JPS5813220A - Tilting pad journal bearing - Google Patents

Abstract

PURPOSE:To make it easy to assemble a tilting pad journal bearing by a method wherein a pivot is made in a form of a ball to hold it with a specific pivot holding member and a mini flexure in relation to the tilting pad journal bearing, a kind of dynamic pressure gas bearing. CONSTITUTION:A pivot holder 4 capable of deflecting slightly toward radial direction of a rotary axis 1 is joined with a hollow part 3 arranged on the inner part of a housing 2. A ball like pivot for holding a tilting pad 6 is held in such a condition as it may contact or not contact in a place facing the outer perpheral surface of the holder 4. A mini flexure 8 feebly forcing the pivot 7 toward a direction such as it may separate from the holder 4 is stationed between the pivot 7 and the pivot holder 4, raising pressure between the pad 6 and the rotary axis 1 at the time of rotation of the rotary axis 1, pushing the holder 4 in the hollow part 3 through the pad 6 and the pivot 7, etc.to fix the pivot 7 easily.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dilting pad journal bearing, which is a type of hydrodynamic gas bearing.

The dilting pad/journal bearing is bivot)K
A plurality of dilting pads, each supported by a dilt, are arranged at equal angular intervals around the outer circumference of the rotating shaft, and dilting pads are formed between the inner circumferential surface of the dilting pads and the outer circumferential surface of the rotating shaft. This bearing is designed to support the rotating shaft by the pressure of a gas film, and is mainly used as a bearing for high-speed rotating shafts in turbo machines and the like.

However, in the conventional one, the pivot has a long bobbin shape with a rounded hemispherical protrusion at the tip that supports the dilting pad69, and this pivot is attached to the housing etc. with a screw. It is screwed into the hole. As a result, the entire bearing is inconveniently large compared to the shaft diameter of the rotating shaft, and each pivot must be fitted with the screw hole K1 of the housing, etc., making assembly difficult. The disadvantage is that it is time consuming. In addition, with such a configuration, the radial gap formed between the inner circumferential surface of the dilting pad and the outer circumferential surface of the rotating shaft is adjusted by moving the pivot forward and backward into engagement with the housing, etc. However, if the pivot is not securely fixed after adjustment, there is a problem in that the screwing position of the pivot will shift due to vibrations, etc., and the size between the fascia A/FJj will change unduly. In addition, since the rigidity of the pivot is extremely high with just this, each part must be machined with extremely high precision in order to set the radius A/gap to the optimal value. Moreover, there is the disadvantage that VC requires delicate adjustments. Further, if the pivot is long, there is a drawback that the distance between the radials 21 is likely to fluctuate due to the influence of thermal distortion, and it is difficult to use it in a place where the temperature changes drastically. Furthermore, it is difficult to machine the tip of the pivot into a hemispherical shape, so even if it takes a lot of man-hours to machine it, a highly accurate spherical surface cannot be obtained and the desired bearing performance cannot be achieved. . □゛、The present invention was made a long time ago under these circumstances.
To provide a teaching pad/journal bearing in which the above-mentioned inconveniences can be eliminated by holding the pivot with a ball-shaped member KL using a special pivot holding member and a mini-flip V-ya. It is something to do.

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

A plurality of recesses 3-m- are provided in the axial direction on the inner peripheral surface of the housing 2 surrounding the rotation axis l, and each of these recesses 3-m-
A pivot holding member 4- is fitted therein.

The three recessed portions are keyway-shaped with one end opened in the end face of the housing 1;
It is closed by an electric body 5 removably attached to the end face of. The pivot holding member 4 has a cylindrical portion 4a at the front and center of the surface.
The tip of the cylindrical portion 4a is fitted into the concave portion 3.'' with the tip of the cylindrical portion 4a facing the outer periphery of the rotating shaft l at an angle of 1°. Further, a hollow portion 4b is formed in the center of the back surface of the pivot holding member 4, so that the center portion of the pivot holding member 4 can be slightly bent 14 in the radial direction of the rotation axis l. And each of these pivots) holding member 40 cylindrical part 4a
(A ball-shaped pivot pad supporting the C dilting pad 6 is fitted into the surface of the pivot holding member 4 so as to be slidable in the direction of approaching and separating. Since the book has a shape of
It is made to face the outer circumferential surface of the rotating shaft l through a gap.

Further, each of the pivots 7 and each of the pivot holding members 40
A mini flexure 8 is interposed between the surface and the surface. The mini flexible rear 8 is made of an elastically deformable material and has the function of urging the biboff in a direction away from the surface of the pivot holding member 4 with a weak force. Note that, if necessary, a Fujia JL/Vum for gap adjustment may be inserted between the pivot holding member 4 and the housing 2 or between the pivot 7 and the pivot holding member 4.

With such a configuration, the length of the pivot 7 and the dimension when the pivot 7 is measured in the radial direction of the rotating shaft 1 can be made extremely short, so long port A/
The entire bearing can be made much more compact than when the teaching pad is supported by the tip of a )-shaped pivot. In addition, there is no need to screw the pivot 7 into the housing, etc., and installation is completed by simply fitting the pivot holding member 4 into the recess 3 of the housing 2, so there is an advantage that assembly does not take much time. be. When the rotating shaft l starts rotating, pressure increases between the inner circumferential surface of the tipping pad 6 and the outer circumferential surface of the rotating shaft l, and this force causes the tilting pad 6, the pivot 7, etc. Since the pivot holding member 4 is pushed into the concave portion 3 of the housing 2 through the pivot holder, the pivot 7 can be fixed during operation without using screws or the like. 'Also, since K screws are not used in this way, there is an inconvenience that vibrations etc. may cause the threaded positions of the pivots to shift and the flare between 1 and 11 to fluctuate.

In addition, by shortening the length of the pivot 7 in this way, it is possible to effectively suppress the disadvantage that the length of the pivot changes due to the influence of thermal strain and the radial clearance changes. It has the advantage of not causing any deterioration in performance even when used in certain places. Furthermore, since the pivot 7 is formed into a ball-shaped book, it is possible to easily obtain a highly accurate spherical surface, and the tilting pad 6 can be supported smoothly. Furthermore, since the mini-flexure 8 with low rigidity is interposed between the pivot 7 and the pivot holding member 4, the mini-flexure 8 can absorb possible dimensional errors of various parts to some extent without affecting the radial clearance. 4.' High machining precision 4'□・1.-The desired pine,
It is possible to eliminate inconveniences such as the need for delicate adjustments during assembly. By the way, the rigidity of this mini-flex rear 8 is extremely low, but after the mini-flex rear 8 is completely bent, it is pivoted by the pivot holding member 4 which can be slightly bent in the radial direction of the rotation axis l. Since the mini flexible rear 8 is directly supported, there is no problem such as loss of bearing rigidity due to the provision of the mini flexible rear 8.

Note that the structure of the pivot holding member is of course not limited to the one described above), and may be, for example, as shown in FIG. 3. In other words, the embodiment shown in FIG. A simple plate-like holding member 4/ is also acceptable, and the pivot holding member 4I is attached to the bottom surface of the recessed part 3/ of the housing 2I.
A hollow portion 3/a is provided to allow the central portion of the rotary shaft to be slightly deflected in the radial direction of the rotation axis l.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the first embodiment of the present invention, and Fig. 2 is a sectional view showing the first embodiment of the present invention.
FIG. 3 is a partial sectional view showing a relaxed embodiment of the present invention. 1----1 rotation axis, 2.2'----heightening, 3%$/-111 concave part, 4.4/----pid y
) Holding member, 6---Tating pad, ?・−
-1---Pivot F. a---=-Mini flexure. Agent: Patent attorney Hiroyabu Akazawa.

Claims (1)

[Claims] A recess is provided on the inner peripheral surface of the housing that surrounds the rotating shaft,
A pivot holding member that can be bent slightly in the radial direction of the rotating shaft is fitted into a recessed portion of the rotating shaft, and a pole-shaped member for supporting a dilting pad is fitted in a portion of the pivot holding member facing the outer periphery of the rotating shaft. A mini-flexure is interposed between the pivot and the pivot holding member to urge the pivot in a direction away from the pivot holding member with a weak force. dilting pad journal bearing.