JPH042819B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a vibration damping device for protecting piping systems and other equipment in power plants, chemical plants, etc. from vibrations caused by earthquakes and the like.

Conventionally, this type of vibration damping device converts the relative movement in the axial direction during vibration between two supporting members connected to the damping target and the structure into rotational motion by a nut and a threaded rod that are screwed together. An inertial vibration damping device is known that transmits this rotational motion to an inertial body and uses the inertia to generate a braking action. Furthermore, in order to reduce the size of the inertial body and to respond sensitively to low-cycle vibrations, a vibration damping device incorporating a speed increasing mechanism equipped with a gear system has been proposed. (Unexamined Japanese Patent Publication No. 1973-
No. 44219).

However, when incorporating a speed increasing mechanism internally, it is inevitably larger and has a larger capacity, and there is also a problem that there is a limit to increasing the speed increasing ratio with a mechanism that combines gears. . Therefore, there is a need for a speed increasing device that is small and lightweight and that can provide a relatively large speed increasing ratio.

The present invention has been made focusing on the above points,
The object of the present invention is to provide an inertial vibration damping device that is small, lightweight, and has a built-in speed increasing mechanism that can provide a relatively large speed increasing ratio.

Embodiments of the invention will be described below with reference to the figures. The main cylinder 1, which is one of the supporting members, has a handle 1b on the outside of the lid 1a at one end, and can be connected to a vibration damping object such as a structure or a piping system via the handle 1b. Also, on the inside of the lid 1a at one end is a first tube extending in the direction of the central axis.
One end of the threaded rod 2 is fixed.

The sub-tube 3, which is the other supporting member, has one end with a lid 3a.
It has a handle 3b on the outside thereof, through which it can be connected to a structure or a vibration damping object. The other end of the sub cylinder 3 is inserted into the main cylinder 1 so as to be freely removable in the axial direction, and the first threaded rod 2 passes through the other end lid 3c so as to be freely removable and removable. One end of a second threaded rod 4 extending in the direction of the central axis is fixed to the inside of the lid 3a of the sub-cylinder 3. The pitch of the second threaded rod 4 is smaller than that of the first threaded rod 2.

A cylindrical inertial body 5 is rotatably housed in the sub-tube 3, and first and second inertia bodies 5 are provided at both ends thereof to be screwed into the first and second threaded rods 2, 4, respectively.
ball nuts 6 and 7 are fixed. Therefore, the first and second threaded rods 2, 4 are connected to the first threaded rod, respectively.
It is screwed into second ball nuts 6 and 7, and can rotate relative to the inertial body 5 and move in and out in the axial direction.

Next, the effect will be explained. This vibration damping device
Alternatively, either one of the sub-tubes 3 can be connected to a structure and the other can be used by connecting it to a vibration damping target. When a slow displacement occurs between the vibration damping target and the structure due to a temperature change, the inertial body 5 rotates slowly together with the first and second nuts 6 and 7, This can be tolerated without difficulty.

On the other hand, when a high acceleration displacement occurs between the vibration damping target and the structure due to an earthquake, etc., the inertial body 5 cannot follow the rotation caused by the threaded rods 2, 4 and nuts 6, 7, and this inertial resistance increases. It becomes a large reaction force against vibration.

In this case, since two threaded rods 2 and 4 and two corresponding ball nuts 6 and 7 are used, the rotational motion is obtained by screwing the first threaded rod and the nut together. The rotation speed will be increased. That is, for example, if the thread pitch of the first threaded rod 2 is P ₁ and that of the second threaded rod P 2, then _{P 1 >}
Assuming P ₂ , when the first ball nut 6 and the first threaded rod 2 move by P ₁ relative to each other, the ball nut 7 rotates once together with the ball nut 6, and rotates with respect to the second threaded rod 4. axially relative to
Move by P ₂ . Therefore, conversely, ball nut 6,
7 and the inertial body 5 by one rotation, the first
relative to the second threaded rod 4 |
It is only necessary to move by P ₁ −P ₂ |. In other words, the rotation speed is increased by P ₁ /(P ₁ −P ₂ ) compared to the case of a combination of a single nut and threaded rod. In other words, if P ₂ is brought closer to P ₁ , the speed increasing ratio will be as large as possible. Therefore, even if the inertial body is made small, a substantially large inertial resistance can be obtained.

Note that the present invention is not limited to the illustrated embodiment. For example, the inertia body 5 is indirectly connected to the nuts 6 and 7, and the inertia of this inertia body is used to activate a friction brake, and it can be applied to various known vibration damping devices that use a rotating inertia body. be.

As explained above, the present invention provides first and second threaded rods integrally connected to the threaded rods 2 and 4 of the main cylinder 1 and the secondary cylinder 3, which are supporting members each having the threaded rods 2 and 4, respectively. The nuts 6 and 7 are screwed together, and the relative movement in the axial direction between the nuts 6 and 7 and the threaded rods 2 and 4 causes the inertia bodies on the nuts 6 and 7 to rotate at an increased speed. The advantage is that it can be made smaller and lighter, and a relatively large speed increasing ratio can be obtained.

[Brief explanation of drawings]

The drawing is a sectional view showing an example of implementation of the present invention. 1... Main cylinder (supporting member), 2... First threaded rod,
3... Sub-tube (supporting member), 4... Second threaded rod,
5... Inertial body, 6... First ball nut, (nut), 7... Second ball nut (nut).

Claims (1)

[Claims] 1. One support member connected to the vibration damping target or structure, the other support member connected to the structure or vibration damping target, a first threaded rod fixed to either one of the support members, and the like. a second threaded rod having a smaller pitch than the first threaded rod fixed to one of the supporting members; and first and second nuts coupled to each other that are screwed into the first and second threaded rods, respectively. and an inertial body provided directly or indirectly on the first and second nuts.