JP5839893B2 - Journal bearing - Google Patents

Description

  The present invention relates to a journal bearing that rotatably supports a rotor (rotating shaft) of a large rotating machine such as a steam turbine or a gas turbine.

  Conventionally, in large rotating machines such as steam turbines and gas turbines, journal (tilting pad) bearings are often used to rotatably support a rotor (see, for example, Patent Document 1). A plurality of journal bearings are arranged in the circumferential direction of the rotor, and a swingable bearing pad is accommodated in the bearing housing.

  In FIG. 5, the schematic block diagram seen from the axial direction of the conventional journal bearing 101 used for a large sized rotary machine is shown. As shown in FIG. 5, each bearing pad 104 that supports the rotor R is supported by a pivot 103 that is provided on the inner surface of the bearing housing 2 and abuts against the back surface of the bearing pad 104.

In addition, journal bearings for large rotating machinery are lubricated with oil to enable safe operation of the machine. Recently, direct lubrication type with low loss and low oil volume (directly on the bearing surface via a nozzle etc.) Many types of bearings have been used.
In the direct lubrication type tilting pad bearing, an oil supply nozzle 106 is provided between the bearing pads 104, and the lubricant oil is supplied from the oil supply nozzle 106 by driving the lubricant oil supply pump 10. Then, the rotation of the rotor R supplies lubricating oil between the outer peripheral surface of the rotor R and the support surface 105 of the bearing pad 104. As a result, a rust-like oil film is formed between the rotor R and the support surface 105 of the bearing pad 104 without the need for dynamic pressure generation, so that the rotor load can be supported via the oil film during rotation.

  Further, a journal bearing is also provided that floats the rotor R when the rotor R starts to rotate or rotates at a low speed by an oil lift mechanism called a jacking oil pump (hereinafter referred to as JOP mechanism). As shown in FIG. 6, the JOP mechanism forcibly supplies high pressure oil from a JOP groove 112 (oil supply hole) formed in the support surface 105 of the bearing pad 104, thereby supporting the support surface 105 of the bearing pad 104 and the rotor. This is a mechanism for forming an oil film with R. High pressure oil is supplied to the JOP groove 112 from the high pressure oil supply pump 15 via the oil supply passage 114.

JP 2001-124062 A

  Incidentally, the power generation turbine is required to have high efficiency and large capacity, and accordingly, the rotor load applied to the journal bearing used to support the rotating shaft of the power generation turbine is also increasing. For this reason, depending on the conditions, there is a problem that the rotor does not float or only the bearing pad on one side floats and does not float on the opposite bearing pad.

  In addition, the JOP groove 112 formed on the support surface 105 of the bearing pad 104 impairs the original performance of the bearing when the rotating machine is in a steady rotation state. Must be kept to a minimum. However, the processing range of the JOP groove 112 tends to increase in order to cope with the increasing rotor load.

  The present invention has been made in consideration of such circumstances, and an object of the present invention is to provide a journal bearing provided with a JOP mechanism without reducing the performance of the journal bearing in a journal bearing applied to a large-sized rotating machine. There is to do.

The present invention employs the following means in order to solve the above problems.
A plurality of journal bearings according to the present invention are installed on the outer peripheral side of the rotating shaft at intervals in the circumferential direction, and between the bearing pads that support the rotating shaft from the outer peripheral side and the bearing pads adjacent to each other in the circumferential direction. In each of the journal bearings provided with the oil supply nozzle that supplies the lubricating oil to the outer peripheral surface of the rotation shaft, at least one oil supply nozzle located below the rotation shaft among the plurality of oil supply nozzles, An oil supply hole for supplying the lubricating oil to the outer peripheral surface of the rotary shaft is provided , and a contact surface that comes into contact with the outer peripheral surface of the rotary shaft when the rotary shaft is stopped is provided. And high pressure oil supply means for supplying high pressure oil having a pressure higher than that of the lubricating oil to the contact surface through a high pressure oil supply hole formed in the contact hole.

  According to the above configuration, since the high-pressure oil supply means is provided in the oil supply nozzle, the high-pressure oil supply groove that constitutes the oil lift mechanism of the rotary shaft that is conventionally provided only in the bearing pad is omitted or reduced. Therefore, the journal shaft can be provided with an oil lift mechanism for the rotating shaft without degrading the performance of the journal bearing.

In the journal bearing according to the present invention, the contact surface is preferably made of a soft metal or a resin material.
According to the said structure, since the contact surface of the oil supply nozzle which contacts a rotating shaft at the time of a stop of a rotating shaft is made into a soft material, it can prevent that a damage | wound generate | occur | produces in a rotating shaft.

Moreover, the journal bearing which concerns on this invention WHEREIN: It is preferable that the said high pressure oil supply means is provided also in the at least 2 oil supply nozzle located in the side of the said rotating shaft among these oil supply nozzles.
According to the above configuration, during rotation of the rotary shaft, high pressure oil is injected from the oil supply nozzle located on the side of the rotary shaft, so that the position of the rotary shaft can be finely adjusted during operation. It is possible to improve the rotational vibration characteristics of the entire rotating machine in which is used.

Furthermore, in the journal bearing according to the present invention, it is preferable that a moving mechanism that allows the oil supply nozzle to move in a direction to retract from the rotating shaft is provided.
According to the above configuration, the contact surface of the oil supply nozzle can be prevented from being damaged due to factors such as vibration of the rotation shaft by retracting the contact surface of the oil supply nozzle while the rotation shaft is rotating.

  According to the present invention, an oil lift mechanism for a rotating shaft can be provided in a journal bearing without degrading the performance of the journal bearing.

It is a schematic block diagram of the journal bearing which concerns on 1st embodiment of this invention. It is an expansion perspective view of the bearing pad which comprises the journal bearing which concerns on 1st embodiment of this invention. It is an expansion perspective view of the bearing pad which comprises the journal bearing which concerns on 2nd embodiment of this invention. It is a schematic block diagram of the bearing pad which comprises the journal bearing which concerns on 3rd embodiment of this invention. It is the schematic block diagram seen from the axial direction of the conventional journal bearing. It is a perspective view which shows the bearing pad of the conventional journal bearing.

(First embodiment)
Embodiments of the present invention will be described below with reference to the drawings. A turbine rotor R is rotatably supported by the journal bearing 1 of the present embodiment. In the present embodiment, the rotor R is supported by the two journal bearings 1 that are provided apart from each other in the axial direction of the rotor R.

  As shown in FIG. 1, the journal bearing 1 is supported by an annular bearing housing 2, pivots 3 provided on the inner peripheral surface of the bearing housing 2 at equal angular intervals, and swingable on the respective pivots 3. Bearing pad 4. That is, the pivot 3 is interposed between the bearing pad 4 and the bearing housing 2. The bearing pad 4 is divided in the circumferential direction. In this embodiment, the bearing pad 4 is divided into four parts, and each bearing pad 4 is supported by the pivot 3.

  Further, between each bearing pad 4, an oil supply nozzle including a first oil supply nozzle 6 provided with one high-pressure oil supply means 11 and three second oil supply nozzles 7 is provided toward the rotor R. . The first oil supply nozzle 6 is an oil supply nozzle provided immediately below the rotor R, and the second oil supply nozzle 7 is an oil supply nozzle provided on the side of the rotor R and immediately above it. The first oil supply nozzle 6 and the second oil supply nozzle 7 are provided so as to protrude toward the radially inner peripheral side of the journal bearing 1. The first oil supply nozzle 6 and the second oil supply nozzle 7 are each connected to a lubricating oil supply pump 10, and are adjacent to the downstream side in the rotational direction of the rotor R by driving the lubricating oil supply pump 10. Lubricating oil is supplied toward the support surface 5 of the bearing pad 4.

The contact surface 8 that constitutes the front end surface of the first oil supply nozzle 6 in the protruding direction is set to a position that contacts the outer peripheral surface of the rotor R when the rotor R is stopped. That is, the contact surface 8 is set so that the distance from the central axis of the rotor R is substantially the same as the support surface 5 of the bearing pad 4.
On the other hand, the front end surface of the second oil supply nozzle 7 in the protruding direction is set at a position slightly separated from the outer peripheral surface of the rotor R when the rotor R rotates.

  As shown in FIG. 2, a plurality of oil supply holes 9 for supplying lubricating oil are formed on two sides along the axial direction of the journal bearing 1 among the four sides constituting the contact surface 8 of the first oil supply nozzle 6. Has been. Specifically, the oil supply holes 9 are circular holes, and are arranged in rows of six on each side. These oil supply holes 9 are connected to a lubricating oil supply pump 10.

The first oil supply nozzle 6 includes a high-pressure oil supply means 11 (JOP mechanism) including a JOP groove 12, a concave groove 13, an oil supply passage 14, and a high-pressure oil supply pump 15.
The JOP groove 12 is a hole for supplying high-pressure oil formed on the contact surface 8 of the first oil supply nozzle 6. Specifically, the contact surface 8 is formed with a rectangular groove 13 along the outer diameter of the contact surface 8, and the JOP groove 12 is formed at a substantially central portion of the groove 13. The depth of the concave groove 13 is appropriately set according to the specifications of the large rotating machine to be applied, such as the diameter of the rotor R. The JOP groove 12 is a circular hole having a slightly larger diameter than the oil supply hole 9, and high pressure oil for floating the rotor R is supplied from the JOP groove 12. The pressure of the high-pressure oil is larger than that of the lubricating oil supplied from the oil supply hole 9.

  The JOP groove 12 communicates with an oil supply passage 14 formed inside the first oil supply nozzle 6, and the oil supply passage 14 is connected to a high-pressure oil supply pump 15. The high-pressure oil supply pump 15 is a pump capable of supplying high-pressure oil whose pressure is higher than that of the lubricating oil.

  Each bearing pad 4 has an arc shape when viewed in a line of sight parallel to the axis of the rotor R, and has a curved plate shape that is wide in the axial direction. The radius of curvature of the support surface 5 of the bearing pad 4 is slightly larger than the radius of curvature of the outer peripheral surface of the rotor R. That is, the entire support surface 5 of the bearing pad 4 does not come into contact with the rotor R. The support surface 5 of the bearing pad 4 is formed of a soft metal such as white metal (babbit metal) or a bearing material such as resin.

  The pivot 3 protrudes from the bearing housing 2 in the radial direction of the rotor R, and supports the bearing pad 4 at the center of the back surface of the bearing pad 4.

Next, the operation of the journal bearing 1 according to the embodiment will be described.
When rotating the rotor R, first, the high pressure oil supply pump 15 is driven in a state where the rotor R is stopped, and the high pressure oil is supplied to the JOP groove 12 through the oil supply passage 14. When this high-pressure oil is supplied to the concave groove 13 via the JOP groove 12, the rotor R floats (oil lift).

  Next, the rotor R is rotated. Since the close contact between the outer peripheral surface of the rotor R and the support surface 5 of the bearing pad 4 is eliminated by the floating of the rotor R by the high pressure oil supply means 11, the lubrication supplied from the first oil supply nozzle 6 and the second oil supply nozzle 7. Accepts oil.

  According to the above-described embodiment, the first oil supply nozzle 6 is provided with the high pressure oil supply means 11 including the JOP groove 12, the concave groove 13, the oil supply passage 14, and the high pressure oil supply pump 15, and has an oil lift function. Since it is not necessary to process the JOP groove on the support surface 5 of the bearing pad 4, it is possible to prevent the performance of the journal bearing 1 from being deteriorated.

  In the above embodiment, the bearing pad 4 is not provided with a JOP mechanism including a JOP groove or the like. However, the present invention is not limited to this, and the bearing pad 4 is used for assisting the oil lift of the first oil supply nozzle 6. A JOP mechanism including a JOP groove or the like may be provided.

(Second embodiment)
Next, the journal bearing which concerns on 2nd embodiment of this invention is demonstrated.
As shown in FIG. 3, the contact surface 8B of the first oil supply nozzle 6B constituting the journal bearing of the present embodiment is formed of a soft metal such as white metal. More specifically, in the contact surface 8B, a member provided with a rectangular hole corresponding to the concave groove 13 is fixed to a thin plate-like white metal.

According to the above embodiment, since the contact surface 8B of the first oil supply nozzle 6B with which the rotor R contacts when the rotor R is stopped is formed of the soft material, the rotor R is formed by the contact surface 8B of the first oil supply nozzle 6B. Scratches can be prevented from occurring.
The material for forming the contact surface 8B is not limited to a soft metal such as white metal, but may be formed of a resin material such as POM.

(Third embodiment)
Next, a journal bearing according to a third embodiment of the present invention will be described. As shown in FIG. 4, the journal bearing 1 </ b> C of the present embodiment includes three third oil supply nozzles 6 </ b> C provided immediately below and on both sides of the rotor R, and one second oil supply nozzle provided directly above the rotor R. 7. The third oil supply nozzle 6C includes a nozzle tip 17 provided with a high-pressure oil supply means 11C, and a hydraulic cylinder 18 that allows the nozzle tip 17 to move in the radial direction.

  The hydraulic cylinder 18 is installed on the inner peripheral surface of the bearing housing 2 such that the advancing / retreating direction of the rod 18a of the hydraulic cylinder 18 is along the radial direction. The nozzle tip 17 is attached to the tip of the rod 18a. Similarly to the first oil supply nozzle 6 of the first embodiment, the nozzle tip portion 17 has a plurality of oil supply holes for supplying lubricating oil and a high pressure oil supply having a JOP groove for supplying high pressure oil. Means 11C are provided.

  The hydraulic cylinder 18 is supplied with hydraulic oil by a hydraulic pump (not shown) driven by a motor (not shown). By operating the electromagnetic switching valve 19 by a control device (not shown), the nozzle The movement in the radial direction of the distal end portion 17 can be controlled. In addition, the electromagnetic switching valve 19 is provided in each 3rd oil supply nozzle 6C.

  The operation of the above embodiment will be described. First, when the rotor R is rotated, the contact surface 8C of the nozzle tip 17 of the third oil supply nozzle 6C directly below the rotor R is operated to the rotor R by operating the hydraulic cylinder 18. The high pressure oil is supplied to the JOP groove 12 in a contact state. Thereby, the rotor R floats (oil lift). Next, after rotating the rotor R, the hydraulic cylinder 18 is operated to retract the nozzle tip 17 to the radially outer peripheral side.

Further, during the operation of the rotor R, the position of the rotor R can be finely adjusted during operation by injecting the high-pressure oil from the third oil supply nozzle 6C located on the side of the rotating shaft. The position adjustment of the rotor R is performed in a state where the contact surface 8C is substantially in contact with the rotor R as in the case of the oil lift, and the nozzle tip 17 is retracted to the radially outer peripheral side after the operation.
Other operations are the same as those in the first embodiment.

According to the above embodiment, the contact surface 8C of the third oil supply nozzle 6C caused by factors such as vibration of the rotor R is retracted by retracting the contact surface 8C of the third oil supply nozzle 6C to the radially outer peripheral side while the rotor R is rotating. Can prevent damage.
Further, by performing fine adjustment of the position of the rotor R during the rotation of the rotor R, the rotational vibration characteristics of the entire turbine can be improved.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the third embodiment, the high pressure oil supply means 11C is provided in the oil supply nozzle located directly below and on both sides of the rotor R, but the high pressure oil supply means is similarly provided in the first embodiment. It is good also as a structure arrange | positioned directly under the rotor R and both sides.

  In the third embodiment, the hydraulic cylinders 18 are provided directly below and on both sides of the rotor R. However, the hydraulic cylinders may be provided only on the oil supply nozzles directly below the rotor R.

Further, the number of bearing pads 4 is not limited to four, and can be appropriately changed according to the configuration of the rotating machine to be applied.
Furthermore, in each said embodiment, although the oil supply nozzle provided with the high pressure oil supply means 11 showed the structure arrange | positioned at least directly under the rotor R, the bearing pad 4 was installed directly under the rotor R, and the both sides are shown in it. It is good also as a structure which provides a high pressure oil supply means in the provided oil supply nozzle.

R ... rotor (rotating shaft), 1 ... journal bearing, 4 ... bearing pad, 6 ... first oil supply nozzle (oil supply nozzle), 7 ... second oil supply nozzle, 8 ... contact surface, 11 ... high pressure oil supply means, 12 ... JOP groove (high pressure oil supply hole), 18 ... hydraulic cylinder (moving mechanism).

Claims (4)

A plurality of bearing pads are provided on the outer peripheral side of the rotating shaft at intervals in the circumferential direction, and bearing pads that support the rotating shaft from the outer peripheral side;
In a journal bearing provided with an oil supply nozzle that is provided between the bearing pads adjacent to each other in the circumferential direction and supplies lubricating oil to the outer peripheral surface of the rotating shaft,
Of the plurality of oil supply nozzles, at least one oil supply nozzle located below the rotation shaft is provided with an oil supply hole for supplying the lubricating oil to the outer peripheral surface of the rotation shaft, A contact surface that comes into contact with the outer peripheral surface of the rotating shaft at the time of stopping is provided, and high-pressure oil having a pressure higher than that of the lubricating oil is supplied to the contact surface through a high-pressure oil supply hole formed inside the oil supply nozzle. A journal bearing comprising a high-pressure oil supply means.   The journal bearing according to claim 1, wherein the contact surface is made of a soft metal or a resin material.   3. The journal according to claim 1, wherein the high-pressure oil supply means is also provided in at least two oil supply nozzles located on a side of the rotation shaft among the plurality of oil supply nozzles. bearing.   The journal bearing according to any one of claims 1 to 3, further comprising a moving mechanism that allows the oil supply nozzle to move in a direction to retract from the rotating shaft.

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