Patent Description:
This application relates to the field of terminal technologies, and in particular, to a foldable electronic device.

In recent years, with continuous development of display technologies and particularly the appearance of flexible displays that can be arbitrarily bended, electronic devices have been able to develop into more product forms, among which mobile phones having a foldable display are currently an emerging form of products.

A mobile phone having a foldable display is unfolded and folded through a rotating shaft structure that is inside a device body. At present, the rotating shaft structure of a mobile phone having a foldable display includes a shaft cover and a main swing arm. The main swing arm has one end in rotatable connection with the shaft cover and the other end extending toward the device body. In this way, when a user applies a force on the device body, the device body is folded or unfolded relative to the shaft cover under action of the external force applied by the user. In addition, the rotating shaft structure further includes a damping component and a secondary swing arm to provide some damping force so as to improve hand feel when the user folds or unfolds the device body. The damping component is arranged inside the shaft cover and may be a cam spring damping component, a gear damping component, or the like, which is not limited in this embodiment of this application. The secondary swing arm is arranged in parallel to the main swing arm, and has one end connected to the rotating shaft structure and the other end extending toward the device body. At the end close to the device body, the main swing arm is connected to the secondary swing arm through a pin. In this way, the damping force produced by the damping component can be transmitted to the main swing arm through the secondary swing arm and the pin and in turn transmitted to a middle frame and the user's hand.

However, because the damping force is transmitted between the secondary swing arm and the main swing arm only through the pin, the pin experiences a strong shear stress when bearing the damping force and therefore is prone to fracture. Such fracture interrupts the transmission of the damping force between the secondary swing arm and the main swing arm, making the device body lose its damping characteristic.

<CIT>, <CIT> and <CIT> are examples of folding mechanisms for electronic devices.

Embodiments of this application provide a foldable electronic device whose device body has more reliable damping when folded or unfolded. The foldable electronic device includes a shaft cover and a device body; a first swing arm connecting the shaft cover and the device body and configured to be rotatable around a first axis that is inside the shaft cover, so that the device body is folded or unfolded around the first axis; a second swing arm distributed in parallel to the first swing arm in a direction of the first axis and coupled to a damping component that is inside the shaft cover; and a pin connecting the first swing arm and the second swing arm at an end close to the device body, so that the second swing arm follows the first swing arm to rotate around a second axis that is inside the shaft cover when the first swing arm rotates and transmits a damping force produced by the damping component to the first swing arm through the pin, where the first axis is parallel to the second axis. The first swing arm further includes an annular groove protruding toward the second swing arm, and the second swing arm further includes a boss protruding toward the first swing arm. The boss is embedded into the annular groove in an axial direction of the pin, so that the boss and the annular groove bear part of the damping force when the second swing arm follows the first swing arm to rotate.

In the foldable electronic device according to the embodiments of this application, fitting between the annular groove and the boss increases a sectional area of a joint between the first swing arm and the second swing arm and reduces shear stress experienced by the pin, avoiding fracture of the pin under an undesirably large shear stress, thereby making the device body of the electronic device have more reliable damping when folded or unfolded.

In an implementation, the first swing arm is provided with a first connection lug at an end that is away from the shaft cover, and the second swing arm is provided with a second connection lug at an end that is away from the shaft cover, where the first connection lug is distributed in parallel to the second connection lug in a direction of the first axis; the first connection lug is provided with a slide groove, where the slide groove runs through the first connection lug in the direction of the first axis; the second connection lug is provided with a pin hole, where the pin hole runs through the second connection lug in the direction of the first axis and is located in a projection of the slide groove in the direction of the first axis; and the pin runs through the slide groove and the pin hole to make the first swing arm and the second swing arm form a pin-shaft connection. In this way, the first connection lug and the second connection lug can increase sizes of the first swing arm and the second swing arm at the joint, guaranteeing that the first swing arm and the second swing arm can have redundant structural strength at the joint even if the first connection lug and the second connection lug are provided with the slide groove and the pin hole for running of the pin, thus improving connection reliability.

In an implementation, the first connection lug includes a first end surface facing the second connection lug, where the annular groove is arranged on the first end surface, and the slide groove is located in a region enclosed by an inner ring of the annular groove; the second connection lug includes a second end surface facing the first connection lug, where the boss is arranged on the second end surface, and the pin hole is located in a region enclosed by an edge of the boss; and the annular groove overlaps with the boss in thickness in an axial direction of the pin. In this way, the annular groove is distributed at an outer periphery of the slide groove and size of the boss is also larger than diameter of the pin hole, making the annular groove and the boss form a larger overlap area in the axial direction of the pin, facilitating transmission of the damping force between the annular groove and the boss.

In an implementation, a gap between the slide groove and the pin is smaller than a gap between the inner ring of the annular groove and the boss, and the pin is configured to deform when transmitting a damping force, so as to reduce the gap between the inner ring of the annular groove and the boss, where, when the damping force transmitted by the pin is greater than a threshold, the pin deforms to make the inner ring of the annular groove contact the boss, so that the boss and the annular groove bear part of the damping force. In this way, when a small damping force is transmitted between the first swing arm and the second swing arm, the pin slightly deforms, and the slide groove contacts the pin first without the annular groove contacting the boss yet. The damping force produced by the damping component is transmitted to the first swing arm through the pin. With the damping force increasing, the pin further deforms to make the gap between the inner ring of the annular groove and the boss further decrease until the annular groove and the boss contact with each other. At this point, the annular groove and the boss begin to bear part of the damping force, which not only reduces the shear stress experienced by the pin but also avoids further deformation of the pin, thereby avoiding fracture of the pin.

In an implementation, the slide groove is a rectangular groove, and a long side of the slide groove is parallel to the first swing arm to make the pin follow the first swing arm to slide in a direction of the long side of the slide groove when the first swing arm rotates and the first axis and the second axis are not coaxial. In this way, the pin, the first axis, and the second axis can be distributed in a dynamically triangular manner in the process of rotation of the first swing arm and the second swing arm to avoid structural deadlock.

In an implementation, the boss includes an upper edge facing the second swing arm and a lower edge facing away from the second swing arm; where the upper edge is parallel to the second swing arm; and the lower edge has an included angle with the upper edge, so that distance between the lower edge and the upper edge is reduced gradually in a direction approaching the shaft cover; where the included angle between the lower edge and the upper edge is greater than or equal to a target angle, where the target angle is a maximum value of an included angle between the first swing arm and the second swing angle when the second swing arm follows the first swing arm to rotate. In this way, when the first swing arm has rotation relative to the second swing arm, the inner ring of the annular groove does not collide with the outer edge of the boss.

In an implementation, length of the boss in a direction parallel to the second swing arm is greater than length of the boss in a direction perpendicular to the second swing arm. Such design helps increase a contact area between the upper edge of the boss and the annular groove, facilitating transmission of the damping force between the first swing arm and the second swing arm so as to reduce the shear stress.

In an implementation, in the direction parallel to the second swing arm, distance between the pin hole and an edge of the boss facing the shaft cover is greater than distance between the pin hole and an edge of the boss facing away from the shaft cover.

In an implementation, in the direction parallel to the first swing arm, distance between the slide groove and a short side of the first connection lug facing the shaft cover is greater than distance between the slide groove and a short side of the first connection lug facing away from the shaft cover. In this way, the pin hole is farther away from the second axis, conducive to increasing length of an arm of force of the second swing arm in transmitting a damping force, thereby reducing internal stress of the second swing arm.

In an implementation, the first connection lug is a rectangular connection lug, where a long side of the first connection lug is parallel to the first swing arm, and a short side of the first connection lug is perpendicular to the first swing arm. In this way, the first connection lug matches the slide groove in shape, and their long sides are in parallel, helping achieve a greater grooving length of the slide groove.

In an implementation, in the direction parallel to the first swing arm, distance between the slide groove and a short side of the first connection lug facing the shaft cover is greater than distance between the slide groove and a short side of the first connection lug facing away from the shaft cover. In this way, the slide groove can be farther away from the first axis, increasing length of an arm of force of the first swing arm, thereby reducing the force experienced by the first swing arm.

In an implementation, the pin includes a pin head and a pin rod, where diameter of the pin head is greater than diameter of the pin rod; the pin head is located at an end of the first connection lug facing away from the second connection lug and is in position interference with the first connection lug in a direction of an axis of the pin; and the pin rod has an end connected to the pin head and the other end extending through the slide groove and the pin hole to the outside of the second connection lug, where a cylindrical surface of the pin rod located outside the second connection lug is provided with a clamp slot, where a clamp spring is arranged inside the clamp slot, and the clamp spring forms position interference with the second connection lug in the direction of the axis of the pin. In this way, fitting between the pin and the clamp spring can restrict the pin from having axial displacement, preventing the pin from falling out of the slide groove and the pin hole.

In an implementation, the device body includes a middle frame, where the first swing arm is connected to the middle frame. In this way, a force applied by a user for folding or unfolding the device body can be transmitted to the first swing arm through the middle frame.

device body, <NUM>. display, <NUM>. middle frame, <NUM>. rotating shaft structure, <NUM>. shaft cover, <NUM>. shaft cover bottom surface, <NUM>. main swing arm, <NUM>. secondary swing arm, <NUM>. pin, <NUM>. first swing arm, <NUM>. annular groove, <NUM>. first connection lug, <NUM>. slide groove, <NUM>. first end surface, <NUM>. second swing arm, <NUM>. boss, <NUM>. upper edge, <NUM>. lower edge, <NUM>. second connection lug, <NUM>. pin hole, <NUM>. second end surface, <NUM>. pin, <NUM>. pin head, <NUM>. pin rod, <NUM>. clamp slot, and <NUM>. clamp spring.

<FIG> is a schematic diagram of an existing mobile phone having a foldable display. As shown in <FIG>, at present, according to different folding directions, mobile phones having a folded display may include mobile phones having an inward-folded display, mobile phones having an outward-folded display, and the like. A mobile phone having an inward-folded display is shown as structure a in <FIG>, and a mobile phone having an outward-folded display is shown as structure b in <FIG>. A device body <NUM> of a mobile phone having an inward-folded display can be folded toward a side of the display <NUM>, and the display <NUM> is hidden at an inner side of the device body <NUM> after the device body <NUM> is folded, so that the display <NUM> is hidden when the device body <NUM> is folded and is presented when the device body <NUM> is unfolded. The device body <NUM> of a device having an outward-folded display can be folded toward the back side of the display <NUM>, and the display <NUM> surrounds the outer side of the device body <NUM> after the device body <NUM> is folded, so that the display <NUM> surrounds the device body <NUM> to form a surrounding display when the device body <NUM> is folded and is presented as a normal straight display when the device body <NUM> is unfolded.

A mobile phone having a foldable display can be unfolded and folded through a rotating shaft structure <NUM> that is inside the device body. <FIG> shows a position of the rotating shaft structure <NUM> in a mobile phone having a foldable display. <FIG> is a local schematic diagram of a rotating shaft structure <NUM> of an existing mobile phone having a foldable display. As shown in <FIG>, the rotating shaft structure <NUM> of an existing mobile phone having a foldable display includes a shaft cover <NUM> and a main swing arm <NUM>. The main swing arm <NUM> has one end in rotatable connection with the shaft cover <NUM> and the other end extending toward the device body <NUM>. In this way, when a user applies a force on the device body <NUM>, the device body <NUM> is folded or unfolded relative to the shaft cover <NUM> under action of the external force applied by the user. In addition, the rotating shaft structure <NUM> further includes a damping component (not shown in <FIG>) and a secondary swing arm <NUM> to provide some damping force so as to improve hand feel when the user folds or unfolds the device body. The damping component is arranged inside the shaft cover <NUM> and may be a cam spring damping component, a gear damping component, or the like, which is not limited in embodiments of this application. The secondary swing arm <NUM> is arranged in parallel to the main swing arm <NUM>, and has one end connected to the shaft cover <NUM> and the other end extending toward the device body <NUM>. At an end close to the device body <NUM>, the main swing arm <NUM> is connected to the secondary swing arm <NUM> through a pin <NUM>. In this way, a damping force produced by the damping component can be transmitted to the main swing arm <NUM> through the secondary swing arm <NUM> and the pin <NUM> and in turn transmitted to the device body <NUM> and a user's hand.

However, for the structure shown in <FIG>, the damping force is transmitted between the secondary swing arm <NUM> and the main swing arm <NUM> only through the pin <NUM>, such that the pin <NUM> experiences more shear stress when being subjected to the damping force and is therefore prone to fracture. As a result, the transmission of the damping force between the secondary swing arm <NUM> and the main swing arm <NUM> is interrupted, making the device body <NUM> lose its damping characteristic.

Embodiments of this application provide a foldable electronic device. The electronic device may be, for example, a mobile phone having a foldable display, a tablet, a laptop, an e-book reader, a charging case for wireless earphones, a wearable device (for example, a pair of virtual reality (VR) glasses, a smart watch, a smart bracelet, and a head mounted display device), an electronic device with a hinge structure connecting two or more parts, or electronic devices in other product forms, which is not specifically limited herein. The foldable electronic device according to the embodiments of this application can avoid fracture of the pin shaft between the secondary swing arm and the main swing arm under an undesirably large shear stress, allowing the device body to have more reliable damping when folded or unfolded.

<FIG> is an overall schematic diagram of a foldable electronic device according to an embodiment of this application.

<FIG> is a local schematic diagram of a foldable electronic device according to an embodiment of this application.

Refer to <FIG> and <FIG>. The electronic device includes a shaft cover <NUM> and a device body <NUM> located on two sides of the shaft cover <NUM>. The device body <NUM> of the electronic device is, on each side, connected to the shaft cover <NUM> through at least one first swing arm <NUM>. The shaft cover <NUM> is a cavity structure, where a rotating shaft mechanism is arranged inside the cavity structure, the first swing arm <NUM> has one end in rotatable connection with the shaft cover <NUM> through the rotating shaft mechanism that is inside the shaft cover <NUM> and the other end extending toward one side of the device body <NUM> to be connected to the middle frame <NUM> of the device body <NUM>. In this way, the first swing arm <NUM> is able to rotate around the first axis C1 that is inside the shaft cover <NUM>, so that the device body <NUM> can be folded or unfolded around the first axis C1.

Furthermore, as shown in <FIG> and <FIG>, each first swing arm <NUM> is correspondingly provided with a second swing arm <NUM>, and the second swing arm <NUM> is distributed in parallel to the corresponding first swing arm <NUM> in a direction of the first axis C1. The second swing arm <NUM> has an end in rotatable connection with the shaft cover <NUM> through the rotating shaft mechanism that is inside the shaft cover <NUM> and the other end extending toward one side of the device body <NUM>. In this way, the second swing arm <NUM> is able to rotate around a second axis C2 that is inside the shaft cover <NUM>, where the first axis C1 is parallel to the second axis C2. In addition, a damping component is arranged inside the shaft cover <NUM>, where the damping component may be a cam spring damping component, a gear damping component, or the like. The damping component is coupled to the second swing arm <NUM> to produce a damping force opposite to the rotating direction of the second swing arm <NUM> when the second swing arm <NUM> rotates around the second axis C2, where the damping force is applied on the second swing arm <NUM>.

Furthermore, as shown in <FIG> and <FIG>, at an end close to the device body <NUM>, the first swing arm <NUM> is connected to the corresponding second swing arm <NUM> through a pin <NUM>. In this way, when a user applies some force on the device body <NUM>, the first swing arm <NUM> connected to the device body <NUM> rotates around the first axis C1 under action of the force, and the second swing arm <NUM> follows the first swing arm <NUM> to rotate around the second axis C2 under action of the pin <NUM> connected. In this way, the damping force applied on the second swing arm <NUM> by the damping component is transmitted to the first swing arm <NUM> through the pin <NUM>, then transmitted to the middle frame <NUM> and the device body <NUM> by the first swing arm <NUM>, and finally transmitted to the user's hand, allowing the user to feel some damping and high class quality when the user folds or unfolds the device body <NUM>.

<FIG> is a sectional view of a first swing arm and a second swing arm being connected to a pin according to an embodiment of this application.

As shown in <FIG>, a gap is provided between the first swing arm <NUM> and the second swing arm <NUM>. The first swing arm <NUM> further includes an annular groove <NUM> protruding toward the second swing arm <NUM>, and the second swing arm <NUM> further includes the boss <NUM> protruding toward the first swing arm <NUM> and corresponding to the annular groove <NUM>, where the boss <NUM> is embedded into the annular groove <NUM> in an axial direction of the pin <NUM>, meaning that the annular groove <NUM> overlaps with the boss <NUM> in thickness in the axial direction of the pin <NUM>. In this way, when the second swing arm <NUM> follows the first swing arm <NUM> to rotate, the annular groove <NUM> contacts the boss <NUM> in a rotating direction of the first swing arm <NUM> and the second swing arm <NUM> (that is, in a direction perpendicular to an axis C3 of the pin <NUM>). In this way, the damping force applied by the damping component on the second swing arm <NUM> can be partly transmitted to the first swing arm <NUM> through the boss <NUM> and the annular groove <NUM>, and partly transmitted to the first swing arm <NUM> through the pin <NUM>, reducing the shear stress experienced by the pin <NUM> at the joint between the first swing arm <NUM> and the second swing arm <NUM> when the pin <NUM> transmits the damping force, thereby avoid fracture of the pin <NUM> caused by an undesirably large shear stress.

The following briefly analyzes stress situations of the pin <NUM> at the joint between the first swing arm <NUM> and the second swing arm <NUM> with reference to <FIG> to illustrate the mechanical principle of this application for reducing the shear stress experienced by the pin <NUM>. As shown in <FIG>, when a user applies a force on the device body of the electronic device so as to fold or unfold the device body, a folding force applied by the user is transmitted to the first swing arm <NUM> through a frame of the device body. At the same time, due to rotation, the second swing arm <NUM> experiences a damping force from the damping component, where the damping force has the same strength as but a different direction than the folding force. Therefore, the folding force applied by the user and the damping force produced by the damping component can together produce a shear force Fs at the joint between the first swing arm <NUM> and the second swing arm <NUM>, where the shear force Fs acts on the joint between the first swing arm <NUM> and the second swing arm <NUM> to make the joint experience a shear stress t. According to a formula for calculating the shear stress t, magnitude of the shear stress t is proportional to magnitude of the shear force Fs and is inversely proportional to the size of the sectional area a of a shearing surface. For the joint between the first swing arm <NUM> and the second swing arm <NUM>, the shear stress t experienced by the joint satisfies the following formula: <MAT>.

In the formula, t is the shear stress experienced by the joint between the first swing arm <NUM> and the second swing arm <NUM>, Fs is the shear force experienced by the joint between the first swing arm <NUM> and the second swing arm <NUM>, and a is a total sectional area of the joint between the first swing arm <NUM> and the second swing arm <NUM>. In the embodiments of this application, the joint between the first swing arm <NUM> and the second swing arm <NUM> includes the pin <NUM> and the annular groove <NUM> and the boss <NUM> that contact each other. For ease of description, herein, a1 is used to represent the sectional area of the pin <NUM>, and a2 is used to represent the sectional area of the joint between the annular groove <NUM> and the boss <NUM>. Then, the total sectional area a of the joint between the first swing arm <NUM> and the second swing arm <NUM> is a=a1+a2.

Therefore, in the embodiments of this application, the shear stress t1 experienced by the pin <NUM> is actually: <MAT>.

By contrast, for the conventional technical solution including no annular groove <NUM> or boss <NUM>, the shear stress t2 experienced by the pin <NUM> is: <MAT>.

As can be seen by comparing formula (<NUM>) and formula (<NUM>), with respect to the conventional technical solution, the embodiments of this application include an additional annular groove <NUM> and boss <NUM> at the joint between the first swing arm <NUM> and the second swing arm <NUM> to provide an additional sectional area a2 at the joint between the first swing arm <NUM> and the second swing arm <NUM>, so that the sectional area of the joint between the first swing arm <NUM> and the second swing arm <NUM> increases to a1+a2 from a1. Due to increase in the sectional area, the shear stress experienced by the pin <NUM> decreases to t1 in the embodiments of this application from t2 in the conventional solution. It can be learned that, in the technical solution according to the embodiments of this application, increasing the sectional area of the joint between the first swing arm <NUM> and the second swing arm <NUM> reduces the shear stress experienced by the pin <NUM>, avoiding fracture of the pin <NUM> under an undesirably large shear stress, thereby making the device body of the electronic device have more reliable damping when folded or unfolded.

<FIG> are exploded views of a first swing arm, a second swing arm, and a pin from different perspectives, according to an embodiment of this application.

As shown in <FIG>, in an implementation, the first swing arm <NUM> is provided with a first connection lug <NUM> at an end that is away from the shaft cover <NUM>, and the second swing arm <NUM> is provided with a second connection lug <NUM> at an end that is away from the shaft cover <NUM>, where the first connection lug <NUM> is distributed in parallel to the second connection lug <NUM> in the direction of the first axis C1. In addition, the first connection lug <NUM> and the second connection lug <NUM> are arranged on the same side as the first swing arm <NUM> and the second swing arm <NUM> in a tangential direction of rotation of the first swing arm <NUM> and the second swing arm <NUM>.

Furthermore, as shown in <FIG>, in an implementation, the first connection lug <NUM> is provided with a slide groove <NUM>, where the slide groove <NUM> runs through the first connection lug <NUM> in the direction of the first axis C1. The second connection lug <NUM> is provided with a pin hole <NUM> corresponding to the slide groove <NUM> and running through the second connection lug <NUM> in the direction of the first axis C1, where diameter of the pin hole <NUM> is equal to diameter of the pin <NUM> and less than size of the slide groove <NUM>, and the pin hole <NUM> is located in a projection of the slide groove <NUM> in the direction of the first axis C1. In this way, the pin <NUM> can pass through the slide groove <NUM> and the pin hole <NUM> to make the first swing arm <NUM> and the second swing arm <NUM> form a pin-shaft connection.

Furthermore, as shown in <FIG>, in an implementation, the first connection lug <NUM> includes a first end surface <NUM> facing the second connection lug <NUM>, where the annular groove <NUM> is arranged on the first end surface <NUM>, size of an inner ring of the annular groove <NUM> is greater than size of the slide groove <NUM>, and the slide groove <NUM> is located in a region enclosed by the inner ring of the annular groove <NUM>. In addition, the second connection lug <NUM> includes a second end surface <NUM> facing the first connection lug <NUM>, where the second end surface <NUM> may be in parallel to and have some gap with the first end surface <NUM>. The boss <NUM> is arranged on the second end surface <NUM>, where size of the boss <NUM> is greater than diameter of the pin hole <NUM>, and the pin hole <NUM> is located in a region enclosed by an edge of the boss <NUM>.

It should be noted that, due to limited sizes of the device body, the first swing arm <NUM>, and the second swing arm <NUM>, the sectional area of the pin <NUM> is typically larger than the sectional area of the annular groove <NUM> and the boss <NUM>. Therefore, in the embodiments of this application, although the pin <NUM>, the annular groove <NUM>, and the boss <NUM> all play a role in transmitting the damping force and bearing the shear stress, the pin <NUM> can serve as a main component for transmitting the damping force and bearing the shear stress, and the annular groove <NUM> and the boss <NUM> can serve as auxiliary components for transmitting the damping force and bearing the shear stress. In a specific implementation, when a user begins to fold or unfold the device body, the pin <NUM> is the first to transmit the damping force and bear the shear stress between the first swing arm <NUM> and the second swing arm <NUM>. As the damping force increases, the annular groove <NUM> and the boss <NUM> begin to take part to share some functions of transmitting the damping force and bearing the shear stress.

<FIG> is a schematic diagram of shear stress experienced by a pin, an annular groove, and a boss changing with a damping force, according to an embodiment of this application. As shown in <FIG>, in order for the pin <NUM> to serve as the main component for transmitting the damping force and bearing the shear stress, and for the annular groove <NUM> and the boss <NUM> to serve as auxiliary components for transmitting the damping force and bearing the shear stress, in embodiments of this application, preferably, the size of the slide groove <NUM> is greater than the diameter of the pin <NUM> and the size of the inner ring of the annular groove <NUM> is greater than the size of the boss <NUM>. In this way, as shown by state a of <FIG>, when the pin <NUM> does not need to transmit any damping force, a gap d1 between the slide groove <NUM> and the pin <NUM> is smaller than a gap d2 between the inner ring of the annular groove <NUM> and the boss <NUM>.

Furthermore, as shown by state b of <FIG>, when a user folds or unfolds the device body of the electronic device, the first swing arm <NUM> first rotates so as to have tangential displacement relative to the pin <NUM> and the second swing arm <NUM> to make the slide groove <NUM> contact the pin <NUM>, which in turn drives the second swing arm <NUM> to rotate. At this point, because the gap d1 between the slide groove <NUM> and the pin <NUM> is smaller than the gap d2 between the inner ring of the annular groove <NUM> and the boss <NUM>, the annular groove <NUM> is not in contact with the boss <NUM> yet, and the damping force produced by the damping component is transmitted to the first swing arm <NUM> through the pin <NUM>.

Furthermore, as shown by state c of <FIG>, when the pin <NUM> is transmitting a damping force, the pin <NUM> experiences a shear force so as to deform, further increasing the tangential displacement of the first swing arm <NUM> relative to the second swing arm <NUM>, so that the gap between the inner ring of the annular groove <NUM> and the boss <NUM> is reduced. The deformation degree of the pin <NUM> is related to the damping force it transmits: a greater damping force brings a greater shear force on the pin <NUM> and causes greater deformation. With the damping force transmitted by the pin <NUM> being greater than a threshold, the deformation thereof makes the gap between the inner ring of the annular groove <NUM> and the boss <NUM> further decrease until the annular groove <NUM> and the boss <NUM> contact each other. At this point, the annular groove <NUM> and the boss <NUM> begin to bear part of the damping force, which not only reduces the shear stress experienced by the pin <NUM>, but also avoids further deformation of the pin <NUM>, thereby avoiding fracture of the pin.

Furthermore, as shown in <FIG>, in an implementation, the pin <NUM> includes a pin head <NUM> and a pin rod <NUM>, where diameter of the pin head <NUM> is greater than diameter of the pin rod <NUM>; the pin head <NUM> is located at an end of the first connection lug <NUM> facing away from the second connection lug <NUM> and is in position interference with the first connection lug <NUM> in a direction of an axis C3 of the pin <NUM> to restrict the pin <NUM> from having axial displacement in the direction of the second connection lug <NUM>; and the pin rod <NUM> has an end connected to the pin head <NUM> and the other end extending through the slide groove <NUM> and the pin hole to the outside of the second connection lug <NUM>, where a cylindrical surface of the pin rod <NUM> located outside the second connection lug <NUM> is provided with a clamp slot <NUM>, where a clamp spring <NUM> is arranged inside the clamp slot <NUM>, and the clamp spring <NUM> forms position interference with the second connection lug <NUM> in the direction of the axis C3 of the pin <NUM> to restrict the pin <NUM> from having axial displacement in the direction of the first connection lug <NUM>. Fitting between the pin <NUM> and the clamp spring <NUM> is for the ultimate purpose of limiting axial displacement of the pin <NUM>, thereby preventing the pin <NUM> from falling out of the slide groove <NUM> and the pin hole.

In the embodiments of this application, the first axis and the second axis can be coaxial, or at different axes, which is not limited in the embodiments of this application. <FIG> is a schematic diagram of a joint between the first swing arm <NUM> and the second swing arm <NUM> in an axial direction of the pin <NUM> when the first axis C1 and the second axis C2 are not coaxial, according to an embodiment of this application. For ease of displaying structures of the first connection lug <NUM> and the slide groove <NUM>, <FIG> displays the second connection arm <NUM> and the pin <NUM> in dotted lines. As shown in <FIG>, with the first axis C1 and the second axis C2 being not coaxial, the pin <NUM>, the first axis C1, and the second axis C2 are distributed in a triangular manner, which provides stability. If the distances of the pin <NUM> relative to the first axis C1 and the second axis C2 are always unchanged, the first swing arm <NUM> and the second swing arm <NUM> will be unable to rotate due to the locking of the triangular structure. To make the first swing arm <NUM> and the second swing arm <NUM> rotatable when the first axis C1 and the second axis C2 are not coaxial, in the embodiments of this application, the first connection lug <NUM> may be a rectangular connection lug, where a long side of the first connection lug <NUM> is parallel to the first swing arm <NUM>, and a short side of the first connection lug <NUM> is perpendicular to the first swing arm <NUM>. Correspondingly, the slide groove <NUM> may also be a rectangular groove, where a long side of the slide groove <NUM> is parallel to the first swing arm <NUM>, and a short side of the slide groove <NUM> is perpendicular to the first swing arm <NUM>. In this way, when the first swing arm <NUM> and the second swing arm <NUM> rotate, the pin <NUM> also follows the first swing arm <NUM> to slide in a direction of the long side of the slide groove <NUM>, so as to dynamically change the distance between the pin <NUM> and the first axis C1, making the pin <NUM>, the first axis C1, and the second axis C2 distributed in a dynamically triangular manner during the rotation of the first swing arm <NUM> and the second swing arm <NUM>, thus avoiding structural deadlock.

Furthermore, as shown in <FIG>, in an implementation, distance d3 between the first axis C1 and a shaft cover bottom surface <NUM> is preferably greater than distance d4 between the second axis C2 and the shaft cover bottom surface <NUM>, and the second axis C2 is closer to a side wall of the shaft cover <NUM> than the first axis C1. In this way, when the first swing arm <NUM> and the second swing arm <NUM> rotate, a wall surface of the second swing arm <NUM> is closer to the shaft cover <NUM> and farther away from the display <NUM> of the electronic device than a wall surface of the first swing arm <NUM>, ensuring that the second swing arm <NUM> does not interfere with the first swing arm <NUM> supporting the display <NUM> during rotation.

Furthermore, as shown in <FIG>, in an implementation, in the direction parallel to the first swing arm <NUM>, distance d5 between the slide groove <NUM> and a short side of the first connection lug <NUM> facing the shaft cover <NUM> is greater than distance d6 between the slide groove <NUM> and a short side of the first connection lug <NUM> facing away from the shaft cover <NUM>. In this way, the slide groove <NUM> can be farther away from the first axis C1 to increase length of an arm of force of the first swing arm <NUM>, reducing the force acting on the first swing arm <NUM>.

<FIG> is a schematic structural diagram of a boss according to an embodiment of this application. As shown in <FIG>, in an implementation, the boss <NUM> includes an upper edge <NUM> facing the second swing arm <NUM> and a lower edge <NUM> facing away from the second swing arm <NUM>. The upper edge <NUM> of the boss <NUM> is parallel to the second swing arm <NUM>. In this way, when the second swing arm <NUM> follows the first swing arm <NUM> to rotate, the upper edge <NUM> of the boss <NUM> can achieve surface contact with the long side of the annular groove, facilitating transmission of the damping force between the first swing arm <NUM> and the second swing arm <NUM> so as to reduce the shear stress; the lower edge <NUM> of the boss <NUM> has an included angle δ' with the upper edge <NUM> of the boss <NUM>, where the included angle δ' makes distance between the lower edge <NUM> and the upper edge <NUM> reduced gradually in a direction approaching the shaft cover, making the lower edge <NUM> of the boss <NUM> form a slope surface relative to the upper edge <NUM> of the boss <NUM>. The included angle δ' between the lower edge <NUM> of the boss <NUM> and the upper edge <NUM> of the boss <NUM> is greater than or equal to a target angle, where the target angle is a maximum value of the included angle δ between the first swing arm <NUM> and the second swing arm <NUM> when the second swing arm <NUM> follows the first swing arm <NUM> to rotate. In the embodiments of this application, a reason why the included angle δ is formed between the first swing arm <NUM> and the second swing arm <NUM> and a method for determining the included angle δ' are specifically described in the subsequent content.

Furthermore, as shown in <FIG>, length of the boss <NUM> in a direction parallel to the second swing arm <NUM> is greater than length of the boss <NUM> in a direction perpendicular to the second swing arm <NUM>. Such design helps increase a contact area between the upper edge <NUM> of the boss <NUM> and the annular groove, facilitating transmission of the damping force between the first swing arm <NUM> and the second swing arm <NUM> so as to reduce the shear stress.

Furthermore, as shown in <FIG>, in the direction parallel to the second swing arm <NUM>, distance d7 between the pin hole <NUM> and an edge of the boss <NUM> facing the shaft cover is greater than distance d8 between the pin hole <NUM> and an edge of the boss facing away from the shaft cover. In this way, the pin hole <NUM> is farther away from the second axis, conducive to increasing length of an arm of force of the second swing arm <NUM> in transmitting the damping force, thereby reducing the force experienced by the second swing arm <NUM>.

<FIG> is a schematic diagram of an included angle δ between a first swing arm and a second swing arm according to an embodiment of this application. With reference to <FIG>, the reason why the included angle δ is formed between the first swing arm <NUM> and the second swing arm <NUM> and the method for determining the included angle δ' are specifically described below.

As shown in <FIG>, for ease of describing rotation poses of the first swing arm <NUM> and the second swing arm <NUM>, herein, the included angle between the first swing arm <NUM> and the shaft cover bottom surface <NUM> (corresponding to the horizontal plane in <FIG>) is denoted as β, and the included angle between the second swing arm <NUM> and the shaft cover bottom surface <NUM> is denoted as α. When the first swing arm <NUM> and the second swing arm <NUM> are parallel to the shaft cover bottom surface <NUM> (corresponding to the device body of the electronic device being entirely unfolded), β=<NUM>° and α= <NUM>°. During folding of the device body, because the first axis and the second axis are not coaxial, the first swing arm <NUM> and the second swing arm <NUM> have different angular velocities. Therefore, the first swing arm <NUM> and the second swing arm <NUM> may have relative rotation to form a changeable included angle δ, where δ=α-β.

Correspondingly, when the first swing arm <NUM> and the second swing arm <NUM> have relative rotation, the annular groove <NUM> and the boss may also have relative rotation, where an angle produced by their relative rotation is also δ. In this case, with no included angle δ' provided between the lower edge <NUM> and the upper edge of the boss (for example, the upper edge of the boss is parallel to the lower edge <NUM> of the boss), the inner ring of the annular groove <NUM> will collide with the lower edge <NUM> of the boss to restrict the first swing arm <NUM> and the second swing arm <NUM> from continuing to rotate, causing structural deadlock. With an included angle δ' provided between the lower edge <NUM> and the upper edge of the boss, even though the annular groove <NUM> and the boss have relative rotation, collision of the inner ring of the annular groove <NUM> with the lower edge <NUM> of the boss can be avoided so long as the angle δ of the relative rotation is less than or equal to the included angle δ'. Therefore, to ensure that the inner ring of the annular groove <NUM> does not collide with the outer edge <NUM> at any state of folding or unfolding of the device body, the value of the included angle <NUM>' should be greater than or equal to the maximum value of the included angle δ, preferably the value of the included angle δ' being equal to the maximum value of the included angle δ. In this way, when the device body is being unfolded from a folded state, the annular groove <NUM> can also contact the boss to transmit part of the damping force so as to reduce the shear stress experienced by the pin <NUM>, thus increasing service life of the pin <NUM> and bearing ability of the joint between the first swing arm <NUM> and the second swing arm <NUM>.

<FIG> is a sketch of a motion mechanism during rotation of a first swing arm and a second swing arm according to an embodiment of this application. With reference to <FIG>, how the maximum value of the included angle δ is determined is described below. In <FIG>, sketch a displays a motion mechanism model of the device body being entirely unfolded using dotted lines and displays a motion mechanism model of the device body being folded to some angle using solid lines. In the drawing, A represents distance between an axis center of the pin and the first swing arm, S represents distance between the axis center of the pin and the second swing arm, α represents an included angle between the second swing arm and the horizontal plane (shaft cover bottom surface), β represents an included angle between the first swing arm and the horizontal plane, D represents a projection length of the distance between the first axis and the second axis on the horizontal plane, L1 represents the first swing arm, and γ represents an included angle between the second swing arm and A, where according to the structure provided by embodiments of this application, A is always perpendicular to L1, and A and S are fixed values.

The following can be learned from the sketch a of <FIG> based on a geometrical relationship: <MAT>.

It can be learned that δ takes a maximum value when γ takes a maximum value. Therefore, the maximum value of δ can be determined so long as the maximum value of γ during rotation of the first swing arm and the second swing arm is determined. From the sketched motion mechanism shown by the sketch diagram a of <FIG>, inference can be made that, during rotation of the device body from being entirely unfolded to being entirely folded, the included angle δ exhibits a trend of increasing first and then decreasing. When a projection of a connection line D between the first axis and the second axis on a distance connection line A between the axis center of the pin and the first swing arm takes a maximum value, the included angle γ reaches its maximum value, and accordingly the included angle δ also reaches its maximum value. At this point, the connection line A is parallel to the connection line D. Sketch b of <FIG> displays a motion mechanism model of the first swing arm and the second swing arm when δ and γ take their maximum values. From the sketch b of <FIG>, it can be learned, based on a geometrical relationship, that the maximum value γmax of γ is: <MAT>.

Therefore, the maximum value δmax of the included angle δ is: <MAT>.

Therefore, so long as the included angle δ' between the lower edge and the upper edge of the boss is greater than or equal to δmax, it can be guaranteed that the inner ring of the annular groove does not collide with the outer edge of the boss.

It can be learned from the foregoing technical solutions that, in the foldable electronic device according to the embodiments of this application, fitting between the annular groove and the boss increases the sectional area of the joint between the first swing arm and the second swing arm so as to reduce the shear stress experienced by the pin, avoiding fracture of the pin under an undesirably large shear stress, thereby making the device body of the electronic device have more reliable damping when folded or unfolded.

It is easy to understand that, based on several embodiments provided in this application, a person skilled in the art may combine, split, or recombine the embodiments of this application to obtain other embodiments, and no such embodiments exceed the protection scope of this application.

Claim 1:
A foldable electronic device, comprising:
a shaft cover (<NUM>) and a device body (<NUM>);
a first swing arm (<NUM>) connecting the shaft cover (<NUM>) and the device body (<NUM>) and configured to be rotatable around a first axis (C1) that is inside the shaft cover (<NUM>), so that the device body (<NUM>) is folded or unfolded around the first axis (C1);
a second swing arm (<NUM>) distributed in parallel to the first swing arm (<NUM>) in a direction of the first axis (C1) and coupled to a damping component that is inside the shaft cover (<NUM>); and
a pin (<NUM>) connecting the first swing arm (<NUM>) and the second swing arm (<NUM>) at an end close to the device body (<NUM>), so that the second swing arm (<NUM>) follows the first swing arm (<NUM>) to rotate around a second axis (C2) that is inside the shaft cover (<NUM>) when the first swing arm (<NUM>) rotates, and transmits a damping force produced by the damping component to the first swing arm (<NUM>) through the pin (<NUM>), wherein the first axis (C1) is parallel to the second axis (C2); wherein
the first swing arm (<NUM>) further comprises an annular groove (<NUM>) protruding toward the second swing arm (<NUM>); the second swing arm (<NUM>) further comprises a boss (<NUM>) protruding toward the first swing arm (<NUM>); and the boss (<NUM>) is embedded into the annular groove (<NUM>) in an axial direction of the pin (<NUM>), so that the boss (<NUM>) and the annular groove (<NUM>) bear part of the damping force when the second swing arm (<NUM>) follows the first swing arm (<NUM>) to rotate.