WO2019172328A1

WO2019172328A1 - Bearing vibration damping device

Info

Publication number: WO2019172328A1
Application number: PCT/JP2019/008919
Authority: WO
Inventors: 智也中村; 奈央林; 聡川崎; 満島垣
Original assignee: Ntn株式会社; 国立研究開発法人宇宙航空研究開発機構
Priority date: 2018-03-07
Filing date: 2019-03-06
Publication date: 2019-09-12
Also published as: JP2019157869A

Abstract

The present invention addresses the problem of preventing an external flow of worn powder from an accommodating space filled with spherical particles in a vibration damping device using the spherical particles as a damper element. This bearing vibration damping device is characterized by: an inner cylinder (4) that can be displaced in a radial direction with respect to an apparatus housing (3); and anti-powder dust seals (12a)(12b) which, in order to prevent a flow of worn powder from an accommodating space (7) provided between an outer peripheral surface of the inner cylinder (4) and an inner peripheral surface of the apparatus housing (3) and filled with spherical particles (6) for producing an anti-vibration action using vibrational friction, are disposed on both sides in an axial direction of the accommodating space (7) filled with the spherical particles (6).

Description

Vibration damping device for bearing

The present invention relates to a vibration damping device for a bearing that suppresses vibrations of a bearing that supports a high-speed rotating shaft such as a rocket engine turbo pump.

高速 In high-speed rotating shafts such as rocket engine turbo pumps, shaft vibration such as forced vibration and self-excited vibration at dangerous speeds is often a problem.

Jet engines and the like employ a squeeze film damper that obtains a vibration damping effect using the viscosity of a lubricating oil as a vibration damping device for a rotating shaft.

However, lubricating oil cannot be used in oilless equipment or rocket engine turbo pumps operated at extremely low temperatures.

For this reason, conventionally, as a vibration damping device for a high-speed rotation shaft such as a rocket engine turbo pump, a ring-shaped wire mesh is disposed between the rotation shaft and the equipment housing, and the force generated by the vibration of the rotation shaft A vibration damping device called a wire mesh damper, which deforms a ring-shaped wire mesh and dissipates vibration energy by friction generated between the wires to attenuate the vibration of the rotating shaft, was introduced in Patent Document 1. ing.

Although the wire mesh damper introduced in this Patent Document 1 can directly apply a damping force to the rotating shaft, the wire mesh is arranged in a ring shape to obtain a damping action, so that the wire mesh is arranged for each device. There is a problem that the shape is easily different and the attenuation performance varies.
By the way, Non-Patent Document 1 introduces the use of spherical particles as a damper element as a vibration damping device for devices operating at extremely low temperatures and oil-free devices, similar to wire mesh dampers.

The vibration damping device using spherical particles as a damper element introduced in Non-Patent Document 1 generally has the following structure shown in FIG.

A vibration damping device 21 using spherical particles 20 as a damper element shown in FIG. 5 includes a device housing 24 of a rotating machine arranged on the outer surface of a bearing 23 that supports a rotating shaft 22 in the rotating machine, and the device. An inner cylinder 25 that is disposed between the inner peripheral surface of the housing 24 and the outer surface of the bearing 23 and can be displaced in the radial direction with respect to the device housing 24, and the outer peripheral surface of the inner tube 25 and the inner periphery of the device housing 24 A storage space 26 provided between the surface and filled with the spherical particles 20 that generate a damping action by vibration friction, and the storage space 26 disposed at the end in the axial direction of the storage space 26 is filled. And a preload ring 27 for applying a preload in the axial direction to the spherical particles 20.

In the vibration damping device 21 using the spherical particles 20 as a damper element, when radial axial vibration is generated on the rotary shaft 22 of the rotary machine, a radial displacement is generated in the inner cylinder 25 via the bearing 23, and the displacement is caused by the displacement. The spherical particles 20 in the housing space 26 flow, and this flow causes friction between the spherical particles 20, between the spherical particles 20 and the inner cylinder 25, and between the spherical particles 20 and the equipment housing 24. Vibration energy is dissipated by this, and it acts as a damper.

When the spherical particle 20 is used as a damper element, the parameters that are considered to affect the characteristics include the particle diameter of the spherical particle 20, the outer diameter of the inner cylinder 25, the inner diameter of the device housing 24, the length of the accommodating space 26, and the preload. The preload by the ring 27, the particle material of the spherical particles 20, the coefficient of friction between the spherical particles 20, and the equipment (controlled by the surface material), these can be industrially controlled and compared to the wire mesh damper Therefore, improvement of quality stability can be expected.

Japanese Patent Laid-Open No. 3-42111

By the way, when the practical application of the vibration damping device 21 using the spherical particle 20 introduced in Non-Patent Document 1 as a damper element is considered, the collision between the spherical particles 20, the collision between the spherical particles 20 and the inner cylinder 25. Alternatively, it is necessary to take measures against contamination of peripheral equipment due to wear powder generated by collision between the spherical particles 20 and the equipment housing 24.

Further, when the vibration damping device 21 using the spherical particles 20 as a damper element is used in a cryogenic environment, the friction surface is prevented from sticking due to freezing of water existing in the storage space 26 filled with the spherical particles 20. Without this, a sufficient damper function cannot be maintained.

Therefore, the present invention can be used even in a cryogenic environment by preventing wear powder from flowing out of the storage space filled with spherical particles to the outside, and preventing freezing of moisture in the storage space. It is an object of the present invention to obtain a vibration damping device using a spherical particle as a damper element.

In order to solve the above-described problems, the present invention provides a device housing disposed at an interval on an outer surface of a bearing that supports a rotating shaft in a rotating machine, an inner peripheral surface of the device housing, and an outer surface of the bearing. An inner cylinder that is disposed with a gap therebetween and is radially displaceable with respect to the device housing, and vibration friction that is provided between the outer peripheral surface of the inner cylinder and the inner peripheral surface of the device housing. A storage space filled with spherical particles that generate a vibration action, and a preload ring that is disposed on the side of the storage space in the axial direction and applies axial preload to the spherical particles filled in the storage space. In the vibration damping device for a bearing, the wear particles of the spherical particles are removed from gaps provided between the inner peripheral surface of the device housing and the outer peripheral surface of the inner cylinder on both sides in the axial direction of the storage space filled with the spherical particles. Dust resistant to prevent outflow Characterized in that a Lumpur.

In addition, it is preferable that an air vent channel that connects the inside of the housing space and the external environment is provided in the device housing.
By the air vent channel, air inside the accommodation space is discharged to the outside environment, and cryogenic gas or cryogenic liquid flows into the accommodation space from the outside environment. As a result, air can be replaced with a cryogenic gas or a cryogenic liquid, and the movement between particles is prevented from being suppressed due to the solidification of moisture contained in the air present in the storage space. Attenuation characteristics can be obtained by generating particle movement even in a low temperature environment.

It is preferable to install a dust-proof filter in the air vent channel.
The material forming the dust-proof filter is preferably a nonwoven fabric made of meta-type wholly aromatic polyamide or polytetrafluoroethylene (PTFE). The non-woven fabric can prevent the wear particles of the spherical particles from flowing out, and the air inside the housing space is released to the external environment while the dust-proof filter is installed in the air vent flow path. The cryogenic gas or the cryogenic liquid can flow into the housing space.

The material forming the dust-proof filter can be a porous sintered metal using austenitic stainless steel such as SUS304 or SUS316. The shape and size of the mesh can be selected in accordance with the shape of the foreign material by austenitic stainless steel.

The spherical particles may be made of SUS440C or Si3N4, and may be of the same size or a combination of different sizes.

As described above, in the vibration damping device for a bearing according to the present invention, the space between the outer peripheral surface of the inner cylinder that forms the accommodating space filled with the spherical particles that generate the damping action by vibration friction and the inner peripheral surface of the equipment housing. Since it is necessary to provide a gap that allows displacement of the inner cylinder in the radial direction, the storage space is filled by installing dust-proof seals on both sides in the axial direction of the storage space for filling the spherical particles. It is possible to prevent the wear powder generated by the friction of the spherical particles from leaking to the outside environment.

If both ends of the housing space in the axial direction are sealed with a dust-proof seal as described above, air can not be ventilated between the spherical particles filled in the housing space, so that the interior of the housing space is connected to the external environment. By installing the air vent flow path in the equipment housing, in the case of equipment used at cryogenic temperatures, use the air vent flow path to move the air in the housing space to hydrogen gas or Since it can be replaced with oxygen gas, it is possible to prevent the moisture contained in the air in the storage space filled with the spherical particles from freezing.

It is a schematic sectional drawing which shows embodiment of the vibration damping device which used the spherical particle which concerns on this invention as the damper element. It is an enlarged view of the accommodation space part with which the spherical particle | grains of FIG. 1 were filled. It is a perspective view which shows the relationship between the apparatus housing and inner cylinder of the vibration damping apparatus of FIG. It is a schematic sectional drawing which shows embodiment which installed the dust-proof filter in the flow path for ventilation of the vibration damping device of FIG. It is the schematic of the vibration damping device which made the spherical particle introduced into the nonpatent literature 1 the damper element.

Hereinafter, a first embodiment of a vibration damping device 1 using spherical particles as damper elements according to the present invention will be described with reference to the accompanying drawings.

The rotary shaft 2 in the rotary machine of this embodiment is rotatably supported on the inner peripheral surface of a cylindrical device housing 3 via an inner cylinder 4 and a bearing 5. In this embodiment, as the bearing 5, a rolling bearing including an inner ring 5a, an outer ring 5b, and a rolling element 5c accommodated between the inner ring 5a and the outer ring 5b is used.

Between the inner peripheral surface of the device housing 3 and the outer peripheral surface of the inner cylinder 4, a storage space 7 for storing spherical particles 6 that are damper elements is provided.

As a material for forming the device housing 3 and the inner cylinder 4, nickel alloy, SUS304, SUS304L, SUS316, SUS16L, SUS316LN, or the like can be used.

At one end in the axial direction of the inner cylinder 4, the inner cylinder 4 is supported so as to be displaceable in the radial direction with respect to the equipment housing 3, and the inner cylinder is supported elastically so as to match the axis of the equipment housing 3. The springs 8 are provided at equal intervals in the circumferential direction.

As shown in FIGS. 1 and 3, the inner cylinder supporting spring 8 includes a protruding piece 8a extending outward in the axial direction of the device housing 3, and a radially outer diameter side from the outer end of the protruding piece 8a. The bent piece 8b is formed into a U-shape composed of a bent piece 8b and a folded piece 8c folded in the axial direction from the outer diameter end of the bent piece 8b. Is engaged.

An inward flange 3 a that forms one end surface of the accommodation space 7 is formed at one end of the inner peripheral surface of the device housing 3. Between the inner peripheral surface of the inward flange 3 a and the outer peripheral surface of the inner cylinder 4. Is provided with a gap a that allows the inner cylinder 4 to be displaced in the radial direction. The gap a is set to a size that prevents the spherical particles 6 that are damper elements from leaking out.

A fixing flange 3b protruding toward the outer diameter in the radial direction is formed on the outer peripheral surface opposite to the outer peripheral surface of the device housing 3 with which the inner cylinder supporting spring 8 is engaged. A ring plate 9 forming the other end face of the accommodation space 7 is fixed by a bolt 10.

A pair of fixing

rings

11a and 11b that do not move in the axial direction are disposed at both ends of the housing space 7 in the axial direction. Between the inner peripheral surface of the pair of fixing

rings

11a and 11b and the outer peripheral surface of the inner cylinder 4, there is provided a gap b that enables displacement of the inner cylinder 4 in the radial direction, and this gap b is a damper element. Is set to a size that prevents the spherical particles 6 from leaking out.

A preloading ring 13b is provided on the housing space 7 side of one of the pair of fixing

rings

11a and 11b via a preloading spring 13a so as to be movable in the axial direction. Between the inner peripheral surface of the preload ring 13b and the outer peripheral surface of the inner cylinder 4, there is provided a gap c that allows the inner cylinder 4 to be displaced in the radial direction. The gap c is a spherical particle that is a damper element. 6 is set to a size that does not leak.

The storage space 7 is filled with spherical particles 6. As the spherical particle 6, for example, a steel ball (SUS440C) or a ceramic ball (Si3N4) having a particle diameter of about 1 mm can be used. The spherical particles 6 may all be the same size or may be a combination of different sizes.

In the axial direction of the fixing rings 11a and 11b provided in the storage space 7, dust particles are prevented so that wear powder generated by friction of the spherical particles 6 filled in the storage space 7 does not leak to the outside.

Seals

12a and 12b are provided.

The dust-

proof seals

12a and 12b have low rigidity so that the radial displacement of the inner cylinder 4 is not hindered, and have an initial interference that does not cause a gap even if the radial displacement of the inner cylinder 4 occurs. doing.

By the way, the rocket engine turbo pump is a rotary machine that pumps a propellant to the combustor, and mainly uses liquid oxygen and liquid hydrogen as the propellant, so that the vicinity of the bearing 5 of the rotating shaft 2 is in a cryogenic environment. . In the case of such a device used at a very low temperature, the air in the accommodation space 7 is prevented from freezing before the water is contained in the accommodation space 7 filled with the spherical particles 6 before the cryogenic environment. Is preferably replaced with a propellant gas (for example, hydrogen gas or oxygen gas).

However, if the storage space 7 is sealed with the dust-

proof seals

12a and 12b as described above, air can not be ventilated between the spherical particles 6 filled in the storage space 7, so that the propellant is contained in the storage space 7. It cannot be replaced with gas.

Therefore, in the embodiment shown in FIG. 1, an air vent channel 14 that connects the inside of the housing space 7 and the external environment is provided between the device housing 3 and the ring plate 9.

Further, in the second embodiment shown in FIG. 4, a dust-proof filter 15 is installed at the outlet of the air vent channel 14.

Next, the operation of the vibration damping device using the spherical particle 6 as a damper element will be described.

As shown by the arrow X1 in FIG. 1, when an axial displacement occurs due to vibration, the exciting force causes the inner cylinder 4 to change in the radial direction through the bearing 5 as shown by the arrow X2. Due to the fluctuation of the inner cylinder 4, the spherical particles 6 filled in the accommodation space 7 between the inner cylinder 4 and the device housing 3 flow, and the spherical particles 6, the spherical particles 6 and the inner cylinder 4, and the spherical particles 6. And the device housing 3, friction is generated, and the frictional energy is dissipated by the friction to attenuate the vibration.

As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

1: Vibration damping device 2: Rotating shaft 3: Equipment housing 4: Inner cylinder 5: Bearing 6: Spherical particle 7: Accommodating space 8: Spring for supporting inner cylinder 9: Ring plate 10:

Bolts

11a and 11b:

Fixed ring

12a, 12b: Dust resistant seal 13a: Preload spring 13b: Preload ring 14: Air vent flow path 15: Dust resistant filter

Claims

An equipment housing that is arranged at an interval on the outer surface of a bearing that supports a rotating shaft in a rotating machine, and an equipment housing that is arranged with a gap between the inner peripheral surface of the equipment housing and the outer surface of the bearing. An inner cylinder that is displaceable in the radial direction, and a housing space that is provided between the outer peripheral surface of the inner cylinder and the inner peripheral surface of the equipment housing, and that is filled with spherical particles that generate vibration damping action by vibration friction; In a vibration damping device for a bearing comprising a preloading ring that is arranged on the side of the housing space in the axial direction and applies a preload in the axial direction to the spherical particles filled in the housing space, the spherical particles are filled. A dust-proof seal is provided on both sides of the housing space in the axial direction to prevent the spherical particles from flowing out from the gap between the inner peripheral surface of the device housing and the outer peripheral surface of the inner cylinder. Bearing vibration Decay apparatus.
2. The vibration damping device for a bearing according to claim 1, wherein a flow path for venting air connecting the inside of the housing space and the external environment is provided in the equipment housing.
3. The vibration damping device for a bearing according to claim 2, wherein a dust filter is installed in the air vent flow path.
4. The vibration damping device for a bearing according to claim 1, wherein the spherical particles are made of SUS440C or Si3N4.
The bearing vibration damping device according to claim 4, wherein all of the spherical particles have the same size.
The bearing vibration damping device according to claim 5, wherein the spherical particles are made of a combination of different sizes.