JPH08334133A - Rotational torque generating mechanism - Google Patents

Abstract

PURPOSE: To provide a rotational torque generating mechanism by which an appropriate torque can be generated stably for a long period of time. CONSTITUTION: A resin-made sliding member 2 having a plurality of recessed parts 3 in its inside is wound around a rotary shaft 1. A metallic band 4 arranged on the outside of the resin-made sliding member 2 is tightened by fastening metal fittings 5, 5' so that a rotational torque can be obtained by frictional force generated between the resin-made sliding member 2 and the rotary shaft 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating torque generating mechanism, and more particularly to a rotating torque generating mechanism which can be suitably used as an opening / closing mechanism for small electronic equipment such as a notebook personal computer and a word processor having a liquid crystal display.

[0002]

2. Description of the Related Art In a small electronic device, a main body case accommodating a keyboard and a display case accommodating a liquid crystal display panel and the like are separately provided for convenience of portability, and the main body case and the display case are hinged. It is known that a display case is foldable with respect to a main body case by being rotatably coupled with a member.

As an example of such a folding type electronic device, as shown in FIG. 3, when the display case 11 is used in an opened state from a main body case 12 provided with a keyboard, the display case 11 is a panel. In order to tilt the display at an angle that is easy to see, a predetermined frictional force is applied to the rotary shaft 13 that connects the display case 11 and the main body case 12, thereby suppressing the free rotation of the display case 11 to the main body case 12. On the other hand, the display case 11 can be tilted and held at an arbitrary angle.

As a rotary torque generating mechanism used for this kind of small electronic equipment, for example, as shown in FIG. 4, a sintered metal 15 is joined to an end of a rotary shaft 14 and a disc spring 17 is provided from above the arm 16. A mechanism having a mechanism of tightening with a screw 19 via a holding plate 18 is known. (Hereinafter, referred to as "conventional rotational torque generating mechanism 1") As shown in FIG. 5, the rotary shaft 20 made of liquid crystal polymer in which the protrusions 20a and 20b are integrally molded is fixed to the injection molding die, and then the bearing 21 is formed. It is known that injection molding is performed and the projections 20a and 20b are tightened by the molding contraction force. (See Japanese Patent Laid-Open No. 5-154864, hereinafter referred to as "conventional rotating torque generating mechanism 2").

[0005]

In the conventional rotary torque generating mechanism 1, since the torque is generated by the friction between the metal members, the sliding surface is worn and the torque decreases as the number of rotations increases. Therefore, in order to obtain a torque equal to or higher than a certain value even after long-term use, it is necessary to set the initial torque to an abnormally high value, which results in further accelerated wear.

Further, since the conventional rotary torque generating mechanism 2 utilizes the tightening force of resin molding shrinkage, not only can the desired torque value not be arbitrarily set, but also the resin tightening force gradually increases. By being alleviated, the torque gradually decreases. Further, the rotary shaft 20 and the resin bearing 2
The abrasion powder of the resin generated by sliding between the rotary shaft 1 and the rotary shaft 1 gradually accumulates, so that a so-called locked state occurs, and the rotary shaft 2
0 may not be able to rotate.

The present invention has been made in view of the above problems of the prior art, and its object is to provide a rotary torque generating mechanism capable of stably generating an appropriate torque for a long period of time. To provide.

[0008]

In order to achieve the above object, the gist of the present invention is to wrap a resin-made sliding member having a plurality of recesses inside on a rotating shaft, and further to make the resin-made sliding member. A rotating torque generating mechanism is characterized in that a rotating torque is obtained by a frictional force generated between the resin sliding member and the rotating shaft by tightening a metal band arranged on the outer side of the rotating member.

[0009]

[Function] By tightening the metal band, a frictional force is generated between the resin sliding member and the rotating shaft, and the rotating torque is obtained by this frictional force. Wear powder generated when the rotating shaft rotates while slidingly contacting the sliding member made of resin is stored in the plurality of recesses, so that the wear powder does not accumulate on the sliding surface and the rotation operation is performed smoothly. be able to.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, 1 is a metal rotary shaft having a diameter of 7 mm,
2 is a resin sliding member having an inner diameter of 7 mm and an outer diameter of 10 mm, and the sliding member 2 is approximately 360 ° along the outer peripheral surface of the rotating shaft 1.
It is circumscribed over. In the portion of the sliding member 2 that is in contact with the rotary shaft 1, six recesses 3 each having a thin groove shape in the lengthwise direction of the rotary shaft are formed at intervals of about 60 °. 4 is 0.5 mm thick
Is a metal band, and is fastened by the fasteners 5 and 5 '. The width W of the sliding member 2 and the metal band 4 is 1
2 mm, and the length of the recess 3 is also 12 mm.

Then, the tightening force of the fasteners 5 and 5'was adjusted so that the initial rotation torque of the rotary shaft 1 was about 5.6 kg.cm, and the open / close test was conducted 26000 times at the open / close angle of 120 degrees.

As Comparative Example 1, a similar open / close test was performed on the "conventional rotating torque generating mechanism 1" shown in FIG. 4, and as Comparative Example 2, a recess 3 was provided in the sliding member 2 of FIG. The same open / close test was conducted for the ones that did not exist. FIG. 2 shows the changes in the torque of the rotating shaft during these opening / closing tests.

The following points are apparent from FIG. In the example according to the present invention, the torque increases until the sliding surface becomes stable, but then gradually decreases to about 200
After about 00 times, the torque was about the same as the initial torque, and no large torque fluctuation was seen overall, and the torque remained stable.

In Comparative Example 1, the torque decreased as the number of times of opening and closing increased, and a torque decrease of about 2.0 kg · cm was observed after the opening and closing test of 26000 times.

In Comparative Example 2, the torque sharply increased with the start of the opening / closing test, and after about 7,000 opening / closing tests, the rotating shaft was in the locked state and was unable to rotate.

[0016]

According to the rotary torque generating mechanism of the present invention,
Since it is possible to generate almost stable torque over a long period of time, a smooth opening / closing operation is possible.

[Brief description of drawings]

1 (a) is a cross-sectional view of a rotary torque generating mechanism of the present invention, and is a cross-sectional view taken along the line AA of FIG. 1 (b), FIG. 1 (b).
FIG. 3 is a right side view of FIG.

FIG. 2 is a diagram showing changes in torque of a rotating shaft during an opening / closing test.

FIG. 3 is a perspective view of a notebook computer.

FIG. 4 is a side view of a conventional rotary torque generating mechanism 1.

FIG. 5 is a partially cutaway perspective view of a conventional rotary torque generating mechanism 2.

[Explanation of symbols]

 1, 13, 14, 20 ... Rotating shaft 2 ... Sliding material 3 ... Recessed portion 4 ... Metal band 5, 5 '... Fastening metal fitting 11 ... Display case 12 ... Main body case 15 ... Sintered metal 16 ... Arm 17 ... Disc spring 18 ... Presser plate 19 ... Screws 20a, 20b ... Projection 21 ... Bearing

Claims (1)

[Claims] 1. A sliding member made of resin, which has a plurality of recesses inside, is wound around a rotary shaft, and a metal band arranged outside the sliding member made of resin is tightened to make the sliding member made of resin. A rotary torque generating mechanism characterized in that a rotary torque is obtained by a frictional force generated between the rotary shaft and the rotary shaft.