JP2006138353A - Slide bearing and rotary electric machine including slide bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent damage of a low-hardness metal layer by reducing thermal stress generated in a bearing body during the operation of a rotary electric machine. <P>SOLUTION: In this slide bearing, the low-hardness metal layer 2 is formed on the inner peripheral surface of a back plate 1, and an eccentricity increasing groove 4 is provided on the inner peripheral surface of the low-hardness metal layer 2. An axial piercing clearance 7 is provided in the boundary part between the low-hardness metal layer 2 and the back plate 1 corresponding to the circumferential position of the low-hardness metal layer 2 which becomes high temperatures, and a hole for guiding some of lubricating oil flowing through the eccentricity increasing groove 4 to the interior of the clearance 7 is provided between the bottom of the eccentricity increasing groove 4 and the clearance 7. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sliding bearing capable of reducing the thermal stress of a bearing body generated during operation of the rotating electrical machine, and a rotating electrical machine including the sliding bearing.

  In general, a sliding bearing is used as a bearing of a rotating electrical machine such as a turbine, a generator, or an electric motor.

  14A and 14B show the structure of a conventional plain bearing, wherein FIG. 14A is a radial sectional view and FIG. 14B is an axial sectional view.

  As shown in FIG. 14, a low hardness metal layer 2 is formed on the inner peripheral surface of the backing metal 1 to constitute a bearing body. In this bearing body, the reason why the low-hardness metal layer 2 is formed is that if foreign matter is mixed in the bearing lubricant during operation of the rotating electrical machine, the bearing surface that is easy to repair is deformed, This is to prevent damage to the surface of the rotating shaft 3.

  Here, as the material of the back metal 1, for example, structural steel such as SS400 is used, and as the material of the low hardness metal layer 2, for example, white metal or the like is used.

  In the sliding bearing, the rotating shaft 3 is decentered downward due to its own weight during operation of the rotating electrical machine, and lubricating oil is caught between the rotating shaft 3 and the low-hardness metal layer 2, and an oil film pressure is generated due to the wedge film effect. Thus, the load on the rotary shaft 3 is supported.

  Some of the plain bearings are provided with a groove (eccentricity increasing groove) 4 extending in the circumferential direction on the surface of the lower hardness metal layer 2 in the lower half. The reason for providing the groove 4 is to increase the eccentric amount of the rotating shaft 3 and improve the vibration stability of the shaft system.

  Of the surface of the low-hardness metal layer 2, the portion that actually contributes to the load support of the rotating shaft 3 excluding the groove 4 is called a bearing sliding surface.

  The bearing having such an eccentricity increasing groove 4 has two bearing sliding surfaces 5 which are divided in the axial direction by the groove 4 as shown in FIG.

  By the way, the thickness of the bearing oil film 6 generated between the rotating shaft 3 and the low hardness metal layer 2 is very thin compared to the inner diameter of the bearing body, and the rotating shaft 3 rotates at a high speed of 50 rps or 60 rps. Therefore, a large bearing loss occurs in the bearing oil film 6. The amount of heat generated by this bearing loss is not only removed by the lubricating oil but also spent on the temperature rise of the bearing structure.

  FIG. 15 is a diagram illustrating an example of the temperature distribution in the circumferential direction and the radial direction of the bearing body during rated operation of the rotating electrical machine. As apparent from this temperature distribution, the bearing loss becomes maximum at the minimum position of the oil film thickness. Therefore, the low-hardness metal layer 2 is heated by the high-temperature lubricating oil that has passed the minimum position of the oil film thickness, and the surface temperature is equal to the oil film thickness. It turns out that it becomes the highest on the downstream side slightly after the minimum position.

  In the example of FIG. 15, the range from the rotation downstream side 25 ° to the rotation upstream side 10 ° is the high temperature region with reference to the minimum oil film thickness position. Further, in the radial direction, when H is the difference between the inner peripheral radius and the outer peripheral radius of the bearing body, the range of H / 4 from the surface of the low hardness metal layer 2 is a high temperature region.

  FIG. 16 is a diagram illustrating an example of the temperature distribution in the circumferential direction and the axial direction of the bearing body during rated operation of the rotating electrical machine. This is a temperature distribution of a plain bearing having an eccentricity increasing groove 4 at the axial center of the bearing body, and has two bearing sliding surfaces 5 with the groove 4 interposed therebetween.

  As apparent from this temperature distribution, when the axial length of each bearing sliding surface 5 is L, the temperature is highest at the center of each bearing sliding surface 5, and the center of each bearing sliding surface 5 is used as a reference. It can be seen that the range of ± L / 4 in the axial direction is a high temperature region.

  Thus, if the bearing body becomes too hot during operation of the rotating electrical machine, problems such as a decrease in load carrying capacity and damage to the low-hardness metal layer (metal) occur.

Incidentally, as means for reducing the bearing temperature, various proposals have been made such as discharging high-temperature lubricating oil before the oil supply hole and reducing the temperature of the oil film (for example, Patent Document 1), and all of them can be expected sufficiently. Is not obtained.
JP 2002-122143 A

  As described above, in the conventional plain bearing, when the temperature of the bearing structure becomes high during rated operation of the rotating electrical machine, and the back metal and the low-hardness metal layer constituting the bearing body are thermally expanded, the difference between the linear expansion coefficients of the two is different. Thermal stress is generated. That is, since the coefficient of linear expansion of the low-hardness metal layer is larger, it tends to expand more than the back metal, but since they are in close contact with each other at the interface, compressive stress acts on the low-hardness metal layer. If the compressive stress acting on the low-hardness metal layer is exceeded, plastic strain is generated in the low-hardness metal layer by one start and stop. In particular, in a plant that frequently starts and stops, the plastic strain gradually increases, which may lead to problems such as damage to the low-hardness metal layer.

  In order to solve the above-described problems, the present invention includes a slide bearing and a slide bearing that can reduce thermal stress generated in the bearing body during operation of the rotating electrical machine and prevent damage to the low-hardness metal layer. An object is to provide a rotating electrical machine.

  In order to achieve the above object, the present invention constitutes a sliding bearing and a rotating electrical machine including the sliding bearing by the following means.

(1) The present invention provides a sliding bearing having a structure in which a low-hardness metal layer is formed on the inner peripheral surface of a back metal, and a boundary between the low-hardness metal layer and the back metal corresponding to the circumferential position of the low-hardness metal layer that becomes high temperature. A gap penetrating in the axial direction is provided in the portion.

(2) The present invention provides a slide bearing having a low hardness metal layer formed on the inner peripheral surface of a back metal and having an eccentricity increasing groove on the inner peripheral surface of the low hardness metal layer. A gap passing through in the axial direction is provided at the boundary between the low hardness metal layer and the back metal corresponding to the circumferential position, and between the bottom of the eccentricity increasing groove and the gap, A hole for guiding a part of the lubricating oil flowing through the gap into the gap is provided.

(3) According to the present invention, in a slide bearing having a structure in which a low-hardness metal layer is formed on the inner peripheral surface of the back metal, a heat radiating hole penetrating in the axial direction is provided in the circumferential direction and radial position of the back metal that becomes high temperature.

(4) The present invention provides a sliding bearing having a structure in which a low-hardness metal layer is formed on the inner peripheral surface of a back metal, and the low-hardness metal layer from the back metal outer peripheral side to the circumferential and radial positions of the low-hardness metal layer that becomes high temperature Lubricating oil injection holes for injecting low temperature lubricating oil through the surface are provided.

(5) The present invention provides a slide bearing having a low hardness metal layer formed on the inner peripheral surface of a back metal and having an eccentricity increasing groove on the inner peripheral surface of the low hardness metal layer. Lubricating oil injection holes for injecting lubricating oil from the outer peripheral side of the back metal to the surface of the low hardness metal layer are provided in the circumferential direction and the radial position, and the circumferential direction and radial direction of the low hardness metal layer provided with the lubricating oil injection holes The position in the circumferential direction is a part of the range from the rotation downstream side 25 ° to the rotation upstream side 10 ° on the basis of the minimum oil film thickness position, and in the axial direction, each bearing is divided by an eccentricity increasing groove. This is a part of a range of ± L / 3 (L is the axial length of each bearing sliding surface) with respect to the center of the sliding surface.

(6) The present invention provides the minimum position of the oil film thickness in the circumferential direction in a slide bearing in which a low-hardness metal layer is formed on the inner peripheral surface of the back metal and the groove for increasing the eccentricity is formed on the inner peripheral surface of the low-hardness metal layer. Is determined within a range of ± 10 ° with respect to the angle, and an eccentricity increasing groove is provided on the upstream side of the rotation from the branching point, and two eccentricity increasing grooves are provided on the downstream side of the rotation from the branching point. These two grooves for increasing the amount of eccentricity are ± L / 3 in the axial direction with respect to the center of each bearing sliding surface on the upstream side of the rotation from the branching point (L is the bearing sliding surface). Branched within the range of (Axial length).

(7) The present invention provides the minimum position of the oil film thickness in the circumferential direction in the slide bearing in which the low hardness metal layer is formed on the inner peripheral surface of the back metal and the groove for increasing the amount of eccentricity is formed on the inner peripheral surface of the low hardness metal layer. A branch point is defined within a range of ± 10 ° with reference to the angle, a groove for increasing the eccentric amount is provided on the upstream side of the branch point, and two eccentric amounts having an axial component on the downstream side of the rotation from the branch point. The increasing groove is branched and the depth of the two eccentricity increasing grooves is made shallower toward the downstream side of the rotation, and the bottom surface of the groove is the bearing sliding surface before reaching the bearing axial end. It is processed so that there is no groove to match.

(8) This invention comprises the rotary electric machine with which the rotor was axially supported by the slide bearing of the invention in any one of said (1)-(7).

  ADVANTAGE OF THE INVENTION According to this invention, the thermal stress which generate | occur | produces in a bearing main body at the time of a driving | running | working of a rotary electric machine can be reduced, and damage to a low-hardness metal layer can be prevented.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
1A and 1B show a first embodiment of a plain bearing according to the present invention, in which FIG. 1A is a radial sectional view and FIG. 1B is an axial sectional view. Note that the same parts as those in FIG. 14 are denoted by the same reference numerals and description thereof is omitted, and different parts are described here.

  In the first embodiment, as shown in FIGS. 1A and 1B, the boundary between the backing metal 1 and the low-hardness metal layer 2 in the circumferential direction of the bearing body and at a position where the low-hardness metal layer 2 is at a high temperature. A gap 7 penetrating in the axial direction is provided in the portion, and contact between the two in this portion is eliminated.

  In this case, the circumferential position when the gap 7 is provided at the boundary portion between the back metal 1 and the low hardness metal layer 2 is rotated upstream from the rotation downstream side 25 ° with reference to the minimum oil film thickness position as shown in FIG. A part of the range up to 10 ° on the side is selected.

  With such a configuration, the boundary portion between the back metal 1 and the low hardness metal layer 2 at a position where the low hardness metal layer 2 is at a high temperature is in a non-contact state by the gap 7 penetrating in the axial direction. The action of restraining the thermal expansion of the metal is reduced, and the thermal stress of the low hardness metal layer 2 can be reduced.

  Moreover, since a part of the range where the thermal stress is expected to be maximized is selected as the circumferential position where the gap 7 is provided, the generation of a large thermal stress can be prevented.

(Second Embodiment)
3A and 3B show a second embodiment of the slide bearing according to the present invention, wherein FIG. 3A is a radial sectional view, FIG. 3B is an axial sectional view, and the same parts as those in FIG. The description is omitted, and different parts are described here.

  In the second embodiment, as shown in FIGS. 3A and 3B, a gap 7 provided at the boundary between the back metal 1 and the low-hardness metal layer 2 is provided as a cooling fluid passage as in the first embodiment. The cooling fluid 8 is made to flow in the axial direction in the gap by a cooling fluid supply means (not shown).

  In this way, in addition to the same effects as the first embodiment, the temperature of the low-hardness metal layer 2 and the back metal 1 around the gap 7 can be reduced. As a result, the gap 7 Thermal stress at the periphery can be reduced.

(Third embodiment)
4A and 4B show a third embodiment of the slide bearing according to the present invention, wherein FIG. 4A is a radial sectional view, FIG. 4B is an axial sectional view, and the same parts as those in FIG. The description is omitted, and different parts are described here.

  In the fourth embodiment, a low-hardness metal layer 2 is formed on the inner peripheral surface of the back metal 1 as shown in FIGS. 4A and 4B, and the low-hardness metal layer 2 has a circumferential direction at the center in the axial direction. In the bearing body having the groove 4 for increasing the eccentric amount extending in the same manner as in the first embodiment, a gap 7 penetrating in the axial direction is provided at the boundary portion between the back metal 1 and the low hardness metal layer 2 and for increasing the eccentric amount. A hole 4 a is formed through the bottom surface of the groove 4 into the gap 7, and a part of the lubricating oil flowing in the eccentricity increasing groove 4 is guided into the gap 7 through the hole 4 a.

  With such a configuration, in addition to obtaining the same operational effects as the first embodiment, a part of the lubricating oil flowing in the eccentricity increasing groove 4 flows into the gap 7 through the hole 4a, Since it flows in the gap 7 in the axial direction and is discharged from the side surface of the bearing body, the temperature around the gap 7 can be reduced, and the thermal stress can be reduced. In this case, since the lubricating oil having a relatively low temperature flows in the eccentricity increasing groove 4, the effect of reducing the ambient temperature of the gap 7 is remarkable.

  Further, in this embodiment, since the lubricating oil flowing in the eccentricity increasing groove 4 is introduced into the gap 7, preparation for supplying the cooling fluid as in the second embodiment, and cooling No fluid supply device is required.

(Fourth embodiment)
5A and 5B show a fourth embodiment of the slide bearing according to the present invention, wherein FIG. 5A is a radial cross-sectional view, and FIG. 5B is an axial cross-sectional view. The description is omitted, and different parts are described here.

  In the fourth embodiment, as shown in FIGS. 5 (a) and 5 (b), in the circumferential direction and the radial direction of the bearing body, the heat radiating hole 9 that penetrates the back metal 1 in the axial direction at a position where the back metal 1 becomes high temperature. Is provided. The reason why the heat radiating hole 9 is provided in the back metal 1 is that the reliability in strength is higher than that provided in the low hardness metal layer 2.

  Here, when the heat sink hole 9 penetrating in the axial direction is provided in the back metal 1, as shown in FIG. 6, in the circumferential direction, the rotation downstream side is 25 ° to the rotation upstream side 10 ° with reference to the minimum position of the oil film thickness. In the radial direction, the boundary between the low-hardness metal layer 2 and the back metal 1 is set as a lower limit, and the position H / 2 from the surface of the low-hardness metal layer 2 is set as an upper limit. However, H is the difference between the inner peripheral radius and the outer peripheral radius of the bearing body.

  Thus, in providing the heat radiating hole 9, the range is prescribed | regulated about the circumferential direction and radial direction of a bearing main body, respectively for the following grounds.

  As is clear from the temperature distribution diagram in the circumferential direction and the radial direction of the bearing body during rated operation of the rotating electrical machine shown in FIG. 15, the region where the back metal 1 becomes high in the circumferential direction is based on the minimum position of the oil film thickness. The rotation downstream side is 25 ° to the rotation upstream side 10 °. Moreover, the area | region where the back metal 1 becomes high temperature regarding a radial direction is the range from the low-hardness metal layer 2 to H / 4. Among these, in the radial direction, the upper limit of the installation range was increased in consideration of the possibility of the high temperature region moving due to changes in operating conditions and bearing materials. In that case, it is assumed that in the position away from the surface of the low-hardness metal layer 2 by H / 2 or more in FIG. 15, it enters a two-step low temperature region from the high temperature region, and no further heat dissipation effect can be expected at the outer periphery. Thus, the position of H / 2 from the surface of the low hardness metal layer 2 is the upper limit in the radial direction.

  With such a configuration, the temperature of the back metal 1 is lowered due to heat radiation from the heat radiation hole 9, and the temperature of the low-hardness metal layer 2 in contact with the back metal 1 is also lowered. As a result, the thermal stress of the low-hardness metal layer 2 is reduced. Can do.

(Fifth embodiment)
7A and 7B show a fifth embodiment of the plain bearing according to the present invention. FIG. 7A is a radial sectional view, FIG. 7B is an axial sectional view, and the same parts as those in FIG. The description is omitted, and different parts are described here.

  In the fifth embodiment, a low-hardness metal layer 2 is formed on the inner peripheral surface of the back metal 1 as shown in FIGS. 7A and 7B, and the low-hardness metal layer 2 has a circumferential direction at the center in the axial direction. In the slide bearing having the eccentricity increasing groove 4 extending to the surface, the surface of the low hardness metal layer 2 (inner side) from the outer peripheral side of the back metal 1 at a position where the low hardness metal layer 2 becomes high in the circumferential direction and the axial direction of the bearing body. A plurality (two in the figure) of lubricating oil injection holes 10 that are removed to the (circumferential surface) side are provided so as to be appropriately separated in the axial direction, and low temperature lubricating oil is injected from these holes during operation of the rotating electrical machine. It is.

  Here, in the case of providing the lubricating oil injection hole 10 that extends from the outer peripheral side of the back metal 1 to the surface of the low hardness metal layer 2, the installation range of the lubricating oil injection hole for obtaining a large thermal stress reduction effect will be described with reference to FIG. .

  With respect to the circumferential direction of the bearing body, a hole is provided in a part of the range from the rotation downstream side 25 ° to the rotation upstream side 10 ° with reference to the minimum oil film thickness position, and the axial direction is increased by the eccentricity increasing groove 4. A hole is provided in a part of a range of ± L / 3 with reference to the center of each divided bearing sliding surface 5. However, L is the axial length of each bearing sliding surface 5.

  The basis for this is described below.

  As is clear from the temperature distribution diagram in the circumferential direction and the radial direction of the bearing body during rated operation of the rotating electrical machine shown in FIG. 15, the region where the back metal 1 becomes high in the circumferential direction is based on the minimum position of the oil film thickness. The rotation downstream side is 25 ° to the rotation upstream side 10 °. Among these, in the axial direction, the installation range is expanded to ± L / 3 in consideration of the possibility of the high temperature region moving due to changes in operating conditions and bearing materials.

  With this configuration, when low temperature lubricating oil is injected to the inner peripheral surface side of the low hardness metal layer 2 through the lubricating oil injection hole 10 by a lubricating oil supply means (not shown) during operation of the rotating electrical machine, this low temperature lubrication is performed. Since the oil is mixed with the lubricating oil in the bearing oil film 6, the temperature of the bearing oil film 6 is lowered and the temperature of the low hardness metal layer 2 is also lowered. As a result, the thermal stress of the low hardness metal layer 2 can be reduced.

  In the above-described embodiment, the slide bearing having the eccentricity increasing groove 4 has been described. However, the present invention can be applied to a sliding bearing without the eccentricity increasing groove 4 in the same manner as described above.

  FIG. 9 shows a case where a lubricating oil injection hole 10 extending from the outer peripheral side of the back metal 1 to the surface of the low-hardness metal layer 2 is provided for a slide bearing without an eccentricity increasing groove, in order to obtain a large thermal stress reduction effect. The installation range of the lubricating oil injection hole is shown.

In a plain bearing without an eccentricity increasing groove, as shown in FIG. 9, a hole is formed in a part of a range of 25 ° from the downstream side of the rotation to 10 ° of the upstream side in the circumferential direction of the bearing body with reference to the minimum position of the oil film thickness. In the axial direction, a hole is provided in a part of a range of ± L / 3 with reference to the center of the bearing sliding surface 5. However, L is the axial length of the bearing sliding surface 5. The grounds for determining such an installation range are the same as in the case of the slide bearing having the eccentricity increasing groove (sixth embodiment).
10A and 10B show a sixth embodiment of the slide bearing according to the present invention, in which FIG. 7A is a radial sectional view, FIG. 10B is an axial sectional view, and FIG. The same reference numerals are given to the same parts and the description thereof is omitted, and different parts will be described here.

  In the sixth embodiment, as shown in FIGS. 10A to 10C, the axial direction in which the outlet of the hole is closest to the surface of the low-hardness metal layer 2 from the axial center position on the outer peripheral side of the back metal 1. Two lubricating oil injection holes 10 are provided so as to incline toward the end.

  With such a configuration, the lubricating oil injected from the surface of the low hardness metal layer 2 through the inclined lubricating oil injection hole 10 has a velocity component in the axial direction, and therefore flows from the upstream side of the rotation of the lubricating oil injection hole. A part of the hot lubricating oil coming in is entrained and discharged from the axial end.

  Therefore, compared to the case where the injection hole 10 is not tilted in the axial direction, the amount of high-temperature lubricating oil flowing on the downstream side of the rotation is reduced, so that the temperature of the low hardness metal layer 2 can be further reduced. The thermal stress generated accordingly can be reduced.

(Seventh embodiment)
FIG. 11 is a radial sectional view showing a seventh embodiment of the plain bearing according to the present invention. The same parts as those in FIG.

  In the seventh embodiment, as shown in FIG. 11, a low hardness metal layer 2 is formed on the inner peripheral surface of the back metal 1, and a slip having an eccentricity increasing groove 4 in the axial center of the low hardness metal layer 2 is provided. In the bearing, a branch point 11 is defined within a range of ± 10 ° with respect to the minimum position of the oil film thickness in the circumferential direction of the bearing body, and a conventional eccentricity increasing groove 4 is provided on the upstream side of the branch point 11 from the rotation. The eccentricity increasing groove 4 is bifurcated in two different axial directions at the branch point 11, and on the downstream side of the rotation from the branch point 11, the shaft is centered on the center of each bearing sliding surface from the branch point 11 to the upstream side of rotation. Each branched groove 12 is provided in the range of ± L / 3 in the direction.

  Here, the circumferential installation range of the branch point and the axial installation range of each groove on the downstream side of the branch point are shown in FIG.

  The grounds for defining such a range will be described below.

  If there is a branch point on the rotation downstream side of the high-temperature region of the low-hardness metal layer, the low-temperature lubricating oil does not pass through the high-temperature region, so that the temperature reduction effect cannot be obtained. As described in the background art section, the surface temperature of the low-hardness metal layer is highest on the downstream side from the minimum oil film thickness position. It is desirable to install.

  On the other hand, if it branches too far upstream, the pressure of the bearing oil film will drop, affecting the amount of eccentricity of the rotating shaft. Theoretically, in order to prevent the oil film pressure from being generated downstream from the minimum oil film thickness position and not to affect the amount of eccentricity, it is desirable to install the branch point downstream from the minimum oil film thickness position.

  From the above, the minimum oil film thickness position is set as a target for branch point installation, and a range of ± 10 ° is set as a branch point installation range as a design margin. Further, the axial position of each groove on the downstream side of the rotation from the branch point is determined on the same basis as in the fifth embodiment described above.

  With such a configuration, since a relatively low temperature lubricating oil flows in the eccentricity increasing groove 4, the surface temperature of the low hardness metal layer 2 is reduced by guiding the lubricating oil in the groove to a high temperature region. As a result, the thermal stress of the low hardness metal layer 2 can be reduced.

(Eighth embodiment)
FIG. 13 is a radial cross-sectional view showing an eighth embodiment of the plain bearing according to the present invention, and the same parts as those in FIG.

  In the eighth embodiment, as shown in FIG. 13, a low hardness metal layer 2 is formed on the inner peripheral surface of the back metal 1, and a slide having an eccentricity increasing groove 4 in the axial center of the low hardness metal layer 2 is provided. In the bearing, a branch point 11 is defined within a range of ± 10 ° with respect to the minimum position of the oil film thickness in the circumferential direction of the bearing body, and an eccentricity increasing groove 4 is provided on the upstream side of the branch point 11 as usual, At the branch point 11, the eccentricity increasing groove 4 is branched into two grooves 12 having an axial component, and the depth of each groove 12 is made shallower on the downstream side of the branch point to rotate the shaft of the bearing body. Before reaching the end in the direction, machining is performed so that the bottom surface of the groove 12 coincides with the bearing sliding surface 5 and the groove is eliminated.

  With such a configuration, the relatively low-temperature lubricating oil flowing in the eccentricity increasing groove 4 flows out to the bearing sliding surface 5 with an axial speed component on the downstream side of the rotation from the branch point. . Part of the high-temperature lubricating oil that has flowed through the bearing sliding surface 5 is caught in the lubricating oil that has flowed out of the groove 12 and discharged from the end in the axial direction.

  Accordingly, since the amount of high-temperature lubricating oil flowing downstream of the rotation decreases, the temperature of the low-hardness metal layer 2 and the back metal 1 can be reduced, and as a result, the thermal stress acting on the low-hardness metal layer 2 can be reduced. Can do.

  The sliding bearing according to any of the first to eighth embodiments described above is used as a bearing that supports the rotor of a rotating electrical machine such as a turbine, a generator, or an electric motor, thereby rotating in a stable state. The electric machine can be operated.

BRIEF DESCRIPTION OF THE DRAWINGS The 1st Embodiment of the slide bearing by this invention is shown, (a) is radial direction sectional drawing, (b) is axial direction sectional drawing. The figure which shows the installation range of the clearance gap for obtaining the big thermal stress reduction effect in the same embodiment. The 2nd Embodiment of the slide bearing by this invention is shown, (a) is radial direction sectional drawing, (b) is axial direction sectional drawing. The 3rd Embodiment of the slide bearing by this invention is shown, (a) is radial direction sectional drawing, (b) is axial direction sectional drawing. The 4th Embodiment of the slide bearing by this invention is shown, (a) is radial direction sectional drawing, (b) is axial direction sectional drawing. The figure which shows the installation range of the heat radiating hole for obtaining the big thermal stress reduction effect in the same embodiment. The 5th Embodiment of the slide bearing by this invention is shown, (a) is radial direction sectional drawing, (b) is axial direction sectional drawing. The figure which shows the installation range of the lubricating oil injection hole for obtaining the big thermal stress reduction effect in the same embodiment. The figure which shows the installation range of the lubricating oil injection hole for obtaining the big thermal stress reduction effect similarly in the slide bearing which does not have the groove | channel for eccentric amount increase. The 6th Embodiment of the slide bearing by this invention is shown, (a) is radial direction sectional drawing, (b) is axial direction sectional drawing, (c) is an expanded view of a bearing sliding surface. The radial direction sectional view showing a 7th embodiment of the slide bearing by the present invention. The figure which shows the axial direction installation range of each groove | channel of the rotation downstream side from a branch point and the circumferential direction installation range of a branch point in the embodiment. A radial direction sectional view showing an 8th embodiment of a slide bearing by the present invention. The structural example of the conventional slide bearing is shown, (a) is radial direction sectional drawing, (b) is an axial direction sectional view. The figure which shows an example of the temperature distribution of the circumferential direction and radial direction at the time of the rated operation of a rotary electric machine in the conventional slide bearing. The figure which shows an example of the temperature distribution of the circumferential direction at the time of rated operation of a rotary electric machine, and an axial direction in the conventional slide bearing.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Back metal, 2 ... Low-hardness metal layer, 3 ... Rotating shaft, 4 ... Eccentricity increasing groove, 4a ... Hole, 5 ... Bearing sliding surface, 6 ... Bearing oil film, 7 ... Clearance, 8 ... Cooling fluid, 9 ... radiation hole, 10 ... lubricating oil injection hole, 11 ... branch point, 12 ... groove after branching.

Claims (13)

  In a plain bearing with a structure in which a low hardness metal layer is formed on the inner peripheral surface of the back metal, it penetrates in the axial direction at the boundary between the low hardness metal layer and the back metal corresponding to the circumferential position of the low hardness metal layer at high temperature. A plain bearing characterized by providing a gap.   2. The slide bearing according to claim 1, wherein a circumferential position of the low-hardness metal layer at a high temperature is a part of a range from a rotation downstream side of 25 ° to a rotation upstream side of 10 ° on the basis of a minimum oil film thickness position. A plain bearing characterized by that.   3. The plain bearing according to claim 1, wherein the clearance provided at the boundary between the low-hardness metal layer and the back metal is used as a cooling fluid passage through which the cooling fluid flows in the axial direction. And plain bearings.   In a slide bearing having a low-hardness metal layer formed on the inner peripheral surface of the back metal and having an eccentricity increasing groove on the inner peripheral surface of the low-hardness metal layer, a low hardness corresponding to the circumferential position of the low-hardness metal layer at a high temperature A part of the lubricating oil flowing in the eccentricity increasing groove is provided between the bottom surface of the eccentricity increasing groove and the gap between the gap extending in the axial direction at a boundary portion between the hard metal layer and the back metal. A plain bearing provided with a hole for guiding the inside of the gap.   A slide bearing having a structure in which a low-hardness metal layer is formed on the inner peripheral surface of a back metal, wherein a heat radiating hole penetrating in the axial direction is provided in a circumferential direction and a radial position of the back metal at a high temperature.   6. The sliding bearing according to claim 5, wherein the circumferential direction and radial direction position of the back metal that becomes high temperature is one in a range from the rotational downstream side of 25 ° to the rotational upstream side of 10 ° with respect to the minimum position of the oil film thickness in the circumferential direction. In the radial direction, the lower limit is the boundary between the low-hardness metal layer and the back metal, and the upper limit is a position that is H / 2 away from the surface of the low-hardness metal layer (H is the difference between the inner and outer radiuses of the slide bearing). A plain bearing that is part of the range.   In a plain bearing with a low-hardness metal layer formed on the inner peripheral surface of the back metal, the low-hardness metal layer has a low temperature through the back metal outer peripheral side to the surface of the low-hardness metal layer in the circumferential direction and radial position of the low-hardness metal layer. A plain bearing provided with a lubricating oil injection hole for injecting lubricating oil.   8. The sliding bearing according to claim 7, wherein the circumferential direction and radial position of the low hardness metal layer in which the lubricating oil injection hole is provided are from the rotational downstream side 25 ° to the rotational upstream side with respect to the minimum position of the oil film thickness in the circumferential direction. Part of the range of 10 ° and part of the range of ± L / 3 (L is the axial length of each bearing sliding surface) with respect to the center of the axial sliding surface in the axial direction A plain bearing characterized by   In a slide bearing having a low-hardness metal layer formed on the inner peripheral surface of the back metal and having a groove for increasing the amount of eccentricity on the inner peripheral surface of the low-hardness metal layer, the low-hardness metal layer at high temperatures is positioned in the circumferential direction and radial position. Lubricating oil injection holes for injecting lubricating oil from the outer peripheral side of the back metal to the surface of the low hardness metal layer are provided, and the circumferential direction and radial position of the low hardness metal layer provided with the lubricating oil injection holes are as follows. A part of the range from 25 ° downstream to 10 ° upstream from the minimum position of the oil film thickness as a reference. In the axial direction, the center of each bearing sliding surface divided by the eccentricity increasing groove is the reference. As a part of a range of ± L / 3 (L is an axial length of each bearing sliding surface).   The sliding bearing according to any one of claims 7 to 9, wherein the lubricating oil injection hole is inclined in the direction of the bearing axial end where the outlet on the surface side of the low hardness metal layer is closest to the outlet of the injection hole. A plain bearing characterized in that it is provided.   In a slide bearing having a low-hardness metal layer formed on the inner peripheral surface of the back metal and having a groove for increasing the amount of eccentricity on the inner peripheral surface of the low-hardness metal layer, it is ± 10 ° with respect to the minimum position of the oil film thickness in the circumferential direction. A branch point is defined within the range, and an eccentric amount increasing groove is provided on the upstream side of the branch from the branch point, and two eccentric amount increasing grooves are provided on the downstream side of the branch point to be branched in the axial direction. These two grooves for increasing the amount of eccentricity are in the range of ± L / 3 (L is the axial length of each bearing sliding surface) in the axial direction with reference to the center of each bearing sliding surface on the upstream side from the branch point. A plain bearing that is branched into the inside.   In a slide bearing having a low-hardness metal layer formed on the inner peripheral surface of the back metal and having a groove for increasing the amount of eccentricity on the inner peripheral surface of the low-hardness metal layer, it is ± 10 ° with respect to the minimum position of the oil film thickness in the circumferential direction. A branch point is set within the range, and an eccentric amount increasing groove is provided on the upstream side of the branch point from the branch point, and two eccentric amount increasing grooves having an axial component are branched from the branch point on the downstream side of the rotation. The two grooves for increasing the amount of eccentricity are made shallower toward the downstream side of the rotation, and the bottom surface of the groove coincides with the bearing sliding surface before reaching the end portion in the bearing axial direction, and the groove disappears. A plain bearing characterized by being processed as described above.   A rotating electrical machine in which a rotor is pivotally supported by the slide bearing according to any one of claims 1 to 12.

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