JP2001173644A - Journal bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conduct electric insulation from a shaft in a jounal bearing. SOLUTION: This journal bearing consists of a lower half-split bearing 12 receiving large radial load formed from a bearing using a resin sliding material which has low friction and is heat-resistant, though expensive, and an upper half-split bearing 11 receiving little radial load formed by coating a bearing alloy 17 of an inexpensive ordinary bearing with a resin layer 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a journal bearing having at least two divided slide bearings, and more particularly to a journal bearing for supporting a shaft on which a radial load acts substantially in one direction.

[0002]

In a power generator of a hydroelectric power plant, a slide bearing using, for example, white metal as a sliding material has been widely used as a journal bearing for supporting a rotor shaft thereof. However, in the generator, the rotor is apt to be charged, and when the potential difference between the rotor shaft and the journal bearing supporting the rotor is increased due to the charging, the oil film between the rotor shaft and the journal bearing is broken and the rotor shaft is discharged. Sparks fly to the journal bearing (current flows), causing a problem that the surface of the white metal is electrolytically eroded.

[0003] In order to prevent the journal bearing from being damaged by such electrolytic corrosion, it is necessary to insulate the middle of the path through which current flows. For this reason, in a conventional generator,
An insulating sheet was laid under the casing to which the journal bearing was attached to electrically insulate it from the installation surface, so that current did not flow from the rotor shaft to the journal bearing. However, when this insulating method is adopted, it is not sufficient to merely lay an insulating sheet between the housing and the installation surface, and in fact, the bolts for fixing the housing to the installation surface and the housing are also electrically insulated. In addition to the necessity, many other insulating parts are required, and the installation work of the housing is troublesome, and much work is required.

In order to prevent a current from flowing from the rotor shaft to the journal bearing without causing such a problem, the journal bearing is constituted by a bearing using a resin material as a sliding material (hereinafter referred to as a resin bearing). It has been considered that the sliding member itself electrically insulates the rotor shaft. However, since the resin bearing alone has insufficient strength, it is necessary to strengthen the joint with a metal material. For example, it is necessary to sinter a sintered body as a bonding medium on a backing metal, and to impregnate the sintered body with a resin to form a resin layer on an upper layer of the sintered body. This raises the problem of becoming high.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a journal bearing capable of electrically insulating a shaft from a shaft while suppressing an increase in cost.

[0006]

SUMMARY OF THE INVENTION According to the present invention, of at least two split bearings constituting a journal bearing, a split bearing which receives a radial load in almost one direction acting on a shaft is mounted with a resin-based sliding member. And the remaining split bearing is constituted by a bearing having a metal bearing surface coated with a resin.

[0007] According to this configuration, the split bearing that receives the radial load acting on the shaft is formed by mounting a resin-based sliding member, and the other split bearing also has a resin coating on the surface that contacts the shaft. No current flows from the shaft to the plain bearing. In this way, the journal bearing itself can be electrically insulated from the shaft,
It is not necessary to adopt a method of laying an insulating sheet under the casing. In addition, among the plurality of split bearings, only the split bearing that receives a large radial load may be constituted by a bearing using a resin-based sliding material having a high manufacturing cost, and the other split bearings can be constituted by bearings that can be manufactured at low cost. Thus, the cost of the entire bearing can be kept low.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings, applying to a journal bearing for supporting a shaft of a rotor of a hydroelectric generator. FIG. 4 shows a bearing device 2 for supporting a rotor shaft 1 of a hydroelectric generator. The bearing device 2 receives a radial load and a thrust load acting on the rotor shaft 1 of the hydraulic power generator. The rotor shaft 1 is passed through the casing 3 of the bearing device 2 from side to side.

The casing 3 is composed of an upper case 4 and a lower case 5 which can be divided at a portion through which the rotor shaft 1 is inserted.
And 7 are integrally formed. A metal bearing housing 8 is fixed between the vertical walls 6 and 7. In addition, the lower case 5 of the casing 3 is used as an oil reservoir, and lubricating oil is stored therein.

A thrust bearing 9 and a journal bearing 10 are provided inside the bearing housing 8. The thrust bearing 9 receives a thrust load acting on the rotor shaft 1, and includes a pair of tilting pad bearings provided so as to sandwich a flange 1 a provided on the rotor shaft 1.

The journal bearing 10 includes a rotor shaft 1
As shown in FIG. 1, it is composed of upper and lower two half bearings (split bearings) 11 and 12, as shown in FIG. The radial load acting on the rotor shaft 1 of the generator is mainly the own weight of the rotor, and the radial load based on the own weight acts substantially downward and is received by the lower half bearing 12.

Of the upper and lower half bearings 11, 12, the lower half bearing 12 which receives most of the radial load is formed of a resin bearing. As shown in FIG. 2, the resin bearing is formed by joining a resin-based sliding member 15 to a steel backing 13 via a joint 14 by heat fusion. The joint body 14 is a porous body formed by sintering, for example, an iron-based or copper-based sintered metal powder on the back metal 13.
The resin-based sliding member 15 is made of, for example, polytetrafluoroethylene (hereinafter, referred to as PTFE), polyetheretherketone (hereinafter, referred to as PEEK), or the like, and is configured by impregnating and covering the combined body 14. .

The upper half bearing 11 which receives almost no radial load is formed by mounting a bearing alloy 17 such as white metal as a sliding material on a normal half bearing, that is, a back metal 16 made of steel plate. It is mainly composed of a half bearing, and a bearing alloy 17 is coated with a resin layer 18. Note that a cutout 11 a through which a ring 19 for supplying lubricating oil to the rotor shaft 1 is formed is formed in an upper portion of the upper half bearing 11.

As described above, according to the present embodiment, the upper half bearing 11 is electrically insulated from the bearing alloy 17 as a bearing surface and the rotor shaft 1 by the resin layer 18, and the lower half bearing 12 With respect to the above, the resin-based sliding member 15 itself electrically insulates the rotor from the rotor shaft 1. In this case, since the upper half bearing 11 hardly receives a radial load, even if the bearing alloy 17 is simply coated with the resin layer 18, it can be sufficiently used for a generator.

As described above, the expensive resin bearing is limited to the lower half bearing 12 to which a large radial load acts, and the upper half bearing 11 to which almost no radial load acts is a bearing alloy 1
Since the bearing 7 is inexpensive simply by coating the resin layer 18, the journal bearing 10 and the bearing device 2 as a whole can be provided at low cost.

The present invention is not limited to the embodiment described above and shown in the drawings, but can be modified or expanded as follows. The journal bearing 10 is not limited to the upper and lower two parts, but may be divided into three parts or more. In this case, the split bearing that receives a large radial load may be formed of a resin bearing. The upper half bearing 11 does not need to be provided with the bearing alloy 17 in particular, and may have a configuration in which a resin layer is coated on an inner peripheral surface of a back metal as a bearing surface. In addition, of the metal housing, the inner peripheral surface of the portion other than the mounting portion of the resin bearing is configured as a bearing surface for receiving the shaft, that is, the journal bearing is formed of a resin bearing and the housing excluding the mounting portion of the resin bearing. And an inner peripheral surface of the housing may be directly coated with a resin layer. Combined 14
May be a structure in which a mesh, an expanded metal, a punched metal, or the like is bonded to the back metal 13 in addition to being sintered porous. It is also possible to adopt a configuration in which the resin-based sliding member 15 is connected to the back metal 13 by the intrusion of the moving member 15.
It is not limited to journal bearings of hydropower generators.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention and is a front view of a journal bearing shown partially broken.

FIG. 2 is a sectional view taken along the line AA of FIG. 1;

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a sectional view of the entire bearing device.

[Explanation of symbols]

In the figure, 1 is a rotor shaft, 8 is a bearing housing, 10
Is a journal bearing, 11 is an upper half bearing (split bearing), 1
2 is a lower half bearing (split bearing), 13 is a back metal, 14 is a combined body, 15 is a resin-based sliding material, 16 is a back metal, 17 is a bearing alloy, and 18 is a resin layer.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Hideyumi Matsumura 2nd Sanage-cho, Kita-ku, Nagoya-shi Inside Daido Metal Industry Co., Ltd. (72) Inventor Takayuki Shibayama 2nd Sanage-cho, Kita-ku, Nagoya-shi F term in the company (reference) 3J011 AA06 AA20 BA09 BA13 BA14 CA05 JA02 KA02 KA03 LA01 LA06 QA05 RA03 SB19 SC01 SC05 SC20

Claims (2)

[Claims] 1. A journal bearing comprising at least two divided sliding bearings, the journal bearing supporting a shaft on which a radial load acts in substantially one direction, wherein the plurality of sliding bearings constitute the journal bearing. Of the split bearings, the split bearing which receives the radial load in the substantially one direction acting on the shaft is constituted by a bearing having a resin-based sliding material attached thereto, and the remaining split bearing is formed of a metal-coated resin bearing. A journal bearing characterized by comprising. 2. The journal bearing according to claim 1, wherein the supporting shaft is a rotor shaft of a generator.