JP7807787B2 - Hinge device and electronic device using the hinge device - Google Patents

Description

The present invention relates to a hinge device for electronic devices such as notebook computers and foldable mobile terminals, which connects the device body and a cover equipped with a display in an openable and closable manner, and which, when closing the cover, applies pressure toward the closed position to retract the cover and pressurize and hold the cover in the closed position without any gaps against the device body, preventing it from opening, and also relates to an electronic device that uses this hinge device and has a rotational biasing mechanism that uses friction to hold the cover at the desired open angle.

In electronic devices such as laptops, a first housing, which is a cover equipped with a display, and a second housing, which is the device body equipped with a keyboard, etc., are connected by a hinge device so that they can be opened and closed. The hinge device is provided with a configuration that includes a free-stop mechanism that uses friction to maintain the open angle at any open position when the first housing is opened from a closed position in which it is closed against the second housing, and a rotational biasing mechanism that applies pressure toward the closed position when the first housing is closed, retracting the first housing and bringing the first housing into pressure contact with the second housing without any gaps against the device body, preventing the opening (Patent Document 1).

In this hinge device, the hinge shaft, which forms the pivot point between the first bracket to which the first housing is attached and the second housing, rotates integrally with the first bracket, and the second bracket is attached so that it can rotate freely relative to the hinge shaft. Friction members that rotate integrally with the hinge shaft are arranged on both axial sides of the bearing portion of the second bracket, and the pair of friction members clamp and hold the bearing portion of the second bracket with the pressure of the spring member, forming a free stop mechanism, and friction torque is generated around the hinge shaft when the first bracket and second bracket rotate relative to each other.

When closing the first housing (cover), the rotational biasing mechanism rotates the cover by manually pushing it in the closing direction up to a predetermined angle close to the closed position. The cover then releases from the hand and rotates toward the closed position, applying a spring force to the second housing, preventing the cover from appearing open relative to the device body. The rotational biasing mechanism converts the relative rotation of the cam recessed member and the cam protruding member around the hinge shaft axis into an increase or decrease in the opposing distance between the cam recessed member and the cam protruding member along the axial direction of the hinge shaft, and the spring member brings the cam recessed member and the cam protruding member into pressurized contact. The cam recessed member has a cam recess with sloped valleys formed on both circumferential sides of a flat valley bottom, and the cam protruding member has a cam protruding member with sloped peaks formed on both circumferential sides of a flat peak. In the closed position, the cam protrusion drops into the cam recess, and the two crests of the cam protrusion press into contact with the two valleys of the cam recess, creating a cam-engaged state. When the cam protrusion drops into the cam recess as the protruding cam plate rotates toward the closed position, a clicking sensation is felt.

On the other hand, when opening the first housing (cover) from the closed position, it is common to perform the initial opening operation by holding the first housing, which is held in the closed position by pressure to prevent it from opening, with one hand and opening it in the open direction. In this case, when the convex cam plate rotates in the closing direction, the crest of the cam convex climbs the valley of the cam recess, causing the convex cam plate to move against the spring force of the spring member, increasing the surface-to-surface distance with the fixed cam washer. During the initial opening operation, the region up to when the crest of the cam convex overcomes the sliding of the valley of the cam recess is called the initial opening operation region. The rotational torque required to overcome the initial opening operation region during the initial opening operation increases as the initial opening operation region nears its end, reaching its maximum rotational torque just before the region is overcome; this rotational torque is called the escape torque. Once the initial opening operation is complete, the flat top of the cam projection comes into pressure contact with the flat surface of the fixed cam washer, and the torque applied to the cover portion shifts from being dominated by the escape torque to being dominated by the friction torque of the free stop mechanism.

JP 2015-48906 A

In the conventional hinge device described above, the friction torque of the free stop mechanism is set to a value that allows an operator of the electronic device to open or close the cover with one hand, and stops and holds the cover in that position when the operator releases their hand. This friction force is highly dependent on the pressure applied by the spring member and the coefficient of friction of the friction member. The breakaway torque is also highly dependent on the pressure applied by the spring member, the inclination angle of the valleys of the cam recess, and the coefficient of friction of the sliding surfaces between the valleys and the peaks of the cam protrusion. Increasing the inclination angle of the valleys can prevent the mouth from opening, but this increases the breakaway torque, which becomes greater than the frictional rotation torque of the free stop mechanism.

However, if the escape torque is greater than the frictional rotation torque of the free stop mechanism, when you try to open the cover that is held in the closed position with one hand, the device body may lift up, requiring you to use both hands to open the cover.

An object of the present invention is to provide a hinge device that allows a cover portion to be opened from a closed position relative to a device body with one hand, and an electronic device using the hinge device.

A first aspect of the present invention provides a hinge device for opening and closing a first housing that constitutes a main body of an electronic device and a second housing that constitutes a cover of the electronic device, the hinge device comprising: a first bracket attached to the first housing; a second bracket attached to the second housing; a hinge shaft fixed to one of the first bracket and the second bracket and rotatably connecting the other; a friction torque generating mechanism having a disc spring and a friction washer attached to the hinge shaft; and a rotational biasing mechanism that is adjacent to the friction torque generating mechanism and that rotates the first housing and the second housing in a closing direction from a predetermined closing angle, the rotational biasing mechanism being rotatably attached to the first bracket and the second housing. a fixed cam washer having cam recesses provided in the circumferential direction on both sides thereof and engaged with either the first bracket or the second bracket; and a rotating cam washer having cam protrusions that are pressed against both sides of the fixed cam washer by the elasticity of the disc springs and that drop into the cam recesses of the fixed cam washer depending on the rotation angle; and by shifting the installation positions of one of the cam recesses and one of the cam protrusions relative to each other in the circumferential direction, the cam protrusions sequentially drop into the cam recesses from a predetermined closing angle of the first housing and the second housing, thereby automatically closing and maintaining the closed state of each housing; and when the first housing and the second housing are opened, the cam protrusions sequentially escape from the cam recesses, thereby reducing the rotational torque at the time of opening.

A hinge device according to a second aspect of the present invention that achieves the object of the present invention is a hinge device that connects a first housing that forms a main body of an electronic device and a second housing that forms a cover of the electronic device in an openable and closable manner, the hinge device comprising: a first bracket attached to the first housing; a second bracket attached to the second housing; a hinge shaft that is fixed to either the first bracket or the second bracket and rotatably connects the other; a friction torque generating mechanism that has a disc spring and a friction washer and is installed on the hinge shaft; and a rotational biasing mechanism that is adjacent to the friction torque generating mechanism and that rotates the first housing and the second housing in a closing direction from a predetermined closing angle, the rotational biasing mechanism being rotatably mounted on the first bracket and the second bracket. a fixed cam washer having cam protrusions provided circumferentially on both sides thereof and engaged with either the first bracket or the second bracket; and a rotating cam washer having cam recesses, into which the cam protrusions of the fixed cam washer are dropped according to the rotation angle, which are pressed against each other by the elasticity of the disc springs, and by shifting the installation positions of one of the cam recesses and one of the cam protrusions relative to each other in the circumferential direction, the cam protrusions sequentially drop into the cam recesses from a predetermined closing angle of the first housing and the second housing, thereby automatically closing and maintaining the mutual closed state; and when the first housing and the second housing are opened, the cam protrusions sequentially escape from the cam recesses, thereby reducing the rotational torque during opening.

The hinge device of the third invention that realizes the object of the present invention is characterized in that, in the hinge device of the first or second invention, the cam recess and cam protrusion provided on the fixed cam washer and each of the rotating cam washers are formed as a single cam-shaped portion on the surface of a disk-shaped cam plate body.

The electronic device of the fourth invention that realizes the object of the present invention is characterized by having a hinge device of any one of the first to third inventions, and a first bracket and a second bracket of the hinge device attached to a first housing and a second housing of the electronic device .

The hinge devices of the first and second inventions reduce the rotational torque required when opening, allowing the second housing, which is in the closed position, to be opened with one hand, eliminating the hassle of having to hold the first housing open with the other hand.

The hinge device of the third invention allows for a simple configuration of the fixed cam washer and rotating cam washer.

The electronic device of the fourth invention allows the second housing, for example, to be opened from a closed position with one hand, making it easier to use.

1A is a perspective view showing an embodiment of an electronic device using a hinge device according to the present invention in an open state, and FIG. 1B is an enlarged perspective view of the left hinge device shown in FIG. 1A. 1A is a perspective view of the electronic device shown in FIG. 1A in a closed state as viewed from the bottom side, and FIG. 1B is an enlarged perspective view of a left hinge device shown in FIG. 1 and 2, (b) is a view of the hinge device of (a) from the first surface side, and (c) is a view of the first bracket of (a) from the second surface side. FIG. 4 is an exploded perspective view of the hinge device shown in FIG. 3 . 5A, 5B, and 5C show a fixed cam washer constituting the hinge device of FIG. 4, in which FIG. 5A is a perspective view of the first surface side, FIG. 5B is a perspective view of the second surface side, and FIG. 5C is a side view. 6A is a front view of the first surface side of the fixed cam washer shown in FIG. 5 , FIG. 6B is a front view of the second surface side of the fixed cam washer shown in FIG. 5 , and FIG. 6C is a diagram showing the shape (depth) of the second cam recess of the fixed cam washer shown in FIG. 5 and the angle of the recess area around the X-axis. 5A and 5B show a first rotating cam washer constituting the hinge device shown in FIG. 4, in which FIG. 5A is a perspective view of the first surface side, and FIG. 5B is a perspective view of the second surface side. 8A is a front view showing the first surface side of the first rotating cam washer shown in FIG. 7, FIG. 8B is a front view showing the first cam protrusion formed on the second surface side of the first rotating cam washer shown in FIG. 7, and FIG. 8C is a diagram showing the shape (height) of the first rotating cam washer shown in FIG. 7 and the angle between the outer protrusion and the inner protrusion around the X-axis. 5A, 5B, and 5C show a second rotating cam washer constituting the hinge device shown in FIG. 4, in which FIG. 5A is a perspective view of the first surface side, FIG. 5B is a perspective view of the second surface side, and FIG. 5C is a side view. 10A is a front view showing the second cam protrusion formed on the first surface side of the second rotating cam washer shown in FIG. 9 , FIG. 10B is a front view showing the second surface side of the second rotating cam washer shown in FIG . 9 , and FIG. 10C is a diagram showing the shape (height) of the second rotating cam washer shown in FIG. 9 and the angle between the outer protrusion and inner protrusion areas around the X-axis. 5A and 5B are diagrams illustrating the positional relationship between the first cam recess and the first cam protrusion in the closed position, where FIG. 5A shows the first cam recess and FIG. 5B shows the first cam protrusion. 10A and 10B are diagrams illustrating the positional relationship between the second cam recess and the second cam protrusion in the closed position, where FIG. 10A shows the second cam recess and FIG.

The present invention will be described below based on the embodiments shown in the drawings.

In Figures 1 and 2, the hinge device of the present invention will be described using a notebook computer 1 as an example of an electronic device. In the notebook computer 1, a first housing 2, which is the device main body and is equipped with a keyboard, etc., is attached to a second housing 3, which is a cover portion equipped with a display, via left and right hinge devices 100L and 100R, so that the second housing 3 can be opened and closed freely. The left-side hinge device 100L and the right-side hinge device 100R are formed symmetrically, so only the left-side hinge device 100L will be described below.

As shown in Figures 3 and 4, the hinge device 100L has a first bracket 10 to which the first housing 2 is attached, a second bracket 20 to which the second housing 3 is attached, and a hinge shaft 30 that connects the first bracket 10 and the second bracket 20 so that they can rotate relative to each other. The hinge device 100L also has a disc spring portion 40 made up of multiple disc springs that form a friction torque generating mechanism, and first and second friction washers 91 and 92 that form friction plates. The hinge device 100L also has a free stop portion 50 and a rotational biasing mechanism 60.

When opening the second housing 3 (cover) from the closed position, the initial opening operation involves holding the second housing 3 in one hand and opening it in the opening direction while it is held in the closed position by a rotational biasing force to prevent it from opening. The free stop unit 50 allows the second housing 3 to be opened or closed with one hand within a specified opening/closing angle range (called the free stop operating range), and allows it to stop at that position due to frictional force when the hand is released.

The rotational biasing mechanism 60 retracts the second housing 3 within a predetermined angular range (called the initial opening operation range) between the closed position and the start end of the free stop operation range, preventing the mouth from opening. The disc spring portion 40 applies pressure to the free stop portion 50 and the rotational biasing mechanism 60.

Configuration of hinge shaft 30

As shown in FIG. 4 , the hinge shaft 30 has a bracket mounting shaft 32 formed at one axial end thereof across the flange 31, and a square shaft 33 formed at the other axial end thereof. The second bracket 20 is fixed to the bracket mounting shaft 32 with a rivet 21. A first stopper 34 formed in a fan shape as shown in FIG. 3( b) is formed on the outer peripheral end surface of the flange 31 and faces radially outward. FIG. 3( b) shows the closed position of the second housing 3, in which a contact surface 34 a at the tip of the first stopper 34 in the opening direction is positioned with a phase difference of 180° in the closing direction about the axis of the hinge shaft 30 from a contact surface 17 a of a second stopper 17 (described later) formed on the first bracket 10. Therefore, when the second housing 3 is rotated 180° from the closed position relative to the first housing 2, the opening of the second housing 3 is restricted. That is, the stopper mechanism formed by the first stopper portion 34 and the second stopper portion 17 allows the second housing 3 to be opened and closed relative to the first housing 2 within a range from the closed position to the horizontal position.

The X-axis, Y-axis, and Z-axis are defined as three mutually perpendicular axes, with the axial direction of the hinge shaft 30 (left-right direction of the first housing 2) defined as the X-axis direction, the front-to-rear direction of the first housing 2 defined as the Y-axis direction, and the up-and-down direction of the first housing 2 defined as the Z-axis direction. In addition, in Figures 1 to 3, the left-to-right direction in the X-axis direction when viewed from the front of the figure is defined as the left-to-right direction, the front-to-rear direction in the Y-axis direction is defined as the front-to-rear direction, and the up-and-down direction of the Z-axis is defined as the up-and-down direction. Furthermore, the right-hand surface of the member attached to the hinge shaft 30 is defined as the first surface, and the left-hand surface is defined as the second surface.

Configuration of the first bracket 10

In FIG. 4 , the first bracket 10 has a support piece 11 extending in the Y-axis direction, which is perpendicular to the axial direction of the hinge shaft 30. The support piece 11 is formed in a rectangular flat plate shape elongated in the Y-axis direction, and a circular plate portion 12 constituting a roughly circular plate-shaped bearing is formed at its rear end. A circular insertion hole 13 is formed in the circular plate portion 12. Long upper mounting pieces 14 extending to the right in the X-axis direction are formed above and below the front side of the support piece 11. The support piece 11 also has a small-diameter anti-rotation engagement hole 16 (see FIG. 3( b)), and a second stopper portion 17 is formed on the outer periphery of the insertion hole 13, facing toward the right in the X-axis direction. The rectangular shaft portion 33 of the hinge shaft 30 is inserted into the insertion hole 13 of the first bracket 10 up to the flange 31. A circular friction contact portion 18 is formed on the second surface side of the circular plate portion 12 (see FIG. 3( c)).

Configuration of the second bracket 20

In Figures 3 and 4, the second bracket 20 is formed by bending a long, thin housing mounting piece 24 along the X-axis direction from the end of the hinge shaft mounting piece 23, where the rivet insertion hole 22 for the rivet 21 is formed.

A disc spring portion 40, a free stop portion 50, a rotation biasing mechanism 60, a first friction washer 91, and a second friction washer 92 are inserted into the angular shaft portion 33 of the hinge shaft 30, and a nut 93 is screwed onto the threaded portion 33a formed on the end of the angular shaft portion 33 to tighten the assembly. The angular shaft portion 33 is equipped with the free stop portion 50, rotation biasing mechanism 60, first friction washer 91, disc spring portion 40, and second friction washer 92, arranged in this order from the disc portion 12 of the first bracket 10 abutting against the flange 31 to the left in the X-axis direction, and the nut 93 is abutted against the second friction washer 92 to tighten the assembly.

Configuration of the disc spring section 40

The disc spring portion 40 is formed by stacking multiple disc springs 41 (eight in this embodiment). Each disc spring 41 has a circular insertion hole 42 formed in its center. A first friction washer 91 and a second friction washer 92 are abutted against both left and right ends of the disc spring portion 40.

Configuration of the free stop section 50

The free stop portion 50 is composed of a friction plate 52, which forms a frictional contact portion 51 on its first surface and is positioned opposite the second surface of the disc portion 12 of the first bracket 10, and a frictional contact portion 18 on its second surface, which forms the frictional contact portion of the disc portion 12. The frictional contact portion 51 of the friction plate 52 and the frictional contact portion 18 of the disc portion 12 are in pressurized contact due to the elastic force of the disc spring portion 40. Furthermore, the free stop portion 50 has a frictional contact portion 19 formed on the first surface of the disc portion 12 and a frictional contact portion (not shown) formed on the second surface of the flange 31 of the hinge shaft 30, which is in frictional contact with the frictional contact portion 19. The friction plate 52 has an engagement hole 53 in its center that is the same shape as the outer shape of the angular shaft portion 33 of the hinge shaft 30, and rotates integrally with the hinge shaft 30. The hinge shaft 30 is freely rotatable relative to the insertion hole 13 of the first bracket 10. Therefore, when the second bracket 20, which is fixed to the hinge shaft 30, rotates around the hinge shaft 30 relative to the first bracket 10, the friction plate 52 rotates relative to the disk portion 12. At this time, the friction contact portion 51 of the friction plate 52 rotates while in frictional contact with the friction contact portion 18 of the disk portion 12, generating friction torque. Similarly, the friction contact portion (not shown) formed on the flange 31 rotates while in frictional contact with the friction contact portion 19 of the disk portion 12, generating friction torque. As the second housing 3 moves from the closed position toward the opening direction, the rotational biasing mechanism 60 leaves the initial opening operation region in which the pressure applied by the disc spring portion 40 gradually increases. When the second housing 3 moves into the free stop operation region, a certain elastic force is applied to the disk portion 12 of the free stop portion 50, the friction plate 52, and the flange 31, generating a predetermined friction torque.

Configuration of the rotational biasing mechanism 60

As shown in Figure 4, the rotational biasing mechanism 60 is disposed between the first friction washer 91 and the friction plate 52. The rotational biasing mechanism 60 is composed of a fixed cam washer 61 (see Figures 5 and 6) having a first cam recess 64A and a second cam recess 64B formed on both sides, a first rotating cam washer 62 (see Figures 7 and 8) disposed on the right side (first surface side) of the fixed cam washer 61 in the figure, and a second rotating cam washer 63 (see Figures 9 and 10) disposed on the left side (second surface side) of the fixed cam washer 61 in the figure.

In the rotational biasing mechanism 60, the first rotating cam washer 62 and the second rotating cam washer 63, which rotate integrally with the hinge shaft 30, are brought into pressure contact with the first cam recess 64A and the second cam recess 64B of the fixed cam washer 61 by the elastic force of the disc spring portion 40.

When the second housing 3 is opened from the closed position to the open position, the first rotating cam washer 62 and the second rotating cam washer 63 rotate, and the peaks of their cam projections slide over the surfaces of the valleys of their cam recesses, climbing against the elastic force of the disc spring 40. In doing so, the first opposing distance L1 (not shown) between the fixed cam washer 61 and the first rotating cam washer 62 increases along the X-axis direction, and similarly, the second opposing distance L2 (not shown) between the fixed cam washer 61 and the second rotating cam washer 63 increases. As the peaks of the cam projections begin to climb the valleys of the cam recesses, the rotational torque applied to the second housing 3 increases, and the rotational torque applied to the second housing 3 reaches its maximum just before it reaches the top. This maximum rotational torque is called the break-out torque.

The third opposing distance L3 (not shown), which is the sum of the first opposing distance L1 and the second opposing distance L2, is the length that compresses the disc spring portion 40, which is made up of multiple disc springs (compression springs), along the X-axis direction, increasing the elastic force. The free stop portion 50 sets the elastic force generated by the multiple disc springs 41 being compressed by the third opposing distance L3 as the appropriate elastic force.

As described above, the rotational biasing mechanism 60 has an initial opening operation region, which is a predetermined angular range between the closed position and the start point of the free stop operation region. This region remains the same whether, for example, only a single first rotating cam washer 62 is used or, as in this embodiment, both a first rotating cam washer 62 and a second rotating cam washer 63 are used. As will be described in detail later, the initial opening operation region is set by the circumferential angular range of the valleys (described below) provided in the cam recesses of the first cam recess 64A and the second cam recess 64B of the fixed cam washer 61. Therefore, for example, when using only a single first rotating cam washer 62, the cam depth of the cam recess and the cam height of the cam protrusion of the first rotating cam washer 62 must be equal to the third opposing distance L3 (not shown) to obtain the appropriate elastic force.

In this case, the angle of the valleys is larger than when the cam depth is set to the length of opposing distances L1 and L2. Conversely, when the cam depth is set to the length of opposing distances L1 and L2, the angle of the valleys can be made smaller. As a result, when the second housing 3 begins to open from the closed position, the rotational torque applied to the first rotating cam washer 62 and the second rotating cam washer 63 is reduced. Therefore, the rotational torque applied to the hinge shaft 30 is the sum of the rotational torque of the first rotating cam washer 62 and the rotational torque of the second rotating cam washer 63, and the escape torque is smaller than when only one first rotating cam washer 62 is used.

In addition, the timing at which the cam protrusions of the first rotating cam washer 62 and the second rotating cam washer 63 disengage from the cam recesses of the fixed cam washer 61 is staggered to disperse the escape torque and avoid concentration of the escape torque. The first cam recess 64A and the first rotating cam washer 62 form a set of rotationally biasing cam portions, and the second cam recess 64B and the second rotating cam washer 63 form a set of rotationally biasing cam portions.

The structure of the fixed cam washer 61 will be explained with reference to Figures 5 and 6.

As shown in Figure 5, the fixed cam washer 61 has a circular insertion hole 65 formed in the center of the disk-shaped fixed cam washer body 64, through which the angular shaft portion 33 is rotatably inserted. A short arm portion 66 extends radially outward from the outer end of the fixed cam washer body 64, and an engagement pin 66a extends from the first surface side of the arm portion 66 to the right in the X-axis direction. The engagement pin 66a is inserted into the anti-rotation engagement hole 16 formed in the support piece 11 of the first bracket 10, and engages the fixed cam washer 61 around the axis of the hinge shaft 30 so that it cannot rotate. The center of the insertion hole 65 is designated C.

As shown in FIG. 5( a), a first cam recess 64A is formed on the first surface of the fixed cam washer body 64, and as shown in FIG. 5( b), a second cam recess 64B is formed on the second surface of the fixed cam washer body 64. In FIG. 6( a), the vertical axis passing through the engagement pin 66a and center C is the Z axis, the left-right axis passing through center C is the Y axis, and the front-to-back direction of the paper passing through center C is the X axis. In FIG. 6( a), the left side of the figure is the front side and the right side is the rear side, and in FIG. 6( b), the left side of the figure is the rear side and the right side is the front side. In FIG. 6( a), the clockwise direction around center C is the rotation direction from the closed position to the open direction, and in FIG. 6 ( b), the counterclockwise direction around center C is the rotation direction from the closed position to the open direction.

The first cam recess 64A shown in Figure 6(a) and the second cam recess 64B shown in Figure 6(b) are formed in the same shape and are symmetrical about the Y axis. A flat first concave planar cam portion 67A and a flat second concave planar cam portion 67B are formed on the first and second surfaces of the fixed cam washer main body 64. The first cam recess 64A has a first outer cam recess 68A formed on the outer periphery of the fixed cam washer main body 64, which constitutes a cam portion with a flat sector-shaped recessed shape as a cam-shaped portion on part of the first concave planar cam portion 67A, and a first inner cam recess 69A formed on the inner periphery of the insertion hole 65. The first outer cam recess 68A and the first inner cam recess 69A are formed in similar shapes with the center C sandwiched between them. In the following explanation, the position directly above on the Z axis is 12 o'clock on a clock face, and the position directly below is 6 o'clock.

The first outer cam recess 68A is formed at the 12 o'clock position, and the first inner cam recess 69A is formed at the 6 o'clock position. The shapes of the first outer cam recess 68A and the first inner cam recess 69A are formed symmetrically in the front-to-back direction (left-to-right direction on the page) across the Z axis, and the first outer cam recess 68A and the first inner cam recess 69A are formed above and below the Y axis.

The first outer cam recess 68A is formed with a radius r1 extending radially inward from the outer peripheral edge of the fixed cam washer body 64, and the first inner cam recess 69A is formed with a radius r2 extending radially outward from the inner peripheral edge of the insertion hole 65. The radius r1 is longer than the radius r2.

As shown in Figure 6(a), a straight line L11 connecting the ends of the first outer cam recess 68A and the first inner cam recess 69A formed on the first surface side in the opening direction and a straight line L12 connecting the ends of the first outer cam recess 68A and the first inner cam recess 69A in the closing direction intersect at the center C, and the diagonal at the intersection is the first sector angle, which is 2α.

The first outer cam recess 68A and the first inner cam recess 69A have a first bottom 68a and a second bottom 69a formed with flat bottom surfaces in the circumferential center. A first valley 681a with an inclined surface is formed at one circumferential end (opening direction) of the first bottom 68a, and a second valley 682a is formed at the other circumferential end (closing direction). The boundary between the first bottom 68a and the first valley 681a is indicated by a first recess boundary 683a, and the boundary between the first bottom 68a and the second valley 682a is indicated by a second recess boundary 684a.

A third valley portion 691a with an inclined surface is formed at one circumferential end (opening direction) of the second bottom portion 69a, and a fourth valley portion 692a with an inclined surface is formed at the other circumferential end (closing direction). The boundary between the second bottom portion 69a and the third valley portion 691a is indicated by the third recessed boundary portion 693a, and the boundary between the second bottom portion 69a and the fourth valley portion 692a is indicated by the fourth recessed boundary portion 694a.

As shown in Figure 6(a), a line L13 connecting the first recessed boundary 683a and the third recessed boundary 693a and a line L14 connecting the second recessed boundary 684a and the fourth recessed boundary 694a intersect at the center C, and the diagonal at the intersection is the second sector angle, which is 2β.

Next, the configuration of the second cam recess 64B will be explained.

As shown in Figure 6(b), the second cam recess 64B on the second surface side has a second outer cam recess 68B and a second inner cam recess 69B, which are cam-shaped cam portions with a flat sector-shaped depression, formed in a similar shape around center C in a part of the second concave flat cam portion 67B. The second outer cam recess 68B is formed at the 6 o'clock position, and the second inner cam recess 69B is formed at the 12 o'clock position. The first outer cam recess 68A and first inner cam recess 69A shown in Figure 6(a) are arranged upside down about the Y axis.

A fifth valley 681b is formed at one circumferential end (opening direction) of the third bottom 68b that constitutes the second outer cam recess 68B, and a sixth valley 682b is formed at the other circumferential end (closing direction) of the third bottom 68b. The boundary between the third bottom 68b and the fifth valley 681b is indicated as a fifth recess boundary 683b, and the boundary between the third bottom 68b and the sixth valley 682b is indicated as a sixth recess boundary 684b.

A seventh valley 691b with an inclined surface is formed on one circumferential end side (opening direction) of the fourth bottom 69b that constitutes the second inner cam recess 69B, and an eighth valley 692b with an inclined surface is formed on the other circumferential end side (closing direction). The boundary between the fourth bottom 69b and the seventh valley 691b is indicated as a seventh recess boundary 693b, and the boundary between the fourth bottom 69b and the eighth valley 692b is indicated as an eighth recess boundary 694b.

As shown in Figure 6(b), a straight line L15 connecting the opening directions of the second outer cam recess 68B and the second inner cam recess 69B formed on the second surface side and a straight line L16 connecting the closing directions of the second outer cam recess 68B and the second inner cam recess 69B intersect at center C, with the diagonal at the intersection being the third sector angle, which is equal to the first sector angle at 2α.

As shown in Figure 6(b), a line L17 connecting the fifth recessed boundary 683b and the seventh recessed boundary 693b and a line L18 connecting the sixth recessed boundary 684b and the eighth recessed boundary 694b intersect at the center C, and the diagonal at the intersection is the fourth sector angle, which is 2β, the same angle as the second sector angle.

6(c), the upper surface in the thickness direction of the fixed cam washer body 64 shows the area (second and fourth sector angles 2β) and shape (depth) of the first inner cam recess 69A and the second inner cam recess 69B in the circumferential direction (range of 0° to 360°), while the lower surface shows the area (first and third sector angles 2α) and shape (depth) of the first outer cam recess 68A and the second outer cam recess 68B in the circumferential direction (range of 0° to 360°). The thickness of the fixed cam washer body 64 is denoted by t.

As shown in Figures 6(a) and 6(b), the starting point of the 0° angle is the 12 o'clock position on the Z axis. The first inner cam recess 69A has a second bottom 69a with a depth h1 within an angle 2β range, and on both circumferential sides thereof, a third valley 691a and a fourth valley 692a are formed, each of which forms an inclined surface within a predetermined sectorial angle range (α-β). The first outer cam recess 68A has a first bottom 68a with a depth h1 within an angle range of ±β from an angle of 180°, and on both circumferential sides thereof, a first valley 681a and a second valley 682a are formed, each of which forms an inclined surface within a predetermined sectorial angle (α-β). The depth of the fourth bottom 69b of the second inner cam recess 69B on the second surface side is h1, and the depth of the third bottom 68b of the second outer cam recess 68B is h1. In this embodiment, the first to fourth bottom portions 68a, 69a, 68b, and 69b have the same depth (h1).

Next, the structure of the first rotating cam washer 62 will be explained with reference to Figures 7 and 8.

The first rotating cam washer 62, which has a first cam protrusion, has a first engagement hole 71A, a rectangular inner hole that matches the outer shape of the angular shaft portion 33 of the hinge shaft 30, formed in the axial center of the first rotating cam washer body 70A. The first rotating cam washer body 70A has the same outer diameter as the fixed cam washer body 64 of the fixed cam washer 61. As shown in Figures 8(a) and (b), the first engagement hole 71A has a long side 71C of its inner diameter surface formed along the Z-axis direction, and a short side 71D of its inner diameter surface formed along the Y-axis direction. The first surface side of the first rotating cam washer body 70A shown in Figures 7(a) and 8(a) is formed as a flat surface, and the first cam protrusion 72A is formed on the second surface side shown in Figures 7(b) and 8(b).

As shown in Figures 7(b) and 8(b), the first cam protrusion 72A has a first outer cam protrusion 74A and a first inner cam protrusion 75A, which are cam-shaped cam protrusions with a flat sector-shaped convex shape formed on part of the first convex flat cam portion 73A, which has a flat outer surface, and which protrude leftward along the X-axis direction. The first cam protrusion 72A comes into pressure contact with the first cam recess 64A by the elastic force of the disc spring portion 40.

In the Z-Y plane, the first outer cam protrusion 74A of the first cam protrusion 72A is formed at a radius r3 extending radially inward from the outer peripheral edge of the first rotating cam washer body 70A, and the first inner cam protrusion 75A is formed at a radius r4 extending radially outward from the inner peripheral edge of the first engagement hole 71A. The first outer cam protrusion 74A and the first inner cam protrusion 75A are formed in similar shapes with the center C of the first engagement hole 71A as the center. The first outer cam protrusion 74A is formed at the 12 o'clock position on the Z axis, and the first inner cam protrusion 75A is formed at the 6 o'clock position on the Z axis. The first outer cam protrusion 74A and the first inner cam protrusion 75A are formed above and below the Y axis, and their respective shapes are formed symmetrically in the front-to-back direction (left-to-right direction on the paper) around the Z axis. The radius r3 is longer than the radius r4.

A straight line L19 connecting the opening ends of the first outer cam protrusion 74A and the first inner cam protrusion 75A and a straight line L20 connecting the closing ends of the first outer cam protrusion 74A and the first inner cam protrusion 75A intersect at center C, and the diagonal at the intersection is the fifth sector angle, which is 2γ. The fifth sector angle 2γ is larger than the first and third sector angles 2α.

As shown in FIG. 8(b), the first outer cam protrusion 74A and the first inner cam protrusion 75A are formed in a convex shape along the circumferential direction, with first and second apexes 76a and 77a formed as flat top surfaces in the circumferential center. In FIG. 8(b), the counterclockwise direction around center C is the opening direction, and the clockwise direction is the closing direction. A first peak 781a with an inclined surface is formed on one circumferential end (opening direction) of the first peak 76a of the first outer cam protrusion 74A, and a second peak 782a with an inclined surface is formed on the other circumferential end (closing direction). The boundary between the first peak 76a and the first peak 781a is indicated by a first convex boundary 783a, and the boundary between the first peak 76a and the second peak 782a is indicated by a second convex boundary 784a.

The first inner cam protrusion 75A has a third peak 791a with an inclined surface formed on one circumferential end side (opening direction) of the second peak 77a, and a fourth peak 792a with an inclined surface formed on the other circumferential end side (closing direction). The boundary between the second peak 77a and the third peak 791a is indicated by the third convex boundary 793a, and the boundary between the second peak 77a and the fourth peak 792a is indicated by the fourth convex boundary 794a.

A line L21 connecting the first convex boundary 783a and the third convex boundary 793a and a line L22 connecting the second convex boundary 784a and the fourth convex boundary 794a intersect at the center C, and the diagonal at the intersection is the sixth sector angle, which is 2δ. The sixth sector angle 2δ is larger than the second and fourth sector angles 2β.

Figure 8(c) shows the circumferential sector-shaped area (sector angle 2γ) and shape (height) of the first outer cam protrusion 74A and first inner cam protrusion 75A on the thicknesswise upper surface of the first rotating cam washer body 70A. As shown in Figure 8(b), the starting point for an angle of 0° is the 12 o'clock position on the Z axis, and the angle increases in the counterclockwise direction. The first peak 76a and second peak 77a of the first outer cam protrusion 74A and first inner cam protrusion 75A have flat top surfaces with a height of h1, and on both sides are the first peak 781a, second peak 782a, third peak 791a, and fourth peak 792a formed within a predetermined sector angle range (γ-δ). In this embodiment, the height of the first top 76a and the second top 77a is h1, which is equal to the depth (h1) of the first bottom 68a and the second bottom 69a.

When the first rotating cam washer 62 is in the closed position, the first outer cam protrusion 74A faces the first outer cam recess 68A of the first cam recess 64A, and the first inner cam protrusion 75A faces the first inner cam recess 69A of the first cam recess 64A. The angle range (α-δ), which is the difference between half the angle α of the first sector angle (third sector angle) 2α and half the angle δ of the sixth sector angle 2δ, defines the first initial opening operation range in the relationship between the first rotating cam washer 62 and the first cam recess 64A, where the second housing 3 is pulled toward the first housing 2 and the elastic force of the disc spring portion 40 prevents the mouth from opening.

The configuration of the second rotating cam washer 63 having the second cam protrusion 72B will be described with reference to FIGS. 9 and 10. FIG.

The second rotating cam washer 63 has a second engagement hole 71B, a rectangular inner hole that matches the outer shape of the angular shaft portion 33 of the hinge shaft 30, formed at the axial center of the second rotating cam washer body 70B. The second rotating cam washer body 70B has the same outer diameter as the first rotating cam washer body 70A of the first rotating cam washer 62. Figures 9(a) and 10(a) show the first surface side of the second rotating cam washer body 70B, while Figures 9(b) and 10(b) show the second surface side of the second rotating cam washer body 70B. In Figures 10(a) and 10(b), Z1 is an inclined axis that passes through center C and has an inclination angle θ with respect to the Z axis. The second engagement hole 71B has a long side 71C of its inner diameter surface that is parallel to the inclined axis Z1, and a short side 71D of its inner diameter surface that is perpendicular to the long side 71C. As shown in Figures 9(a), (c), and 10, a mark 71E indicating the Z-axis position is formed on the outer peripheral surface of the second rotating cam washer body 70B at the 12 o'clock position on the Z-axis.

The rotation direction of the second rotating cam washer 63 from the closed position to the open position is clockwise when viewed from the first surface side shown in Figure 10(a), and the tilt axis Z1 is tilted counterclockwise with respect to the Z axis at an angle θ.

As shown in Figures 9(a), (c), and 10(a), a second cam protrusion 72B is formed on the first surface side of the second rotating cam washer body 70B, and as shown in Figures 9(b), 10(b), and (c), the second surface side of the second rotating cam washer body 70B is formed as a flat surface. The second cam protrusion 72B is formed on the Z-Y plane in the same way as the first cam protrusion 72A.

The second cam protrusion 72B has a second outer cam protrusion 74B and a second inner cam protrusion 75B, which are cam-shaped portions formed on part of the second convex flat cam portion 73B, which has a flat outer surface, and which protrude toward the right along the X-axis direction. The second cam protrusion 72B comes into pressure contact with the second cam recess 64B due to the elastic force of the disc spring portion 40.

In the Z-Y plane, the second cam protrusion 72B has a second outer cam protrusion 74B formed radially inward from the outer peripheral edge of the second rotating cam washer body 70B at a radius r3, and a second inner cam protrusion 75B formed radially outward from the inner peripheral edge of the second engagement hole 71B at a radius r4. The second outer cam protrusion 74B is formed at the 6 o'clock position on the Z axis, and the second inner cam protrusion 75B is formed at the 12 o'clock position on the Z axis. The second inner cam protrusion 75B and the second outer cam protrusion 74B are formed above and below the Y axis, and the shapes of the second outer cam protrusion 74B and the second inner cam protrusion 75B are formed symmetrically in the front-to-back direction (left-to-right direction on the page) around the Z axis.

The second outer cam protrusion 74B has a fifth inclined peak 781b formed on one circumferential end side (opening direction) of the third peak 76b, and a sixth inclined peak 782b formed on the other circumferential end side (closing direction) of the third peak 76b. Meanwhile, the second inner cam protrusion 75B has a seventh inclined peak 791b formed on one circumferential end side (opening direction) of the fourth peak 77b, and an eighth inclined peak 792b formed on the other circumferential end side (closing direction) of the fourth peak 77b.

Here, the boundary between the third peak 76b and the fifth peak 781b is indicated by the fifth convex boundary 783b, and the boundary between the third peak 76b and the sixth peak 782b is indicated by the sixth convex boundary 784b. Furthermore, the boundary between the fourth peak 77b and the seventh peak 791b is indicated by the seventh convex boundary 793b, and the boundary between the fourth peak 77b and the eighth peak 792b is indicated by the eighth convex boundary 794b.

A straight line L23 connecting the ends of the second outer cam convex portion 74B and the second inner cam convex portion 75B in the opening direction and a straight line L24 connecting the ends of the second outer cam convex portion 74B and the second inner cam convex portion 75B in the opening direction intersect at the center C, and the diagonal at the intersection is the seventh sector angle, which is 2γ.

A line L25 connecting the fifth convex boundary 783b and the seventh convex boundary 793b and a line L26 connecting the sixth convex boundary 784b and the eighth convex boundary 794b intersect at the center C, and the diagonal at the intersection is the eighth sector angle, which is 2δ.

Figure 10(c) shows the circumferential area (sector angle 2γ) and shape (height) of the second outer cam protrusion 74B and the second inner cam protrusion 75B on the thicknesswise upper surface of the second rotating cam washer body 70B. As shown in Figure 10(a), the 12 o'clock position on the Z axis is the starting point for the 0° angle. The third peak 76b and fourth peak 77b of the second outer cam protrusion 74B and the second inner cam protrusion 75B have flat top surfaces with a height of h1, and on both sides are the fifth peak 781b, sixth peak 782b, seventh peak 791b, and eighth peak 792b formed within a predetermined sector angle range (γ-δ). In this embodiment, the height of the third peak 76b and fourth peak 77b is h1, which is equal to the depth (h1) of the third bottom 68b and the fourth bottom 69b.

In the hinge device 100L of this embodiment, the hinge shaft 30 is rotatably supported in the insertion hole 13 of the first bracket 10, and the hinge shaft 30 rotates integrally with the second bracket 20. The fixed cam washer 61 has an engagement pin 66a that engages with the anti-rotation engagement hole 16 of the first bracket 10, and the hinge shaft 30 is rotatably inserted through the insertion hole 65. The first rotating cam washer 62 has a first engagement hole 71A that engages with the square shaft portion 33 of the hinge shaft 30, and the second rotating cam washer 63 has a second engagement hole 71B that engages with the square shaft portion 33 of the hinge shaft 30, so that the first rotating cam washer 62 rotates integrally with the hinge shaft 30.

The positional relationship between the first cam recess 64A of the fixed cam washer 61 and the first cam protrusion 72A of the first rotating cam washer 62 will be explained with reference to Figure 11. Note that for ease of explanation, Figure 11 shows the state as viewed from the first surface side, and the first cam protrusion 72A formed on the second surface side is shown in perspective in Figure 11(b) and indicated by solid lines.

When the second housing 3 is closed relative to the first housing 2 in the closed position, the first cam recess 64A of the fixed cam washer 61 is positioned such that the circumferential centers of the first bottom 68a of the first outer cam recess 68A and the second bottom 69a of the first inner cam recess 69A are located at the 12 o'clock and 6 o'clock positions on the Z axis, as shown in FIG. 11(a). In contrast, the first cam protrusion 72A of the first rotating cam washer 62 is positioned such that the circumferential centers of the first peak 76a of the first outer cam protrusion 74A and the second peak 77a of the first inner cam protrusion 75A are located at the 12 o'clock and 6 o'clock positions on the Z axis.

The first outer cam protrusion 74A of the first rotating cam washer 62 abuts against the first outer cam recess 68A of the first cam recess 64A so as to overlap, and the first inner cam protrusion 75A abuts against the first inner cam recess 69A so as to overlap. In the closed position, the overlapping state is symmetrical in the front-to-back direction (left-to-right direction on the paper) around the Z axis. The first sector angle 2α of the first outer cam recess 68A is smaller than the fifth sector angle 2γ of the first outer cam protrusion 74A. Furthermore, the second sector angle 2β of the first bottom 68a of the first outer cam recess 68A is smaller than the sixth sector angle 2δ of the first top 76a of the first outer cam protrusion 74A.

Therefore, the first peak 781a abuts the first outer cam convexity 74A so that the first convex boundary 783a is located on the slope of the first valley 681a that constitutes the first outer cam recess 68A. Similarly, the second peak 782a abuts the second valley 682a so that the second convex boundary 784a is located on the slope. Furthermore, the third peak 791a abuts the third convex boundary 793a of the first inner cam convexity 75A is located on the slope of the third valley 691a that constitutes the first inner cam recess 69A, and the fourth peak 792a abuts the fourth convex boundary 794a is located on the slope of the fourth valley 692a.

The depth h1 of the first bottom 68a of the first outer cam recess 68A is equal to the height h1 of the first apex 76a of the first outer cam protrusion 74A, and the depth h1 of the second bottom 69a of the first inner cam recess 69A is equal to the height h1 of the second apex 77a of the first inner cam protrusion 75A. However, the first convex boundary 783a, the second convex boundary 784a, the third convex boundary 793a, and the fourth convex boundary 794a abut against the slopes of the first valley 681a, the second valley 682a, the third valley 691a, and the fourth valley 692a, respectively. Therefore, in the closed position, a first initial gap D1 (not shown) is formed along the X-axis direction between the first concave flat cam portion 67A of the fixed cam washer 61 and the first convex flat cam portion 73A of the first rotating cam washer 62. Therefore, the elastic force of the disc spring portion 40 generated by the first initial gap D1 urges the first rotating cam washer 62 toward the fixed cam washer 61, and an elastic force (first pressure) in the closing direction is applied to the first rotating cam washer 62. In other words, when the second housing 3 is in the closed position, a first spring force is applied in the closing direction, preventing the mouth from opening.

When the second housing 3 is initially opened from the closed position in the opening direction, the hinge shaft 30 rotates in the opening direction, and a rotational torque in the opening direction is applied to the first rotating cam washer 62. At this time, the first peak 781a and third peak 791a on the opening direction side of the first rotating cam washer 62 slide up the slopes of the first valley 681a and third valley 691a. The second peak 782a and fourth peak 792a on the closing direction side move away from the slopes of the second valley 682a and fourth valley 692a. Here, the first peak 781a and third peak 791a, where the peak and valley slide against each other when the hinge shaft 30 rotates in the opening direction, are referred to as first click peaks, and the first valley 681a and third valley 691a are referred to as first click valleys. The first click crest slides against the first click valley, resisting the elastic force of the disc spring 40, and a clicking action is performed in which the fixed cam washer 61 and the first rotating cam washer 62 rotate while widening the opposing distance along the X-axis direction.

When the first click peak overcomes the first click valley and the sliding movement ends, the first rotating cam washer 62 transitions to a free stop region where the first peak 76a and second peak 77a contact and slide against the first concave flat surface cam portion 67A. The escape torque applied to the first rotating cam washer 62 when the first click peak overcomes the first click valley is greater than the rotational torque after transitioning to the free stop region, because the first click peak climbs while sliding circumferentially on the slope of the first click valley.

When the first click lobe abuts against the first concave flat cam portion 67A, the inter-surface distance (gap) between the first concave flat cam portion 67A of the fixed cam washer 61 and the first convex flat cam portion 73A of the first rotating cam washer 62 is the cam height h1 of the first click lobe. The frictional rotation torque required for the free stop portion 50 depends on the elastic force of the disc spring portion 40, and is dependent on the elastic force (hereinafter referred to as the appropriate elastic force) corresponding to the spring compression amount (hereinafter referred to as the appropriate spring compression amount) of twice the length (2h1) of the cam height (h1) of the first click lobe. Therefore, the first rotating cam washer 62 alone cannot provide the appropriate elastic force. Therefore, the first rotating cam washer 62 and the second rotating cam washer 63 are used to obtain the appropriate spring compression amount.

Next, the positional relationship between the second cam recess 64B of the fixed cam washer 61 and the second cam protrusion 72B of the second rotating cam washer 63 will be explained based on Figure 12. Note that for ease of explanation, Figure 12 shows the state as viewed from the second surface side, and the second cam protrusion 72B formed on the first surface side is shown in perspective in Figure 12(b) and indicated by solid lines.

When the second engagement hole 71B of the second rotating cam washer 63 is engaged with the square shaft portion 33 of the hinge shaft 30, the Z1 axis of the second rotating cam washer 63 coincides with the Z axis of the second cam recess 64B. This causes the second cam protrusion 72B of the second rotating cam washer 63 to overlap with the second cam recess 64B with a rotational offset of angle θ in the opening direction. Furthermore, the second cam protrusion 72B is positioned offset by angle θ in the opening direction with respect to the first cam protrusion 72A of the first rotating cam washer 62.

When the second housing 3 is closed relative to the first housing 2 in the closed position, the second cam recess 64B of the fixed cam washer 61 is positioned such that the circumferential centers of the third bottom 68b of the second outer cam recess 68B and the fourth bottom 69b of the second inner cam recess 69B are at the 6 o'clock and 12 o'clock positions on the Z axis, as shown in FIG. 12(a). In contrast, the second cam protrusion 72B of the second rotating cam washer 63 is positioned such that the circumferential centers of the third peak 76b of the second outer cam protrusion 74B and the fourth peak 77b of the second inner cam protrusion 75B are offset by an angle θ in the opening direction from the 6 o'clock and 12 o'clock positions on the Z axis.

The second outer cam protrusion 74B of the second rotating cam washer 63 abuts against the second outer cam recess 68B of the second cam recess 64B, overlapping with an offset of angle θ in the opening direction, and the second inner cam protrusion 75B abuts against the second inner cam recess 69B, overlapping with an offset of angle θ in the opening direction. The third sector angle 2α of the second outer cam recess 68B is smaller than the seventh sector angle 2γ of the second outer cam protrusion 74B. Furthermore, the fourth sector angle 2β of the fourth bottom 69b of the second inner cam recess 69B is smaller than the eighth sector angle 2δ of the third top 76b of the second outer cam protrusion 74B. Therefore, the second rotating cam washer 63 overlaps with the second cam recess 64B, just as the first rotating cam washer 62 overlaps with the first cam recess 64A of the fixed cam washer 61.

However, the closed position is reached when the second outer cam protrusion 74B and second inner cam protrusion 75B of the second rotating cam washer 63 overlap with the second outer cam recess 68B and second inner cam recess 69B of the second cam recess 64B, with a rotational offset of angle θ in the opening direction. Here, the fifth crest 781b of the second outer cam protrusion 74B and the seventh crest 791b of the second inner cam protrusion 75B (hereinafter referred to as the second click crest) abut the fifth valley 681b and seventh valley 691b (hereinafter referred to as the second click valley) of the second outer cam recess 68B. In this case, the contact position where the fifth convex boundary 783b and the seventh convex boundary 793b of the second click crest contact the second click valley is shifted by an angle θ in the opening direction from the contact position between the first click crest of the first rotating cam washer 62 and the first click valley of the first cam recess 64A in the closed position. Because the second click crest climbs the second click valley in response to this shift in angle θ, a second initial gap D2 (not shown) is formed along the X-axis direction between the second convex flat cam portion 73B of the second rotating cam washer 63 and the second concave flat cam portion 67B of the fixed cam washer 61. The second initial gap D2 is longer than the first initial gap D1.

Therefore, in reality, the elastic force (second spring force) of the disc spring portion 40 generated by the first initial gap D1 and the second initial gap D2 urges the first rotating cam washer 62 and the second rotating cam washer 63 toward the fixed cam washer 61, and the second spring force is applied to the first rotating cam washer 62 and the second rotating cam washer 63 in the closing direction.

In this embodiment, the first rotating cam washer 62 and the second rotating cam washer 63 are used to lower the cam height and reduce breakaway torque, and the offset angle θ is provided to disperse the breakaway torque. In other words, this configuration reduces the rotational torque when the valve is opened.

First, the reason for lowering the cam height is as follows. The difference between angle α and angle β (α-β) is the area on the plane of the first valley portion 681a (third valley portion 691a), as shown in Figure 11. If an attempt were made to ensure the appropriate elastic force using only the first rotating cam washer 62, the cam depth of the first cam recess 64A of the fixed cam washer 61 would have to be doubled to 2h1, and the cam height of the first cam protrusion 72A of the first rotating cam washer 62 would also have to be doubled to 2h1. Because the rotation angle of the first initial opening operation region (α-δ) remains unchanged, the inclination angle of the first click valley portion would increase.

When the appropriate elastic force is applied to the first rotating cam washer 62 along the X-axis direction, a comparison is made between when the cam depth of the first cam recess 64A is set to h1 and when it is doubled to 2h1. The greater the inclination angle of the first click valley, the greater the escape torque applied to the hinge shaft 30. Therefore, the escape torque is smaller when the cam depth of the first cam recess 64A is set to h1 than when the cam depth is doubled to 2h1.

The first initial opening operation range is the angle range (α-δ) which is the difference between angle α, which is half of the first sector angle (third sector angle) 2α, and angle δ, which is half of the eighth sector angle 2δ. The angle (α-δ-θ), obtained by further subtracting angle θ from this, is the second initial opening operation range in which, in relation to the second rotating cam washer 63 and the second cam recess 64B, the second housing 3 is pulled toward the first housing 2, preventing the mouth from opening with the elastic force of the disc spring portion 40.

For this reason, when the second housing 3 begins to open in the closing direction from the closed position, first the click crest portion of the click convex portion of the second rotating cam washer 63 climbs up the click valley portion of the click recessed portion of the fixed cam washer 61 , and then the click crest portion of the click convex portion of the first rotating cam washer 62 climbs up the click valley portion of the click recessed portion of the fixed cam washer 61 and moves into the free stop region. Because there is a difference between the timing at which the click crest portion of the first rotating cam washer 62 climbs up the click valley portion of the fixed cam washer 61 and the timing at which the click crest portion of the second rotating cam washer 63 climbs up the click valley portion of the fixed cam washer 61, the generation of the breakaway torque is dispersed.

As a result, when the second housing 3 of the notebook computer 1 is closed to the first housing 2 in the closed position, the rotational force required to open the second housing 3 in the closing direction is lighter than before, allowing the opening operation to be performed with one hand.

Other embodiments

Contrary to the above embodiment, the fixed cam washer 61 may be provided with a first cam protrusion and a second cam protrusion, and the first rotating cam washer 62, which rotates integrally with the hinge shaft 30, may be provided with a first concave cam portion, and the second rotating cam washer 63 may be provided with a second concave cam portion.

Furthermore, the first cam recess 64A and second cam recess 64B of the fixed cam washer 61 each have a pair of similarly shaped outer cam recesses and inner cam recesses formed on the outer and inner peripheries as cam-shaped portions, and the first cam protrusion 72A of the first rotating cam washer 62 and the second cam protrusion 72B of the second rotating cam washer 63 also have a pair of similarly shaped outer cam protrusions and inner cam protrusions formed on the outer and inner peripheries as cam-shaped portions. Alternatively, the cam-shaped portions may be combined into one by widening the radial width of either one of the pair of outer cam recesses or inner cam recesses.

The hinge device of the present invention allows the second housing to be closed with one hand, making it suitable for use in electronic devices such as video display devices, portable game consoles, and laptop computers.

1: Notebook PC 2: First housing 3: Second housing 100: Hinge device 10: First bracket 20: Second bracket 30: Hinge shaft 40: Disc spring portion 50: Free stop portion 60: Rotation biasing mechanism 61: Fixed cam washer 62: First rotating cam washer 64A: First cam recess
67A: First concave flat cam portion 68A: First outer cam recess 69A: First inner cam recess
64B: Second cam recess
67B: Second concave flat cam portion 68B: Second outer cam recess
69B: Second inner cam recess 70A: First rotating cam washer body 70B: Second rotating cam washer body 72A: First cam protrusion
73A: First convex flat cam portion 74A: First outer cam convex portion
75A: First inner cam protrusion
63: Second rotating cam washer 75B: Second inner cam protrusion
91: First friction washer 92: Second friction washer 93: Nut

Claims (4)

A hinge device that connects a first housing that forms a main body of an electronic device and a second housing that forms a cover of the electronic device in an openable and closable manner,
a first bracket attached to the first housing;
a second bracket attached to the second housing;
a hinge shaft fixed to one of the first bracket and the second bracket and rotatably connecting the other of the first bracket and the second bracket;
a friction torque generating mechanism having a disc spring and a friction washer installed on the hinge shaft;
A rotational biasing mechanism is provided adjacent to the friction torque generating mechanism and biases the first and second housings to rotate in a closing direction from a predetermined closing angle,
a rotating cam washer provided on both sides of the fixed cam washer, the rotating cam washer being pressed against the first bracket or the second bracket by the elasticity of the disc spring, the rotating cam washer having cam protrusions that drop into the cam recesses of the fixed cam washer depending on the rotation angle; and by shifting the installation positions of the one cam recess and the other cam protrusion relative to each other in the circumferential direction, the cam protrusions sequentially drop into the cam recesses from a predetermined closing angle of the first housing and the second housing, thereby automatically closing and maintaining the closed state of the first housing and the second housing; and when the first housing and the second housing are opened, the cam protrusions sequentially escape from the cam recesses, thereby reducing the rotational torque during opening. A hinge device that connects a first housing that forms a main body of an electronic device and a second housing that forms a cover of the electronic device in an openable and closable manner,
a first bracket attached to the first housing;
a second bracket attached to the second housing;
a hinge shaft fixed to one of the first bracket and the second bracket and rotatably connecting the other of the first bracket and the second bracket;
a friction torque generating mechanism having a disc spring and a friction washer installed on the hinge shaft;
A rotational biasing mechanism is provided adjacent to the friction torque generating mechanism and biases the first and second housings to rotate in a closing direction from a predetermined closing angle,
a rotating cam washer provided on each side of the fixed cam washer by the elastic force of the disc spring, and having cam recesses into which the cam protrusions of the fixed cam washer drop according to the rotation angle; and by shifting the installation positions of one of the cam recesses and one of the cam protrusions relative to each other in the circumferential direction, the cam protrusions sequentially drop into the cam recesses from a predetermined closing angle of the first and second housings, thereby automatically closing and maintaining the closed state of the first and second housings; and when the first and second housings are opened, the cam protrusions sequentially escape from the cam recesses, thereby reducing the rotational torque during opening. The hinge device according to claim 1 or 2,
The hinge device is characterized in that the cam recess and cam protrusion provided on the fixed cam washer and each of the rotating cam washers are formed by forming a single cam-shaped portion on the surface of a disk-shaped cam plate body. An electronic device comprising the hinge device according to any one of claims 1 to 3, and the first bracket and the second bracket of the hinge device attached to the first and second housings of the electronic device.