JP2002250332A - Hinge device and portable electronic apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hinge device capable of energizing turn (energizing blocking) and generating large turn resistance when turning (when opening and closing), and to provide a portable electronic apparatus using the hinge device. SOLUTION: This hinge device is constituted such that a pivotal shaft 8 is provided in a first connection part 3 to be connected with a first member, a bearing part 9 having a C-shaped cross section and fastened and fitted to the pivotal shaft 8 is provided in a second connection part 4 to be connected with a second member, an engaging projecting part 6 or an engaging recessed part 7 turning together with the pivotal shaft 8 is provided in the first connection part 3, a small diameter part 10 which is engaged with the engaging projecting part 6 or the engaging recessed part 7 and in which a shaft cross-section diameter becomes small in the pivotal shaft 8 is provided in the second connection part 4, and a C-shaped end part 9A of the hearing part 9 is positioned in the small diameter part 10 at a turn position where a turn energizing force is generated by an engaging with a cam force of the engaging projecting part 6 and the engaging recessed part 7 to reduce a fastening force of the bearing part 9 for the pivotal shaft 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hinge device for pivotally connecting a first member and a second member, and a portable electronic device using the hinge device.

[0002]

2. Description of the Related Art A typical example of a portable electronic device includes a notebook personal computer and a portable telephone.
It is necessary to provide a lid or flip on the D side so that it can be opened and closed freely.

[0003] In this case, for example, when the member to be opened / closed is heavy, a sufficient torque (large rotation resistance) is configured to be generated. It is desirable to realize a free stop in which the rotation is stopped at that position when the rotation is stopped.

For example, a pivot shaft (rotating shaft or fulcrum shaft) is provided on the main body side, and a cylindrical bearing portion fitted on the pivot shaft is provided on the opening / closing member side. The fitting is performed so that a tightening force is generated by the setting, and a large torque (rotational resistance) is generated by the press-contact frictional resistance due to the tightening force. Further, the friction surface may be devised so as to increase the rotation resistance, or a mechanism for generating torque may be separately incorporated.

On the other hand, the hinge device is configured to be locked in the closed state and to be urged to close at least to some extent in the opening angle range, and a rotation lock mechanism and a rotation urging mechanism are provided separately from the hinge device. Even if it is not provided, it is preferable that the closing device is configured to be biased by the structure of the hinge device (rotationally biased in the closing direction).

For example, the hinge device is provided with an engagement projection and an engagement recess which are urged by an engagement urging mechanism such as a coil spring or a disc spring. When disengaging, one of the engaging projections and the engaging recesses is rotated against the engagement urging mechanism to disengage. Until this engagement is disengaged. The hinge device is configured such that the engagement convex portion is biased to rotate in the return direction (blocking bias) by the generation of an engaging cam force that causes the engaging convex portion to fall into the engaging concave portion by the engaging biasing mechanism. .

However, if the rotation resistance is increased by, for example, increasing the tightening force of the bearing portion with respect to the pivot shaft so as to generate a large torque (rotation resistance) at the time of opening and closing, the engaging cam force is increased by this rotation. Since it works against dynamic resistance, the engagement cam force may not be sufficiently exerted, and the closing urging function and the rotation locking function of the hinge device may not be exhibited.

Conversely, if the closing cam is biased by the engaging cam force, a large rotational resistance cannot be generated at the time of opening and closing. Cannot be realized.

The present invention is an epoch-making creation which solves such a problem by a simple improvement, and can be rotated (closed) and rotated (opened / closed). Can generate a large rotational resistance. In other words,
Rotation bias (blocking bias) while generating large rotation resistance
Innovative hinge device and hinge device wherein the large rotation resistance is automatically reduced when the engagement cam force is generated so that a sufficient engagement cam force is generated in a rotation position that must be performed. It is an object of the present invention to provide a portable electronic device using the same.

[0010]

The gist of the present invention will be described with reference to the accompanying drawings.

A hinge device for pivotally connecting a first member 1 and a second member 2, wherein a pivot shaft 8 is provided on a first connecting portion 3 connected to the first member 1 and connected to the second member 2. The second connecting portion 4 is provided with a bearing portion 9 having a C-shaped cross section which is fastened and fitted to the pivot shaft 8, and the first connecting portion 3 is provided with an engaging projection 6 or an engaging portion which rotates together with the pivot shaft 8. A concave portion 7 is provided, and the second concave portion 4 engages with the engaging convex portion 6 or the engaging concave portion 7 and rotates together with the bearing portion 9.
And at least one of the engaging protrusions 6 and the engaging recesses 7 is slidably provided in the engaging and disengaging direction, and is disengaged when at least one of the engaging protrusions 6 and the engaging recesses 7 is disengaged. An engagement urging mechanism 5 that urges in the engaging direction when moved in the direction is provided, and the engagement between the engaging convex portion 6 and the engaging concave portion 7 is not disengaged by the engaging urging mechanism 5. The rotation lock state is maintained, and one of the engagement protrusions 6 and the engagement recesses 7 is slid in the separating direction against the engagement urging mechanism 5 while rotating. As a result, the engaging projection 6 is disengaged from the engaging recess 7, and the first member 1 is opposed to the first member 1 against the rotational resistance caused by the tightening force of the bearing 9 with respect to the pivot shaft 8. In the hinge device configured to relatively rotate the second member 2, the pivot shaft 8 has an axial cross-sectional diameter. The small-diameter portion 10 is provided with a small-diameter portion 10, and the bearing portion 9 is attached to the small-diameter portion 10 at a rotation position at which a rotational biasing force is generated by the engagement cam force between the engagement convex portion 6 and the engagement concave portion 7. The C-shaped end 9A of the bearing 9
The hinge device according to claim 1, wherein a tightening force of the hinge device is reduced.

Further, the bearing 9 with respect to the pivot 8
Is reduced by the C-shaped end portion 9A of the bearing portion 9 being located at the small-diameter portion 10, and the bearing portion 9 with respect to the pivot shaft 8 is reduced by the reduction of the fastening force. The rotation resistance is reduced, and a rotation biasing force is generated against the reduced rotation resistance by the engagement cam force between the engagement projection 6 and the engagement recess 7. The hinge device according to claim 1.

The rotation urging force generated when the tightening force is reduced by the C-shaped end portion 9A of the bearing portion 9 being located at the small-diameter portion 10 is applied to the engagement convex portion 6 and the engagement concave portion 7. The hinge device according to any one of claims 1 and 2, characterized in that it is configured to promote a rotation urging force by an engagement cam force with the hinge device.

The small diameter portion (10) is formed by forming a flat cut surface in the length direction of the outer peripheral surface of the column-shaped pivot shaft (8). The present invention relates to the hinge device described in (1).

5. The bearing according to claim 1, wherein an end of said second connecting portion made of a metal plate is curled to provide said bearing portion having a C-shaped cross section. The present invention relates to the hinge device described above.

Further, the inside of the recess of the engaging recess 7 is defined as an engaging portion with which the engaging projection 6 engages.
Is a sliding surface 13 that slides in a state in which the engagement convex portion 6 is pressed by the engagement urging mechanism 5 when the engagement convex portion 6 rotates. In a rotation urging region in which a rotation urging force is generated by the engagement cam force that is about to fall from the surface 13 into the recess, the C of the bearing 9 is
The end portion 9A is located at the small diameter portion 10 of the pivot shaft 8 so as to be in a rotation resistance reduction region where the rotation resistance is reduced, and the rotation urging force by the engagement cam force is used. The hinge device according to any one of claims 1 to 5, wherein the second member (2) is configured to be rotationally biased with respect to the first member (1).

Further, the base members of the first member 1 and the second member 2 are pivotally connected to each other so that one of the first member 1 and the second member 2 can be moved to a predetermined position from a closed state in which both are overlapped. A hinge device which can be opened and closed in an open state rotated to an open angle, and at least in the closed state, the engagement lock portion is engaged with the engagement convex portion 6 and the engagement concave portion 7 and the rotation lock state is established. The second member 2 is configured to be urged to close by the engagement cam force with respect to the one member 1 up to a predetermined rotation angle. The engagement recess 7 is disengaged from the engagement recess 7, and after the engagement and disengagement, the C-shaped end 9 </ b> A of the bearing 9 is detached from the small-diameter portion 10. The second member 2 is relatively rotated with respect to the first member 1 against the rotation resistance. Characterized in that the number claim 1
7. The hinge device according to any one of items 1 to 6, above.

Further, the base members of the first member 1 and the second member 2 are pivotally connected to each other to open one of the first member 1 and the second member 2 in a predetermined state from a closed state in which both are overlapped. A hinge device that can be opened and closed in an open state rotated to an angle, wherein at the predetermined open angle, the engagement convex portion 6 and the engagement concave portion 7 are engaged again to be in the rotation locked state. 8. The method according to claim 1, wherein
The present invention relates to the hinge device described in (1).

According to another aspect of the present invention, there is provided a portable electronic device using the hinge device, wherein the hinge device according to any one of claims 1 to 8 is provided at a pivot portion.

The main body as the first member 1 or the second member 2 and the second member 2
Alternatively, the hinge device according to any one of claims 1 to 9 is attached to a pivot portion that pivotally opens and closes a lid or a flip as the first member 1 from a superimposed state to a predetermined opening angle. A portable electronic device using the hinge device according to claim 9.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention (how to implement the invention) will be briefly described with reference to the drawings, showing the operational effects thereof.

The pivot shaft 8 rotates together with the first member 1 via the first connecting portion 3, and a bearing portion 9 fitted on the pivot shaft 8.
Rotates together with the second member 2 via the second connecting portion 4.

Therefore, for example, when the second member 2 is rotated with respect to the first member 1, the bearing 9 rotates with respect to the pivot shaft 8.

At this time, since the bearing portion 9 has a C-shaped cross section and is fastened and fitted to the pivot shaft 8, a turning resistance is generated by the tightening force (in addition, the turning surface (friction surface) is devised ( Or a biasing mechanism for generating friction or rotation resistance may be provided to further increase the rotation resistance.), And the first member 1 may resist the rotation resistance. , The second member 2 is rotated.

That is, for example, the rotational resistance can be increased or decreased by setting the diameter of the bearing portion 9, and a large torque (rotation resistance) can be obtained by designing the bearing to reduce the diameter and increase the tightening force. Even if the member (the second member 2) that opens and closes as it is opened is heavy, it can be designed so as to realize free stop.

On the other hand, an engagement projection 6 or an engagement recess 7 which rotates together with the first member 1 is provided. In other words, an engagement projection fixed and disposed at least in the rotation direction with respect to the pivot shaft 8. The engaging portion 7 or the engaging concave portion 7 is provided, and the engaging concave portion 7 or the engaging convex portion 6 that rotates together with the second member 2 is provided. An engaging concave portion or an engaging convex portion is provided, and at least one of the engaging convex portion and the engaging concave portion to be engaged with each other is provided movably in a separating direction against the engaging urging mechanism.

Therefore, for example, when the second member 2 is rotated with respect to the first member 1 (when the bearing portion 9 is rotated with respect to the pivot shaft 8), the engaging convex portions 6, the engaging concave portions 7 are formed. While one of the members rotates together with the second member 2, one of the members moves in the separating direction against the engagement urging mechanism 5 and the engagement is disengaged.

That is, the engagement between the engagement projection 6 and the engagement recess 7 locks the rotation, and the engagement urging mechanism 5 urges the rotation until the rotation angle at which the engagement is disengaged. An engagement cam force is generated so that the engagement convex portion 6 tends to fall into the engagement concave portion 7, and a rotational urging force is generated in the return rotational direction.

For example, when the state in which the engaging projection 6 and the engaging recess 7 are engaged is a closed state in which the first member 1 and the second member 2 overlap, this closed state is rotationally locked, In addition, the closing cam is biased by the engaging cam force up to the rotation range in which the engagement is disengaged at the time of opening.

Further, according to the present invention, the pivot shaft 8 is provided with a small-diameter portion 10 having a smaller cross-sectional diameter, and the engagement convex portion 6 and the engagement concave portion 7 are rotated by an engagement cam force. In the rotating position where the urging force is generated, the C-shaped end 9A of the bearing 9 is located at the small diameter portion 10 so that the tightening force of the bearing 9 against the pivot shaft 8 is reduced. .

That is, the tightening force of the bearing portion 9 on the pivot shaft 8 is automatically reduced by the C-shaped end portion 9A of the bearing portion 9 being located at the small diameter portion 10. The rotation resistance of the bearing portion 9 with respect to the pivot shaft 8 decreases due to the decrease in the tightening force, and the rotation due to the engagement cam force between the engagement projection 6 and the engagement recess 7 is opposed to the reduced rotation resistance. It is configured such that a dynamic urging force is generated.

Therefore, according to the present invention, the rotation urging (closing urging) is performed.
And at the time of rotation (at the time of opening and closing), large rotation resistance can be generated. In other words, if the rotational resistance is increased by, for example, increasing the tightening force of the bearing portion 9 on the pivot shaft 8, the engaging cam force acts against the rotational resistance. At the time (at the time of opening / closing), while a large turning resistance is generated by the tightening force of the bearing portion 9 with respect to the pivot shaft 8, the turning position of the bearing portion 9 in the turning position in which the turning bias (closing bias) is required. C-shaped end 9
By setting A to be located at the small diameter portion 10, the revolution resistance is automatically reduced, so that a sufficient engaging cam force is generated and the innovative hinge device in which the closing bias is performed is provided. Become.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described with reference to the drawings.

This embodiment is applied to a laptop type notebook personal computer as shown in the drawing.
The main body is the first member 1, the opening / closing lid 2 having the LCD is the second member 2, and the opening / closing lid 2 is rotated from, for example, about 90 to 120 degrees from a closed state where the main body 1 and the opening / closing lid 2 overlap. The hinge device of the present invention is applied to a pivotable structure that can be brought into an open state (used position).

In this embodiment, the pivot shaft 8 is provided in the first connecting portion 3 (connecting metal fitting) connected to the first member 1 (main body) in a non-rotating state, and connected to the second member 2 (opening / closing lid 2). A bearing portion 9 having a C-shaped section is provided on the second connecting portion 4 (connecting fitting) to be fastened and fitted to the base of the pivot shaft 8.

The bearing 9 is formed by curling the end of the second connecting portion 4 made of a metal plate to form the bearing 9 having the C-shaped cross section. The diameter is slightly smaller than the base diameter, and is configured to be tightly fitted to the pivot shaft 8 so as to generate a torque (rotation resistance due to pressure contact) sufficient to realize the free stop.

In this embodiment, an end of the bearing portion 9 is provided with an engaging concave portion 7 which faces the engaging convex portion 6 and engages with the engaging convex portion 6 so as to pivot between the bearing portions 9. 8 and a caulking nut 12
A plate spring or a coil spring is provided as an engagement urging mechanism 5 between the plate 11 and the engagement concave portion 7, and the engagement concave portion 7 separates from the engagement convex portion 6 at the time of disengagement. It is configured so as to be biased when engaging.

In this embodiment, the engagement urging mechanism 5
Thus, the engagement between the engaging projection 6 and the engaging recess 7 is not disengaged and the rotation locked state is maintained, and the engaging and disengaging recess 7 is opposed to the engagement urging mechanism 5. By rotating the engaging protrusion 6 together with the bearing 9 while sliding in the separating direction, the engaging protrusion 6 is disengaged from the engaging recess 7. The second member 2 with respect to the first member 1 against rotational resistance due to the tightening force of
Are relatively rotated.

That is, in the present embodiment, the proximal ends of the first member 1 and the second member 2 are pivotally connected to each other so that either of the first member 1 and the second member 2 can be changed from the closed state where both are overlapped. A hinge device which can be opened and closed in an open state in which one of them is rotated to a predetermined open angle, wherein at least in the closed state, the rotation locked state in which the engagement convex portion 6 and the engagement concave portion 7 are engaged. It is configured so that

In this embodiment, the pivot shaft 8 is provided with a small-diameter portion 10 having a smaller cross-sectional diameter, and a rotational urging force generated by an engaging cam force between the engaging convex portion 6 and the engaging concave portion 7. In the rotation position where the rotation occurs, the C-shaped end portion 9A of the bearing portion 9 is located at the small-diameter portion 10 so that the tightening force of the bearing portion 9 on the pivot shaft 8 is reduced. Specifically, a flat cut surface is formed in the length direction of the outer peripheral surface of the base cylindrical portion of the pivot shaft 8 to form the small diameter portion 10.
Is formed.

That is, the inside of the concave portion of the engaging concave portion 7 is an engaging portion with which the engaging convex portion 6 is engaged, and the top surface portion between the concave portions is formed.
13 when the engaging projection 6 rotates.
The sliding surface 13 is slid in a state of being pressed against the sliding surface 13. The engaging urging mechanism 5 causes the engaging convex portion 6 to rotate from the sliding surface 13 into the recess by the engaging cam force. In the rotation urging region where the urging force is generated, the C-shaped end 9A of the bearing 9 is located at the small diameter portion 10 of the pivot shaft 8 so that the rotation resistance is reduced in the rotation resistance reducing region. The second member 2 is configured to be rotationally urged with respect to the first member 1 by the rotational urging force of the engagement cam force.

Therefore, when the second member 2 is rotated with respect to the first member 1, the bearing 9 rotates with respect to the pivot shaft 8. At this time, the bearing 9 has a C-shaped cross section. Since the fastening shaft 8 is strongly tightened and fitted, a large turning resistance is generated by the tightening force (in addition, the turning surface (friction surface) is devised (processed), and other friction and turning resistance are generated). May be provided to further increase the rotational resistance.)

On the other hand, when the second member 2 is rotated with respect to the first member 1, the bearing 9 is rotated with respect to the pivot shaft 8. The engagement concave portion 7 is disengaged while rotating together with the bearing portion 9 while the engagement concave portion 7 moves in the separating direction against the engagement urging mechanism 5.

That is, the engagement between the engagement projection 6 and the engagement recess 7 locks the rotation, and the engagement urging mechanism 5 urges the rotation until the rotation angle at which the engagement is disengaged. The engaging projection 6 rotates relative to the engaging recess 7 to generate an engaging cam force that tends to fall, and a rotational urging force is generated in the return rotational direction.

Therefore, it is possible to apply a rotational bias (close bias), and to generate a large rotational resistance when rotating (opening / closing). In other words, for example, the tightening force of the bearing portion 9 with respect to the pivot shaft 8 is increased to increase the rotational resistance. Therefore, according to the conventional configuration, the engaging cam force acts against the large rotational resistance. However, in the present embodiment, during rotation (at the time of opening and closing), the rotation must be biased (closed) while a large rotation resistance is generated by the tightening force of the bearing portion 9 with respect to the pivot shaft 8. By setting the C-shaped end portion 9A of the bearing portion 9 to be located at the small-diameter portion 10 in the rotation position, the rotation resistance is automatically reduced, so that a sufficient engagement cam force is generated. The hinge device is a closing bias. That is, the tightening force of the bearing portion 9 with respect to the pivot shaft 8 is configured to be reduced by the C-shaped end portion 9A of the bearing portion 9 being located at the small-diameter portion 10. The rotation resistance of the bearing portion 9 with respect to the shaft 8 is reduced, and a rotation urging force is generated against the reduced rotation resistance by the engagement cam force between the engagement protrusion 6 and the engagement recess 7. It is composed.

In this embodiment, a V-shaped concave portion is formed at a position 180 degrees symmetric to the engaging concave portion 7, and at the predetermined opening angle, the engaging convex portion 6 and the engaging concave portion 7 It is configured to be engaged to be in the rotation locked state.

In this embodiment, the rotational urging force generated when the tightening force is reduced by the C-shaped end 9A of the bearing 9 being located at the small-diameter portion 10 is generated by the engagement convex portion 6 The rotation urging force generated by the engagement cam force with the engagement concave portion 7 is configured to be promoted.

That is, in this embodiment, the end of the flat surface obtained by cutting the base cylindrical portion of the pivot shaft 8 into a D shape, that is, the edge of the small-diameter portion 10 is used as the C-shaped end 9A ( Either the distal end or the proximal end can be reached.)
The rotation urging force generated when the tightening force of the bearing unit 9 is released coincides with the rotation urging force due to the engagement cam force in the direction and the timing, so that the engagement cam force is increased. If the urging mechanism 5 is made strong,
A strong rotational bias (blocking biasing force) will be generated even if the engaging slope between the and the engaging recess 7 is not sharpened.

It should be noted that the present invention is not limited to the present embodiment, and the specific configuration of each component can be appropriately designed.

[0050]

As described above, the present invention is constructed as described above. Therefore, while a large rotation resistance is generated with a simple structure, sufficient engagement is required in a rotation position where rotation must be biased (blocking bias). As with the cam force, when the engaging cam force is generated, the large pivotal resistance is automatically reduced, so that an innovative hinge device and a portable electronic device using the hinge device are obtained.

That is, according to the present invention, when rotating (opening / closing), the rotation must be biased (closed) while a large rotation resistance is generated by the tightening force of the bearing portion with respect to the pivot shaft. In the pivoting position, by setting the C-shaped end portion of the bearing portion to be located at the small diameter portion, the pivoting resistance is automatically reduced, so that a sufficient engaging cam force is generated and the closing bias is generated. And a portable electronic device using the hinge device.

According to the third aspect of the present invention,
The rotation urging force generated when the tightening force of the bearing part is released coincides with the rotation urging force due to the engagement cam force in the direction and timing, so that the engagement is performed to increase the engagement cam force. An extremely innovative hinge device in which a strong rotational urging force (blocking urging force) is generated without making the urging mechanism strong or making the engaging inclined surface between the engaging convex portion and the engaging concave portion sharp. In addition, a portable electronic device using the hinge device is obtained.

Further, according to the third to eighth aspects of the present invention, the hinge device can be easily realized with a simpler configuration, or is extremely easy to use.

[Brief description of the drawings]

FIG. 1 is an explanatory perspective view of a use state of the present embodiment.

FIG. 2 is an explanatory exploded perspective view of the present embodiment.

FIG. 3 is an explanatory cross-sectional view of an engagement portion between a pivot shaft 8 and a bearing portion 9 at the time of opening and closing when a large rotation resistance occurs in the embodiment.

FIG. 4 is an explanatory cross-sectional view of an engagement portion between the engagement convex portion 6 and the engagement concave portion 7 at the time of opening and closing when a large rotation resistance occurs in the embodiment.

FIG. 5 is an explanatory sectional view of an engagement portion between the pivot shaft 8 and the bearing 9 when the rotation resistance of the present embodiment is automatically reduced.

FIG. 6 is an explanatory cross-sectional view of an engagement portion between the engagement convex portion 6 and the engagement concave portion 7 when the rotation resistance of the present embodiment is automatically reduced.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st member 2 2nd member 3 1st connection part 4 2nd connection part 5 Engaging urging mechanism 6 Engagement convex part 7 Engagement recessed part 8 Pivot shaft 9 Bearing part 9A C-shaped end part 10 Small diameter part 13 Top surface, sliding surface

Continued on the front page F term (reference) 3J105 AA02 AA03 AA12 AB11 AB14 AC07 DA15 DA23 4E360 AB16 AB42 BA08 BB02 BB12 BB22 BB27 BC06 BC07 EC14 ED04 ED23 ED28 GA02 GA06 GB46 GC02

Claims (10)

[Claims] 1. A hinge device for pivotally connecting a first member and a second member, wherein a hinge shaft is provided at a first connection portion connected to the first member, and a second connection portion is connected to the second member. A bearing portion having a C-shaped cross-section that is fastened and fitted to the pivot shaft, an engagement projection or an engagement recess that rotates together with the pivot shaft is provided in the first connection portion, and the second connection portion is provided in the second connection portion. An engaging concave portion or an engaging convex portion which engages with the engaging convex portion or the engaging concave portion and rotates together with the bearing portion is provided, and at least one of the engaging convex portion and the engaging concave portion is disengaged in the engaging and disengaging direction. An engaging urging mechanism is provided to be slidably movable and to urge in at least one of the engaging convex portion and the engaging concave portion in the engaging direction when the engaging convex portion and the engaging concave portion are disengaged. By the urging mechanism, the engagement between the engagement convex portion and the engagement concave portion is not disengaged and the rotation locked state is maintained. The engagement protrusion is engaged with the engagement recess by rotating one of the engagement protrusion and the engagement recess while sliding in the separating direction against the engagement urging mechanism. A hinge device configured to disengage a portion and to relatively rotate the second member with respect to the first member against rotation resistance due to a tightening force of the bearing portion with respect to the pivot shaft. The pivot shaft is provided with a small-diameter portion having a smaller cross-sectional diameter, and at a rotation position where a rotation urging force is generated by an engagement cam force between the engagement protrusion and the engagement recess, the small-diameter portion is provided. Wherein the C-shaped end portion of the bearing portion is located to reduce the tightening force of the bearing portion on the pivot shaft. 2. A structure in which a tightening force of the bearing portion with respect to the pivot shaft is reduced by positioning a C-shaped end of the bearing portion at the small-diameter portion. The rotation resistance of the bearing portion with respect to the pivot shaft is reduced, and a rotation urging force is generated against the reduced rotation resistance by the engagement cam force between the engagement protrusion and the engagement recess. The hinge device according to claim 1, wherein the hinge device is configured. 3. An engagement cam between the engagement projection and the engagement recess, the rotation urging force generated when the tightening force is reduced due to the C-shaped end of the bearing being located at the small diameter portion. The hinge device according to any one of claims 1 and 2, wherein the hinge device is configured to promote a rotational urging force by a force. 4. The small diameter portion is formed by forming a flat cut surface in a length direction of an outer peripheral surface of the column-shaped pivot shaft. Hinge device. 5. The bearing according to claim 1, wherein an end of the second connecting portion made of a metal plate is curled to provide the bearing having the C-shaped cross section. Hinge device. 6. The inside of the recess of the engaging concave portion is an engaging portion with which the engaging convex portion is engaged, and a top surface between the concave portions is formed by the engaging urging mechanism when the engaging convex portion rotates. The sliding surface slides in a pressed state, and the engaging urging mechanism generates a rotational urging force due to the engaging cam force which attempts to drop the engaging convex portion from the sliding surface into the concave portion. In the rotation urging region, the C-shaped end of the bearing portion is set at the small diameter portion of the pivot shaft so as to be a rotation resistance reduction region in which the rotation resistance is reduced, and The said 2nd member was comprised so that it was rotationally urged | biased with respect to the said 1st member by the rotation urging | biasing force by an engagement cam force, The Claims any one of Claims 1-5 characterized by the above-mentioned. Hinge device. 7. A base member between the first member and the second member is pivotally connected to each other to rotate one of the first member and the second member from a closed state in which both are overlapped to a predetermined opening angle. A hinge device that can be opened and closed in a moved open state, wherein at least in the closed state, the engagement convex portion and the engagement concave portion are engaged in the rotation locked state, and the hinge device is moved relative to the first member. The second member is configured to be biased to close by the engagement cam force up to a predetermined rotation angle, and the engagement protrusion and the engagement recess are disengaged against the closure bias. After engaging and disengaging, the C-shaped end of the bearing portion is detached from the small-diameter portion and increases with respect to the first member against a rotational resistance caused by a tightening force of the bearing portion with respect to the pivot shaft. 7. The method according to claim 1, wherein the second member is relatively rotated. The hinge device according to claim 1. 8. A base member of the first member and the second member are pivotally connected to each other, and one of the first member and the second member is turned to a predetermined opening angle from a closed state where both are overlapped. A hinge device that can be opened and closed in the open state, wherein at the predetermined opening angle, the engaging convex portion and the engaging concave portion are engaged again to be in the rotation locked state. The hinge device according to any one of claims 1 to 7, wherein 9. A portable electronic device using a hinge device, wherein the hinge device according to claim 1 is provided at a pivot portion. 10. The main body as the first member or the second member, and the lid or the flip as the second member or the first member superimposed thereon can be opened and closed from a superimposed state to a predetermined opening angle. 10. A portable electronic device using the hinge device according to claim 9, wherein the hinge device according to any one of claims 1 to 9 is used for a pivot portion that pivots as described above.