JPH01242816A - Dynamic pressure thrust fluid bearing - Google Patents

Abstract

PURPOSE:To prevent thermal deformation effectively by providing an underlayer of a spring foil with bearing foils, and providing a shim foil having pillow-like projections and fluid supply ports in underlayer of the bearing foils. CONSTITUTION:Bearing foils 20 having a pad piece 11 respectively are provided in underlayer of a spring foil 10 having filament projections 1 and pad piece inserting holes 2, and a shim foil 30 having pillow like projections 21 and fluid supply ports 22 is provided in underlayer of the bearing foils 20. Revolution speed of a runner 50 gets the faster, the greater becomes heat generation due to fluid friction, but thereby also flowing in from the fluid supply ports 22 increases in proportion thereto, therefore the pad pieces 11 are cooled effectively with the fluid and thermal deformation can be prevented effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a hydrodynamic thrust fluid bearing whose bearing surface is made of an elastic foil, and particularly to a tapered land type bearing tapered by pads.

[Prior Art] The construction of a tapered land type bearing by attaching a taper with a foil pad is disclosed in, for example, Japanese Patent Laid-Open No. 61-165011.
It is known from the publication no.

However, in this known bearing, the pad is connected to the pad foil body at one point, so it is necessary to reinforce the pad by welding the connecting end of the pad to the back foil laminated under the pad foil. . For this reason, there have been disadvantages in that the machining is troublesome and the positioning accuracy during welding is also difficult.

Also, the back foil laminated under the pad foil is in the form of a continuous ring and has no slits or holes, so r! J
The heat generated in the pad due to rubbing cannot be effectively dissipated downward.

Therefore, when the bearing rotates at high speed, the pad is thermally deformed due to heat generation, resulting in deterioration of bearing performance.

[Problems to be Solved by the Invention] As mentioned above, conventional thrust bearings have the drawbacks that the pads are welded, which is cumbersome to work with, and that the heat generated in the pads cannot be effectively dissipated. Ta.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hydrodynamic thrust fluid bearing that eliminates the problems of the prior art described above, eliminates the need for welding, and can effectively prevent thermal deformation.

[Means for Solving the Problems] The hydrodynamic thrust fluid bearing of the present invention is constructed by laminating in order from above a spring foil having a spring function, a bearing foil having a bearing function, and a shim foil having a backup function. be done.

The spring foil has linear protrusions arranged alternately on the front and back sides along the rotational direction of the runner of the rotating shaft, and windows for inserting pads that interrupt the linear protrusions are provided at appropriate intervals.

The bearing foil integrally has a pad piece that can be cut and bent, and this pad piece is inserted through a window of the spring foil to form a tapered land that can be supported by a linear projection of the spring foil.

The shim foil has a pillow-like projection that supports the linear projection of the spring foil and reinforces the taper land, and is also provided with a fluid supply hole that communicates with the window through the cut-and-raised gap between the pad pieces.

[Function] When the pad piece is inserted through the window of the spring foil, the pad piece rides on the spring foil in an inclined manner, so that a structural wedge-shaped gap is formed between the pad piece and the runner.

As the runner rotates, the fluid is dragged by its viscosity and forced into the wedge-shaped gap, creating pressure.

The inclined pad piece is pressed toward the lower layer side by this pressure and tries to become flat, but it maintains its tapered land because it is supported by the linear projection of the spring foil and the pillow-like projection of the shim foil.

In addition, each pad piece is independently divided by the fluid supply hole that communicates with the window through the cut-and-raised gap between the pad pieces, so that it functions as an independent bearing, so the runner will not tilt due to unbalanced loads. However, the tapered land has a restoring force and high angular rigidity.

On the other hand, as the rotation speed of the runner increases, heat generation due to fluid friction increases, but the amount of fluid flowing in from the fluid supply hole also increases in proportion to this, so that the pad piece is effectively cooled by this fluid.

[Example] Hereinafter, an example of the present invention will be described using FIGS. 1 to 4.

FIG. 2 shows an exploded view of an example of the dynamic pressure thrust fluid bearing of the present invention. As can be seen from the figure, this bearing consists of three disc-shaped foils punched out around the rotating shaft hole, and the spring foils 10. Bearing foil 20.
Shim foil 30 is laminated.

The spring foil 10 has a large number of linear protrusions 1 arranged alternately on the front and back sides and extending in the radial direction along the rotation direction (arrow ω) of a runner (not shown) of the rotation shaft. are doing. The linear protrusion 1 is formed by digging into the land portion by photoetching. The etched areas are shown in matte finish. Further, the spring foil 10 is provided with windows 2 for inserting pad pieces at appropriate intervals in a shape that interrupts the linear protrusion 1.
Similarly, multiple pieces are etched by photoetching. In the illustrated example, six windows 2 are provided, and four linear protrusions 1 are provided between the windows 2, but these numbers are not limited to the illustrated example.

The pitch between the linear protrusions 1 is gradually narrowed in the direction of rotation between the windows 2 to increase rigidity.

The bearing foil 20 has six pad pieces 11 corresponding to the windows 2. This pad piece 11 is fan-shaped, and is formed by etching a substantially inverted opening-shaped slit groove around the pad piece 11 so that about two-thirds of its length can be cut and raised.

Pad piece 1 adjacent to the tilling edge of pad piece 11
The slit groove 12, which serves as a cut-and-raised gap between the leading edge 1 and the leading edge 1, is made slightly wider than the slit groove 12 in order to be used as a fluid introduction hole. When the foils are laminated, in order to make the pillow-like protrusions 21 of the shim foil 30 effective, the land portion of the foil except for the pad piece 11 is dug out by etching.

The shim foil 30 has six pillow-like protrusions 21 on its surface for supporting the pad pieces 11 of the bearing foil 20 via the linear protrusions 1 of the spring foil 10. This pillow-shaped protrusion 21 is provided to counteract loads that cannot be supported by the spring foil 10 on the pad piece 11. The position of the pillow-shaped protrusion 21 relative to the pad piece 11 is located where the fluid film pressure exhibits the maximum value. As described above, the land portion is dug down by photoetching to form the pillow-like protrusion 21. Further, the shim foil 30 is provided with a fluid supply hole 22 for actively supplying fluid from the outside of the bearing to the inside of the bearing. The fluid supply hole 22 is a long hole extending in the radial direction, and its radially outer end extends to the attachment hole 24 of the attachment piece 23 that projects outward from the outer circle of the disc-shaped shim foil 30. Further, the position of the fluid supply hole 22 is such that the counter-rotation direction side of the window 2 of the spring foil 10 and the slit groove 12 between the pad pieces 11 are aligned and communicated with each other, so that the fluid supplied from the fluid supply hole 22 is passed through the slit groove 12. It can be installed within Windows 2.

Attachment pieces 3.13.degree. 23 with attachment holes 4, 14 and 24 are provided protruding from the outer periphery of each of the foils 10, 20.30 described above. In the example, six are provided, but
By matching these between each foil 10, 20, 30, positioning between the foils is achieved.

Note that the attachment piece for the attachment hole may not be a projecting piece as in the illustrated example, but may be a circular outer edge portion formed by enlarging the outer circle of the foil a little more radially outward.

FIG. 3 is an assembled view in which the pad piece 11 of the second layer of bearing foil 20 is inserted through the window 2 of the first layer of spring foil 10 and placed on the top layer. The insertion is performed up to about 273 of the total length of the pad piece 11 which can be cut and raised. When inserted this far, the insertion pad piece 11 rides on the edge of the window 2, as shown in FIG. 1, and structurally forms an inclined plane or tapered land above the spring foil 10.

As shown in FIG. 4, the laminated foil is attached to the bearing case 4.
0, but if a fluid guide tM41 is provided on the surface of the bearing case 40 corresponding to the fluid supply hole 22 position,
Fluid can be supplied to the pad piece 11 more smoothly.

Further, when the runner 50 receiving the load W moves in the direction of the arrow, the pad piece 11 moves between the spring foil 20 and the shim foil 30.
A tapered land A as shown in the figure is formed by being supported by the fluid supply hole 22 and has a peak at the position of the pillow-like protrusion 21.
A wedge-shaped fluid film pressure exhibiting atmospheric pressure is generated at the groove 41 position.

At this time, the external fluid introduced from the groove 41 and supplied from the fluid supply hole 22 has a cooling effect that actively cools the pad piece 11.

[Effect of the invention] According to the present invention, there are the following effects.

(1) A wedge-shaped gap is created by simply inserting the pad piece of the bearing foil through the window of the spring foil.
It is much easier to work with than conventional ones that require welding. Furthermore, since the pad piece inserted through the window is supported by the linear protrusion of the spring foil and the pillow-like protrusion of the shim foil, a tapered land can be secured even when the rotational speed increases, and excellent high-speed stability is achieved.

(2) Each pad piece is divided independently by a fluid supply hole that communicates with the window through the cut-and-raised gap between the pad pieces, so even if an uneven load is applied to the launch, restoring force can be easily generated. Therefore, the angular rigidity is extremely large. Furthermore, since fluid is actively supplied from the fluid supply hole, a cooling effect is exerted and the device is extremely resistant to thermal deformation.

[Brief explanation of the drawing]

FIG. 1 is a circumferential cross-sectional view showing an embodiment of a hydrodynamic thrust fluid bearing according to the present invention, FIG. 2 is an exploded plan view of the entire thrust fluid bearing shown in FIG. 1, and FIG. FIG. 4, which is also an assembly plan view, is a thrust foil state diagram and a fluid film pressure characteristic diagram at high speed. In the figure, 1 is a linear projection, 2 is a window, 10 is a spring foil, 1
1 is a pad piece, 12 is a slit groove as a cut and raised gap,
20 is a bearing foil, 21 is a pillow-shaped projection, 22 is a fluid supply hole, 30 is a shim foil, 50 is a runner, and A is a tapered land. Patent Applicant: Ishikawajima Harima Heavy Industries Co., Ltd. Representative Patent Attorney Nobuo Kinuya Figure 3 Figure 4

Claims (1)

[Claims] 1. A spring foil having linear protrusions arranged alternately on the front and back sides along the rotation direction of the runner of the rotating shaft, and the spring foil is provided with windows interrupting the linear protrusions at appropriate intervals. A bearing foil integrally having a pad piece that can be cut and raised is provided below the spring foil, and the pad piece is inserted through a window of the spring foil to form a tapered land that can be supported by a linear protrusion of the spring foil. The lower layer of the bearing foil is equipped with a shim foil having a pillow-like projection that supports the linear projection of the spring foil and reinforces the taper land, and the shim foil has a fluid supply that communicates with the window through the cut and raised gap between the pad pieces. A hydrodynamic thrust fluid bearing with holes.