JPS6392814A - Journal pad bearing device - Google Patents

Abstract

PURPOSE:To enable a turning shaft to be stably supported, by detecting the loaded weight acting on each load cell fitted with a pivot, and equalizing the respective load values by the application of voltage on respective piezoelectric actuators. CONSTITUTION:In respective pads 4, a resultant force Wn resulting from the production of an oil film pressure acts on each load cell 8 fitted with a pivot. The load value acting on each load cell 8 with a pivot is detected by a strain detector on each load cell 8 with a pivot, and the load value on each pad 4 is calculated and compared with a predetermined set pressure value by means of the arithmetic circuit of a control circuit, and then, in accordance with the comparison quantity, each power amplifier applies a voltage to each piezoelectric actuator 7 of each pad 4. Accordingly, the loaded weight of a turning shaft 5 is uniformly distributed on the first pad 4a, second pad 4b, third pad 4c ...the eighth pad 4h, and the thickness of oil film is also equalized, so that the turning shaft can be stably supported.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention relates to a heavy-load journal pad used for a rotating shaft to which a heavy load is applied, such as a rotating shaft of a turbine or a rotating electrical machine. Regarding bearing devices.

(Prior Art) Generally, journal bearings are used for the rotating shafts of high-speed rotating machines such as turbines, turbine generators, and turbo compressors.
Journal pad bearings with arc bearings and multi-arc bearings are used. This journal pad bearing has a large vibration damping force, excellent high load capacity, and high stability.

In particular, although journal pad bearings have excellent stability against self-excited vibrations compared to conventional bearings, their load capacity is inferior compared to cylindrical bearings.

That is, the reason why the journal butt bearing is inferior to the cylindrical bearing is that (1) the sliding surface of each butt is divided, (2) the load is concentrated only on a specific butt,
(3) The temperature of the oil film on the sliding surface increases, which reduces the viscosity effect of the fluid and reduces the thickness of the oil film.

Next, the already proposed journal butt bearing has f
It is configured as shown in FIG.

That is, in figure f45, a plurality of adjustment bolts 2 (eight in the figure) are screwed in the radial direction in the cylindrical bearing pedestal 1, and each adjustment bolt 2 has a Pads 4 each forming a seat 3 are attached, and a rotating shaft 5 is mounted on each pad 4 with a gap C therebetween.

Note that the gap C between each of the pads 4 and the rotation shaft 5 is finely adjusted using each of the adjustment bolts 2, and then
are tightened and fixed with each tightening nut 6.

Therefore, the journal pad bearing described above is configured so that the load of the rotating shaft 5 is supported by each pad 4. Particularly, among the pads 4, the first pad 4a9, the second pad 4b, and the eighth pad 4h in FIG. 5 receive the load of the rotating shaft 5.

(The problem to be solved by the invention) However, in the journal pad bearing described above, as shown in FIGS. 6 and 7, the rotating shaft 5 is eccentric ff
When eccentric at 1e, the oil film pressure distribution is as follows:
becomes the maximum size, and the second pad 4b and the eighth pad 4h
The result is similar to this.

In other words, when the resultant force of each oil film pressure is Wn, the resultant force Wn of each oil film pressure is equal to the oil film thickness h of each pad 4.
Depending on pn, the thinner the oil film thickness hpn, the larger the resultant force Wn becomes.

In this way, the first pad 4a of the journal pad bearing receives the most severe load, and as a result, wear and damage to the bearing occurs from the first pad 4a.

In order to solve the above-mentioned difficulties, the present invention provides a journal pad bearing in which a plurality of pads divided into circular arcs are built into the bearing pedestal, and the combined force of each pad is applied to the bearing load, rotation speed, and oil temperature. Even under negative let conditions due to changes, these are automatically detected and distributed evenly to each pad, and by making the oil film thickness uniform on each pad, it can be used for a long time under heavy loads. It is an object of the present invention to provide a reliable journal pad bearing that stably supports a rotating shaft throughout.

[Structure of the invention]

(Means for solving the problems and their effects) The present invention includes:
In a journal pad bearing device in which a number of pads divided into circular arcs are built into the bearing pedestal, a plurality of adjustment bolts are attached to the bearing pedestal so as to support each of the pads through a load cell with a pivot and a piezoelectric actuator. Each of the piezoelectric type By applying a voltage to the actuator, the load value of each pad is equalized, and the oil film thickness of each pad is made uniform to stably support the rotating shaft.

(Example) Hereinafter, the present invention will be described with reference to an illustrated embodiment.

It should be noted that the present invention will be described with the same reference numerals attached to the same constituent members as in the above-described specific example.

1 and 2, reference numeral 1 denotes a cylindrical bearing pedestal, and this bearing pedestal 1 has a plurality of bearing pedestals (8 in the figure).
Adjustment bolts 2 are threaded in the radial direction, and each piezoelectric actuator 7 and each pivoted load cell 8 are arranged in order at the inner end of each adjustment bolt 2. Further, each pivoted load cell 8 is attached with each pad 4 having each seat 3, and a rotary shaft 5 is rotatably mounted on each pad 4 with a gap C therebetween. There is. In addition, during assembly, the gap C between each pad 4 and the rotating shaft 5
is adjusted in advance using each of the adjustment bolts 2, and then each adjustment bolt 2 is tightened and fixed with each tightening nut 6.

In this way, the load on the rotating shaft 5 is reduced to each pad 4.
It is supported by That is, each pad 4 is composed of a first pad 4a, a second pad 4b, a third pad 4C, . . . an eighth pad 4h, as shown in FIG.
The first pad 4a, the second pad 4b and the eighth pad 4h are designed to receive the greatest load from the rotating shaft 5.

Therefore, the present invention sequentially arranges each voltage actuator 7 and each pivot load cell 8 on each adjustment bolt 2, and as shown in FIG. The detector is connected to a control circuit 9 having an arithmetic circuit, and each power-up 10a is connected to the control circuit 9.

10b...10h are connected to each of the piezoelectric actuators 7 described above.

Note 1. The piezoelectric actuator 7 utilizes, for example, the characteristic of lead zirconate titanate (PZT)-based ceramic that its dimension in the thickness direction changes in proportion to the applied voltage. As shown in , this piezoelectric actuator 7 has the property of contracting when a negative voltage is applied, and expanding when a positive voltage is applied.

Hereinafter, the effects of the present invention will be explained.

Therefore, when the rotating shaft 5 starts rotating now, and the load conditions based on the bearing load, rotational speed, and oil viscosity are set, the rotating shaft 5 is moved to the position of the eccentric He, as shown in FIG. Determined by At this time, a resultant force Wn based on the generation of oil film pressure acts on each pivoted load cell 8 on each pad 4 .

Then, the load value acting on each pivoted load cell 8 is detected by the strain detector of each pivoted load cell. This detection signal is obtained by calculating and comparing the set pressure value set in advance and the load value of each pad 4 in the arithmetic circuit of the control circuit 9, and in order to equalize the load value of each pad 4, The amount or the offset amount is calculated, and each voltage corresponding to this is outputted from the control circuit 9 to each power-up 10a, 10b, -10h, and each power-up 10a, 10b...10h is connected to each pad 4. Each voltage is applied to each piezoelectric actuator 7.

In this way, the load of the rotating shaft 5 is evenly distributed and applied to the first pad 4a, the second pad 4b, the third pad 4C, . . . the eighth pad 4h.

That is, in the present invention, as shown in the load distribution diagram of FIG. 4, each pad 4 can equalize the load value and also equalize the oil film thickness.

〔Effect of the invention〕

As described above, according to the present invention, under any load conditions, the load of each pad 4 is equally shared and the rotating shaft 5 is
Not only can the oil film thickness of each pad 4 be made equal, the load sharing of each pad 4 can be controlled freely from the outside when starting or stopping the rotating machine, and furthermore, each pad 4 can be Since each piezoelectric actuator 7 and the load cell 8 with a pivot are attached, the gap between each pad 4 and the rotating shaft 5 can be adjusted from the outside according to each load direction.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a journal pad bearing device according to the present invention, FIG. 2 is a diagram showing a control circuit of the present invention, and FIG.
The figure is a graph showing the characteristics of the piezoelectric actuator incorporated in the present invention, Figure 4 is an explanatory diagram showing the load distribution according to the present invention, and Figure 5 is a cross-sectional view of the journal pad bearing device that has already been proposed. , FIG. 6, and FIG. 7 are diagrams for explaining the load applied to each pad of the journal pad bearing device. DESCRIPTION OF SYMBOLS 1... Bearing pedestal, 2... Adjustment bolt, 4... Bad, 5... Rotating shaft, 7... Piezoelectric actuator,
8... Load cell with pivot, 9... Control circuit. Applicant's representative Mr. Sato: “Figure 2 hps: hp+ = hp2Ws =
W+ = W2 Figure 4

Claims (1)

[Claims] 1. In a journal pad bearing device in which a plurality of pads divided into arc shapes are built into a bearing pedestal, a plurality of adjustment bolts are connected to the bearing pedestal via a load cell with a pivot and a piezoelectric actuator. A journal pad bearing device characterized in that each pad is threaded in a radial direction so as to support it. 2. Claim 1, characterized in that the strain detector in the load cell with a pivot is connected to a control circuit, and the output signal of the control circuit is powered up to apply a voltage to the voltage actuator. Journal pad bearing device as described.