Braking mechanisms, hinge devices, and foldable electronic devices

Abstract

The present application provides a braking mechanism, a hinge device, and a foldable electronic device. The braking mechanism includes a fixed base, a braking swing arm, a rolling element, and a pressing device. The braking swing arm is rotatably arranged on the fixed base using a braking member. On the side wall of the braking member, a first recess, a protrusion, and a second recess are arranged. The protrusion has a guiding surface inclined with respect to the axis. When the pressing device presses the guiding surface of the protrusion using the rolling element, the guiding surface can improve the effect of the pressing force of the pressing device. As a result, the braking member receives a greater pressure, and when the braking swing arm rotates, the braking torque increases. Therefore, in the same space, the braking mechanism can provide a greater braking force. This enables the braking swing arm to stably stop at any rotation position and improves the comfort of rotating the braking swing arm.

Description

Technical Field

[0001] This application claims the priority of Chinese Patent Application No. 202221152690.9, titled "Braking Mechanism, Hinge Device, and Folding Electronic Device", filed with the China National Intellectual Property Administration on May 13, 2022, the entire content of which is incorporated herein by reference.

[0002] This application relates to the field of folding electronic devices, and particularly to braking mechanisms, hinge devices, and folding electronic devices.

Background Art

[0003] With the development of flexible screens, folding electronic devices have become an important direction in the development of electronic devices. Conventional folding electronic devices usually include a first body, a second body, and a hinge mechanism that rotatably connects the first body and the second body, and the first body and the second body can be folded or unfolded relative to each other. The hinge device of a folding electronic device is an important component for the folding of the electronic device. Usually, the hinge device has a braking mechanism, whereby the folding electronic device receives the braking force provided by the braking mechanism of the hinge device in the processes of being relatively folded and relatively unfolded, including when the folding electronic device is relatively folded to the folding position and when the folding electronic device is relatively unfolded to the unfolding position. In this way, the first body and the second body of the folding electronic device can stop at any angle, and the operational comfort of relative folding or relative unfolding is improved. Alternatively, the folding electronic device is stably held at the folding position or the unfolding position.

[0004] However, the space available for foldable electronic devices to accommodate the hinge mechanism is limited, and the braking mechanisms of existing foldable electronic devices are constrained by this space, resulting in difficulties in providing sufficient braking force. Consequently, when the first and second bodies rotate relative to each other, it is difficult to stably stop at any rotational position. Furthermore, when the user rotates the first and second bodies, it is difficult to obtain sufficient braking feedback, reducing user comfort when using foldable electronic devices. [Overview of the project] [Means for solving the problem]

[0005] The purpose of this application is to solve the problem of the prior art in which it is difficult for a braking mechanism to provide sufficient braking force in a limited space. Therefore, this application relates to a braking mechanism, Fixed base and A damping arm is provided, wherein at least one braking member is positioned at one end of the damping arm, and at least one of the braking members is rotatably connected to a fixed base, thereby allowing the damping arm to rotate back and forth around an axis relative to the fixed base to switch the damping arm between a folded position and an extended position, and the braking member has a first recess, a projection, and a second recess sequentially connected in the circumferential direction of the braking member, the projection having a guide surface inclined with respect to the axis, and the damping arm is provided. A rolling element and a pressing device, wherein the pressing device contacts the rolling element, and the rolling element contacts a first recess, projection, or second recess of a braking member, thereby the pressing device applies contact pressure to the braking member using the rolling element. Includes, When the damping arm is in the folded position, the rolling element contacts the first recess. When the damping arm is in the deployed position, the rolling element contacts the second recess, or When the damping arm rotates from the folded or unfolded position to a position between the folded and unfolded positions, the rolling element rolls from the first or second recess into the guide surface of the projection and contacts the guide surface. In response, the pressing device moves together with the rolling element, thereby compressing the pressing device in a direction along the axis, opposite to that of the damping member. To provide a braking mechanism.

[0006] By using the aforementioned technical solution, when the damping arm rotates from the folded or unfolded position to a position between the folded and unfolded positions, the pressing device applies a pressing force to the guide surface of the damping member using rolling elements, causing the guide surface to be inclined with respect to the axis. In this way, the pressing force of the pressing device can be amplified, so that the force acting on the guide surface by the rolling elements becomes greater than the pressing force provided by the pressing device. This generates a greater braking force during the rotation process of the damping arm. Therefore, the damping arm can stop more stably at any position during the rotation process, improving the braking feedback obtained when the user rotates the damping arm and enhancing the comfort obtained when the user rotates the damping arm.

[0007] Furthermore, the rolling elements and braking members are connected in a way that allows them to roll, resulting in rolling friction. Compared to sliding friction connection methods, the frictional force between the rolling elements and braking members is significantly reduced. This greatly reduces wear between the rolling elements and braking members, improving the durability of the braking mechanism.

[0008] Furthermore, the pressing device, rolling elements, and braking member of the damping arm are brought into contact in sequence. This has the advantages of a simple structure and compact arrangement, resulting in a reduction in the overall volume of the braking mechanism and the space occupied by the braking mechanism. In addition, power is transmitted directly between the pressing device, rolling elements, and the braking member of the damping arm. This effectively avoids the loss of pressing force of the pressing device during the transmission process and has the advantage of high transmission efficiency.

[0009] In some embodiments, the pressing device includes the following:

[0010] A sliding member is included, which is slidably connected to a fixed base and located at one end of a braking member, thereby allowing the sliding member to slide relative to the fixed base along its axis, either toward the braking member or toward the opposite direction from the braking member, with a contact portion positioned on the sliding member, the contact portion having a pressing surface, and a rolling element making contact with the pressing surface of the contact portion so as to roll.

[0011] A pressing member is included, positioned on the side of the sliding member opposite to the end of the braking member, and applies a pressing force to the sliding member. In this way, the pressing member presses the sliding member so as to contact the rolling elements along its axis in order to apply a force in a certain direction to the rolling elements. Alternatively, the pressing force of the pressing member can be transmitted directly to the rolling elements using the sliding member, and directly to the braking member using the rolling elements. This reduces the loss of pressing force in the transmission process and improves the efficiency of pressing force transmission.

[0012] When the damping arm rotates from the folded or unfolded position to a position between the folded and unfolded positions, the rolling elements roll from the first or second recess to the guide surface of the projection. In response, the sliding member moves with the rolling elements, causing the sliding member to slide relative to the fixed base along the axis in the opposite direction to the damping member, and to press the pressing member in the opposite direction to the damping member. In this way, the pressing force of the pressing member increases, and the force transmitted to the rolling elements by the pressing member using the sliding member increases. Furthermore, the rolling elements further increase the force transmitted to the rolling elements by the sliding member using the guide surface inclined with respect to the axis, so that the force of the rolling elements on the guide surface becomes greater than the pressing force of the pressing member, increasing the braking force in the rotation process of the damping member. Therefore, the damping arm can stably stop toward any position between the folded and unfolded positions, whether in the folded or unfolded position, improving the damping feedback obtained when the user rotates the damping arm and enhancing the comfort obtained when the user rotates the damping arm.

[0013] In some embodiments, the first recess, projection, and second recess are located on the outer wall surface of the side wall of the braking member, and the side of the projection facing away from the axis is the guide surface.

[0014] The contact portion of the sliding member is located on the side of the first recess, projection, and second recess that is opposite to the axis.

[0015] The fixed base has a first recess, a projection, and a contact surface positioned toward the second recess, the contact surface contacting the side of the rolling element opposite to the axis and / or the side of the contact portion opposite to the axis, thereby causing the rolling element to contact the outer wall surface of the side wall of the braking member in the axial direction. When the rolling element presses against the guide surface, the pressing member uses a sliding member to generate an axial pressing force on the rolling element, and the contact surface uses a sliding member to directly generate or cause to generate an axial contact pressure on the rolling element in a direction perpendicular to the axis. In this way, a greater resultant force is generated on the braking member, increasing the braking force generated when the braking arm rotates.

[0016] In some embodiments, the projection uses a wedge-shaped curved structure, and the projection has a first end near the end of the braking member and a second end facing away from the end of the braking member. The thickness of the projection increases in the direction from the first end to the second end.

[0017] In some embodiments, the guide surface is provided in an arc shape in the circumferential direction of the braking member. In this way, when the rolling element moves relative to the guide surface, the rolling element moves in an arc, and as a result, the position of the rolling element in the axial direction remains unchanged. The displacement and force that compress the pressing member by the sliding member also remain unchanged. Therefore, when the braking arm rotates between the folded position and the extended position, the braking arm receives a uniform braking force, which in turn improves the comfort of rotating the braking arm.

[0018] In some embodiments, the projection has a first transition surface and a second transition surface located on both sides of the guide surface and connected to the guide surface, the first transition surface being further connected to the bottom surface of the first recess, and the second transition surface being further connected to the bottom surface of the second recess. Both the first transition surface and the second transition surface are inclined toward the first end of the projection. When the damping arm rotates from the folded or unfolded position to a position between the folded and unfolded positions, the rolling elements move along the first or second transition surface in a direction toward the first end of the projection, rolling on the guide surface and pressing against the contact surface, thereby causing the sliding member to move relative to the fixed base in a direction toward the pressing member along the axis.

[0019] Furthermore, when the damping arm rotates from the intermediate position to a position close to the folded position, or from the intermediate position to a position close to the deployed position, the first or second transition surface of the projection guides the rolling element to automatically roll into the first or second recess, thereby causing the damping arm to automatically rotate to the folded or deployed position, and consequently achieving the effect of automatic opening and closing.

[0020] In some embodiments, arc-shaped corners are provided at the joint between the first transition surface and the first recess, and at the joint between the first transition surface and the guide surface, respectively, and the corners between the tangential curved surfaces of the side edges of the first transition surface and the guide surface are obtuse.

[0021] Arc-shaped corners are provided at the joints between the second transition surface and the second recess, and at the joints between the second transition surface and the guide surface, while the corner between the second transition surface and the tangential curved surface of the other side edge of the guide surface is provided at an obtuse angle. In this way, the process of the rolling elements rolling along the first or second transition surface to the guide surface becomes smoother, the rotation process of the damping and swaying arm becomes smoother, and wear that occurs when the rolling elements collide with the first and second transition surfaces is reduced.

[0022] In some embodiments, the first recess, the protrusion, and the second recess are disposed on the end face of the side wall of the braking member, and the surface of the protrusion facing the axis is the guiding surface.

[0023] The contact portion of the sliding member is located on the side opposite to the end face of the braking member of the first recess, the protrusion, and the second recess, abuts on the side opposite to the guiding surface of the rolling element, and the pressing surface of the contact portion is inclined with respect to the axis.

[0024] The fixed base has a contact surface disposed toward the first recess, the protrusion, and the second recess, and the contact surface abuts on the side opposite to the end face of the braking member of the rolling element along the axis.

[0025] When the braking swing arm rotates from the folded position or the deployed position to a position between the folded position and the deployed position, the rolling element presses the pressing surface of the contact portion in the direction facing the axis, whereby the sliding member slides in a direction opposite to the braking member with respect to the fixed base. In this way, the pressing force of the pressing member increases, and the acting force transmitted to the rolling element by the pressing member using the sliding member increases. Further, the rolling element further increases the acting force transmitted to the rolling element by the sliding member using the guiding surface inclined with respect to the axis, whereby the acting force of the rolling element on the guiding surface becomes larger than the pressing force of the pressing member, and the braking force in the rotation process of the braking member increases. Therefore, the braking swing arm can stably stop toward an arbitrary position between the folded position and the deployed position in the folded position or the deployed position, the braking feedback obtained when the user rotates the braking swing arm is improved, and the comfort obtained when the user rotates the braking swing arm is improved.

[0026] In some embodiments, the pressing surface has a first end and a second end, and the pressing surface extends in a direction opposite to the axis perpendicular to the axis from the first end to the second end, and extends in a direction facing the inside of the sliding member along the axis, whereby the extending direction of the pressing surface from the first end to the second end is inclined with respect to the axis.

[0027] In some embodiments, the guide surface of the projection has a first edge located on the end face of the braking member and a second edge facing away from the end face of the braking member. The distance between the guide surface and the axis increases in the direction from the first edge to the second edge.

[0028] In some embodiments, the guide surface is provided in an arc shape in the circumferential direction of the braking member. In this way, when the rolling element moves relative to the guide surface, the rolling element moves in an arc rotating around the axis, and as a result, the position of the rolling element in the direction perpendicular to the axis remains unchanged. The displacement and force that compresses the pressing member by the sliding member also remain unchanged. Therefore, when the damping arm rotates between the folded position and the extended position, the damping arm receives a uniform braking force, which in turn improves the comfort of rotating the damping arm.

[0029] In some embodiments, the projection has a first transition surface and a second transition surface located on both sides of the guide surface and connected to the guide surface, the first transition surface being further connected to the bottom surface of the first recess, and the second transition surface being further connected to the bottom surface of the second recess. When the damping arm rotates from the folded or unfolded position to a position between the folded and unfolded positions, the rolling elements roll along the guide surface along the first or second transition surface, and the first or second transition surface of the projection and the contact surface of the fixed base press against each other, thereby causing the rolling elements to move in a direction perpendicular to the axis and approaching the axis, pressing against the contact surface of the contact portion, and the sliding member moves relative to the fixed base in a direction along the axis and facing the pressing member.

[0030] Furthermore, when the damping arm rotates from the intermediate position to a position close to the folded position, or from the intermediate position to a position close to the deployed position, the first or second transition surface of the projection guides the rolling element to automatically roll into the first or second recess, thereby causing the damping arm to automatically rotate to the folded or deployed position, and consequently achieving the effect of automatic opening and closing.

[0031] In some embodiments, arc-shaped corners are provided at the joint between the first transition surface and the first recess, and at the joint between the first transition surface and the guide surface, respectively, and the corners between the tangential curved surfaces of the side edges of the first transition surface and the guide surface are obtuse.

[0032] Arc-shaped corners are provided at the joints between the second transition surface and the second recess, and at the joints between the second transition surface and the guide surface, while the corner between the second transition surface and the tangential curved surface of the other side edge of the guide surface is provided at an obtuse angle. In this way, the process of the rolling elements rolling along the first or second transition surface to the guide surface becomes smoother, the rotation process of the damping and swaying arm becomes smoother, and wear that occurs when the rolling elements collide with the first and second transition surfaces is reduced.

[0033] In some embodiments, a connecting shaft is positioned on a fixed base, and the braking member uses a sleeve structure and is attached to the connecting shaft. The braking member is rotatably connected to the connecting shaft, so that the damping arm rotates back and forth around the connecting shaft relative to the fixed base, with its axis being the axis of the connecting shaft. Therefore, when the rolling element presses against the braking member, frictional resistance is generated due to the pressure between the braking member and the connecting shaft, resulting in a braking effect on the rotational motion of the damping arm.

[0034] In some embodiments, the sliding member is slidably connected to a connecting shaft and is capable of moving along the axis of the connecting shaft, with the side of the sliding member facing the pressing member being planar. In this way, the pressure applied to the side of the sliding member by the pressing member can be distributed more evenly. This ensures that the sliding process and power transmission process of the sliding member are more stable.

[0035] In some embodiments, the pressing member is an elastic member, which is sleeved onto the connecting shaft, and the elastic member is elastically deformed along the axis of the connecting shaft, applying a pressing force to the sliding member. In this way, the pressing member can provide a stable pressing force under constant deformation, and the braking effect of the braking member in rotational motion is uniformly maintained.

[0036] In some embodiments, two symmetrically positioned braking members are located at the end of the damping arm, and rolling elements and pressing devices are located at each of the two ends of the damping arm along its axis, corresponding to the two braking members. The arrangement of two braking members effectively increases the braking force applied to the damping arm. Furthermore, the symmetrical arrangement of the braking members balances the braking forces provided by the two braking members. In this way, the rotation of the damping arm becomes more stable, and the braking effect is improved.

[0037] One embodiment of this application provides a hinge device including a braking mechanism of any one of the embodiments described above.

[0038] By using the aforementioned technical solutions, the structure of the hinge device becomes simpler and more compact, and the force acting on the braking member by the rolling element is greater than the pressing force of the pressing device. In this way, the hinge device can be housed in the limited space inside the foldable electronic device, sufficient braking force is provided, and as a result, the braking effect obtained when the hinge device rotates is ensured.

[0039] In some embodiments, the hinge device includes two symmetrically arranged braking mechanisms.

[0040] One embodiment of the present application provides a foldable electronic device comprising a first body and a second body, and further comprising a hinge device of any one of the embodiments described above. The hinge device is configured to drive the first body and the second body to unfold or fold relative to each other.

[0041] By using the aforementioned technical solution, the hinge device has a smaller size, thereby occupying less internal space in the first and second bodies. This helps optimize the layout of the internal spaces of the first and second bodies. In addition, the hinge device has high durability, good braking effect, and low manufacturing cost, thereby allowing the folding electronic device to have a longer service life for folding and unfolding. The braking comfort of folding or unfolding the first and second bodies relative to each other is improved. It is ensured that the first and second bodies can be stopped at any angle. [Brief explanation of the drawing]

[0042] [Figure 1] This is a schematic diagram of the structure of a foldable electronic device in a folded state according to one embodiment of this application. [Figure 2] This is a schematic diagram of the structure of a foldable electronic device in an unfolded state according to one embodiment of this application. [Figure 3] This is a schematic exploded view of a partial structure of a hinge device for a foldable electronic device according to one embodiment of this application. [Figure 4] This is a schematic diagram of the cross-sectional structure of a synchronous mechanism of a foldable electronic device in a folded state, according to one embodiment of this application. [Figure 5] This is a schematic diagram of the cross-sectional structure of a synchronous mechanism of a foldable electronic device in an unfolded state, according to one embodiment of this application. [Figure 6] This is a schematic exploded view of the structure of a hinge device according to one embodiment of this application. [Figure 7] This is a top view of the structure of a hinge device in a folded state according to one embodiment of this application. [Figure 8] This is a top view of the structure of an intermediate hinge device according to one embodiment of the present application. [Figure 9] This is a top view of the structure of a hinge device in an unfolded state according to one embodiment of this application. [Figure 10] This is a schematic diagram of the structure of the first braking arm of a first braking mechanism according to one embodiment of the present application. [Figure 11] This is a schematic diagram of the structure of a sliding member of a first braking mechanism according to one embodiment of this application. [Figure 12] This is a schematic diagram of the structure of the sliding member of a first braking mechanism according to one embodiment of this application, as viewed from a different viewpoint. [Figure 13] This is a perspective view of the structure at the position of the rolling element when a hinge device according to one embodiment of this application is in a folded state. [Figure 14] This is a perspective view of the structure at the position of the rolling element when a hinge device according to one embodiment of this application is in an intermediate state. [Figure 15] This is a perspective view of the structure at the position of the rolling element when a hinge device according to one embodiment of this application is in the deployed state. [Figure 16] This is a cross-sectional view of the structure at the position of the rolling element when a hinge device according to one embodiment of this application is in a folded state. [Figure 17] This is a cross-sectional view of the structure at the position of the rolling element when a hinge device according to one embodiment of this application is in an intermediate state. [Figure 18] This is a cross-sectional view of the structure at the position of the rolling element when a hinge device according to one embodiment of this application is in the deployed state. [Figure 19] This is an enlarged schematic diagram of a substructure at the position of the rolling element when a hinge device according to one embodiment of this application is in an intermediate state. [Figure 20] Figure 19 is a schematic diagram of the force analysis of the rolling elements and guide surfaces. [Figure 21] This is a cross-sectional view of a substructure at the position of the rolling element when a hinge device according to one embodiment of this application rotates from a folded state to an intermediate state. [Figure 22a] Figure 21 is a schematic diagram of the force analysis of the rolling element. [Figure 22b] Figure 21 is a schematic diagram of the force analysis that exists when the rolling element is viewed from a different perspective. [Figure 23]This is a schematic diagram of the structure of the first braking arm of the first braking mechanism according to another embodiment of the present application. [Figure 24] This is a schematic diagram of the structure of the sliding member of a first braking mechanism according to another embodiment of the present application. [Figure 25] This is a schematic diagram of the structure of the sliding member of the first braking mechanism according to another embodiment of this application, as viewed from a different viewpoint. [Figure 26] This is a cross-sectional top view of the structure of a hinge device in a folded state according to another embodiment of the present application. [Figure 27] This is a cross-sectional top view of the structure of an intermediate hinge device according to another embodiment of the present application. [Figure 28] This is a cross-sectional top view of the structure of a hinge device in an unfolded state, according to another embodiment of the present application. [Figure 29] This is an enlarged schematic diagram of a substructure at the position of the rolling element when a hinge device according to another embodiment of this application is in an intermediate state. [Figure 30] Figure 29 is a schematic diagram of the force analysis of the rolling element. [Figure 31] This is a cross-sectional view of a substructure at the position of the rolling element present when a hinge device according to another embodiment of this application is in a folded state. [Figure 32] Figure 31 is a schematic diagram of the force analysis of the rolling element. [Figure 33] This is a cross-sectional view of a substructure at the position of the rolling element when the hinge device according to another embodiment of this application is in the folded state, viewed from a different perspective. [Figure 34] Figure 33 is a schematic diagram of the force analysis of the rolling element. [Modes for carrying out the invention]

[0043] The following describes embodiments of this application using specific embodiments. Those skilled in the art will readily understand other advantages and effects of this application based on what is disclosed herein. Although this application is described with reference to certain embodiments, this does not mean that the features of this application are limited to those embodiments. Rather, the purpose of the description of this application with reference to embodiments is to include alternative options or modifications that may be derived in accordance with the claims of this application. In order to provide a deeper understanding of this application, the following description includes many specific details. This application may, alternatively, be carried out without using these details. Also, in order to avoid confusion or obscuration of the focus of this application, some specific details have been omitted from the description. It should be noted that the embodiments and features of the embodiments of this application may be combined with each other insofar as they do not conflict.

[0044] In this specification, similar reference numerals and letters in the following attached drawings represent the same thing. Therefore, once something is defined in the attached drawings, it does not need to be further defined or interpreted in the following attached drawings.

[0045] In the description of this application, orientation or positional relationships indicated by terms such as “center,” “top,” “bottom,” “left,” “right,” “vertical,” “horizontal,” “inside,” and “outside” are orientation or positional relationships based on the accompanying drawings and are intended solely to facilitate and simplify the description of this application, and are not intended to indicate or imply that the specified apparatus or element has a particular orientation or needs to be constructed and operated in a particular orientation. Therefore, this should not be understood as a limitation on this application. Also, the terms “first” and “second” are used solely for illustrative purposes and should not be understood as indicating or implying relative importance.

[0046] It should be noted that, in the description of this application, unless otherwise explicitly specified and limited, the terms “attach,” “connect,” and “connect.” For example, such terms may refer to a fixed connection, a detachable connection, or an integral connection, or to a direct connection, an indirect connection via an intermediate medium, or internal communication between two elements. Those skilled in the art will be able to understand the specific meaning of the aforementioned terms in this application based on the particular circumstances.

[0047] To further clarify the purpose, technical solutions, and advantages of this application, embodiments of this application will be described in more detail below with reference to the accompanying drawings.

[0048] Please refer to Figures 1 and 2. Figure 1 is a schematic diagram of the structure of a foldable electronic device in a folded state according to one embodiment of the present application. Figure 2 is a schematic diagram of the structure of a foldable electronic device in an unfolded state according to one embodiment of the present application. As shown in Figures 1 and 2, the foldable electronic device 1 includes a first body 11, a second body 12, and a hinge device 20. The first body 11 and the second body 12 are rotatably connected via the hinge device 20. When a user uses the foldable electronic device 1, the first body 11 and the second body 12 can be rotated relative to each other. For example, the first body 11 and the second body 12 can be folded relative to each other or unfolded. In this way, the foldable electronic device 1 remains in a folded state (as shown in Figure 1) or an unfolded state (as shown in Figure 2). Alternatively, the first body 11 and the second body 12 are rotated relative to each other so that they are in an intermediate state (not shown) between a folded state and an unfolded state. The foldable electronic device 1 may be, but is not limited to, a foldable telephone, a foldable tablet computer, a foldable notebook computer, a foldable display, or a smart wearable device. In this embodiment, the foldable electronic device 1 is described using a foldable telephone as an example.

[0049] Please refer to Figure 3. Figure 3 is a schematic exploded view of a partial structure of a hinge device for a foldable electronic device according to one embodiment of the present application. As shown in Figure 3, the hinge device 20 includes a fixed base 21 and a first damping arm 22 and a second damping arm 23 rotatably positioned on the fixed base 21. The first damping arm 22 is connected to a first body 11 via a first connecting member 31 and is configured to drive the first body 11 to rotate relative to the fixed base 21. The second damping arm 23 is connected to a second body 12 via a second connecting member 32 and is configured to drive the second body 12 to rotate relative to the fixed base 21. Those skilled in the art will understand that multiple connection methods may be used between the first damping arm 22 and the first body 11, and between the second damping arm 23 and the second body 12. In another alternative embodiment, the first damping arm 22 may be directly connected to the first body 11, and the second damping arm 23 may be directly connected to the second body 12.

[0050] A braking mechanism is provided in the hinge device 20, thereby controlling the first damping arm 22 and the second damping arm 23 with a braking force during the rotation process. In this way, when the user folds or unfolds the first body 11 and the second body 12 relative to each other, the braking mechanism can provide a braking force that prevents the first body 11 and the second body 12 from folding or unfolding relative to each other. Thus, the user can feel clear braking feedback when rotating the first body 11 and the second body 12. User operation comfort when folding or unfolding the foldable electronic device 1 relative to each other is improved, and it becomes easier to control the rotation angle between the first body 11 and the second body 12. When the first body 11 and the second body 12 lose external force, the braking mechanism of the hinge device 20 can continue to allow the first body 11 and the second body 12 to stop in any intermediate state.

[0051] Furthermore, when the first body 11 and the second body 12 are in a folded or unfolded state, the braking mechanism can provide a braking force that limits the relative rotation of the first body 11 and the second body 12, thereby ensuring that the first body 11 and the second body 12 remain stably in the folded or unfolded state.

[0052] Please refer to Figures 4 and 5. Figures 4 and 5 are schematic cross-sectional diagrams of the synchronous mechanism of a foldable electronic device in a folded and unfolded state according to embodiments of the present application. As shown in Figures 4 and 5 and as understood with reference to Figure 3, the synchronous mechanism 40 is located at each end of the hinge device 20 in the longitudinal direction L of the hinge device 20, and the synchronous mechanisms 40 at both ends are arranged symmetrically. In this way, the first body 11 and the second body 12 can rotate synchronously with respect to the fixed base 21, thereby ensuring a good user experience of rotating the foldable electronic device 1 to obtain symmetrical rotation. The synchronous mechanism 40 includes a first rotating arm 41, a second rotating arm 42, and a transmission assembly 43. Both the first rotating arm 41 and the second rotating arm 42 are rotatably positioned on the fixed base 21. The rotation axis of the first rotating arm 41 coincides with the rotation axis of the first damping arm 22, and the first rotating arm 41 is connected to the first connecting member 31, so the first rotating arm 41 can rotate in sync with the first damping arm 22 using the first connecting member 31. The rotation axis of the second rotating arm 42 coincides with the rotation axis of the second damping arm 23, and the second rotating arm 42 is connected to the second connecting member 32, so the second rotating arm 42 can rotate in sync with the second damping arm 23 using the second connecting member 32. Furthermore, a first transmission gear 411 is positioned on the outer wall surface of one end of the first rotating arm 41 closest to the rotation axis. A second transmission gear 421 is positioned on the outer wall surface of one end of the second rotating arm 42 closest to the rotation axis. The first transmission gear 411 and the second transmission gear 421 are connected via a transmission assembly 43. The transmission assembly 43 includes two transmission gears rotatably mounted on a fixed support. In this way, the first rotating arm 41 and the second rotating arm 42 can rotate synchronously. In another alternative embodiment, the transmission assembly 43 may not be provided, and the first transmission gear 411 and the second transmission gear 421 are engaged to perform synchronous rotation.Those skilled in the art will understand that the first rotating arm 41 and the second rotating arm 42 are not limited to gear transmission, and alternatively, multiple transmission methods such as chain transmission and belt transmission may be used to achieve synchronous rotation of the first rotating arm 41 and the second rotating arm 42.

[0053] Furthermore, those skilled in the art will understand that two symmetrically arranged synchronous mechanisms 40 are used to achieve a better synchronous effect between the first rotating arm 41 and the second rotating arm 42. In another alternative embodiment, only a single synchronous mechanism 40 may be provided, or three or more synchronous mechanisms 40 may be provided when the length of the hinge device 20 is long.

[0054] Furthermore, those skilled in the art will understand that the synchronous mechanism 40 is used to enable the synchronous rotation of the first damping arm 22 and the second damping arm 23, thereby allowing the first body 11 and the second body 12 to rotate symmetrically and synchronously with respect to the fixed base 21 of the hinge device 20. Thus, in another alternative embodiment, the synchronous mechanism 40 may not be provided, thereby allowing the first body 11 and the second body 12 to rotate independently with respect to the fixed base 21 of the hinge device 20.

[0055] Please refer to Figures 6 to 9. Figure 6 is a schematic exploded view of the structure of a hinge device according to one embodiment of the present application. Figures 7 to 9 are top views of the structure of a hinge device according to an embodiment of the present application in the folded state, intermediate state, and unfolded state.

[0056] As shown in Figures 6 to 9, the hinge device 20 includes a first braking mechanism and a second braking mechanism arranged symmetrically. The first braking mechanism includes a fixed base 21, a first damping arm 22, a first rolling element 26, and a first pressing device. The second braking mechanism includes a fixed base 21, a second damping arm 23, a second rolling element 27, and a second pressing device. The first and second braking mechanisms share the same fixed base 21, on which a first connecting shaft 24 and a second connecting shaft 25 are arranged parallel to each other. One end of the first damping arm 22 is rotatably mounted on the first connecting shaft 24, and the axis of rotation of the first damping arm 22 is the axis of the first connecting shaft 24. One end of the second damping arm 23 is rotatably positioned on the second connecting shaft 25, and the axis of rotation of the second damping arm 23 is the axis of the second connecting shaft 25. In this way, the first damping arm 22 and the second damping arm 23 can rotate back and forth relative to the fixed base 21 to switch between the folded position and the extended position. Thus, the first damping arm 22 and the second damping arm 23 have a folded position, an intermediate position, and an extended position, corresponding to the folded state, intermediate state, and extended state of the hinge device 20.

[0057] Furthermore, those skilled in the art will understand that the first braking mechanism and the second braking mechanism may be alternatively arranged asymmetrically. In the same hinge device 20, the first braking mechanism and the second braking mechanism may alternatively be braking mechanisms having different structures, or only one braking mechanism may be provided.

[0058] Since the first and second braking mechanisms have the same structure and function, the first braking mechanism will be used as an example for explanation purposes below.

[0059] Please refer to Figures 10 to 12. Figure 10 is a schematic diagram of the structure of the first braking arm of the first braking mechanism according to one embodiment of the present application. Figures 11 and 12 are schematic diagrams of the structure of the sliding member of the first braking mechanism according to one embodiment of the present application. As shown in Figure 10 and as understood with reference to Figure 6, a first braking member 221 and a second braking member 222 are arranged at one end of the first braking arm 22 of the first braking mechanism. In one embodiment, both the first braking member 221 and the second braking member 222 are arranged using a sleeve structure. Both the first braking member 221 and the second braking member 222 are rotatably arranged on a first connecting shaft 24, thereby allowing the first braking arm 22 to rotate back and forth about the axis of the first connecting shaft 24 relative to a fixed base 21. The first braking member 221 and the second braking member 222 are arranged symmetrically in a plane perpendicular to the axis of the first connecting shaft 24. In another alternative embodiment, the first braking member 221 and the second braking member 222 may use a different structure in which they are rotatably mounted on a fixed base 21. For example, cantilever beams may be placed at both ends of the first braking member 221 and the second braking member 222, thereby rotatably mounting the first braking member 221 and the second braking member 222 on the fixed base 21 using the cantilever beams.

[0060] The structure of the first braking member 221 is the same as that of the second braking member 222, and the first braking member 221 and the second braking member 222 are arranged symmetrically. Therefore, the first braking member 221 will be used as an example for illustrative purposes below. Those skilled in the art will understand that the first braking member 221 and the second braking member 222 use the same structure and are arranged symmetrically in order to improve the stability of the rotation process of the first damping arm 22 and to better balance the frictional forces between the first braking member 221 and the first connecting shaft 24 and between the second braking member 222 and the first connecting shaft 24. Therefore, in some embodiments, the first braking member 221 and the second braking member 222 may alternatively use different structures. Furthermore, in another alternative embodiment, only a single braking member may be located at one end of the first damping arm 22.

[0061] The first braking member 221 includes an inner wall surface a corresponding to the first connecting shaft 24, an outer wall surface b facing away from the first connecting shaft 24, and end faces located at both ends of the first braking member 221. The end of the first braking member 221 facing away from the second braking member 222 is the first end face c, and the end of the first braking member 221 facing the second braking member 222 is the second end face d. The inner wall surface a of the first braking member 221 is rotatably connected to the outer wall surface of the first connecting shaft 24 by contact. The fixed base 21 extends to a position between the first braking member 221 and the second braking member 222, and the second end face d of the first braking member 221 abuts against the fixed base 21. When an interaction is formed between the inner wall surface a of the first braking member 221 and the outer wall surface of the first connecting shaft 24, and when an interaction is formed between the second end surface d of the first braking member 221 and the fixed base 21, a frictional force can be generated that hinders the rotation of the first braking member 221. In this way, a braking force is formed that partially hinders the rotation of the first damping arm 22, and the braking effect in the rotation process of the first damping arm 22 is improved.

[0062] On the outer wall surface b of the first braking member 221, a first recess 223, a projection 224, and a second recess 225 are arranged in sequence in the circumferential direction of the first braking member 221. The projection 224 protrudes from the outer wall surface b of the first braking member 221, and the first recess 223 and the second recess 225 are recessed relative to the projection 224 in a direction facing the first connecting shaft 24.

[0063] The first rolling element 26 and the first pressing device are positioned on the fixed base 21 near the first end face c of the first braking member 221. The second rolling element 27 and the second pressing device are positioned at the end corresponding to the second braking member 222 and facing away from the first braking member 221. The structure and function of the first rolling element 26 and the first pressing device are the same as those of the second rolling element 27 and the second pressing device. The first rolling element 26 and the second rolling element 27, as well as the first and second pressing devices, are arranged symmetrically. Therefore, the first rolling element 26 and the first pressing device will be used as an example for explanation below.

[0064] In one embodiment, the first rolling element 26 may be arranged using a ball structure. The first pressing device includes a sliding member 28 slidably positioned on the first connecting shaft 24 and a pressing member 29 that abuts against the side of the sliding member 28, facing away from the first end face c of the first braking member 221. The pressing member 29 is positioned using a spring and sleeved to the first connecting shaft 24, providing a pressing force to the sliding member 28 along the axis of the first connecting shaft 24. Those skilled in the art will understand that the pressing member 29 is used to provide a pressing force in a constant direction. Thus, in another embodiment, the pressing member 29 may alternatively be a structure capable of providing a stable pressing force, such as a pneumatic pressing device, a motor pressing device, or a rubber pressing member.

[0065] The sliding member 28 has a flat surface on the side facing the pressing member 29, so that the pressure from the pressing member 29 can act evenly on the sliding member 28, making the sliding process and force transmission process of the sliding member 28 relative to the first connecting shaft 24 more stable. On the side of the sliding member 28 that is opposite to the pressing member 29, a contact portion 281 is located. The contact portion 281 corresponds to the first recess 223, projection 224, and second recess 225 of the first braking member 221. The contact portion 281 is provided with a pressing surface p. The first rolling element 26 is also positioned to roll on the contact portion 281 and to abut against the pressing surface p of the contact portion 281, so that the sliding member 28 transmits the pressing force of the pressing member 29 to the first rolling element 26 using the pressing surface p of the contact portion 281. In this manner, the first rolling element 26 presses against the first recess 223, projection 224, or second recess 225. In one embodiment, the pressing surface p is perpendicular to the axis of the first connecting shaft 24. Those skilled in the art will understand that the pressing surface p of the contact portion 281 is used to transmit the force between the first rolling element 26 and the sliding member 28. Thus, in another embodiment, the pressing surface p may alternatively be positioned at an angle to the axis of the first connecting shaft 24.

[0066] Furthermore, the fixed base 21 has a contact surface e positioned toward the first recess 223, the projection 224, and the second recess 225. The contact surface e abuts against the side of the first rolling element 26 and the contact portion 281 that is facing away from the first connecting shaft 24. In this way, the first rolling element 26 abuts against the first recess 223, the projection 224, or the second recess 225 in the direction toward the first connecting shaft 24, and the movement of the first rolling element 26 in the direction perpendicular to the first connecting shaft 24 is restricted. In this way, the first rolling element 26 can apply sufficient force to the first recess 223, projection 224, or second recess 225 of the first braking member 221, thereby forming interaction forces between the first rolling element 26 and the first recess 223, between the first rolling element 26 and the projection 224, or between the first rolling element 26 and the second recess 225. In this way, a frictional force is generated that hinders the rotation of the first braking member 221 during its rotation process, and a braking force is generated that hinders the rotation of the first damping arm 22 (the braking force is the main braking force applied to the first damping arm 22 during rotation). Therefore, the braking effect during the rotation process of the first damping arm 22 is improved.

[0067] The first recess 223 is a first bottom surface f supporting the first rolling element 26, and the first bottom surface f is flush with the outer wall surface b of the first braking member 221. It includes a first side surface g and a first opening 2231 provided opposite to each other along the axis of the first connecting shaft 24, and a first transition surface h and a second side surface i provided opposite to each other in the circumferential direction of the first connecting shaft 24. The first side surface g is separately connected to the first bottom surface f, the second side surface i, and the first transition surface h. The first transition surface h is separately connected to the first bottom surface f and the first side surface g.

[0068] Please refer to Figures 13 to 23. Figures 13 to 15 are perspective views of the structure at the position of the rolling elements when the hinge device according to an embodiment of this application is in the folded, intermediate, and unfolded state. Figures 16 to 18 are cross-sectional views of the structure at the position of the rolling elements when the hinge device according to an embodiment of this application is in the folded, intermediate, and unfolded state. Figure 19 is an enlarged schematic view of a partial structure at the position of the rolling elements when the hinge device according to one embodiment of this application is in the intermediate state. Figure 20 is a schematic diagram of the force analysis of the rolling elements and guide surface of Figure 19 according to one embodiment of this application. Figure 21 is a cross-sectional view of a partial structure at the position of the rolling elements when the hinge device according to one embodiment of this application is in the folded state. Figures 22a and 22b are schematic diagrams of the force analysis of the rolling elements of Figure 21 according to an embodiment of this application.

[0069] As shown in Figures 13, 16, 21, 22a, and 22b, and as understood with reference to Figures 6, 7, and 10, when the first damping arm 22 is in the folded position, the first rolling element 26 contacts the first recess 223 of the first damping member 221. In this case, the pressing member 29 applies a pressing force to the sliding member 28 along the axis of the first connecting shaft 24. The sliding member 28 transmits pressure to the first rolling element 26 using the pressing surface p of the contact portion 281, applying pressure to the first rolling element 26 along the axis of the first connecting shaft 24, thereby pressing the first rolling element 26 by the sliding member 28 so as to contact the first side surface g of the first recess 223. Thus, the movement of the first rolling element 26 in the direction of the axis of the first connecting shaft 24 is restricted. Furthermore, the first transition surfaces h and second side surfaces i on both sides of the first rolling element 26 restrict the movement of the first rolling element 26 in the circumferential direction of the first connecting shaft 24, thereby tightening the first braking member 221 by the sliding member 28 using the first rolling element 26, and forming a braking force that restricts the rotation of the first braking member 221 relative to the first connecting shaft 24. Thus, the first braking arm 22 is stably held in the folded position.

[0070] The projection 224 uses a wedge-shaped curved surface structure. The projection 224 has a first end 2241 near the first end face c of the first braking member 221 and a second end 2242 near the second end face d of the first braking member 221. The projection 224 has a guide surface j facing away from the first connecting shaft 24, the guide surface j is connected to a first transition surface h, and the first transition surface h is inclined toward the first end 2241 of the projection 224.

[0071] As shown in Figures 21 to 22b, Figure 22a is a schematic diagram of the force analysis in a plane parallel to the axis of the first connecting shaft 24. Figure 22b is a schematic diagram of the force analysis in a plane perpendicular to the axis of the first connecting shaft 24. When the first damping arm 22 rotates from the folded position to the intermediate position under the action of an external force, first a sufficient rotational torque is applied to the first damping arm 22, which causes the first rolling element 26 to apply a force Fn2 to the first transition surface h. As shown in Figure 22a, the force Fn2 of the first rolling element 26 on the first transition surface h can be decomposed into a component force F1 parallel to the axis of the first connecting shaft 24 and a component force F2 perpendicular to the axis of the first connecting shaft 24 (the direction of component force F2 is toward the axis of the first connecting shaft 24). In this case, the component force F1 is provided by the pressing force of the pressing member 29 for pressing the sliding member 28 (in this embodiment, the pressing force of the pressing member 29 is the elastic force of the spring). F2 is provided by the supporting force of the contact surface e. The inclination angle of the first transition surface h with respect to the axis of the first connecting shaft 24 is θ6. Thus, F2 = F1 / tanθ6 can be obtained.

[0072] As shown in Figure 22b, the inclination angle of the first transition surface h with respect to the connection line between the circle center O1 of the first rolling element 26 and the axis O2 of the first connecting shaft 24 is θ2. The narrow angle between the connection line O1O2 and the connection line QO2 is θ4. O1 is the circle center of the first rolling element 26, O2 is the axis of the first connecting shaft 24, and Q is the point of contact of the first rolling element 26 with respect to the first transition surface h. The force Fn2 acting on the first rolling element 26 with respect to the first transition surface h can be further decomposed into a torsional force Fa that opposes the rotation of the first damping arm 22 (in this case, the direction of the torsional force Fa is opposite to the direction of rotation of the first damping arm 22). Thus, the magnitude of Fa can be obtained to be (F2 / sinθ2)*cos(θ2-θ4). After substituting F2 = F1 / tanθ6, Fa = (F1 / (tanθ6*sinθ2))*cos(θ2-θ4) can be obtained. The rotational force arm of the torsional force Fa is the distance L2 between the contact point Q of the first rolling element 26 with respect to the first transition surface h and the axis O2 of the first connecting shaft 24. Therefore, when the first damping and oscillating arm 22 rotates from the folded position to the intermediate position, the rotational torque applied to the first transition surface h by the first rolling element 26 can be obtained as Fa*L2. In one embodiment, appropriate angles of θ2, θ4, and θ6 are set so that Fa can be greater than F1.

[0073] Furthermore, under the action of an external force, the first rolling element 26 moves toward the first end 2241 of the projection 224 in the inclined direction of the first transition surface h, thereby driving the sliding member 28 to move synchronously in the direction toward the pressing member 29 by pressing the pressing surface p of the contact portion 281. In this way, the sliding member 28 compresses the pressing member 29. This increases the elastic deformation of the pressing member 29 and the pressing force of the pressing member 29. Also, the first braking member 221 rotates relative to the sliding member 28, thereby causing the first rolling element 26 in the contact portion 281 to roll out of the first opening 2231 of the first recess 223 of the first braking member 221 and roll toward the guide surface j of the projection 224.

[0074] Therefore, in the process of the first damping arm 22 rotating from the folded position to the intermediate position, when the first rolling element 26 contacts the first transition surface h, the first rolling element 26 can form forces F1, F2, and Fa (in one embodiment, Fa is greater than F1) acting on the first transition surface h in three different directions. In this way, the effect of the elastic force of the pressing member 29 on the first braking member 221 (the magnitude of the elastic force of the pressing member 29 is only F1) is improved, the frictional force applied to the first braking member 221 is increased, and the braking effect in the rotation process of the first damping arm 22 is improved.

[0075] When the first damping arm 22 rotates from the intermediate position to the folded position and the first rolling element 26 rolls from the projection 224 to the first transition surface h, the rotational torque applied to the first transition surface h by the first rolling element 26 is Fa*L2 (in this case, the direction of the torsional force Fa is the same as the rotation direction of the first damping arm 22, and in one embodiment, Fa is greater than F1). In this way, the first damping arm 22 can automatically rotate to the folded position and is stably held in the folded position. Thus, the effect of automatic folding is achieved.

[0076] Furthermore, arc-shaped corners are provided at the joint between the first transition surface h and the bottom surface of the first recess 223, and at the joint between the first transition surface h and the guide surface j, respectively, and the corner between the first transition surface h and the tangential curved surface of the side edge of the guide surface j is provided at an obtuse angle. In this way, the process of the first rolling element 26 rolling from the first recess 223 to the guide surface j becomes smoother, and the process of the first damping arm 22 rotating from the folded position to the intermediate position becomes smoother. Therefore, the stepping sensation in the rotation process of the first damping arm 22 is reduced, and the comfort of rotating the first damping arm 22 is improved.

[0077] The thickness of the projection 224 increases from the first end 2241 to the second end 2242, so that the guide surface j is inclined with respect to the first connecting shaft 24. The guide surface j is provided in an arc shape in the circumferential direction of the first connecting shaft 24. In one embodiment, the center of the arc is located on the axis of the first connecting shaft 24. Those skilled in the art will understand that in another alternative embodiment, the center of the arc does not have to be located on the axis of the first connecting shaft 24.

[0078] As shown in Figures 14, 16, 19, and 20, and as can be understood by referring to Figures 6, 8, and 10, when the first damping arm 22 is in the intermediate position, the first rolling element 26 is in contact with the guide surface j, which supports the first rolling element 26 at an inclination with respect to the first connecting shaft 24, with an inclination angle of θ3. In this case, the sliding member 28 applies a pressing force to the first rolling element 26 in a direction parallel to the axis of the first connecting shaft 24, and the contact surface e of the fixed base 21 directly applies a contact force to the first rolling element 26 in a direction perpendicular to the axis of the first connecting shaft 24. In this way, under the action of the sliding member 28 and the contact surface e, the first rolling element 26 forms a resultant force Fn1 perpendicular to the guide surface j with respect to the guide surface j. The effect of the resultant force Fn1 on the guide surface j of the first braking member 221 can be decomposed into a component force F1 parallel to the axis and a component force F2 perpendicular to the axis, where F2 = F1 / tan(θ3). In one embodiment, an appropriate θ3 is set so that F2 can be greater than F1. Component force F1 enables the generation of an interaction force of magnitude F1 between the second end face d of the first braking member 221 and the fixed base 21, and component force F2 enables the generation of an interaction force of magnitude F2 between the inner wall surface a of the first braking member 221 and the outer wall surface of the first connecting shaft 24. In this case, F1 is the pressing force of the pressing member 29 (i.e., the elastic force of the spring). A force of magnitude Fn1 (Fn1 is equal to F1 / sinθ3) is simultaneously generated between the first rolling element 26 and the guide surface j.

[0079] Therefore, compared to the conventional technology, in this solution, the resultant force Fn1 of the first rolling element 26 against the first braking member 221 is greater than the pressing force F1 of the pressing member 29, and the component force F2 perpendicular to the direction of the first connecting shaft 24, generated on the first braking member 221 by the first rolling element 26, is greater than the pressing force F1 of the pressing member 29. In this way, the force acting on the first braking member 221 by the pressing force F1 of the pressing member 29 is amplified, and the braking force in the rotation process of the first braking member 221 is increased. Therefore, the first braking arm 22 can stably stop toward any position between the folded position and the extended position in the folded position or the extended position, improving the braking feedback obtained when the user rotates the first braking arm 22, and improving the comfort obtained when the user rotates the first braking arm 22.

[0080] As shown in Figures 15 and 18 and as understood with reference to Figures 6, 9, and 10, the second recess 225 is a second bottom surface supporting the first rolling element 26, the second bottom surface being flush with the outer wall surface b of the first braking member 221, and includes a second side surface k and a second opening provided opposite to each other along the axis of the first connecting shaft 24, and a second transition surface m and a fourth side surface n provided opposite to each other in the circumferential direction of the first connecting shaft 24. The third side surface k is separately connected to the second bottom surface, the fourth side surface n, and the second transition surface m. The second transition surface m is separately connected to the guide surface j, the second bottom surface, and the third side surface k. The second transition surface m is inclined toward the first end 2241 of the projection 224.

[0081] When the first damping arm 22 rotates from the intermediate position to the deployed position under the action of an external force, the first rolling element 26 rolls from the guide surface j to the second transition surface m. In this case, the first rolling element 26 loses the support of the guide surface j, and as a result, the first rolling element 26 rolls along the second transition surface m to the second bottom surface of the second recess 225. Also, under the action of the sliding member 28 pressing in a direction parallel to the axis of the first connecting shaft 24, the first rolling element 26 rolls in a direction opposite to that of the pressing member 29. In this case, the first rolling element 26 receives the support force of the second transition surface m. The first rolling element 26 applies a torsional force Fa' (in this case, the direction of the torsional force Fa' is the same as the direction of rotation of the first damping arm 22) to the second transition surface m, which drives the first braking member 221 to rotate toward the deployed position. For the magnitude of the torsional force Fa' and the magnitude of the components in different directions, please refer to the analysis of Fa described above. When the first transition surface h and the second transition surface m are provided symmetrically, Fa and Fa' have the same magnitude. In this way, the first damping arm 22 can automatically roll into the second recess 225 under the pushing action of the first rolling element 26, thereby automatically deploying the first damping arm 22 when it approaches the deployed position.

[0082] When the first damping arm 22 rotates from the deployed position to the intermediate position, the torsional force Fa' (in this case, the direction of the torsional force Fa' is opposite to the direction of rotation of the first damping arm 22) applied to the second transition surface m by the first rolling element 26 serves to hinder the rotation of the first damping arm 22. In addition, the first rolling element 26 further applies a component force F1' parallel to the axis of the first connecting shaft 24 and a component force F2' perpendicular to the axis of the first connecting shaft 24 to the second transition surface m. This increases the frictional force applied to the first braking member 221. In this way, the braking force generated when the first damping arm 22 rotates from the deployed position to the intermediate position is increased. The comfort obtained when the first damping arm 22 rotates can be improved. Also, the first damping arm 22 can be stably held in the deployed position.

[0083] Furthermore, arc-shaped corners are provided at the joints between the second transition surface m and the second bottom surface of the second recess 225, and at the joints between the second transition surface m and the guide surface j, while the corners between the second transition surface m and the tangential curved surfaces of the side edges of the guide surface j are obtuse. In this way, the process of the first rolling element 26 rolling from the guide surface j to the second recess 225 becomes smoother, and the process of the first damping arm 22 rotating from the intermediate position to the deployed position becomes smoother. Consequently, the stepping sensation in the rotation process of the first damping arm 22 is reduced, and the comfort of rotating the first damping arm 22 is improved.

[0084] When the first damping arm 22 is in the deployed position, the first rolling element 26 contacts the second recess 225 of the first damping member 221. In this case, the pressing member 29 applies a pressing force to the sliding member 28 along the axis of the first connecting shaft 24. The sliding member 28 transmits pressure to the first rolling element 26 using the pressing surface p of the contact portion 281, applying pressure to the first rolling element 26 along the axis of the first connecting shaft 24, thereby pressing the first rolling element 26 by the sliding member 28 so that it contacts the third side surface k of the second recess 225. Thus, the movement of the first rolling element 26 in the direction of the axis of the first connecting shaft 24 is restricted. Furthermore, the second transition surfaces m and fourth side surfaces n on both sides of the first rolling element 26 restrict the movement of the first rolling element 26 in the circumferential direction of the first connecting shaft 24, thereby creating a braking force that restricts the rotation of the first braking member 221 relative to the first connecting shaft 24, by using the first rolling element 26 to tighten the first braking member 221 with the sliding member 28. Thus, the first braking arm 22 is stably held in the deployed position.

[0085] Those skilled in the art will understand that when the first damping arm 22 rotates from the extended position to the folded position, the first rotating arm 41 can also be stopped at any intermediate position. When the first damping arm 22 rotates from the intermediate position to the folded position under the action of an external force, the first damping arm 22 can also be folded automatically without the need to apply an external force when the first damping arm 22 approaches the folded position.

[0086] Please refer to Figures 23 to 33. Figure 23 is a schematic diagram of the structure of the first braking arm of the first braking mechanism according to another embodiment of the present application. Figures 24 and 25 are schematic diagrams of the structure of the sliding member of the first braking mechanism according to another embodiment of the present application. Figures 26 to 28 are cross-sectional top views of the structure of the hinge device in the folded, intermediate, and extended states according to another embodiment of the present application. Figure 29 is an enlarged schematic diagram of the substructure at the position of the first rolling element present when the hinge device is in the intermediate state according to another embodiment of the present application. Figure 30 is a schematic diagram of the force analysis of the first rolling element of Figure 29 according to the present application. Figures 31 and 33 are cross-sectional views of the substructure at the position of the first rolling element present when the hinge device is in the folded state according to another embodiment of the present application. Figures 32 and 34 are schematic diagrams of the force analysis of the first rolling element of Figures 31 and 33.

[0087] In this embodiment, the structure of the first braking member 221, the first rolling element 26, and the first pressing device is basically the same as that of the first embodiment, with the differences being as follows.

[0088] As shown in Figures 23 to 25 and as understood with reference to Figure 6, the first end face c of the first braking member 221 has a first recess 223, a projection 224, and a second recess 225 arranged in the circumferential direction of the first braking member 221. On the side of the sliding member 28 opposite to the pressing member 29, there is a contact portion 281. The contact portion 281 corresponds to the first recess 223, projection 224, and second recess 225 of the first braking member 221. The contact portion 281 has a pressing surface p inclined with respect to the axis of the first connecting shaft 24. The first rolling element 26 abuts against the pressing surface p of the contact portion 281 so as to roll. The pressing surface p has a first end p1 and a second end p2. The pressing surface p extends from the first end p1 to the second end p2 in a direction perpendicular to the axis of the first connecting shaft 24 and opposite to the axis of the first connecting shaft 24, and extends in a direction along the axis of the first connecting shaft 24 and toward the interior of the sliding member 28. As a result, the direction of extension of the pressing surface p from the first end p1 to the second end p2 is inclined with respect to the axis of the first connecting shaft 24.

[0089] Furthermore, the fixed base 21 has a contact surface e positioned toward the first recess 223, the projection 224, and the second recess 225. The contact surface e abuts against the side of the first rolling element 26 that faces away from the first end face c of the first braking member 221, in the direction of the axis of the first connecting shaft 24. In this way, the contact surface e of the fixed base 21 and the pressing surface p of the contact portion 281 bring the first rolling element 26 into contact with the first recess 223, the projection 224, and the second recess 225 of the first braking member 221.

[0090] The projection 224 has a guide surface j provided toward the first connecting shaft 24. The guide surface j has a first edge 2243 located on the first end face c of the first braking member 221 and a second edge 2244 facing away from the first end face c of the first braking member 221. The distance between the guide surface j and the first connecting shaft 24 increases in the direction from the first edge 2243 to the second edge 2244.

[0091] The first recess 223 of the first braking member 221 has a first bottom surface f perpendicular to the axis of the first connecting shaft 24, and a first transition surface h connected to the first bottom surface f and the guide surface j of the projection 224. The first transition surface h is inclined toward one end of the projection 224, facing away from the first braking member 221.

[0092] As shown in Figures 23, 26, 31, and 33, and as understood with reference to Figure 6, when the first damping arm 22 is in the folded position, the first rolling element 26 abuts against the first recess 223 of the first braking member 221. In this case, the pressing member 29 applies a force to the first rolling element 26 using the sliding member 28. The first transition surface h of the first recess 223 faces the contact surface e of the fixed base 21, tightening the first rolling element 26. This restricts the movement of the first rolling element 26 in the axial direction of the first connecting shaft 24. In this case, the first rolling element 26 forms a braking force against the first transition surface h that prevents the rotation of the first braking member 221. In this way, the first braking member 221 is tightened by the sliding member 28 using the first rolling element 26, forming a braking force that limits the rotation of the first braking member 221 relative to the first connecting shaft 24. Thus, the first braking arm 22 is stably held in the folded position.

[0093] As shown in Figures 31 to 34, Figure 31 is a schematic cross-sectional view of the substructure in a direction parallel to the axis of the first connecting shaft 24. Figure 33 is a schematic cross-sectional view of the substructure in a direction perpendicular to the axis of the first connecting shaft 24. As shown in Figures 31 and 32, when the first damping arm 22 rotates from the folded position to the intermediate position under the action of an external force, first a sufficient rotational torque is applied to the first damping arm 22, thereby causing the first rolling element 26 to apply a force Fn2 to the first transition surface h. In this case, the pressing surface p of the sliding member 28 contacts the first rolling element 26, generating a component force F1 on the first rolling element 26 that is parallel to the axis of the first connecting shaft 24. The magnitude of the component force F1 is equal to the pressing force of the pressing member 29 (i.e., the elastic force of the spring). Furthermore, the angle of inclination of the pressing surface p with respect to the axis of the first connecting shaft 24 is θ1. Therefore, the pressing surface p generates a component force F5 on the first rolling element 26 that is perpendicular to the axis of the first connecting shaft 24. The magnitude of F5 is F1 / tanθ1. Also, the force Fn2 acting on the first transition surface h by the first rolling element 26 can be decomposed into a component force F2 parallel to the axis of the first connecting shaft 24 and a component force F4 perpendicular to the axis of the first connecting shaft 24. The angle of inclination of the first transition surface h with respect to the axis of the first connecting shaft 24 is θ2. Therefore, F4=F5=F1 / tanθ1 and F2=F4*tanθ2, i.e., F2=(F1 / tanθ1)*tanθ2 can be obtained.

[0094] As shown in Figures 33 and 34, the inclination angle of the first transition surface h with respect to the connection line between the circle center O1 of the first rolling element 26 and the axis O2 of the first connecting shaft 24 is θ5. The narrow angle between the connection line O1O2 and the connection line QO2 is θ4. O1 is the circle center of the first rolling element 26, O2 is the axis of the first connecting shaft 24, and Q is the point of contact of the first rolling element 26 with respect to the first transition surface h. The force Fn2 acting on the first rolling element 26 with respect to the first transition surface h can be further decomposed into a torsional force Fa that opposes the rotation of the first damping arm 22 (in this case, the direction of the torsional force Fa is opposite to the direction of rotation of the first damping arm 22). Therefore, the magnitude of Fa can be obtained as F4*cos(θ5+θ4), i.e., Fa=(F1 / tanθ1)*cos(θ5+θ4). The rotational force arm of the torsional force Fa is the distance L2 between the contact point Q of the first rolling element 26 with respect to the first transition surface h and the axis O2 of the first connecting shaft 24. Therefore, when the first damping and oscillating arm 22 rotates from the folded position to the intermediate position, the rotational torque applied to the first transition surface h by the first rolling element 26 can be obtained as Fa*L2. In one embodiment, appropriate angles of θ1, θ4, and θ5 are set so that Fa can be greater than F1.

[0095] Furthermore, under the action of an external force, the first rolling element 26 moves along the first transition surface h in a direction toward the first connecting shaft 24, pressing against the pressing surface p of the contact portion 281, thereby causing the sliding member 28 to move synchronously in a direction toward the pressing member 29. In this way, the sliding member 28 compresses the pressing member 29. This increases the elastic deformation of the pressing member 29 and the pressing force of the pressing member 29. Also, the first braking member 221 rotates relative to the sliding member 28, thereby causing the first rolling element 26 within the contact portion 281 of the sliding member 28 to roll out of the first recess 223 and to the guide surface j of the projection 224.

[0096] Therefore, in the process of the first damping arm 22 rotating from the folded position to the intermediate position, when the first rolling element 26 contacts the first transition surface h, the first rolling element 26 can form forces F2, F4, and Fa (in one embodiment, Fa is greater than F1) acting on the first transition surface h in three different directions. In this way, the effect of the elastic force of the pressing member 29 on the first braking member 221 (the magnitude of the elastic force of the pressing member 29 is F1) is improved, the frictional force applied to the first braking member 221 is increased, and the braking effect in the rotation process of the first damping arm 22 is improved.

[0097] When the first damping arm 22 rotates from the intermediate position to the folded position and the first rolling element 26 rolls from the projection 224 to the first transition surface h, the rotational torque applied to the first transition surface h by the first rolling element 26 is Fa*L2 (in this case, the direction of the torsional force Fa is the same as the rotation direction of the first damping arm 22, and in one embodiment, Fa is greater than F1). In this way, the first damping arm 22 can automatically rotate to the folded position and is stably held in the folded position. Thus, the effect of automatic folding is achieved.

[0098] Furthermore, arc-shaped corners are provided at the joint between the first transition surface h and the first bottom surface of the first recess 223, and at the joint between the first transition surface h and the guide surface j, respectively, and the corner between the first transition surface h and the tangential curved surface of the side edge of the guide surface j is provided at an obtuse angle. In this way, the process of the first rolling element 26 rolling from the first recess 223 to the guide surface j becomes smoother, and the process of the first damping arm 22 rotating from the folded position to the intermediate position becomes smoother. Therefore, the stepping sensation in the rotation process of the first damping arm 22 is reduced, and the comfort of rotating the first damping arm 22 is improved.

[0099] The distance between the guide surface j and the first connecting shaft 24 increases in the direction from the first edge 2243 to the second edge 2244, thereby causing the guide surface j to be inclined with respect to the first connecting shaft 24. The guide surface j is also provided in an arc shape in the circumferential direction of the first connecting shaft 24. In one embodiment, the center of the arc is located on the axis of the first connecting shaft 24. Those skilled in the art will understand that in another alternative embodiment, the center of the arc does not have to be located on the axis of the first connecting shaft 24.

[0100] As shown in Figures 23, 27, 29, and 30, and as understood with reference to Figure 6, when the first damping arm 22 is in the intermediate position, the first rolling element 26 is in contact with the guide surface j, which supports the first rolling element 26 at an inclination with respect to the first connecting shaft 24, with an inclination angle of θ3. In this case, the sliding member 28 receives the elastic force F1 of the pressing member 29, thereby applying a pressing force to the first rolling element 26 that causes the pressing surface p of the contact portion 281 of the sliding member 28 to bend away from the first connecting shaft 24. Thus, an inclination angle θ1 of the axis of the pressing surface p with respect to the first connecting shaft 24 can be obtained. In this way, under the action of the sliding member 28, the first rolling element 26 forms a resultant force Fn2 perpendicular to the guide surface j with respect to the guide surface j. The effect of the resultant force Fn2 on the guide surface j of the first braking member 221 can be decomposed into a component force F2 parallel to the axis of the first connecting shaft 24 and a component force F3 perpendicular to the axis of the first connecting shaft 24. Component force F2 enables the generation of an interaction force of magnitude F2 between the second end face d of the first braking member 221 and the fixed base 21, and component force F3 enables the generation of an interaction force of magnitude F3 between the inner wall surface a of the first braking member 221 and the outer wall surface of the first connecting shaft 24. Furthermore, F3 = F1 / tanθ1 and F2 = F3*tanθ3, i.e., F2 = (F1 / tanθ1)*tanθ3. F1 is equal to the pressing force of the pressing member 29, and the resultant force Fn2 is equal to F2 / sinθ3. In one embodiment, appropriate angles of θ1 and θ3 are set so that F2 can be greater than F1. Furthermore, the resultant force Fn2 is also greater than F1.

[0101] Therefore, compared to the conventional technology, in this solution, the resultant force Fn2 of the first rolling element 26 against the first braking member 221 is greater than the pressing force F1 of the pressing member 29, and the component force F2 parallel to the direction of the first connecting shaft 24, generated on the first braking member 221 by the first rolling element 26, is greater than the pressing force F1 of the pressing member 29. In this way, the force acting on the first braking member 221 by the pressing force F1 of the pressing member 29 is amplified, and the braking force in the rotation process of the first braking member 221 is increased. Therefore, the first braking arm 22 can stably stop toward any position between the folded position and the extended position in the folded or extended position, the braking feedback obtained when the user rotates the first braking arm 22 is improved, and the comfort obtained when the user rotates the first braking arm 22 is enhanced.

[0102] As shown in Figures 23 and 29 and as understood with reference to Figure 6, the second recess 225 of the first braking member 221 has a second bottom surface perpendicular to the axis of the first connecting shaft 24 and a second transition surface m connected to the second bottom surface and the guide surface j of the projection 224. The second transition surface m is inclined toward the end of the projection 224, facing away from the first braking member 221.

[0103] When the first damping arm 22 rotates from the intermediate position to the deployed position under the action of an external force, the first rolling element 26 rolls from the guide surface j to the second transition surface m. In this case, the first rolling element 26 loses support from the guide surface j, and as a result, the first rolling element 26 rolls along the second transition surface m to the second recess 225. The sliding member 28 moves toward the first end face c of the first damping member 221 under the action of the pressing member 29. Also, the first rolling element 26 rolls in a direction opposite to the first connecting shaft 24 under the action of the pressing of the sliding member 28. In this case, the first rolling element 26 receives the support force of the second transition surface m. The first rolling element 26 applies a torsional force Fa' (in this case, the direction of the torsional force Fa' is the same as the direction of rotation of the first damping arm 22) to the second transition surface m, which drives the first braking member 221 to rotate toward the deployed position. For the magnitude of the torsional force Fa' and the magnitude of the components in different directions, please refer to the analysis of Fa described above. When the first transition surface h and the second transition surface m are provided symmetrically, Fa and Fa' have the same magnitude. In this way, the first damping arm 22 can automatically roll into the second recess 225 under the pushing action of the first rolling element 26, thereby automatically deploying the first damping arm 22 when it approaches the deployed position without the need to apply an external force.

[0104] When the first damping arm 22 rotates from the deployed position to the intermediate position, the torsional force Fa' (in this case, the direction of the torsional force Fa' is opposite to the direction of rotation of the first damping arm 22) applied to the second transition surface m by the first rolling element 26 serves to hinder the rotation of the first damping arm 22. In addition, the first rolling element 26 further applies a component force F2' parallel to the axis of the first connecting shaft 24 and a component force F4' perpendicular to the axis of the first connecting shaft 24 to the second transition surface m. This increases the frictional force applied to the first braking member 221. In this way, the braking force generated when the first damping arm 22 rotates from the deployed position to the intermediate position is increased. The comfort obtained when the first damping arm 22 rotates can be improved. Also, the first damping arm 22 can be stably held in the deployed position.

[0105] Furthermore, arc-shaped corners are provided at the joints between the second transition surface m and the second bottom surface of the second recess 225, and at the joints between the second transition surface m and the guide surface j, while the corners between the second transition surface m and the tangential curved surfaces of the side edges of the guide surface j are obtuse. In this way, the process of the first rolling element 26 rolling from the guide surface j to the second recess 225 becomes smoother, and the process of the first damping arm 22 rotating from the intermediate position to the deployed position becomes smoother. Consequently, the stepping sensation in the rotation process of the first damping arm 22 is reduced, and the comfort of rotating the first damping arm 22 is improved.

[0106] As shown in Figures 23 and 28 and as understood with reference to Figure 6, when the first damping arm 22 is in the deployed position, the first rolling element 26 abuts against the second recess 225 of the first damping member 221. In this case, the second transition surface m of the second recess 225 faces the contact surface e of the fixed base 21, tightening the first rolling element 26. This restricts the movement of the first rolling element 26 in the direction of the axis of the first connecting shaft 24. The second transition surface m also forms a torsional force Fa' on the first damping member 221 using the first rolling element 26, which prevents the rotation of the first damping member 221 (in this case, the direction of the torsional force Fa' is opposite to the direction of rotation of the first damping arm 22). In this way, the first braking member 221 is tightened by the sliding member 28 using the first rolling element 26, forming a braking force that limits the rotation of the first braking member 221 relative to the first connecting shaft 24. Thus, the first braking arm 22 is stably held in the deployed position.

[0107] Those skilled in the art will understand that when the first damping arm 22 rotates from the extended position to the folded position, the first rotating arm 41 can also be stopped at any intermediate position. When the first damping arm 22 rotates from the intermediate position to the folded or extended position under the action of an external force, the first damping arm 22 can also be automatically folded or extended without the need to apply an external force when the first damping arm 22 approaches the folded or extended position.

[0108] It will be apparent to those skilled in the art that various modifications and variations can be made to this application without departing from the spirit and scope of this application. This application is intended to encompass such modifications and variations, provided that they fall within the scope defined by the claims of this application and the equivalent art. [Explanation of symbols]

[0109] 1. Foldable electronic device 11 The first body 12 The second body 20 Hinge device 21 Fixed base e Contact surface 22 First damping motion arm 221 First braking member a. Interior wall surface b External wall surface c First end face d Second end face 222 Second braking member 223 First recess 2231 First opening f First base g First aspect h First transition surface i. Second aspect 224 Protrusion 2241 First end 2242 Second end j Guide surface 2243 The First Connection 2244 The second connection 225 Second recess k Third aspect m Second transition surface n The fourth aspect 23. Second damping motion arm 24 First connecting shaft 25 Second connecting shaft 26 First rolling element 27 Second rolling element 28 Sliding member 29 Pressing member 281 Contact area p push surface p1 First edge p2 Second edge 31 First connecting member 32 Second connecting member 40 Synchronization mechanism 41 First rotating arm 42 Second Rotating Arm 43 Transmission Assembly 411 First transmission gear 421 Second transmission gear L (Length direction)

Claims

1. Fixed base and A damping arm is provided, wherein at least one braking member is positioned at one end of the damping arm, and one of the at least one braking member is rotatably connected to the fixed base, thereby allowing the damping arm to rotate back and forth around an axis relative to the fixed base to switch between a folded position and an extended position, and the braking member has a first recess, a projection, and a second recess sequentially connected in the circumferential direction of the braking member, and the projection has a guide surface inclined with respect to the axis, A rolling element and a pressing device, wherein the pressing device contacts the rolling element, and the rolling element contacts the first recess, the projection, or the second recess of the braking member, thereby the pressing device applies contact pressure to the braking member using the rolling element. Equipped with, When the damping arm is in the folded position, the rolling body contacts the first recess. When the damping arm is in the deployed position, the rolling body abuts against the second recess, When the damping arm rotates from the folded position or the unfolded position to a position between the folded position and the unfolded position, the rolling element rolls from the first recess or the second recess onto the guide surface of the projection and contacts the guide surface. In response, the pressing device moves together with the rolling element, thereby compressing the pressing device in a direction along the axis, opposite to that of the damping member. Braking mechanism.

2. The aforementioned pressing device is A sliding member, wherein the sliding member is slidably connected to the fixed base and is located at one end of the braking member, thereby the sliding member slides relative to the fixed base in a direction toward the braking member or toward the opposite direction toward the braking member along the axis, the contact portion is positioned on the sliding member and the contact portion has a pressing surface, and the rolling element abuts the pressing surface of the contact portion so as to roll, A pressing member, wherein the pressing member is positioned on the side of the sliding member opposite to the one end of the braking member, and applies a pressing force to the sliding member. Equipped with, When the damping arm rotates from the folded position or the unfolded position to the position between the folded position and the unfolded position, the rolling element rolls from the first recess or the second recess onto the guide surface of the projection, and in response, the sliding member moves together with the rolling element, thereby causing the sliding member to slide relative to the fixed base in the direction opposite to that of the damping member and to press the pressing member in the direction opposite to that of the damping member. The braking mechanism according to claim 1.

3. The first recess, the projection, and the second recess are located on the outer wall surface of the side wall of the braking member, and the surface of the projection facing away from the axis is the guide surface. The contact portion of the sliding member is located on the side of the first recess, the projection, and the second recess that is opposite to the axis, The fixed base has a first recess, a projection, and a contact surface positioned toward the second recess, the contact surface abutting the side of the rolling element facing away from the axis and / or the side of the contact portion facing away from the axis, thereby causing the rolling element to abut the outer wall surface of the side wall of the braking member in the direction toward the axis. The braking mechanism according to claim 2.

4. The projection uses a wedge-shaped curved structure, and the projection has a first end near the one end of the braking member and a second end facing away from the one end of the braking member. The thickness of the projection increases in the direction from the first end to the second end. The braking mechanism according to claim 3.

5. The braking mechanism according to claim 4, wherein the guide surface is provided in an arc shape in the circumferential direction of the braking member.

6. The projection is located on both sides of the guide surface and has a first transition surface and a second transition surface connected to the guide surface, the first transition surface being further connected to the bottom surface of the first recess, and the second transition surface being further connected to the bottom surface of the second recess. Both the first transition surface and the second transition surface are inclined toward the first end of the projection, When the damping arm rotates from the folded position or the unfolded position to the position between the folded position and the unfolded position, the rolling element moves along the first transition surface or the second transition surface in a direction toward the first end of the projection, rolls on the guide surface and presses against the pressing surface of the contact portion, thereby causing the sliding member to move relative to the fixed base in a direction toward the pressing member along the axis. The braking mechanism according to claim 4.

7. Arc-shaped corners are provided at the joint between the first transition surface and the first recess, and at the joint between the first transition surface and the guide surface, and the corner between the first transition surface and the tangential curved surface of the side edge of the guide surface is provided at an obtuse angle. Arc-shaped corners are provided at the joint between the second transition surface and the second recess, and at the joint between the second transition surface and the guide surface, and the corner between the second transition surface and the tangential curved surface of the other side edge of the guide surface is provided at an obtuse angle. The braking mechanism according to claim 6.

8. The first recess, the projection, and the second recess are arranged on the end face of the side wall of the braking member, and the surface of the projection facing the axis is the guide surface. The contact portion of the sliding member is located on the side of the first recess, the projection, and the second recess that is opposite to the end face of the braking member, and abuts against the side of the rolling element that is opposite to the guide surface, and the pressing surface of the contact portion is inclined with respect to the axis, The fixed base has a first recess, a projection, and a contact surface positioned toward the second recess, the contact surface abutting the rolling element on the side opposite to the end face of the braking member along the axis, When the damping arm rotates from the folded position or the unfolded position to the position between the folded position and the unfolded position, the rolling element presses the contact surface of the contact portion in the direction toward the axis, thereby causing the sliding member to slide relative to the fixed base in the direction opposite to that of the damping member. The braking mechanism according to claim 2.

9. The braking mechanism according to claim 8, wherein the pressing surface has a first end and a second end, and the pressing surface extends from the first end to the second end in a direction perpendicular to the axis and opposite to the axis, and extends along the axis and toward the interior of the sliding member, so that the direction of extension of the pressing surface from the first end to the second end is inclined with respect to the axis.

10. The guide surface of the projection has a first edge located on the end face of the braking member and a second edge facing away from the end face of the braking member. The distance between the guide surface and the axis increases in the direction from the first edge to the second edge. The braking mechanism according to claim 8.

11. The braking mechanism according to claim 10, wherein the guide surface is provided in an arc shape in the circumferential direction of the braking member.

12. The projection is located on both sides of the guide surface and has a first transition surface and a second transition surface connected to the guide surface, the first transition surface being further connected to the bottom surface of the first recess, and the second transition surface being further connected to the bottom surface of the second recess. When the damping arm rotates from the folded position or the unfolded position to the position between the folded position and the unfolded position, the rolling element rolls along the first transition surface or the second transition surface on the guide surface, and the first transition surface or the second transition surface of the projection and the contact surface of the fixed base press against each other, thereby causing the rolling element to move in a direction perpendicular to the axis and approaching the axis, pressing against the pressing surface of the contact portion, and the sliding member moves relative to the fixed base in a direction along the axis and facing the pressing member. The braking mechanism according to claim 10.

13. Arc-shaped corners are provided at the joint between the first transition surface and the first recess, and at the joint between the first transition surface and the guide surface, and the corner between the first transition surface and the tangential curved surface of the side edge of the guide surface is provided at an obtuse angle. Arc-shaped corners are provided at the joint between the second transition surface and the second recess, and at the joint between the second transition surface and the guide surface, and the corner between the second transition surface and the tangential curved surface of the other side edge of the guide surface is provided at an obtuse angle. The braking mechanism according to claim 12.

14. The braking mechanism according to claim 2, wherein a connecting shaft is arranged on the fixed base, the braking member uses a sleeve structure and is attached to the connecting shaft with a sleeve, the braking member is rotatably connected to the connecting shaft, and thereby the braking arm rotates back and forth around the connecting shaft relative to the fixed base, and the axis is the axis of the connecting shaft.

15. The braking mechanism according to claim 14, wherein the sliding member is slidably connected to the connecting shaft and is capable of moving along the axis of the connecting shaft, and the side of the sliding member facing the pressing member is provided in a planar shape.

16. The braking mechanism according to claim 14, wherein the pressing member is an elastic member, the elastic member is sleeve-attached to the connecting shaft, the elastic member is elastically deformed along the axis of the connecting shaft, and applies the pressing force to the sliding member.

17. The braking mechanism according to claim 1, wherein two symmetrically arranged braking members are positioned at one end of the braking and swaying arm, and the rolling element and the pressing device are positioned at each of the two ends of the one end of the braking and swaying arm along the axis, corresponding to the two braking members.

18. A hinge device comprising the braking mechanism described in any one of claims 1 to 17.

19. The hinge device according to claim 18, wherein the hinge device comprises two symmetrically arranged braking mechanisms.

20. A foldable electronic device comprising a first body and a second body, further comprising a hinge device according to claim 18, wherein the hinge device is configured to drive the first body and the second body to unfold or fold relative to each other.

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