JP2565564Y2 - Foil journal bearings - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foil journal bearing which is formed by winding a continuous foil (elastic thin plate) in multiple turns and is mainly used as a bearing for a high-speed rotating machine.

[0002]

2. Description of the Related Art As a conventional foil journal bearing of this type, as shown in FIGS. 3 and 4, a large number of linear projections 3 are formed in a bush-shaped bearing case 1 on one side by etching or the like in the longitudinal direction. Long foils 2 protruding at intervals of a predetermined pitch P are stored in multiple windings so that the linear projections 3 face outward in the radial direction, and the bearing case is formed by the spring elasticity of the foils 2 outward in the radial direction. When the foil 2 is pressed against the inner bearing surface 1a and the foil 2 is wound multiple times, the radially inner foil 2 is interposed between the linear projections 3 extending in the axial direction of the radially outer foil 2. (Japanese Patent Application No. 61-188649) has been proposed in which the linear projections 3 are stacked so as to be positioned so that the journal 4 bears a load acting in a direction perpendicular to the axial direction.

[0003] In such a foil journal bearing, the journal 4 rotates in a floating state in the bearing case 1 in the presence of air, and air pressed during rotation enters between the laminated foils 2 to generate elasticity. Have 4 supported.

[0004]

However, in the conventional foil journal bearing described above, the continuous foil 2 is wound multiple times so that the linear projections 3 are on the outside so that elasticity is generated outward in the radial direction. Due to the configuration accommodated in the bearing case 1, each layer of the laminated foil 2 has a circular cross section, and each layer is in contact with a linear projection 3, but a predetermined distance is provided between the innermost layer and the journal 4. There is a gap in the journal 4
The foil cannot move immediately along with the movement of the linear projections 3, and the elasticity between the linear projections 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 foil so as to increase stability against self-excited vibration of the journal, and also to process the foil. It is intended to be easy.

[0006]

According to the present invention, in order to solve the above-mentioned problems, a plurality of grooves extending in the width direction over the entire length are different for each of a plurality of grooves inside a bearing case having an inner peripheral surface as a bearing surface. The foil provided at the pitch is stored in multiple windings by bending each groove as a fold, and each layer is formed into a multi-arc shape by the beam portion and the bent portion formed over the entire length of the multiple wound foil, The outermost layer bends are pressed against the bearing surface of the bearing case by the radially outward elastic force of the foil itself, and the inner layer bends are brought into contact with the outer layer beams to form a multi-arc bearing. Configuration.

[0007]

According to the present invention, each layer is formed into a multi-arc shape by a beam portion and a bent portion formed over the entire length of a multiply-wound foil. Is brought into contact with the beam of the outer layer, the beam of the foil is deformed along with the movement of the journal, and a stable bearing against self-excited vibration is obtained. When the beam portion is deformed, the elasticity of the beam portion and the frictional attenuation of the contact portion due to the contact of the bent portion are obtained, and the self-excited vibration generated by high-speed rotation of the journal can be suppressed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show an embodiment of the present invention. Similar to 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. Then, a continuous foil (elastic thin plate) 2 is housed as multiple windings, and the multilayer foil is pressed against the bearing surface 1a of the bearing case 1 by the radially outward elastic force of the foil 2 itself. In the configuration in which the journal 4 is supported, a large number of grooves 6, 7 extending in the width direction (axial direction at the time of assembly) at an appropriate pitch from one end to the other end in place of the foil 2 are formed on the upper surface A. Alternatively, a foil 5 having a configuration provided on the lower surface B is used.

More specifically, the foil 5 according to the present invention will be described.
Has an appropriate number (four in this embodiment) of grooves 6 extending in parallel at an appropriate pitch P on an upper surface A on one end side, and a pitch P ₁ narrower than the pitch P on the upper surface A on the other end side. in the groove 6 of the several suitable (six in the embodiment) provided, further, the thickness of the intermediate portion slightly thinner to its lower surface B, several suitable slightly narrower pitch P ₂ than the pitch P ₁ ( (In the embodiment, seven grooves) are provided, and inside the bearing case 1, the upper surface A is inward and the grooves 6 are provided at wide pitches P in order from the one end side, and are housed in a triple winding manner. Then, the foil 5 itself is pressed against and held against the bearing surface 1a of the bearing case 1 by the radially outward elastic force of the foil 5 itself.

The foil 5 housed in the bearing case 1 by being wound multiple times is bent with its elasticity and the grooves 6 and 7 as folds.
The innermost layer is deformed into a square shape, the second layer is deformed into a substantially heptagonal shape, and the outermost layer is deformed into a substantially hexagonal shape. As a result, the inside of the bearing case 1 has a structure composed of a multiple bent portion 5a formed by a large number of 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 of the work will work.

Therefore, when the journal 4 rotates at a high speed, if the journal 4 shakes, the beam 5b is elastically deformed along with the movement of the journal 4, and the frictional damping effect due to the movement of the bent portion 5a along with the deformation. Thereby, the self-excited vibration of the journal 4 can be suppressed.

The present invention is not limited to the above-described embodiment. For example, the grooves 6 provided in the foil 5 may be used.
The number 7 is an example, and it goes without saying that the number of grooves 6 and 7 may be changed to arbitrarily change the number of angles of the multi-arc.

[0014]

As described above, according to the foil journal bearing of the present invention, a large number of grooves extending in the width direction over the entire length are provided in the bearing case having the inner peripheral surface as the bearing surface. The foil provided in the above is bent and wound with each groove as a fold, and stored in a multiple winding, and each layer is formed into a multi-arc shape by a beam portion and a bent portion formed over the entire length of the multiple wound foil. The outermost layer is pressed against the bearing surface of the bearing case by its own radially outward elastic force, and the bent portion of each inner layer is brought into contact with the beam portion of the outer layer to form a multi-arc bearing. Because of the configuration, of the beams and bends that form a multi-arc in each layer, the self-excited vibration generated by high-speed rotation of the journal due to the elasticity of the beams and the friction damping effect due to the contact of the bends But As a result, the bearing can be made stable against self-excited vibration, and the foil can be manufactured easily with a simple structure provided with grooves, and furthermore, the foil can be a multi-arc bearing with multiple arcs in each layer. By doing so, it is possible to achieve an excellent effect that the elasticity of the beam portion and the frictional attenuation of the contact portion due to the bent portion can be more effectively exerted in each layer.

[Brief description of the 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 for 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 an exploded perspective view of the foil used in FIG. 3;

[Explanation of symbols]

1 bearing case 1a bearing surface 4 journal 5 foil 5a bent portion 5b beam portions 6 and 7 grooves P, P _1, P ₂ pitches

Claims (1)

(57) [Scope of request for utility model registration] 1. A foil in which a plurality of grooves extending in the width direction over the entire length are provided at different pitches for each of a plurality of grooves inside a bearing case having an inner peripheral surface as a bearing surface, and each of the grooves is bent as a fold. Each layer is formed into a multi-arc shape by a beam portion and a bent portion formed over the entire length of the multi-turned foil, and the bent portion of the outermost layer is formed by a radially outward elastic force of the foil itself. A foil journal bearing, which is pressed against a bearing surface of a bearing case and a bent portion of each inner layer is brought into contact with a beam portion of the outer layer to form a multi-arc bearing.