WO2017090531A1

WO2017090531A1 - Damper and bearing unit provided with same

Info

Publication number: WO2017090531A1
Application number: PCT/JP2016/084280
Authority: WO
Inventors: 真人吉野; 藤原　宏樹; 智彦小畑
Original assignee: Ntn株式会社
Priority date: 2015-11-26
Filing date: 2016-11-18
Publication date: 2017-06-01
Also published as: JP2017096442A

Abstract

A damper 1 is provided with the following: a first surface 21; a second surface 11 that faces the first surface 21, and that can move relative to the first surface 21; and a plurality of fibers 30 that are disposed between the first surface 21 and the second surface 11. The plurality of fibers 30 are fixed to the first surface 21 and can slide against the second surface 11.

Description

Damper and bearing unit having the same

The present invention relates to a damper and a bearing unit including the damper.

For example, Patent Document 1 discloses a squeeze film damper that uses a viscous resistance of oil to attenuate vibrations of a bearing or the like. A squeeze film damper is a type in which when a vibrating movable body comes close to a fixed body, a resistance force is generated by the flow and compression of a viscous fluid (for example, oil) filled between them, thereby damping the vibration of the movable body. It is. The squeeze film damper has a feature that it is easy to miniaturize because the vibration damping effect increases as the gap between the movable body and the fixed body is reduced.

Japanese Patent Laid-Open No. 07-119743

The squeeze film damper as described above can adjust the vibration damping effect by changing the gap width between the movable body and the fixed body, the type of oil (viscosity), and the like. However, since the gap width between the movable body and the fixed body and the type of oil cannot be easily changed in design, it is not easy to adjust the damping effect.

Therefore, the problem to be solved by the present invention is to provide a damper capable of easily adjusting the vibration damping effect.

The present invention relates to one surface, the other surface facing the one surface and movable relative to the one surface, and a large number disposed between the one surface and the other surface. And a damper in which the plurality of fibers are fixed to the one surface and are slidable on the other surface.

According to this damper, relative vibration between one surface and the other surface can be attenuated by friction energy when a large number of fibers fixed on one surface are slid with the other surface. it can. In this case, the damping effect of the damper can be easily adjusted by adjusting the fiber specifications (number, density, length, thickness, material, etc.).

In this damper, for example, a large number of fibers can be composed of short fibers extending from one surface to the other surface.

Further, the present invention is arranged between one surface, the other surface facing the one surface and movable relative to the one surface, and the one surface and the other surface. A plurality of fibers, the plurality of fibers having a first fiber fixed to the one surface and a second fiber fixed to the other surface, the first fiber And a damper capable of sliding with the second fiber.

In this damper, the relative vibration between one surface and the other surface can be attenuated by the frictional energy when the first fiber and the second fiber are slid. In this case, the damping effect of the damper can be easily adjusted by adjusting the specifications of the first fiber and the second fiber.

This damper may have a configuration in which the first fiber and the second fiber enter each other's fibers. In this case, since the contact area between the first fiber and the second fiber becomes very large, the damping effect of the damper can be greatly enhanced. Also, since the relative movement between the first surface and the second surface is restricted by the frictional force between the first fiber and the second fiber, other structures for positioning these surfaces with each other Can be omitted or simplified.

In this damper, for example, the first fiber is composed of short fibers extending from one surface to the other surface, and the second fiber is composed of short fibers extending from the other surface to one surface. can do.

Further, the present invention is arranged between one surface, the other surface facing the one surface and movable relative to the one surface, and the one surface and the other surface. And a damper having a large number of fibers and a viscous fluid (for example, oil) filled between the one surface and the other surface.

As described above, by arranging a large number of fibers in the gap filled with the viscous fluid, the flow resistance of the viscous fluid is increased and a high vibration damping effect can be obtained. In this case, by adjusting the specifications of the fiber, the flow resistance of the viscous fluid, and hence the damping effect of the damper can be easily adjusted.

In addition, in the above-described damper that attenuates vibration by frictional energy caused by sliding between the fiber and one surface or the other surface, or between fibers, fill the viscous fluid between one surface and the other surface. For example, in addition to the vibration damping effect due to the friction energy, the vibration damping effect due to the flow resistance of the viscous fluid can be obtained.

If a damper as described above is attached to the bearing, a bearing unit having a vibration control mechanism can be obtained. By the way, an air dynamic pressure bearing (for example, a foil bearing) that uses air as a pressure generating fluid does not fill the bearing gap with oil, and therefore cannot be expected to have a vibration damping effect due to the oil. In this case, since the damper attached to the bearing is required to have a high damping effect, it is preferable to apply the damper of the present invention. Specifically, the present invention provides a bearing unit including an air dynamic pressure bearing and the damper attached to the air dynamic pressure bearing. As the air dynamic pressure bearing, for example, a foil bearing including a foil having a bearing surface and a foil holder to which the foil is attached can be used.

As described above, according to the damper of the present invention, the relative vibration between one surface and the other surface can be attenuated by the frictional energy of many fibers. In this case, the damping effect of the damper can be easily adjusted by adjusting specifications such as the number of fibers.

It is sectional drawing of the damper which concerns on embodiment of this invention. It is an enlarged view of the fiber fixed to the movable body. It is sectional drawing of the damper which concerns on other embodiment. It is sectional drawing of the damper which concerns on other embodiment. It is sectional drawing of the damper which concerns on other embodiment. It is sectional drawing of the damper which concerns on other embodiment.

Hereinafter, embodiments of a damper according to the present invention will be described with reference to the drawings.

FIG. 1 shows a bearing unit including a damper 1 according to an embodiment of the present invention. The bearing unit includes a bearing 3 and a damper 1 attached to the outer periphery of the bearing 3. The bearing 3 is an air dynamic pressure bearing that rotatably supports the shaft 2 with the pressure of the air film. The bearing 3 of this embodiment is a foil bearing and includes a cylindrical foil holder 3a and one or more foils 3b attached to the inner peripheral surface of the foil holder 3a. When the shaft 2 rotates in the direction of the arrow, an air film is formed in the radial bearing gap R between the outer peripheral surface 2a of the shaft 2 and the inner diameter surface (bearing surface) of the foil 3b, and the shaft 2 is rotated by the pressure of the air film. It is supported freely.

The damper 1 includes a cylindrical fixed body 10, a cylindrical movable body 20 disposed on the inner periphery of the fixed body 10, an outer peripheral surface 21 (one surface) of the movable body 20, and an inner peripheral surface of the fixed body 10. 11 (the other surface) and a large number of fibers 30. Both the inner peripheral surface 11 of the fixed body 10 and the outer peripheral surface 21 of the movable body 20 form a cylindrical surface and face each other in the radial direction. The space between the fixed body 10 and the movable body 20 is filled with air. The outer peripheral surface of the fixed body 10 is fixed to a housing or the like (not shown), and the movable body 20 can be moved minutely with respect to the fixed body 10. The damper 1 is provided with positioning means for restricting movement of the movable body 20 with respect to the fixed body 10 in the shear direction (axial direction and circumferential direction) (not shown). It is preferable that this positioning means allows a minute movement of the movable body 20 with respect to the fixed body 10 and keeps the movement amount within a predetermined range.

The fiber 30 has one end (inner diameter end) fixed to the outer peripheral surface 21 of the movable body 20 and the other end (outer diameter end) extending toward the inner peripheral surface 11 of the fixed body 10. That is, the fiber 30 is in a state of rising from the outer peripheral surface 21 of the movable body 20 (a state substantially orthogonal to the outer peripheral surface 21 of the movable body 20). Specifically, as shown in FIG. 2, a large number of fibers 30 are composed of a large number of short fibers that are densely arranged on the outer peripheral surface 21 of the movable body 20. In the illustrated example, one end of the fiber 30 is fixed to the outer peripheral surface 21 of the movable body 20 via the sheet 40. Note that one end of the fiber 30 may be directly fixed to the outer peripheral surface 21 of the movable body 20. Alternatively, the movable body 20 may be omitted, and the sheet 40 on which a large number of fibers 30 are fixed may be directly attached to the outer peripheral surface of the foil holder 3a of the bearing 3.

The other end (outer diameter end) of each fiber 30 is a free end and is in contact with the inner peripheral surface 11 of the fixed body 10. The other end of the fiber 30 and the inner peripheral surface 11 of the fixed body 10 are not fixed. Therefore, when the movable body 20 vibrates with respect to the fixed body 10, the other end of the fiber 30 and the inner peripheral surface 11 of the fixed body 10 slide. In FIGS. 1 and 2, the length of each fiber 30 and the radial distance between the movable body 20 and the fixed body 10 are exaggerated. Moreover, in FIG. 1, in order to show that the other end of each fiber 30 is a free end, the fiber 30 and the inner peripheral surface 11 of the fixed body 10 are slightly separated from each other. is doing.

As the fiber 30, for example, a resin fiber made of a synthetic resin such as polyamide or polyester, or a natural fiber such as cotton or wool can be used. Among these, polyamide fibers are preferable because they are excellent in high temperature durability and stable in quality. If further strength is required, it is preferable to use aromatic polyamide fibers.

The fiber 30 is fixed to a construction surface (in this embodiment, the surface of the sheet 40) by electrostatic flocking, for example. Specifically, first, an adhesive is applied to the surface of the flat flexible sheet 40, and then the sheet 40 is grounded, and a negative potential of tens of thousands of volts is applied to an electrode on which a large number of fibers 30 are placed. Is applied. As a result, the polarized fibers 30 fly substantially perpendicular to the sheet 40, and one end of each fiber 30 is embedded in an uncured adhesive. Thereafter, the adhesive is cured to obtain a sheet 40 in which a large number of fibers 30 are densely planted. A large number of fibers 30 are fixed to the outer peripheral surface 21 of the movable body 20 by affixing the sheet 40 to the outer peripheral surface 21 of the movable body 20 while rolling the surface on which the fibers 30 are provided on the outer diameter side. The In addition, as a method for fixing the fibers 30 to the construction surface, electrostatic spraying flocking in which air is sprayed on the polarized fibers 30 to adhere to the construction surface may be employed.

In this embodiment, a large number of fibers 30 are composed of short fibers having the same specifications. Specifically, many fibers 30 are composed of short fibers having the same length, thickness, and material. Further, the fibers 30 are provided uniformly over the entire outer peripheral surface 21 of the movable body 20. If the fibers 30 are too short or too long, it is difficult to fix the fibers 30 to the outer peripheral surface 21 of the movable body 20 (in this embodiment, fixing to the sheet 40). For this reason, the length (average length) of the fibers 30 is desirably 0.3 to 5 mm, for example. Specifically, for example, when fixing the fiber 30 to the sheet 40 by electrostatic flocking, if the fiber 30 is less than 0.3 mm, the entire fiber 30 may be buried in the adhesive. If the fibers 30 are longer than 5 mm, the fibers 30 are entangled with each other at the time of flocking, and it is difficult to plant each fiber 30 on the sheet 40 substantially perpendicularly. The thickness (average thickness) of the fibers 30 is set in the range of, for example, 5 to 50 μm, preferably 10 to 30 μm.

When the shaft 2 rotates, the shaft 2 is rotatably supported by the pressure of the air film in the radial bearing gap R between the bearing surface of the foil 3b of the bearing 3 and the outer peripheral surface 2a of the shaft 2. When vibration occurs in the bearing 3, the vibration is transmitted to the damper 1 provided on the outer periphery of the bearing 3, and the movable body 20 of the damper 1 vibrates with respect to the fixed body 10. At this time, the other end of the large number of fibers 30 fixed to the movable body 20 and the inner peripheral surface 11 of the fixed body 10 slide, whereby the vibration of the movable body 20 due to the frictional energy caused by this sliding, and consequently the bearing 3. Vibration is attenuated.

According to the damper 1, the vibration damping effect can be easily adjusted by changing the configuration of the numerous fibers 30. For example, the damping effect of the damper 1 can be adjusted by changing one or more of the number (density), thickness, length, and material of the fibers 30. Specifically, for example, if the number of the fibers 30 is increased (that is, if the density of the fibers 30 is increased), the contact area between the fibers 30 and the inner peripheral surface 11 of the fixed body 10 increases, Since the friction energy is increased, the damping effect of the damper 1 can be enhanced.

The present invention is not limited to the above embodiment. Hereinafter, although other embodiment of this invention is described, description of the point which overlaps with said embodiment is abbreviate | omitted.

In the embodiment shown in FIG. 3, one end (outer diameter end) of the fiber 30 is fixed to the inner peripheral surface 11 of the fixed body 10, and the other end (inner diameter end) of the fiber 30 faces the outer peripheral surface 21 of the movable body 20. It differs from the above embodiment in that it extends. In the illustrated example, a large number of fibers 30 are fixed to the inner peripheral surface 11 of the fixed body 10 via the sheet 40. The other end (inner diameter end) of each fiber 30 is a free end, and can slide on the outer peripheral surface 21 of the movable body 20.

The damper 1 shown in FIG. 4 has one end fixed to the inner peripheral surface 11 of the fixed body 10 and the other end fixed to the outer peripheral surface 21 of the movable body 20 and a number of first fibers 31 having a free end. , And a plurality of second fibers 32 whose other ends are free ends. The first fiber 31 and the second fiber 32 enter between the fibers of the other party. Specifically, the other end (free end) of the first fiber 31 enters between the second fibers 32, and the other end (free end) of the second fiber 32 enters between the first fibers 31. .

If the bearing 3 vibrates during rotation of the shaft 2, the movable body 20 of the damper 1 vibrates with respect to the fixed body 10. At this time, the first fiber 31 fixed to the fixed body 10 and the second fiber 32 fixed to the movable body 20 slide, whereby the vibration of the bearing 3 is attenuated. Thus, by sliding the

fibers

31 and 32, compared to the case of sliding the fibers 30 and the inner peripheral surface 11 of the fixed body 10 or the outer peripheral surface 21 of the movable body 20 as in the above-described embodiment. As the sliding area is greatly increased, the vibration control effect is greatly improved.

Moreover, the friction coefficient of the shear direction (rotation direction and axial direction) with respect to the fixed body 10 of the movable body 20 by the 1st fiber 31 and the 2nd fiber 32 entering between each other's fibers as mentioned above. Is extremely high, the movable body 20 can be held against the fixed body 10 by the frictional force between the

fibers

31 and 32. Thereby, the positioning means for restricting the movement of the movable body 20 relative to the fixed body 10 in the shear direction can be omitted or simplified, and the structure of the damper 1 can be simplified.

Moreover, in the damper 1 shown in FIG. 4, it is good also as a structure like a hook-and-loop fastener by bending the front-end | tip (free end) of both the

fibers

31 and 32. FIG. In this case, since the intertwining force is increased by engaging both the

fibers

31 and 32 in the radial direction, the fixing force between the movable body 20 and the fixed body 10 is increased, and the movement in the shear direction is suppressed.

In the embodiment shown in FIG. 5, the gap between the fixed body 10 and the movable body 20 is filled with a viscous fluid (indicated by scattered points), and a large number of fibers 30 are arranged in the gap. In the illustrated example, the fiber 30 extends from the outer peripheral surface 21 of the movable body 20 to the outer diameter side. In the illustrated example, the free end (outer diameter end) of each fiber 30 stays at the intermediate portion in the radial direction between the fixed body 10 and the movable body 20 and does not slide on the inner peripheral surface 11 of the fixed body 10. It has become. Oil or water can be used as the viscous fluid, and oil is particularly preferable. A seal mechanism (not shown) for sealing the viscous fluid is provided at the opening (both ends in the axial direction) of the gap between the fixed body 10 and the movable body 20 filled with the viscous fluid.

When the movable body 20 vibrates with respect to the fixed body 10, the vibration is attenuated by the flow resistance of the viscous fluid of the damper 1. At this time, since a large number of fibers 30 are interposed between the fixed body 10 and the movable body 20, the flow resistance of the viscous fluid is increased and the vibration damping effect is enhanced. In this case, the flow resistance of the viscous fluid can be adjusted and the vibration damping effect can be adjusted by changing the specifications of the fiber 30 (fiber density, length, thickness, material, etc.).

Further, a configuration in which a large number of fibers 30 fixed to the movable body 20 are slid with the inner peripheral surface 11 of the fixed body 10 (see FIG. 1), and a large number of fibers 30 fixed to the fixed body 10 are outer peripheral surfaces 21 of the movable body 20. In a configuration (see FIG. 3) or a configuration in which a large number of fibers 31 fixed to the fixed body 10 and a large number of fibers 32 fixed to the movable body 20 are slid (see FIG. 4). If the gap between the movable body 20 and the movable body 20 is filled with a viscous fluid, it is possible to obtain a vibration damping effect due to the flow resistance of the viscous fluid in addition to the vibration damping effect due to the frictional energy when the fiber slides.

In the above embodiment, the case where the fiber 30 is provided in the entire region of the gap between the fixed body 10 and the movable body 20 is shown, but not limited to this, the gap between the fixed body 10 and the movable body 20 is not limited. You may provide the fiber 30 only in a partial area | region. For example, among the gaps between the fixed body 10 and the movable body 20, the fibers 30 may be provided in a plurality of regions spaced in the circumferential direction, and the fibers between the circumferential directions of these regions may be omitted.

Moreover, although the case where many fibers 30 were comprised with the fiber of the same specification was shown in the above embodiment, the specifications (length, thickness, material, density, etc.) of the fiber 30 may be varied. . For example, the specifications of the fiber 30 may be continuously changed in the circumferential direction. Alternatively, the fibers 30 may be provided in a plurality of circumferential regions, and the specifications of the fibers 30 in each circumferential region may be different. Or you may fix to the fixed body 10 or the movable body 20 in the state which mixed the multiple types of fiber 30 from which specifications differ.

Moreover, in the above embodiment, the case where the outer peripheral side member is the fixed body 10 and the inner peripheral side member is the movable body 20 is shown. However, the present invention is not limited to this. The side member may be a fixed body, or both members may be a movable body that is relatively movable.

Moreover, although the case where the damper 1 which concerns on this invention was attached to the radial bearing which supports a shaft in a radial direction was shown in the above embodiment, not only this but the damper concerning this invention is provided in a shaft. It is also possible to attach the thrust collar to a thrust bearing that supports the thrust collar in the thrust direction. For example, the damper 101 shown in FIG. 6 includes a disk-shaped fixed body 110 and a movable body 120, and a large number of fibers 130 arranged between the flat end surface 112 of the fixed body 110 and the flat end surface of the movable body 120. Prepare. As the thrust bearing, for example, an air dynamic pressure bearing, particularly a foil bearing is used.

The damper 101 shown in FIG. 6 has, for example, a configuration in which a large number of fibers 130 fixed to the movable body 120 are slid with the end surface 112 of the fixed body 110 (a configuration similar to FIG. 1), and a large number of fibers fixed to the fixed body 110. A configuration in which 130 is slid with the end face of the movable body 120 (a configuration similar to FIG. 3), a configuration in which a large number of fibers fixed to the fixed body 110 and a large number of fibers fixed to the movable body 120 are slid ( A similar configuration) or a configuration in which a large number of fibers 130 and viscous fluid are interposed between the fixed body 110 and the movable body 120 (a configuration similar to FIG. 5) can be applied. Moreover, each modification of the damper 1 of the said embodiment is applicable to the damper 101 shown in FIG.

The damper according to the present invention can be used, for example, for vibration control of a bearing incorporated in a turbo machine such as a gas turbine or a supercharger, a vehicle, an industrial device, or a home appliance. The damper according to the present invention is not limited to a bearing, and can be attached to a component that needs to attenuate vibration. In addition, when fixing a fiber using an adhesive agent, since it is necessary to use in a low temperature environment rather than the heat resistance of an adhesive agent, it is preferable to apply to the use used at normal temperature, for example.

1 damper 2 shaft 3 bearing 10 fixed body 11 inner peripheral surface (the other surface)
20 movable body 21 outer peripheral surface (one surface)
30 Fiber 31 First fiber 32

Second fiber

40, 42, 43 Sheet R Radial bearing clearance

Claims

One surface, the other surface facing the one surface and movable relative to the one surface, and a plurality of fibers disposed between the one surface and the other surface Prepared,
A damper in which the plurality of fibers are fixed to the one surface and slidable with the other surface.
The damper according to claim 1, wherein the plurality of fibers are composed of short fibers extending from the one surface toward the other surface.
One surface, the other surface facing the one surface and movable relative to the one surface, and a plurality of fibers disposed between the one surface and the other surface Prepared,
The plurality of fibers have a first fiber fixed to the one surface and a second fiber fixed to the other surface;
A damper in which the first fiber and the second fiber are slidable.
The damper according to claim 3, wherein the first fiber and the second fiber are inserted into each other's fibers.
The first fiber is composed of short fibers extending from the one surface toward the other surface, and the second fiber is composed of short fibers extending from the other surface toward the one surface. The damper according to claim 3 or 4.
The damper according to any one of claims 1 to 5, wherein a viscous fluid is filled between the one surface and the other surface.
One surface, the other surface facing the one surface and movable relative to the one surface, a number of fibers disposed between the one surface and the other surface; A damper comprising a viscous fluid filled between the one surface and the other surface.
The damper according to claim 6 or 7, wherein the viscous fluid is oil.
A bearing unit comprising an air dynamic pressure bearing and the damper according to any one of claims 1 to 8 attached to the air dynamic pressure bearing.
The bearing unit according to claim 9, wherein the air dynamic pressure bearing is a foil bearing including a foil having a bearing surface and a foil holder to which the foil and the damper are attached.