JPS6032427Y2 - Tilting pad/journal bearing - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a tailing pad journal bearing, which is a type of hydrodynamic gas bearing.

A tailing pad journal bearing has a plurality of tailing pads, each supported by a pivot, arranged at equal angular intervals around the outer circumference of the rotating shaft, and the inner peripheral surface of the tailing pads and the outer circumference of the rotating shaft. The rotary shaft is supported by the pressure of a gas film generated between the rotary shaft and the rotary surface, and is mainly used as a bearing for a high-speed rotary shaft in a turbomachine or the like.

However, in the conventional type, the pivot is a long bolt-shaped thing having a hemispherical protrusion at the tip for pivotally supporting the tailing pad, and this pivot is attached to a housing or a pivot attached to the housing. It is screwed into the screw hole of the support, etc.

This has the disadvantage that the entire bearing is large compared to the diameter of the rotating shaft, and it is time-consuming to assemble each pivot as it must be screwed into a threaded hole in the pivot support, etc. There is a drawback.

In addition, with such a configuration, the radial gap formed between the inner circumferential surface of the tailing pad and the outer circumferential surface of the rotating shaft is adjusted by moving the pivot forward and backward into engagement with the pivot support. If the pivot is not securely fixed after adjustment, the screwing position of the pivot may shift due to vibrations, etc., and the size of the radial gap may change unduly.

Furthermore, if the pivot is long, the radial clearance is likely to fluctuate due to the influence of thermal strain, so there is a drawback that it is difficult to use it in a machine that experiences rapid temperature changes.

Note that some models use shims to adjust the radial clearance between the tailing pad and the rotating shaft, but conventional models have shims installed inside the housing, and the shims There is a problem in that it takes time and effort to adjust the gap because sufficient consideration has not been given to the replacement of the gap.

This invention was developed with a focus on these circumstances.
An axial groove is provided on the inner peripheral surface of the housing, the outer end of which is open to the end surface of the housing, and a pivot having a hemispherical projection for supporting a tailing pad is fitted into the groove. A shim for adjusting the radial clearance is interposed between the pivot and the bottom surface of the groove, and a lid body for holding the shim in the groove is removably provided on the end surface of the housing. We have created a tailing pad/journal bearing that is easy to downsize, requires no effort to assemble or adjust the clearance, and does not cause problems such as the radial clearance once adjusted due to vibration or temperature changes. This is what we provide.

An embodiment of the present invention will be described below with reference to the drawings.

An inner housing 3 surrounding a rotating shaft 2 is fitted onto the inner periphery of a cylindrical outer housing 1.

A plurality of grooves 4 are formed on the inner peripheral surface of the inner housing 3.
... are provided in the axial direction, and pivots 6 for supporting tailing pads 5 are fitted into these grooves 4, respectively.

The groove 4 has a keyway shape extending from one end surface to the other end surface of the inner housing 3, and the right end opening of the groove 4 is closed by a locking wall 1a provided on the outer housing 1, and the left end opening is closed by a locking wall 1a provided on the outer housing 1. That is, the outer end opened in the end face of the housing 3 is closed by the lid 7 detachably attached to the outer housing 1.

The pivot 6 is a thin plate having a hemispherical protrusion 6a integrally protruding from the center of one side, and is fitted into the groove 4 with the hemispherical protrusion 6a protruding in the direction of the rotation axis 2. There is.

The tailing pad 5 has a shape obtained by taking out a part of a cylindrical body, and has a hemispherical protrusion 6a of the pivot 6 rotatably fitted into a spherical seat 5a provided at a predetermined location on its outer circumferential surface. The inner circumferential surface is opposed to the outer circumferential surface of the rotating shaft 2 with a small radial gap C interposed therebetween.

Furthermore, shims 8 are interposed between each of the pivots 6 and the bottom surfaces of the grooves 4.

The shim 8 is a thin plate-like member that fits into the groove 4, and is used to adjust the radial gap C by selecting the thickness or number of shims.

Further, flexures 9, 9 are interposed between the required pivots 6.6 and shims 8, 8.

The flexure 9 is a thin plate made of an elastically deformable material, and is used to support the pivot 6 in an elastically movable manner.

Thus, the pivot 6 supported by the flexure 9 has a function as a so-called movable pivot, and the other pivots 6 have a function as a so-called fixed pivot.

The pivot 6, shim 8 and flexure 9 are
For example, with the lid 7 removed, it is inserted into the groove 4 from the left end opening of the groove 4.

With such a structure, the length of the pivot 6, that is, the dimension when measuring the pivot 6 in the radial direction of the rotating shaft 2, can be made extremely short. The entire bearing can be made much more compact than when the tilting pad is supported by the tilting pad.

Further, the assembly is completed by simply inserting the pivot 6, shim 8, and flexure 9 into the groove 4 from the outside of the housing 3 and attaching the lid 7, so there is an advantage that the assembly work does not take much time.

Moreover, once the lid 7 is removed from the housing 3, the shim 8 can be easily replaced from the outside even after assembly.

That is, since the shim 8 is simply fitted into the groove 4, it can be easily installed in an appropriate position and can be quickly replaced with one of a different thickness.

Therefore, adjustment of the radial clearance C is also extremely easy.

Furthermore, since the radial clearance C is adjusted using the shim 8, once the adjustment is made, there will be no misalignment, and there will be no inconvenience such as the radial clearance fluctuating due to the screwing position of the pivot being shifted due to vibration, etc. does not occur.

In addition, by shortening the length of the pivot 6, it is possible to effectively suppress the inconvenience of changing the radial clearance due to changes in the length of the pivot due to the influence of thermal strain, so it is possible to effectively prevent It has the advantage of not causing a decrease in performance even when used.

Note that the shim is not limited to a constant length, and may be, for example, a wedge-shaped one whose thickness gradually changes in the longitudinal direction.If this is the case, the radial gap can be adjusted depending on the degree of insertion of the shim. Can be adjusted.

In the illustrated example, the housing is of a double type to provide compatibility as a bearing, but the structure is not limited to this and a single type of housing may be used.

Because the present invention has the above-mentioned configuration, it is easy to downsize, and it is also possible to assemble and adjust the radial clearance easily and quickly. It is possible to provide an excellent tailing pad/journal bearing that does not cause deviation in the radial clearance.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing one embodiment of the present invention, and Fig. 2 is a cross-sectional view showing an embodiment of the present invention.
It is a sectional view taken along the line ■-■ in the figure. 2...Rotating shaft, 3...Housing (inner housing), 4...Groove, 5...Tilting pad, 6...・Pivot, 8...
...Shim, C...Radial clearance.

Claims (1)

[Scope of utility model registration request] An axial groove is formed on the inner peripheral surface of the housing that surrounds the rotating shaft.
The outer end thereof is provided with an opening in the end face of the housing,
A pivot having a hemispherical protrusion for supporting the tailing pad is fitted into this groove, a shim for adjusting the radial clearance is interposed between the pivot and the bottom of the groove, and the end surface of the housing is A tailing pad journal bearing characterized in that a lid body for holding the shim and the pivot in the groove is removably provided.