JPH10306836A - Rotary damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent air bubbles from generating by forming an air venting passage of which one opening part is opened on the recessed part of a rotor and the other opening part is opened on the outer circumferential face of the rotor, in the rotor rotatably arranged in a casing. SOLUTION: A rotor 3 is constituted of a rotary shaft part 31 and a rotor part 32 having nearly the same outer diameter as the inner diameter of a casing 2, and the rotor part 32 is formed with a hollow air bleeder passage 33 extending in the lateral direction. The air venting passage 33 is formed so that the one opening part 33a is opened at a recessed art 32a formed on the rotor 3 and the other opening part 33b is opened on the outer circumferential face 32a of the rotor 3, and when the rotor 3 is incorporated in the casing 2 containing viscous liquid 5, air accumulated in the recessed part 3a of the rotor 3 can be immediately discharged. Hereby, the characteristics of a rotary damper can be stabilized, and defective welding of the casing and a cover member can be dissolved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary damper.

[0002]

2. Description of the Related Art Conventionally, opening / closing lids for portable personal computers, copy machines and other office equipment, opening / closing lids for pianos and the like, opening / closing operations for toilet seats and toilet lids for Western-style toilets, cassette tape outlets for cassette tape recorders, ashtrays in cars, and the like. In order to delay the rotation, a rotary damper that fills a gap between the rotating body and the casing with a viscous liquid such as grease and generates torque by using the viscous resistance of the viscous liquid has been used. As shown in FIG. 2, this rotary damper 10
At the center of the inner surface of the bottom wall of the casing 20, a protruding portion 20a protruding upward is formed.
The recess 30 a formed in the center of the lower surface of the rotating body 30 was fitted, and the rotating body 30 was incorporated in the casing 20.

[0003]

However, the conventional rotary damper 10 incorporates the rotating body 30 after injecting the viscous liquid 50 into the casing 20.
When the rotating body 30 is to be incorporated, the concave portion 3 of the rotating body 30
After the air was accumulated at 0a and the rotary body 30 was further pushed in and incorporated, the air was pushed out from the recess 30a and remained as bubbles in the viscous liquid 50. As a result, the torque characteristics of the rotary damper 10 were not stable. Also, the bubbles generated in the viscous liquid 50 burst,
The viscous liquid 50 sometimes adheres to the welding surface 20 c of the casing 20, which has caused poor welding between the casing 20 and the lid member 40 that closes the upper opening 20 b of the casing 20. As a result, there is a problem that the viscous liquid 50 leaks out of the poorly welded portion.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to provide a rotary damper which prevents generation of bubbles which cause poor characteristics and poor welding.

[0005]

In order to achieve the above object, a rotary damper according to the present invention comprises a bottomed substantially cylindrical casing having a protruding portion projecting upward at the center of the inner surface of a bottom wall, and at the center of the lower surface. A rotator having a concave portion fitted to the convex portion of the casing and rotatably disposed in the casing filled with the viscous liquid, a lid member for closing an upper opening of the casing, In the rotary damper having the structure, the rotating body is formed with an air vent passage in which one opening is opened in a concave portion of the rotating body and the other opening is opened in an outer peripheral surface of the rotating body. And

[0006]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the figure, reference numeral 1 denotes a rotary damper according to the present embodiment, which includes a casing 2, a rotating body 3, and a lid member 4.

The casing 2 is formed in a substantially cylindrical shape with a bottom and an upper surface opening. In the center of the inner surface of the bottom wall, a convex portion 2a having a substantially trapezoidal section is fitted into a concave portion 3a of the rotating body 3 described below.
Are formed to protrude upward. Further, a welding surface 2c to which a lid member 4 described later is welded is formed in the upper surface opening 2b. And in the casing 2,
After the viscous liquid 5 has been injected, the rotating body 3 is inserted through the upper opening 2b of the casing 2 and is arranged freely to rotate.

The rotating body 3 comprises a rotating shaft portion 31 and a rotor portion 32 having an outer diameter substantially equal to the inner diameter of the casing 2. Then, one end 31a of the rotating shaft portion 31 is inserted into a rotating shaft insertion hole 4a formed in the lid member 4 described later, and a concave portion 3a formed in the center of the lower surface of the rotor portion 32 is formed.
The casing 2 is disposed so as to be fitted to a convex portion 2 a formed on the inner surface of the bottom wall.

A hollow air vent passage 33 extending in the lateral direction is formed in the rotor portion 32 constituting the rotating body 3. That is, the air vent passage 33 is formed such that one opening 33a opens in the concave portion 3a formed in the rotating body 3 and the other opening 33b opens in the outer peripheral surface 32a of the rotating body 3. ing. The formation of the air vent passage 33 allows the recess 3 of the rotating body 3 to be incorporated into the casing 2 into which the viscous liquid 5 has been injected.
The air accumulated in a can be immediately released to the outside.

The cover member 4 is substantially disc-shaped, and has a rotary shaft insertion hole 4a formed at the center thereof. A viscous liquid 5 filled in the casing 2 is provided around the rotation shaft insertion hole 4a. An O-ring 4b is provided so as not to leak outside, and the lower surface edge is welded to the welding surface 2c formed in the upper surface opening 2b of the casing 2 to close the upper surface opening 2b of the casing 2.

[0011]

According to the rotary damper of the present invention, an air vent passage is formed in the rotating body, with one opening opening in the recess of the rotating body and the other opening opening in the outer peripheral surface of the rotating body. Therefore, when the rotating body is incorporated into the casing into which the viscous liquid has been injected, the air accumulated in the concave portion of the rotating body can be immediately discharged to the outside through the air vent passage. As a result, since no bubbles are generated in the viscous liquid, the characteristics of the rotary damper can be stabilized, and the poor welding between the casing and the lid member can be eliminated.

[Brief description of the drawings]

FIG. 1 is an exploded sectional view showing a rotary damper according to an embodiment of the present invention.

FIG. 2 is an exploded sectional view showing a conventional rotary damper.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotary damper 2 Casing 3 Rotating body 33 Air vent passage 4 Lid member 5 Viscous liquid

Claims (1)

[Claims] 1. A bottomed substantially cylindrical casing having a convex portion protruding upward at the center of the inner surface of a bottom wall, a concave portion fitted to the convex portion of the casing at the center of a lower surface, and a viscous liquid is provided. In a rotary damper having a rotating body rotatably disposed in the casing to be filled, and a lid member for closing an upper opening of the casing, one opening of the rotating body has the rotation. A rotary damper, characterized in that an air vent passage is formed that opens in a concave portion of the body and opens on the outer peripheral surface of the rotating body with the other opening.