US-12624742-B2 - Multi-degree anti-vibration unit

US12624742B2US 12624742 B2US12624742 B2US 12624742B2US-12624742-B2

Abstract

Anti-vibration units are provided for vibration suppression in multiple directions. The anti-vibration units may have an X-shaped structure as part of its support structure. The anti-vibration units can work for ultra-low frequency vibration isolation in three directions in a passive manner. The anti-vibration units can achieve a flexible nonlinear stiffness, which contains zero or quasi-zero stiffness, negative stiffness and positive stiffness. A smooth multi-equilibria state is also achievable. Compared with traditional spring-mass-damper (SMD) and typical QZS systems, the provided anti-vibration units can have an enhanced QZS range of larger stroke with guaranteed loading capacity, and can also achieve a lower resonant frequency with a lower resonant peak. At least some embodiments of the anti-vibration units may include a new and innovative arrangement of components that enables a more compact design than typical anti-vibration systems.

Inventors

Xingjian JING

Assignees

CITY UNIVERSITY OF HONG KONG

Dates

Publication Date: 20260512
Application Date: 20220928

Claims (14)

1 . An anti-vibration unit comprising: a base member; a first support member including a first segment at a first angle to a second segment, wherein the first support member is rotatable about a first axis, wherein the first angle is fixed; a second support member including a third segment at a second angle to a fourth segment, wherein the second support member is rotatable about a second axis, wherein the second angle is fixed; a first resilient member connecting the first segment of the first support member to the base member; a third support member connected to the first support member and rotatable about the first axis; a second resilient member connecting the third segment of the second support member to the base member; and a fourth support member connected to the second support member and rotatable about the second axis.
2 . The anti-vibration unit of claim 1 , wherein the second segment of the first support member has a greater length than the first segment.
3 . The anti-vibration unit of claim 1 , wherein each of the first and second resilient members are rotatable about a same axis.
4 . The anti-vibration unit of claim 1 , wherein the first axis extends through a point at which the first segment meets the second segment of the first support member, and wherein the second axis extends through a point at which the third segment meets the fourth segment of the second support member.
5 . The anti-vibration unit of claim 1 , wherein the first support member is rotatably connected to the base member at a first joint through which the first axis extends, and wherein the second support member is rotatably connected to the base member at a second joint through which the second axis extends.
6 . The anti-vibration unit of claim 1 , wherein the base member is a first base member, the anti-vibration unit further comprising a second base member, wherein the third support member is rotatably connected to the second base member at a third joint and to the second segment of the first support member at a fourth joint, and wherein the fourth support member is rotatably connected to the second base member at a fifth joint and to the fourth segment of the second support member at a sixth joint.
7 . The anti-vibration unit of claim 6 , further comprising: a fifth support member rotatably connected to the second base member at the third joint; and a sixth support member rotatably connected to the second base member at the fifth joint, wherein the fifth support member crosses over the sixth support member at a first crossover point.
8 . The anti-vibration unit of claim 7 , further comprising: a seventh support member rotatably connected to the fifth support member at a sixth joint, wherein the seventh support member is rotatable about the first axis; and an eighth support member rotatably connected to the sixth support member at a seventh joint, wherein the eighth support member is rotatable about the second axis.
9 . An anti-vibration unit comprising: a base member; a first support member including a first segment at a first angle to a second segment, wherein the first support member is rotatable about a first axis, wherein the first angle is fixed; a second support member including a third segment at a second angle to a fourth segment, wherein the second support member is rotatable about a second axis, wherein the second angle is fixed; a first resilient member connecting the first segment of the first support member to the base member, wherein the first resilient member is rotatable about a third axis; and a second resilient member connecting the third segment of the second support member to the base member, wherein the second resilient member is rotatable about the third axis.
10 . The anti-vibration unit of claim 9 , wherein the second segment of the first support member has a greater length than the first segment.
11 . The anti-vibration unit of claim 9 , wherein the first axis extends through a point at which the first segment meets the second segment of the first support member, and wherein the second axis extends through a point at which the third segment meets the fourth segment of the second support member.
12 . The anti-vibration unit of claim 9 , wherein the first support member is rotatably connected to the base member at a first joint through which the first axis extends, and wherein the second support member is rotatably connected to the base member at a second joint through which the second axis extends.
13 . The anti-vibration unit of claim 9 , further comprising: a third support member rotatably connected to the second segment of the first support member at a third joint; and a fourth support member rotatably connected to the fourth segment of the second support member at a fourth joint.
14 . The anti-vibration unit of claim 9 , further comprising: a third support member rotatable about the first axis; and a fourth support member rotatable about the second axis.

Description

TECHNICAL FIELD The present application relates generally to anti-vibration structures. More specifically, the present application relates to quasi-zero stiffness (QZS) anti-vibration devices. BACKGROUND Vibration problems are often considered a negative factor in many engineering systems. Detrimental vibrations may significantly affect the accuracy of precision equipment, reduce service life of instruments, and cause structural fatigue damage. As such, the unwanted vibrations need to be controlled within a rational and acceptable range in engineering systems. Various vibration suppression systems attempt to address this issue, such as traditional linear passive vibration isolators, active/semi-active isolation elements, and nonlinear quasi-zero stiffness (QZS) passive isolators, though each have their own drawbacks. Traditional linear vibration isolators can only suppress structural vibration with excitation frequency larger than √{square root over (2)} times of the natural frequency, which makes it difficult to achieve low-frequency vibration isolation. Active or semi-active isolation elements often need additional active actuators and controllers, causing considerable energy inputs and increasing the complexity of vibration isolation systems. Many typical nonlinear QZS passive isolators are designed to attenuate the transmission of a single vertical vibration. With performance improvement in high precision manufacturing and measuring equipment, however, external excitations often distribute in more than a single direction, and therefore multi-direction low-frequency isolation with high efficiency is needed for attenuating transmission of multi-direction vibrations. Additionally, There remains room for improvement with respect to typical nonlinear QZS passive isolators having multiple degrees of freedom. SUMMARY The present disclosure provides new and innovative anti-vibration units for vibration suppression in multiple directions. The provided anti-vibration units may include a passive X-shaped mechanism for vibration suppression. The included passive X-shaped mechanism may have less bars than typical anti-vibration units having an X-shaped mechanism and can therefore be more compact than such typical anti-vibration units. At least some aspects of the anti-vibration units do not include a guiding slider for motion restriction, which helps reduce friction generated by motion of such aspects of the anti-vibration units. At least some of the anti-vibration units disclosed herein may include a new and innovative component arrangement. This component arrangement may enable more flexible usage of the X-shaped mechanism for vibration suppression than typical anti-vibration units including an X-shaped mechanism. For instance, combining two or more of the provided anti-vibration units, and/or restricting the motion of the vibration suppression mechanism in one or more directions, can achieve various degrees-of-freedom of vibration isolation (e.g., 1, 2, 3, 4, 5, or 6 degrees-of-freedom). In an example, an anti-vibration unit includes a base member, a first support member, and a second support member. The first support member includes a first segment at an angle to a second segment, and the first support member is rotatable about a first axis. The second support member includes a third segment at an angle to a fourth segment, and the second support member is rotatable about a second axis. The example anti-vibration unit further includes a first resilient member connecting the first segment of the first support member to the base member, and a second resilient member connecting the third segment of the second support member to the base member. In another example, an anti-vibration unit includes a first support member and a second support member rotatably connected to the first support member at a first joint. The example anti-vibration unit further includes a first resilient member, a second resilient member, and a third resilient member. Each of the first, second, and third resilient members is rotatable about a first axis that extends through the first joint. In another example, an anti-vibration unit includes a first base member and a first X-shaped support structure connected to the first base member at first and second rotation joints. The example anti-vibration unit further includes a first support member connected to the first base member at the first rotation joint and a second support member connected to the first base member at the second rotation joint. The first support member has a first segment at an angle to a second segment, and the second support member has a first segment at an angle to a second segment. Additional features and advantages of the disclosed method and apparatus are described in, and will be apparent from, the following Detailed Description and the Figures. The features and advantages described herein are not all-inclusive and, in particular, many additional features and advantages w