Vibration damping device and elevator apparatus

Patent metadata

Field	Value
Publication number	US-2021094799-A1
Application number	US-201817051786-A
Country	US
Kind code	A1
Filing date	Dec 3, 2018
Priority date	May 15, 2018
Publication date	Apr 1, 2021
Grant date	—

Abstract

An object of the present invention is to provide a vibration damping device including an instability preventing means, for efficiently suppressing amplification of vibration of a long structure, which is mechanically flexible, due to a resonance phenomenon. A vibration damping device (100) for reducing vibration of a long structure (1) includes a displacement amplifier (7) and limiting members (8). The displacement amplifier (7) is arranged along a given position in the longitudinal direction of the structure (1). The displacement amplifier (7) amplifies a displacement of the structure (1). The limiting members (8) control displacement amplification performed by the displacement amplifier (7) such that the displacement of the structure (1) amplified by the displacement amplifier (7) does not become greater than a first displacement, the first displacement being a displacement of the structure (1) by which the structure (1) is not allowed to return to the equilibrium position of the vibration.

First claim

1 . A vibration damping device for reducing vibration of a long structure, comprising:
a displacement amplifier arranged along a given position in a longitudinal direction of the structure, the displacement amplifier being configured to amplify a displacement of the structure; and a limiting member that controls displacement amplification performed by the displacement amplifier such that the displacement of the structure amplified by the displacement amplifier does not become greater than a first displacement, the first displacement being the displacement of the structure by which the structure is not allowed to return to an equilibrium position of the vibration.

2 . The vibration damping device according to claim 1 , wherein the displacement amplifier is arranged at a position where a distance between the displacement amplifier and a node of the vibration of the structure is shorter than a distance between the displacement amplifier and an antinode of the vibration of the structure and is greater than zero.

3 . The vibration damping device according to claim 1 , wherein the displacement amplifier includes a mechanical structure that exerts negative stiffness for applying an elastic force, the elastic force being greater as the displacement of the structure is greater.

4 . The vibration damping device according to claim 1 , wherein the limiting member includes an elastic body with positive stiffness.

5 . The vibration damping device according to claim 1 , wherein the limiting member controls displacement amplification performed by the displacement amplifier such that a force exerted by the displacement amplifier does not exceed a force in a direction of the displacement of the structure generated due to equivalent stiffness between a fixed position of the structure and a coupled position of the structure where the displacement amplifier amplifies the displacement.

6 . The vibration damping device according to claim 1 , wherein the limiting member controls amplification of the displacement of the structure performed by the displacement amplifier based on the first displacement as a displacement where a force exerted by the displacement amplifier exceeds a force in a direction of the displacement of the structure generated due to equivalent stiffness between a fixed position of the structure and a coupled position of the structure where the displacement amplifier amplifies the displacement of the structure.

7 . The vibration damping device according to claim 1 , wherein the displacement amplifier applies a component of a force in a direction of the displacement of the vibration of the structure and thus in a direction of the displacement of the structure.

8 . The vibration damping device according to claim 1 , further comprising a vibration damper that reduces the vibration of the structure.

9 . The vibration damping device according to claim 1 , wherein when the structure is an elevator rope,
the displacement amplifier is arranged along a given position in a longitudinal direction of the elevator rope, and amplifies a displacement of the elevator rope, and the limiting member controls displacement amplification performed by the displacement amplifier such that the displacement of the elevator rope amplified by the displacement amplifier does not become greater than the first displacement.

10 . The vibration damping device according to claim 9 , wherein the displacement amplifier is arranged at a position where a distance between the displacement amplifier and a node of the vibration of the elevator rope is shorter than a distance between the displacement amplifier and an antinode of the vibration of the elevator rope and is greater than zero.

11 . The vibration damping device according to claim 9 , wherein when the elevator rope is a main rope that is connected to a car and a counterweight of an elevator and is wound on a sheave,
the displacement amplifier is arranged along a given position in a longitudinal direction of the main rope, and amplifies the displacement of the main rope, and the limiting member controls displacement amplification performed by the displacement amplifier such that the displacement of the main rope amplified by the displacement amplifier does not become greater than the first displacement.

12 . The vibration damping device according to claim 11 , wherein the displacement amplifier is arranged at a position where a distance between the displacement amplifier and the car, the counterweight, or the sheave is shorter than a distance between the displacement amplifier and a midpoint between both fixed positions of the main rope and is greater than zero.

13 . The vibration damping device according to claim 11 , wherein the limiting member controls amplification of the displacement of the main rope performed by the displacement amplifier such that a force exerted by the displacement amplifier becomes smaller than a force with which the main rope attempts to return to the equilibrium position with a tension of the main rope.

14 . The vibration damping device according to claim 11 , wherein the displacement amplifier and the limiting member amplify the displacement of the main rope by exerting a force based on a modulus of elasticity K that satisfies an inequality:

-

T

x
0



L

L
-

x
o

<
K
<
0

where T is a tension of the main rope, x 0 is a distance from a connection point between the car or the counterweight and the main rope to a position where the displacement amplifier is arranged, and L is the total length of the main rope.

15 . The vibration damping device according to claim 11 , wherein the limiting member controls amplification of the displacement of the main rope performed by the displacement amplifier based on the first displacement as a displacement where a force is exerted with a modulus of elasticity that has a value obtained by dividing a tension acting on the main rope when the car in an empty state is at a top floor of the elevator by a distance from a fixed position of the main rope to a position of the main rope coupled to the displacement amplifier.

16 . The vibration damping device according to claim 9 , wherein when the elevator rope is a plurality of main ropes that are connected to a car and a counterweight of an elevator and are wound on a sheave,
the vibration damping device further comprises a restraining member that maintains a constant distance between each of the plurality of main ropes in a horizontal direction.

17 . The vibration damping device according to claim 16 , wherein the restraining member is fixed to each of the plurality of main ropes.

18 . The vibration damping device according to claim 16 , wherein when the plurality of main ropes are aligned in the horizontal direction,
the restraining member includes a pair of rollers having rotation axes parallel with the direction in which the plurality of main ropes are aligned, the pair of rollers being ad

Assignees

• Mitsubishi Electric Corp

Inventors

• Saito Eiichi
• Hirai Takahide
• Watanabe Seiji
• Nakazawa Daisuke
• Fukui Daiki
• Asamura Tomohiro
• Chikada Yusuke

Classifications

• F16F15/035 Primary

  by use of eddy or induced-current damping (dynamo-electric brakes of the eddy-current type H02K49/04) · CPC title

• B66B5/125

  electrical · CPC title

• F16F2230/0029

  Location, co-location · CPC title

• B66B5/022 Primary

  where the abnormal operating condition is caused by a natural event, e.g. earthquake · CPC title

• B66B7/10

  for equalising rope or cable tension · CPC title