JPH0676716U - Foil journal bearing - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent self-excited vibration that occurs when the journal rotates at high speed. [Structure] The foil 5 is housed in a bush-shaped bearing case 1 in a multiple winding manner. The foil 5 is pressed against the bearing surface 1a of the bearing case 1 by the elastic force of the multi-wrapped foil 5 itself in the radial direction. The foil 5 is provided with a large number of grooves 6, 7 so that the grooves 6 and 7 can be bent in a multi-arc shape, and the bent portion 5a and the beam portion 5b between the bent portions 5a are formed.
To form. The bent portions 5a contact each other between the layers, and the beam portions 5b
Due to the elasticity of and the friction damping of the contact portion of the bent portion 5a, self-excited vibration that occurs when the journal 4 rotates at high speed is suppressed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a foil journal bearing suitable for use mainly as a bearing of a high-speed rotating machine by winding a continuous foil (elastic thin plate) in multiple turns.

[0002]

[Prior art]

 As a conventional foil journal bearing of this type, as shown in FIGS. 3 and 4, an example is shown in FIG. 3 and FIG. 4, in which a plurality of linear projections 3 are formed on one surface of a bush-shaped bearing case 1 by etching or the like at a predetermined pitch P in the longitudinal direction. The long foils 2 protruding at intervals are housed in multiple windings so that the linear projections 3 face outward in the radial direction. The foil 2 itself springs outward in the radial direction, and When the foil 2 is wound multiple times while being pressed against the bearing surface 1a, the line of the foil 2 on the radially inner side is provided between the linear projections 3 extending in the axial direction of the foil 2 on the radially outer side. It has been proposed that the protrusions 3 are stacked so that they are positioned so that the journal 4 bears a load acting from a direction perpendicular to the axial direction (Japanese Patent Application No. 61-188649).

In such a foil journal bearing, the journal 4 rotates in the bearing case 1 in a floating state in the presence of air, and the air pushed during the rotation enters between the laminated foils 2 to generate elasticity. , Support journal 4.

[0004]

[Problems to be solved by the device]

 However, in the conventional foil journal bearing described above, the continuous foil 2 is housed in the bearing case 1 in such a manner that the linear projection 3 is placed on the outer side in multiple turns so as to generate an elastic force outward in the radial direction. Each layer of the laminated foil 2 has a circular cross section, and the layers are in contact with each other by the linear protrusions 3. However, there is a predetermined gap between the innermost layer and the journal 4, and the journal 4 The foil cannot move immediately along with the movement, and the elasticity between the linear protrusions 3 is weak, so that there is a problem in stability against self-excited vibration.

In view of the above, the present invention provides elasticity to at least the innermost portion of the laminated foils so that the journal is highly stable against self-excited vibration, and the foils are processed. Is also trying to be easy.

[0006]

[Means for Solving the Problems]

 SUMMARY OF THE INVENTION In order to solve the above problems, the present invention stores a foil in a multi-winding manner inside a bearing case having an inner peripheral surface as a bearing surface, and the bearing case is elastically outward in the radial direction of the foil itself. It is configured to be pressed against the bearing surface, and at least the innermost layer is formed into a multi-arc shape to form a beam portion and a bent portion, and the bent portion is in contact with the outer layer.

[0007]

[Action]

 When at least the innermost part of the multiple-wrapped foil is deformed into a multi-arc shape, the beam part of the foil is deformed along with the movement of the journal, and the bearing becomes stable against self-excited vibration. When the beam part is deformed, the elasticity of the beam part and the friction damping of the contact part due to the contact of the bent part are obtained, and the self-excited vibration generated by the high speed rotation of the journal can be suppressed. Also, if a large number of grooves are provided over the entire length of the foil, the multi-layer can be deformed into a multi-arc shape by multiple winding, resulting in a multi-arc bearing.

[0008]

【Example】

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

FIG. 1 and FIG. 2 show an embodiment of the present invention, and like the conventional foil journal bearing shown in FIG. 3, the inside of a bush-shaped bearing case 1 having an inner peripheral surface as a bearing surface 1a. The continuous foil (elastic thin plate) 2 is housed as multiple windings, and the elastic force of the foil 2 itself in the radial direction causes the multilayer foil to be pressed into contact with the bearing surface 1a of the bearing case 1. In the structure in which the threaded journal 4 is supported, instead of the foil 2, a large number of grooves 6, 7 extending in the width direction (axial direction during assembly) by an appropriate pitch from one end to the other end. Is used on the upper surface A or the lower surface B.

More specifically, the foil 5 according to the present invention is provided with an appropriate number (four in this embodiment) of grooves 6 extending in parallel at an appropriate pitch P 1 on the upper surface A on one end side and the upper surface on the other end side. An appropriate number of grooves 6 (six in the embodiment) are provided at A at a pitch P ₁ narrower than the pitch P, and the intermediate portion is made slightly thinner to provide the pitch P _{1 at the} lower surface B. An appropriate number (seven in the embodiment) of grooves 7 are provided at a pitch P ₂ slightly narrower than the above, and the grooves 6 are provided inside the bearing case 1 with the upper surface A inside and at a wider pitch P. The foil 5 is housed in such a manner that it is wound in a triple manner from the one end side to the outside, and is pressed against the bearing surface 1a of the bearing case 1 by the radial outward force of the foil 5 itself to be held.

The foil 5, which is housed in the bearing case 1 by being wound in multiple layers, is bent by the elasticity of the foil 5 and the grooves 6 and 7, so that the innermost portion of the foil 5 can be bent according to the number of the grooves 6 and 7. It is deformed into a quadrangular shape on the side, an approximately heptagonal shape on the second layer, an approximately hexagonal shape on the outermost side, and an overall polygonal shape. As a result, the inside of the bearing case 1 has a structure composed of a bent portion 5a formed by multiple grooves 6 and 7 and a linear beam portion 5b, and the elasticity of the beam portion 5b and the contact portion at the bent portion 5a. The friction and damping that are possessed become effective.

Therefore, when the journal 4 swings at a high speed when the journal 4 swings, the beam portion 5b elastically deforms along with the movement of the journal 4, and the bending portion 5a moves due to this deformation, which causes friction. The damping effect makes it possible to suppress the self-excited vibration of the journal 4.

It should be noted that the present invention is not limited to the above-mentioned embodiment, and for example, the case where the foil 5 is made into three layers and each layer has a multi-arc shape is shown. However, the innermost layer has many layers. If it is an arc, the second layer and the third layer may be arcs. The number of grooves 6 and 7 provided in the foil 5 is an example, and the number of grooves 6 and 7 can be changed to set the number of angles of multiple arcs arbitrarily. Needless to say, change to

[0014]

[Effect of device]

 As described above, according to the foil journal bearing of the present invention, since the foil is housed in the bearing case by multiple winding, and at least the innermost layer is formed into the multi-arc shape, the multi-circle is formed. Of the beams and bends that are formed, the elasticity of the beams and the friction damping effect of the contact of the bends can suppress the self-excited vibration that occurs when the journal rotates at high speed. It is possible to make the bearing stable and stable, and the foil has a simple structure with grooves so that it can be easily manufactured. When the layers are wound, each layer becomes a multi-circle so as to form a multi-circle bearing, which makes it possible to more effectively reduce the elasticity of the beam and the friction damping of the contact part due to the bent part. It can be use, an excellent effect.

[Brief description of drawings]

FIG. 1 is a sectional view showing an assembled state of a foil journal bearing of the present invention.

FIG. 2 is an exploded perspective view of a foil used in the foil journal bearing of the present invention.

FIG. 3 is a sectional view showing an example of an assembled state of a conventional foil journal bearing.

FIG. 4 is a developed perspective view of the foil used in FIG.

[Explanation of symbols]

1 Bearing case 1a Bearing surface 4 Journal 5 Foil 5a Bent part 5b Beam part 6,7 Groove P, P ₁ , P ₂ pitch

Claims (1)

[Scope of utility model registration request] 1. A bearing case having an inner peripheral surface as a bearing surface, wherein the foil is housed in a multi-winding manner and is pressed against the bearing surface of the bearing case by elastic force of the foil itself in a radial direction. A foil journal bearing, wherein at least the innermost layer has a multi-arc shape, a beam portion and a bent portion are formed, and the bent portion is in contact with the outer layer.