JP6617729B2 - Rotating machine and method for adjusting static balance of rotating machine - Google Patents

Description

  The present invention makes it easy to adjust the static balance of a rotating body of a rotating machine including a rotating shaft and a rotating body that rotates around this axis, such as an exhaust fan or a turbine having a large blower as a typical example. It is about the structure to make. Furthermore, this invention relates to the static balance adjustment method of the rotary body in this rotary machine.

Since a rotating body such as an impeller or a rotor is supplied with a rotational force from an external drive source via a rotating shaft, a rotating machine generally has the rotating shaft.
For example, as shown in FIG. 1, an exhaust fan that is a typical example of a rotating machine has a blower 20 including a casing 1 and an impeller 2 disposed inside the casing 1 disposed in a suction box 3. The impeller 2 of the blower 20 is rotated, and the gas introduced from the opening 3 a of the suction box 3 is discharged from the blower 20. The blower 20 is attached to the rotating shaft 5 supported by the shaft 2 a of the impeller 2 via the boss 21 between the bearings 4 a and 4 b, and is rotated by a driving force from the rotating shaft 5. The rotating shaft 5 is connected to an electric motor 6 which is a driving source through a coupling 50, for example. In addition, although the illustrated exhaust fan is provided with two blowers 20 in pairs, the number of blowers 20 may be one.

The rotating machine having the above-described exhaust fan as a typical example needs to perform balance adjustment at the time of manufacture and maintenance in order to prevent damage due to vibration caused by imbalance of the impeller as a rotating body. In particular, a large exhaust fan or the like is difficult to move from the installation location, and therefore maintenance is performed at the installation location.
As a procedure for this balance adjustment,
(1) Turn the impeller to check the approximate balance and weld the weight (static balance adjustment)
(2) Rotate by power and weld weight to position calculated from vibration analysis result (dynamic balance adjustment)
In general, a so-called field balancing method is applied.

Here, in a large-scale exhaust fan having a large weight of the impeller (rotating body), a metal bearing is often adopted for the bearings 4a and 4b that support the rotating shaft 5 from the viewpoint of load capacity. This metal bearing has a structure in which a shaft is received by a sliding surface made of metal. As shown in FIG. 2A, oil 41 serving as a working fluid is supplied between the rotating shaft 5 and the sliding surface 40 of the bearing. The contact between the shaft 5 and the bearing sliding surface 40 and adhesion are prevented by the formed oil film.
As shown in FIG. 2 (b), the rotating shaft 5 supported by such a metal bearing is connected to the blower 20 in a state where the rotating machine (exhaust fan) is not operated and the impeller is stationary. It is placed under contact with the lower circular arc portion of the sliding surface 40 of the bearing without passing through the oil 41 due to its own weight. Naturally, the rotational shaft 5 in this state has a large rotational resistance, and the stationary impeller cannot be rotated by hand, so that it is difficult to perform the static balance adjustment (1). Therefore, when the balance adjustment of the exhaust fan or the like is performed on site, the static balance adjustment of (1) is omitted, and the dynamic balance adjustment of (2) is inevitably performed directly.

  However, if the balance of the rotating body of the rotating machine has been greatly lost, rotating the rotating body with power will apply an excessive load on the rotating shaft, causing damage to the blower body or seizure of the sliding surface of the metal bearing. May occur. In addition, when dynamic balance adjustment is performed without performing static balance, the weight that must be newly loaded tends to be large, and as a result of increasing local stress on the mounting portion, there is a possibility that damage will still occur. Get higher. Further, in the exhaust fan, when a heavy weight is attached to the impeller, there is a concern that dust or the like during the exhaust will adhere to the weight.

  The present invention has been made to solve the above-described problems, and in particular, a structure capable of easily adjusting the static balance of a rotating body in a large-sized rotating machine that needs to support a rotating shaft with a metal bearing. The purpose is to give. Furthermore, an object of the present invention is to provide a way to reliably adjust the static balance of a rotating machine.

The gist of the present invention is as follows.
1. A rotating body, a rotating shaft that is connected to the rotating body and drives the rotating body, and a metal bearing that rotatably supports the rotating shaft,
The rotating shaft is a rotating machine having a horizontal level adjusting mechanism.

2. 2. The rotating machine according to 1, wherein the horizontal level adjusting mechanism is a rolling bearing that is detachably attached to the rotating shaft.

3. The rotating machine according to 1 or 2, wherein the rotating body is an impeller.

4). In a rotating machine, comprising: a rotating body; a rotating shaft connected to the rotating body to drive the rotating body; and a metal bearing that rotatably supports the rotating shaft, and adjusting a static balance of the rotating body. At the time, a rolling bearing is attached to the rotating shaft, the rolling bearing is raised to a position where the shaft of the rolling bearing coincides with the shaft of the metal bearing, and the rotating shaft is supported by the rolling bearing, and the rotating shaft A method for adjusting the static balance of a rotating body in a rotating machine for adjusting the static balance of the body.

5). 5. The method for adjusting a static balance of a rotating body in the rotating machine according to 4, wherein the rotating body is an impeller.

  The present invention includes a level adjusting mechanism on a rotating shaft supported by a metal bearing, and the position of the rotating shaft in the metal bearing when the rotating machine is stopped can be adjusted by the level adjusting mechanism. Adjustment work can be simplified. In particular, by providing a rolling bearing of a type that can be disassembled without removing the rotating shaft as the level adjusting mechanism, the static balance adjustment work at the site can be reliably performed. As a result, static balance adjustment can be reliably performed prior to dynamic balance adjustment, so the risk of damage to rotating machinery during dynamic balance adjustment is reduced and construction time is reduced by reducing the amount of weight attached during dynamic balance adjustment. A shortening effect can be obtained.

It is a figure which shows the structure of an exhaust fan. It is a figure which shows the state at the time of rotation of the axis | shaft in a metal bearing, and a stationary state. It is a figure which shows the structure of the rotary machine according to this invention. It is a figure which shows the structure of a horizontal level adjustment mechanism.

Hereinafter, the rotary machine of the present invention will be described in detail by taking the exhaust fan shown in FIG. 1 as an example.
FIG. 3 shows the structure of the exhaust fan according to the present invention. Here, with respect to the exhaust fan shown in FIG. 3, the same components as those of the exhaust fan shown in FIG.
Now, as shown in FIG. 2, when the rotating shaft 5 that drives the impeller 2 is supported by the metal bearings 4a and 4b, the rotating shaft 5 does not pass through the oil 41 due to the weight of the blower 20 when stationary. Being placed in contact with the lower circular arc portion of the sliding surface 40 serves as a rotational resistance of the impeller 2 at the time of static balance adjustment, and hinders rotation for static balance adjustment. Therefore, in the exhaust fan according to the present invention, as shown in FIG. 3, the horizontal level adjusting mechanism 7 of the rotating shaft 5 is provided, and the axis of the rotating shaft 5 at rest is operated via the horizontal level adjusting mechanism 7. By raising to the axial center position, it is avoided that the rotating shaft 5 contacts with the lower circular arc portion of the sliding surface 40 of the bearing. That is, since the horizontal level adjusting mechanism 7 has a function of moving the rotating shaft 5 up and down and rotatably supporting it, the position of the rotating shaft 5 at rest shown in FIG. 2B is shown in FIG. It is possible to return to the position at the time of running. Accordingly, the rotating shaft 5 at rest can be placed in an environment where the same rotation as that at the time of operation is possible, and the rotational resistance of the impeller 2 is lower than the rotational torque applied to the impeller during static balance adjustment even at rest. It becomes possible to adjust the balance.

The horizontal level adjusting mechanism 7 will be specifically described with reference to FIG.
As the horizontal level adjusting mechanism 7, for example, a rolling bearing, particularly a split roller bearing can be used. That is, as shown in FIG. 4, an inner ring 7a into which the rotating shaft 5 is inserted, an outer ring 7b having a larger diameter than the inner ring 7a, and a plurality of rollers 7c interposed between the inner ring 7a and the outer ring 7b are combined with a bearing box 7d. It is housed inside. As shown in FIG. 4C, this roller bearing is a so-called split roller bearing having a structure that can be divided into two with a dividing line L in the radial direction as a boundary. Therefore, after attaching to the rotating shaft 5 in the divided state of FIG. 4 (c), the upper and lower portions can be combined and attached to the rotating shaft 5, and it can be divided again from the attached state and removed. In this way, by disposing the split roller bearing so as to be detachable with respect to the rotating shaft 5, it is possible to provide an air exhaust having the horizontal level adjusting mechanism 7 of the rotating shaft 5 as necessary. Further, the horizontal level adjusting mechanism 7 has a taper liner 7f between the bearing box 7d and the base 7e fixed to the floor where the exhaust fan is installed. Can be adjusted up and down. Note that a lifting device such as a hydraulic jack may be incorporated instead of the taper liner 7f.

  When a split roller bearing is used as the horizontal level adjusting mechanism 7, the bearing needs to have a load capacity capable of supporting the weight of the blower. Further, the horizontal level adjusting mechanism 7 is not limited to the split roller bearing, and for example, a V block that can accommodate a central V-shaped rotation groove can be applied.

Next, the static balance adjustment method in the above exhaust fan will be described.
As described above, when the rotary shaft 5 is not operating when the exhaust fan is not operating, the rotary shaft 5 does not pass through the oil 41 due to the weight of the blower 20 as shown in FIG. The sliding surface 40 is placed in contact with the lower arc portion. Therefore, the split roller bearing which is the horizontal level adjusting mechanism 7 is mounted on the rotating shaft 5, and the roller bearing is moved to an appropriate position where the shaft center of the rotating shaft 5 coincides with the rotation center of the metal bearings 4a and 4b by, for example, the taper liner 7f. Raise and fix the roller bearing in this proper position.

Thus, if it is set as the same rotating shaft 5 arrangement | positioning as the driving | running state shown to Fig.2 (a), the impeller 2 is rotated manually and static balance adjustment is performed according to the known field balancing method, for example.
After the static balance adjustment, it is preferable that the bearing is divided and removed from the rotating shaft 5 in order to prevent the roller bearing from being damaged before the dynamic balance adjustment described above.

DESCRIPTION OF SYMBOLS 1 Casing 2 Impeller 3 Suction box 4a, 4b Bearing 5 Rotating shaft 6 Electric motor 7 Horizontal level adjustment mechanism 7a Inner ring 7b Outer ring 7c Roller 7d Bearing box 7e Base 7f Taper liner 20 Blower 50 Coupling

Claims (5)

A rotating body, a rotating shaft connected to the rotating body to drive the rotating body, a metal bearing that rotatably supports the rotating shaft, and a horizontal level adjustment mechanism that supports the rotating shaft to be moved up and down and rotatably If, you have a rotary machine.   The rotating machine according to claim 1, wherein the horizontal level adjusting mechanism is a rolling bearing that is detachably attached to the rotating shaft.   The rotating machine according to claim 1, wherein the rotating body is an impeller.   In a rotating machine, comprising: a rotating body; a rotating shaft connected to the rotating body to drive the rotating body; and a metal bearing that rotatably supports the rotating shaft, and adjusting a static balance of the rotating body. At the time, a rolling bearing is attached to the rotating shaft, the rolling bearing is raised to a position where the shaft of the rolling bearing coincides with the shaft of the metal bearing, and the rotating shaft is supported by the rolling bearing, and the rotating shaft A method for adjusting the static balance of a rotating body in a rotating machine for adjusting the static balance of the body.   The method according to claim 4, wherein the rotating body is an impeller.

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