JP2008131713A - Lubricant device for rotary machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricant device for a rotary machine which can increase/decrease lubricant amount to shift the critical speed Ncr of the rotary machine while keeping its rotating speed constant. <P>SOLUTION: In the lubricant device for the rotary machine using a sliding bearing, when a vibration value detected by a vibration sensor attached to the sliding bearing exceeds a specified value, the lubricant oil amount of the bearing is adjusted to reduce the vibration value, allowing the critical speed to be shifted from the operating rotation speed for the safety operation of the rotary machine in a use rotational area. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lubricating oil device for a rotating machine using a sliding bearing.

A lubricating oil system for a rotating machine using a conventional plain bearing will be described with reference to FIGS.
In the conventional lubricating oil system shown in FIG. 3, reference numeral 1 denotes a rotor shaft of a rotating machine, 2a and 2b denote bearings, 3 denotes a lubricating oil device, and the lubricating oil device 3 supplies the lubricating oil to the oil supply line 4 of the bearings 2a and 2b. Collect from the delivery oil discharge line 5. FIG. 4 is a cross-sectional view of the bearing portion in which an oil film 8 of lubricating oil is formed in the gap between the rotor shaft 1 and the bearing metal 6, that is, the clearance 7.

  The critical speed Ncr of a rotating machine that relies on oil lubrication is determined by the oil film rigidity of the lubricating oil of the bearing, in addition to the mass, rigidity, and length of the rotor shaft. Normally, the design is made so that the critical speed Ncr does not exist in the use rotation region and the rotation acceleration region.

  However, the clearance 7 depends on the processing accuracy of the rotor shaft 1 and the bearing metal 6 in the case where the rotation range used is wide in the design of the rotating machine, the mass, rigidity, length, etc. of the rotor shaft cannot be changed. Even when there is variation, the critical speed Ncr varies, the dangerous speed Ncr exists in the operating rotation range, and vibration may be excessive.

As a method for dealing with excessive vibration during operation, in the operation control method based on abnormality diagnosis of a rotating machine disclosed in Patent Document 1, when abnormal vibration is detected during acceleration, acceleration, holding, deceleration, Operation control is performed using an operation pattern consisting of trips.
Japanese Examined Patent Publication No. 1-56244

  FIG. 5 shows the relationship between the rotational speed of the rotating machine and the shaft vibration value. When the critical speed Ncr is between the rotational speeds N1 and N2, the rotational speed coincides with the critical speed Ncr and enters a resonance state. As a result, the shaft vibration value exceeds the threshold value, which hinders the operation of the rotating machine, and in some cases, the rotor shaft of the rotating machine is damaged.

  The present invention has been made to solve the above-mentioned problem, and the problem is that the lubricating oil for a rotating machine can shift the critical speed Ncr of the rotating machine while keeping the rotating speed constant by increasing or decreasing the amount of lubricating oil. To provide an apparatus.

  In order to solve the above-mentioned problems, the present invention provides a rotating machine using a sliding bearing, wherein a vibration value detected by a vibration sensor attached to the sliding bearing exceeds a predetermined value with respect to the rotational speed of the rotating machine. Thus, the amount of lubricating oil of the bearing is adjusted so as to keep away the critical speed in the shaft system of the rotating machine.

  According to the present invention, in a rotating machine using a sliding bearing, when the vibration value detected by a vibration sensor attached to the bearing exceeds a predetermined value, the critical speed of the rotating machine is shifted by adjusting the amount of lubricating oil in the bearing. Therefore, it is possible to provide a lubricating oil device for a rotating machine that reduces the vibration value.

(First embodiment)
FIG. 1 is an overall view showing a lubrication system of a rotating machine according to a first embodiment of the present invention. The same components as those in the prior art are denoted by the same reference numerals, and redundant description is omitted.

  As shown in FIG. 1, in this embodiment, vibration sensors 9a and 9b for detecting the vibration value of the rotor shaft 1 are attached to the bearings 2a and 2b, and the vibration values 10a and 10b of the bearings 2a and 2b are attached by the vibration sensors 9a and 9b. Is detected. The rotation sensor 12 is attached so as to detect the rotational speed (N) 13 of the rotor shaft 1. The detected vibration values 10a and 10b and the rotational speed (N) 13 are input to the lubricating oil device 3a, and the magnitude of the vibration values 10a and 10b and the rotational speed (N) 13 within the lubricating oil device 3a are supplied to the oil supply line 4. A command for opening / closing operation of the opening / closing device 11 such as a solenoid valve mounted on the top is issued.

  FIG. 2 is a flowchart of vibration value determination and opening / closing operation of the opening / closing device performed inside the lubricating oil device.

  In FIG. 2, first, it is determined whether or not the magnitudes of the vibration values 10a and 10b input to the lubricating oil device 3a do not exceed a predetermined value Vlimit. If either one of the vibration values 10a and 10b exceeds the predetermined value Vlimit, it is determined whether the rotational speed (N) 13 is larger or smaller than the critical speed Ncr, and the rotational speed (N) 13 is determined to be the critical speed Ncr. If smaller, the opening / closing device 11 is opened to increase the amount of lubricating oil. When the rotational speed (N) 13 is larger than the critical speed Ncr, the switchgear 11 is operated by a command from the lubricant device 3a to close the switchgear 11 and reduce the amount of lubricant.

  That is, in the characteristic diagram showing the relationship between the rotational speed and the shaft vibration in FIG. 5, the vibration values 10a and 10b of the used rotating machine exceed a predetermined value (threshold value) Vlimit and the rotational speed (N) 13 is close to the critical speed Ncr. If it is found that the speed is present, the relationship between the rotational speed (N) 13 and the critical speed Ncr is grasped, and the critical speed Ncr is increased due to an increase in the amount of oil supply, because the critical speed Ncr is moved away from the rotational speed (N) 13. Based on the principle of decreasing due to a decrease in the amount of oil supply, an operation to increase or decrease the amount of lubricating oil is performed.

  As described above, according to the lubricating oil device for a rotating machine of the present embodiment, the critical speed Ncr is increased or decreased by increasing or decreasing the amount of oil supply even when the rotational speed of the rotating machine approaches the critical speed Ncr and the vibration becomes excessive. Can be shifted from the operating rotational speed, and the rotating machine can be stably operated in the operating rotational range.

The systematic diagram of the 1st Embodiment of this invention. The flowchart of FIG. The system diagram of the lubricating oil of the conventional rotary machine. Sectional drawing of the bearing part of FIG. The characteristic view which shows the relationship between a rotation speed and a shaft vibration value.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Rotor shaft, 2a, 2b ... Bearing, 3, 3a ... Lubricating oil device, 4 ... Oil supply line, 5 ... Oil discharge line, 6 ... Bearing metal, 7 ... Clearance, 8 ... Oil film, 9a, 9b ... Vibration sensor, 10a, 10b ... vibration value, 11 ... opening / closing device, 12 ... rotation sensor, 13 ... rotation speed (N).

Claims (1)

  In a lubricating oil device for a rotating machine using a sliding bearing, when the vibration value detected by a vibration sensor attached to the sliding bearing exceeds a predetermined value, the shaft system of the rotating machine with respect to the rotational speed of the rotating machine. A lubricating oil device for a rotating machine, characterized in that the amount of lubricating oil in a bearing is adjusted so as to keep away the critical speed in the motor.

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