Rotary Damper

Abstract

This is a rotary damper that uses a viscous fluid that contains tiny air particles that accumulate inside the cylinder and prevent torque fluctuations that occur. [Solution] By providing an air reservoir 8 in the cylinder 1 portion of the rotary damper, air is prevented from flowing through the flow path of the viscous fluid, making torque fluctuations less likely to occur.

Description

Technical Field

[0001] The present invention relates to the technical field of rotary dampers, and particularly to dampers using viscous fluids.

Background Art

[0002] In recent years, at large-scale construction sites using large cranes, a method has been adopted in which a camera is attached near the tip of the boom, and the captured video is displayed on a monitor in front of the operator. The crane is operated while grasping the direction of the suspended conveyed object and its positional relationship with the building on the monitor. At this time, no matter how much the boom changes its angle, the camera needs to face the direction of the conveyed object suspended directly below the tip of the boom, and it is necessary not to wobble in order to obtain a stable video. A rotary damper is used to prevent this wobbling. (Patent Document 1)

[0003] As a rotary damper used for such applications, conventionally, a damper in which a viscous fluid is sealed has been used. In a rotary damper as described above, due to the high temperature environment caused by direct sunlight in summer during outdoor use, the internal viscous fluid expands, causing the internal viscous fluid to flow out exceeding the holding force of the packing or O-ring that maintains the seal. Also, when the internal viscous fluid contracts due to low temperatures such as in winter, a negative pressure is generated inside the rotary damper. If the holding force of the packing or O-ring that maintains the seal is exceeded, outside air or rainwater may enter the inside, resulting in torque fluctuations (unevenness of the buffering force).

[0004] To address this drawback, a method has been devised to reduce leakage of the viscous fluid and intrusion of outside air and rainwater by arranging a buffer material that absorbs changes in internal pressure inside the cylinder. (Patent Document 2).

[0005] However, the viscous fluid used in rotary dampers often contains minute air bubbles. After sealing the viscous fluid containing these air bubbles inside the damper, over time, they may combine into a larger size and pass through the flow path inside the cylinder. This causes torque fluctuations.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] The problem to be solved is the torque fluctuation of the rotary damper

Means for Solving the Problems

[0008] An air pocket is provided in the cylinder structure part to prevent the air inside the cylinder from passing through the flow path inside the cylinder by collecting the internal air

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0010] First, the internal structure and mechanism of the rotary damper of the present invention will be described with reference to FIGS. 1 and 2. The rotary damper of the present invention has a structure in which a cylinder 1 is sandwiched by flanges 2, and a rotating shaft 3 passes through their centers. The inside 4 of the cylinder is filled with a viscous fluid, and a rotor 5 is arranged. A key is provided on the rotating shaft 3, and the rotating shaft and the rotor are engaged with the groove portion of the rotor and rotate integrally. The viscous fluid pushed out by the rotating rotor moves through the flow path 4 inside the cylinder. The amount of movement of the viscous fluid is adjusted by a flow rate adjustment valve 7 that moves back and forth by a screw arranged in the middle of the flow path, and the torque of the rotary damper can be adjusted.

[0011] An air pocket 8 shown in FIG. 2 is provided. Since this air pocket has a depth in the direction of the rotating shaft, the air that has once entered is difficult to escape from the cylinder. This collects the air bubbles inside the cylinder and prevents air from flowing into the flow path 4.

Explanation of reference numerals

[0012] 1 Cylinder, 2 Flange, 3 Rotating shaft, 4 Inside of cylinder, 5 Rotor, 6 Flow path, 7 Flow rate adjustment valve, 8 Air pocket

Claims

[Claim 1] A rotary damper that prevents torque fluctuations by creating an air pocket in the cylinder structure to prevent air from flowing through the flow path.

Images