotating the disk 28 to which the eccentric weight 29 is attached together with the rotating shaft 24, a whirling bearing load is applied to the lower test bearing 26. As shown in FIG.

The lower test bearing 26 is detachably fixed in a test bearing installation box 30 which is movable in the front, rear, left and right directions. to apply a radial load to the lower test bearing 25 . A right side load cell 32 and a left side load cell 33 for measuring whirling radial load are installed at both ends of the test bearing installation box 30 to measure the bearing load. Furthermore, in order to grasp the sliding state of the lower test bearing 26, in addition to the load measured by the left and right load cells 32 and 33 and the load torque by the torque detector 23, the rotating shaft 24 near the lower test bearing 26 was measured. A displacement meter 34 for measuring the whirling displacement of the test bearing installation box 30 Vibration accelerometer 35 for measuring the vibration acceleration of the test bearing installation box 30 Inside the lower test bearing 26 installed in the test bearing installation box 34 An upper thermometer 36 and a lower thermometer 37 for measuring the temperature of each part are installed. Further, the test bearing installation box 30 is connected to a supply line 38 for lubricating medium such as slurry.

In the sliding test conducted by this sliding bearing actual test device, the lower test bearing was rotated and slid at a portion with an inner diameter of 100 mm and a sliding length of 60 mm. Obtained by measuring the temperature rise of the bearing part due to the bearing sliding in floating foreign matter-contaminated water in which a maximum of 400 g (4 rolls of toilet paper) of floating fibrous foreign matter was dissolved in 40 liters of water at a speed of 6 m / sec x 180 minutes. The data are shown in Table 1 below.

Symbols A to O in Table 1 and Table 2 below are combinations of slide receiving sliding members provided with conventional bearing cooling fluid passage grooves, and P and Q are sliding members 10 on the rotating shaft side. The cooling fluid flow path 8 of the present invention is arranged from the bottom to the top of the rotating shaft side sliding member 10 while maintaining the inclination angle 7 of 30° from the rotating shaft cross section on the outer periphery of the surface and spirally turning the outer periphery of the sliding surface. is a bearing sliding mechanism of the present invention using a rotating shaft side sliding member 10 provided with T and U are the cooling fluid flow in which the inclination angle 7 of the cooling fluid flow path 8 is a steep angle of 60 ° It is a bearing sliding mechanism that employs a path 8 .

When the sliding bearing is rotated and slid in a cargo liquid containing a large amount of fibrous floating foreign matter, in the bearing of the conventional sliding member combined with sliding bearings, the lubricating medium such as slurry is supplied from the supply line 38 of the actual bearing test device. It was confirmed that fibrous floating foreign matter in the cargo liquid accumulated in the bottom of the test bearing installation box 30 of the test apparatus, and the supply of the liquid that governs lubrication to the sliding portion of the sliding bearing was blocked. In the side sliding member 10, the cooling fluid flow path 8 of the present invention is arranged from the bottom to the top of the rotating shaft side sliding member 10 while maintaining an inclination angle 7 of 30° from the cross section of the rotating shaft and spirally turning. When the bearing sliding mechanism using the rotating shaft side sliding member 10 provided is used, the fibrous floating foreign matter is quickly discharged from the bearing sliding portion without stagnation at the inner bottom of the test bearing installation box 30. It was confirmed that the sliding part of the bearing was always supplied with a liquid that governs lubrication. In addition, it was confirmed that the effect of the cooling fluid flow path 8 having the steep inclination angle 7 of 60° was limited.

Table 2 below shows the data obtained by measuring the temperature rise of the bearing due to sliding in ISO VG460 lubricating oil at a sliding surface pressure of 0.2 MPa, a sliding speed of 6 m/sec, and 60 minutes.

Given the numerical value assuming operation under clear water and 260 cSt viscous fluid for the bearing clearance, in the ultra-high viscosity load of ISO VG460, which is beyond the design assumption, in the bearing of the conventional slide bearing combination sliding member, The temperature rise due to sliding heat generation becomes remarkable. In the conventional bearing of the slide bearing combination sliding member, the axial rotation of the bearing portion cannot obtain the force to carry the viscous fluid, which is the cargo liquid, from the lower part of the bearing to the upper part. However, the rotating shaft sleeve side sliding member 10 is provided with the cooling fluid passage 8 of the present invention that spirally turns while maintaining the inclination angle 7 of 30°. When the bearing sliding mechanism using the member 10 is used, the high-viscosity fluid in the test bearing installation box 30 flows through the bearing sliding part without stagnation due to the fluid carry-out effect of the spiral groove due to the rotation of the shaft. , it was confirmed that the heat generated by the sliding was quickly exhausted. In addition, it was confirmed that the effect of the cooling fluid flow path 8 having the steep inclination angle 7 of 60° was limited.

In this way, the cooling fluid passage 8 of the present invention is provided in the rotating shaft side sliding member 10 and arranged from the lower part to the upper part of the rotating shaft side sliding member 10 while spirally turning around the outer periphery of the sliding surface. When the bearing sliding mechanism using the rotating shaft side sliding member 10 is used, even in a cargo liquid containing a large amount of foreign matter that tends to stay in the bearing sliding part and clog the bearing sliding part, It was confirmed that even in a sliding environment in a highly viscous cargo liquid that greatly exceeds the design viscosity, the high-viscosity cargo liquid that tends to stagnate in the sliding part of the bearing can be quickly discharged.

Here, usefulness when the bearing sliding mechanism of the present invention disclosed in FIG. 3 is applied to the vertical centrifugal pump shown in FIG. 6 and the vertical mixed flow pump shown in FIG. 8 will be described.

First, in the vertical centrifugal pump shown in FIG. 6, the bearing sliding mechanism of the present invention is provided with a cargo-liquid lubrication type slide bearing 17 for supporting the impeller shaft 15 for rotationally driving the impeller 14 for carrying out the fluid inside the pump casing 16 . are used as In most cases, the type of liquid handled by the centrifugal pump is fixed, but depending on the location where the centrifugal pump is used, the type of liquid may not be clean, or liquids with greatly different properties may be handled. . If the liquid is not clean, solid foreign matter such as turbid particles, fibrous substances, and highly viscous aggregates accumulate in the liquid-lubricated sliding bearing, clogging the cooling fluid passage grooves. The danger of doing so cannot be ruled out. Also, when handling liquids such as crude oil whose viscosity varies greatly depending on the place of production, especially when handling highly viscous liquids as cargo liquids, the amount of cooling fluid sufficient to cool the heat generated by sliding is not sufficient in the bearing clearance provided in the slide bearing. If it is not possible to secure it, heat generated in the sliding part of the bearing will cause the sliding bearing to stick, and the risk of damage to the sliding bearing cannot be ruled out.
However, according to the present invention, this problem can be solved because the foreign matter in the fluid that remains in the bearing gap and obstructs the flow of the cooling fluid and the highly viscous fluid can be discharged.

That is, if the bearing sliding mechanism according to the present invention is applied to the sliding bearings of rotating machines such as the pumps, excellent non-lubricating sliding characteristics, thermal shock resistance, and wear resistance can be ensured, and cooling can be achieved in normal operating environments. It is possible to provide great reliability to rotating machines that are in use despite the risk of abnormal heat generation of bearings due to defects.

As a bearing slide mechanism of the present invention used for other applications, as shown in FIG. 7, it is used in a vertical mixed flow pump for handling domestic wastewater in addition to earth and sand slurry. In this mixed flow pump, water containing particles such as sediments such as rainwater is usually handled as cargo liquid in many cases, but in recent years sewage including domestic wastewater is also often handled as cargo liquid. Unlike rainwater, which contains sediment, domestic wastewater contains a large amount of floating contaminants that do not have a large density difference with water, which is the medium. This foreign matter includes excrement, highly associative fibrous foreign matter contained in toilet paper, highly viscous detergents, and dissolved components of soap. It is a substance with extremely poor fluidity in a narrow passage such as a fluid passage channel. If the pump is operated under such an environment, the cooling fluid flow path and the bearing gap of the sliding bearing used in the intermediate bearing installation portion 20 of the impeller shaft 19 that rotates the impeller 18 for carrying out the fluid become turbid. Solid foreign matter and highly viscous associative substances such as particles and fibrous substances that tend to stay in the air accumulate and accumulate, and after the pump runs, the solid foreign matter and highly viscous associative substances that remain in the intermediate bearing dry and solidify and flow through the bearing gap. In the area where the water level inside the pump rises, solid foreign matter remaining in the bearing gap causes abnormal heat generation and slippage. The possibility of bearing sticking cannot be ruled out. In addition, if a conventional sliding bearing is used for the impeller holding part 21 at the bottom of the pump, which is always exposed to a cargo liquid containing a high concentration of solid foreign matter and highly viscous associative substances, abnormal heat generation will occur if a conventional sliding bearing is used under lubrication conditions that include a high concentration of foreign matter. Although it cannot be ruled out that the sliding bearing may stick, the bearing sliding mechanism of the present invention prevents solid particles, fibrous substances, and other solid foreign substances and high-viscosity associations contained in the cargo liquid. It is possible to quickly discharge substances from the sliding parts of the sliding bearing, supply sufficient lubricating fluid to the sliding parts, and secure the ability to sufficiently cool the heat generated by sliding that induces sticking in the bearing. did.

In particular, securing the range of response to cargo liquids with various properties, which is required for highly public pumps, is important for pumps that are forced to operate in which the properties of cargo liquids fluctuate over a wide range, especially when operating highly viscous cargo liquids. In addition, it is possible to provide a great effect in suppressing the loss of sliding bearing function caused by the sticking phenomenon due to abnormal heat generation of the sliding bearing portion during operation in a turbid liquid containing a large amount of foreign matter.

Other applications include pumps, stirrers, electric motors, and screws that handle liquids whose viscosity changes greatly depending on the ambient temperature, clayey liquids with a high concentration of very fine particles, and gel-like liquids. It has applicability as a sliding bearing for

REFERENCE SIGNS LIST 1 rotating shaft 2 rotating shaft side sliding member 3 fixed shaft side sliding member 4 cooling fluid passage groove 5 fixed shaft side split type sliding member 6 arrangement gap of split type sliding member 7 rotating shaft side sliding member sliding Angle of the cooling fluid channel of the present invention arranged spirally on the surface with respect to the cross section of the rotating shaft 8 Cooling fluid channel of the present invention 9 Fixed shaft side sliding member 10 Rotating shaft side sliding member 11 Rotating direction 12 Sliding surface 13 of rotating shaft side sliding member Direction in which foreign matter remaining in the fluid passage groove is scooped up by shaft rotation 14 Fluid discharge impeller 15 Impeller shaft 16 Pump casing 17 Liquid-lubricated slide bearing 18 Fluid discharge Impeller 19 Impeller shaft 20 Intermediate bearing installation part 21 Impeller holding part 22 Electric motor 23 Torque detector 24 Rotating shaft 25 Upper bearing 26 Lower test bearing 27 Test rotating shaft sliding member 28 Disc for generating eccentric load 29 Eccentric weight 30 Test bearing installation box 31 Restraining hydraulic pressure 32 Right load cell 33 Left load cell 34 Displacement gauge 35 Vibration accelerometer 36 Upper thermometer 37 Lower thermometer 38 Lubricating medium supply line

Claims (1)

A sliding mechanism comprising a rotating shaft-side sliding member fitted and fixed to a rotating shaft, and a fixed shaft-side sliding member fitted to the outer periphery of the rotating shaft-side sliding member so as to be rotatably slidable. A bearing sliding mechanism, wherein a cooling fluid passage through which a cooling fluid flows is formed only on an outer peripheral surface of said rotating shaft side sliding member, and said cooling fluid passage is formed in a spiral shape. .

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