Rotating shaft mechanism and electronic equipment

Abstract

The invention provides a rotating shaft mechanism and electronic equipment. Comprising a middle beam, a synchronous gear, a first swing arm and a second swing arm, the synchromesh gear comprises a first gear and a second gear which are meshed with each other and installed on the middle beam, and the first gear and the second gear are connected with the first swing arm and the second swing arm respectively. The first gear comprises a first tooth, and the first tooth comprises a first end and a second end which are oppositely arranged in the tooth width direction of the first tooth; the second gear comprises a second tooth, the second tooth comprises a third end and a fourth end which are oppositely arranged in the tooth width direction of the second tooth, the third end and the first end are located on one side of the synchromesh gear, and the fourth end and the second end are located on the other side of the synchromesh gear; the tooth crest thickness of the first tooth is gradually changed from the first end to the second end, the tooth crest thickness of the second tooth is gradually changed from the third end to the fourth end, and the change trend of the tooth crest thickness of the second tooth is opposite to the change trend of the tooth crest thickness of the first tooth. According to the technical scheme, the synchronization structure is good in synchronization effect, and synchronous rotation of the structures on the two sides of the rotating shaft is easily achieved.

Description

Technical Field

[0001] The present application relates to the technical field of electronic equipment, and in particular to a rotating shaft mechanism and electronic equipment. Background Art

[0002] As flexible foldable screen technology matures, the application of foldable terminal products (such as foldable phones, foldable tablets, and foldable computers) is becoming increasingly widespread. In these foldable terminal products, a synchronization mechanism is generally required in the hinge to achieve synchronous rotation of the structures on both sides of the hinge. However, the synchronization mechanism in existing hinges is poor, making it difficult to achieve synchronous rotation of the structures on both sides of the hinge. Summary of the Invention

[0003] The embodiments of the present application provide a rotating shaft mechanism and an electronic device, wherein the synchronization structure has a good synchronization effect and can easily enable the structures on both sides of the rotating shaft to achieve synchronous rotation.

[0004] In a first aspect, the present application provides a rotating shaft mechanism, comprising:

[0005] middle beam;

[0006] a synchronous gear, comprising a first gear and a second gear, wherein the first gear and the second gear are both mounted on the center beam and arranged in sequence along the width direction of the center beam, and the first gear is meshed with the second gear;

[0007] The first gear includes a plurality of first teeth, the plurality of first teeth are spaced apart along a circumferential direction of the first gear, the first teeth include a first end and a second end, the first end and the second end are oppositely arranged in a tooth width direction of the first teeth;

[0008] The second gear includes a plurality of second teeth, the plurality of second teeth being spaced apart along a circumferential direction of the second gear, the plurality of second teeth being configured to mesh with the plurality of first teeth, the second teeth including a third end and a fourth end, the third end and the fourth end being arranged opposite to each other in a tooth width direction of the second teeth, the third end and the first end being located on one side of the synchronous gear, and the fourth end and the second end being located on the other side of the synchronous gear;

[0009] The tooth tip thickness of the first tooth gradually changes from the first end to the second end, the tooth tip thickness of the second tooth gradually changes from the third end to the fourth end, and the changing trend of the tooth tip thickness of the second tooth is opposite to the changing trend of the tooth tip thickness of the first tooth; and

[0010] A first swing arm and a second swing arm, wherein the first swing arm and the second swing arm are respectively located on both sides of the width direction of the center beam, the first swing arm is fixedly connected to the first gear, and the second swing arm is fixedly connected to the second gear.

[0011] It is understood that in foldable electronic devices, the overlap of the gears in the synchronization assembly is a key factor affecting the synchronization of movement between the two housings of the electronic device. To improve the synchronization of movement between the two housings of the electronic device, it is necessary to increase the overlap of the gears in the synchronization assembly to ensure the transmission efficiency and stability of the synchronization assembly.

[0012] The gear contact ratio refers to the ratio of the actual meshing line length to the normal tooth pitch. A gear contact ratio greater than is a condition for continuous meshing of gears. The contact ratio represents the ratio of the frequency of two teeth meshing simultaneously to the frequency of one tooth meshing during the meshing process. The higher the frequency of two teeth meshing simultaneously, the higher the contact ratio, the better the synchronization performance of the synchronous gear, the smaller the load on a single tooth, the more stable the meshing structure of the gear, the less likely it is to bend, and the quieter the gear rotation process. Furthermore, the greater the gear contact ratio, the higher the transmission efficiency and stability of the gear.

[0013] In the related art, when designing the synchronous gear and the center beam, a clearance must be left between them to ensure that the synchronous gear can be smoothly installed on the center beam. This clearance prevents the synchronous gear from getting stuck when installed on the center beam due to the clearance between the synchronous gear and the center beam being too small or too large. However, in the actual operation of the synchronous gear, the two meshing gears are prone to loose fit, resulting in one gear moving closer to the center beam below it, reducing or eliminating the clearance between it and the center beam. The other gear also moves closer to the center beam below it, reducing or eliminating the clearance between it and the center beam. This causes the two gears to expand outwards away from each other, causing the involute surfaces of the two gears to change from tangent to offset, resulting in an increase in the tooth side clearance between the two gears and preventing complete meshing, which reduces the overlap and meshing effect of the synchronous gears.

[0014] Based on this, in this embodiment, by gradually changing the tooth top thickness of the first tooth from the first end to the second end, and gradually changing the tooth top thickness of the second tooth from the third end to the fourth end, and the changing trend of the tooth top thickness of the second tooth is opposite to the changing trend of the tooth top thickness of the first tooth, the tooth shape of the first tooth and the tooth shape of the second tooth can both have inclined surfaces, and the inclination trends of the inclined surfaces can be set in opposite directions.

[0015] Under this setting, when the first tooth and the second tooth are engaged, the opposite tooth shapes of the first tooth and the second tooth can be arranged crosswise, and the mating surfaces of the first tooth and the second tooth can be changed from plane mating to inclined mating, thereby effectively increasing the relative mating area between the first tooth and the second tooth. The increase in the mating area between the first tooth and the second tooth can make the tooth profile of the first tooth and the tooth profile of the second tooth fit more compactly, so that the tooth grooves can further fit together when the tooth profiles of the first tooth and the second tooth contact, which is conducive to the tooth profiles of the next pair of first teeth and the second tooth entering into meshing before the meshing of the tooth profiles of the first pair of teeth and the second tooth ends (at least at the same time), so that the involute surface of the first tooth and the involute surface of the second tooth remain tangent, effectively improving the overlap and meshing effect, and ensuring the continuity and smoothness of the transmission. In addition, since the overlap is improved, the synchronization effect between the first gear and the second gear will be better, so that the structures on both sides of the shaft mechanism can achieve synchronous rotation.

[0016] In one possible embodiment, the first tooth further includes a first tooth top surface, the first tooth top surface is connected between the first end and the second end, the first tooth top surface includes a first top edge located at the first end and a second top edge located at the second end, and the length of the first top edge is different from the length of the second top edge;

[0017] The second tooth includes a second tooth top surface, which is connected between the third end and the fourth end. The second tooth top surface includes a third top edge located at the third end and a fourth top edge located at the fourth end. The length of the third top edge is different from the length of the fourth top edge. The relationship between the length of the first top edge and the length of the second top edge is opposite to the relationship between the length of the third top edge and the length of the fourth top edge.

[0018] It can be understood that by making the length of the second top edge different from the length of the first top edge, the tooth width of the first tooth can gradually change in the axial direction of the first gear, so that the first tooth is a gear tooth with a certain radial displacement, so that the mating surface of the first tooth that cooperates with the second tooth can be a bevel, which is beneficial to increase the mating area between the second tooth, optimize the meshing effect between the first tooth and the second tooth, and increase the overlap of the synchronous gear.

[0019] In addition, by making the length of the third top side different from the length of the fourth top side, the tooth width of the second tooth can gradually change in the axial direction of the second gear, so that the second tooth is a gear tooth with a certain radial displacement, so that the mating surface of the second tooth that cooperates with the first tooth can be a bevel, which is beneficial to increase the mating area between the first tooth, optimize the meshing effect between the first tooth and the second tooth, and increase the overlap of the synchronous gear.

[0020] Furthermore, by making the length relationship between the third top side and the fourth top side opposite to the length relationship between the first top side and the second top side, the mating surface of the first tooth and the second tooth can be changed from a flat mating surface to an oblique mating surface, thereby effectively increasing the relative mating area between the first tooth and the second tooth. The increase in the mating area between the first tooth and the second tooth allows the tooth profile of the first tooth and the tooth profile of the second tooth to fit well in any cross-section, thereby achieving a tight fit between the first tooth and the second tooth. The tight fit between the first tooth and the second tooth refers to the fit between the first tooth and the second tooth being within a certain range, so that the first gear and the second gear can operate normally without relative sliding or jumping. This matching method can ensure the transmission accuracy and stability of the gear pair and avoid vibration, noise and wear caused by improper matching.

[0021] In one possible embodiment, the length of the first top side is greater than the length of the second top side, the first tooth has a first draft angle θ1, the length of the first top side is S1, the length of the second top side is S2, the tooth width of the first tooth is B1, and the first draft angle θ1, the length of the first top side S1, the length of the second top side S2, and the tooth width B1 of the first tooth satisfy the relationship: tanθ1 = (S1-S2) / B1.

[0022] It can be understood that by providing the first tooth with the first draft angle θ1, not only can the first gear's machining allowance be ensured during production, reducing friction between the mold and the workpiece surface, and improving the quality of the finished first gear, but the finished first gear can also be ejected smoothly and quickly from the mold, saving the cost and time of removing the first gear from the mold, thereby reducing the difficulty and cost of machining the first gear.

[0023] In a possible implementation manner, the first draft angle θ1 may be in an angle range of 3° to 30°.

[0024] It is understood that by setting the angle range of the first draft angle θ1 within the aforementioned range, the first gear can be easily removed from the mold by adjusting the angle of the draft angle. The larger the angle of the first draft angle θ1, the less force is required to remove the first gear from the mold, and the shorter the time it takes to remove the first gear from the mold.

[0025] In one possible embodiment, the first tooth further includes a first side surface and a second side surface, wherein the first side surface and the second side surface are both connected between the first end and the second end and are arranged opposite to each other in the circumferential direction of the first gear, the first side surface includes a first side edge located at the first end and a second side edge located at the second end, and the second side surface includes a third side edge located at the first end and a fourth side edge located at the second end;

[0026] In the circumferential direction of the first gear, the first side and the second side are staggered, and the third side and the fourth side are overlapped, or, in the circumferential direction of the first gear, the first side and the second side are overlapped, and the third side and the fourth side are staggered.

[0027] It is understood that by arranging the first and second sides of the first side surface to overlap in the circumferential direction of the first gear, and by arranging the third and fourth sides of the second side surface to be offset in the circumferential direction of the first gear, the first side surface can be made flat and the second side surface can be made into an inclined surface with a certain inclination angle. This arrangement facilitates the first gear to have a structural form with a large tooth thickness at one end and a small tooth thickness at the other end, thereby allowing the first gear to have a structural configuration with a single side of the second side surface having a unilateral radial displacement. By arranging the first gear to have a unilateral radial displacement, not only can the first gear be easily demolded, but the load-bearing capacity, wear resistance, processing accuracy, and installation accuracy of the first gear can also be improved, the gear ratio and speed adaptability can be optimized, and it is beneficial for the synchronous gear to have a good overlap and good meshing effect.

[0028] In one possible embodiment, the first tooth further includes a first side surface and a second side surface, wherein the first side surface and the second side surface are both connected between the first end and the second end and are arranged opposite to each other in the circumferential direction of the first gear, the first side surface includes a first side edge located at the first end and a second side edge located at the second end, and the second side surface includes a third side edge located at the first end and a fourth side edge located at the second end;

[0029] In the circumferential direction of the first gear, the first side and the second side are staggered, the third side and the fourth side are staggered, and the minimum distance between the first side and the third side is less than or greater than the minimum distance between the second side and the fourth side.

[0030] It is understood that by staggering the first and second sides of the first side surface in the circumferential direction of the first gear, and staggering the third and fourth sides of the second side surface in the circumferential direction of the first gear, the first and second side surfaces can each be inclined surfaces having a certain inclination angle. Furthermore, by making the minimum distance between the first side surface of the first side surface and the third side surface of the second side surface less than or greater than the minimum distance between the second side surface of the first side surface and the fourth side surface of the second side surface, the extension direction of the first side surface and the extension direction of the second side surface can intersect, thereby facilitating the first gear to have a structure with a larger tooth thickness at one end and a smaller tooth thickness at the other end. This allows the first gear to have a bilateral radial displacement configuration of the first and second side surfaces. Providing the first gear with bilateral radial displacement not only facilitates demolding of the first gear, but also improves the load-bearing capacity, wear resistance, machining accuracy, and installation precision of the first gear, optimizes the gear ratio and speed adaptability, and facilitates achieving a good overlap and meshing effect for the synchronous gears.

[0031] In a possible implementation manner, the addendum radius of the first end is different from the addendum radius of the second end.

[0032] It can be understood that by making the tooth top circle radius of the first end different from the tooth top circle radius of the second end, the first tooth top surface can be made into an inclined surface with a certain inclination. Under this setting, the first gear can be easily demolded from the mold.

[0033] The addendum radius of the third end is different from the addendum radius of the fourth end.

[0034] It can be understood that by making the tooth top circle radius of the third end different from the tooth top circle radius of the fourth end, the second tooth top surface can be made into an inclined surface with a certain inclination. Under this setting, the second gear can be easily demolded from the mold.

[0035] In a possible implementation manner, the synchronous gear includes a first rotating shaft, a second rotating shaft, a first limiting member, and a second limiting member;

[0036] The first rotating shaft and the second rotating shaft are both mounted on the center beam and are arranged opposite to each other along the width direction of the center beam and are capable of rotating relative to the center beam. The first gear is sleeved on the outer periphery of the first rotating shaft and is fixedly connected to the first rotating shaft. The second gear is sleeved on the outer periphery of the second rotating shaft and is fixedly connected to the second rotating shaft.

[0037] The first limiting member is sleeved on one end of the first rotating shaft and one end of the second rotating shaft, and is elastically connected between the middle beam and one end of the first gear and one end of the second gear;

[0038] The second limiting member is sleeved on the other end of the second rotating shaft and the other end of the second rotating shaft, and is elastically connected between the middle beam and the other end of the first gear and the other end of the second gear.

[0039] Under this setting, the first limit member and the second limit member can cooperate to press the two ends of the first gear in the axial direction and the two ends of the second gear in the axial direction, so that the first gear and the second gear can always remain in meshing, avoiding axial movement of the first gear and the second gear during the meshing process, which may cause the meshing failure of the first gear and the second gear. This is conducive to achieving axial tight fit between the first gear and the second gear, improving the meshing effect of the first gear and the second gear, and having good reliability.

[0040] In one possible embodiment, the first limiting member includes a first connecting portion, a first elastic portion, and a second elastic portion, the first connecting portion is connected between the first elastic portion and the second elastic portion, the first elastic portion is wound around the first rotating shaft and extends spirally along the axial direction of the first rotating shaft, the second elastic portion is wound around the second rotating shaft and extends spirally along the axial direction of the second rotating shaft, and the rotation direction of the second elastic portion is opposite to that of the first elastic portion.

[0041] It can be understood that by having the first elastic portion wound around the first rotating shaft and extending in a spiral along the axial direction of the first rotating shaft. The second elastic portion is wound around the second rotating shaft and extending in a spiral along the axial direction of the second rotating shaft. The rotation direction of the second elastic portion is opposite to that of the first elastic portion, so that the opposite rotation directions of the first elastic portion and the second elastic portion can be adapted to the opposite tooth shape of the first tooth and the tooth shape change trend of the second tooth, so that the first gear and the second gear can always maintain engagement, avoiding the problem of axial movement of the first gear and the second gear during the engagement process, which leads to the failure of the engagement of the first gear and the second gear. This is conducive to further achieving axial tight fit between the first gear and the second gear, improving the meshing effect of the first gear and the second gear, and having good reliability.

[0042] In a second aspect, the present application further provides an electronic device, comprising a first shell, a second shell and the above-described hinge mechanism, wherein the hinge mechanism is connected between the first shell and the second shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 is a simplified structural diagram of an electronic device provided by an embodiment of the present application in a folded state;

[0044] Figure 2 is a simplified structural diagram of an electronic device provided by an embodiment of the present application in an intermediate state;

[0045] Figure 3is a schematic structural diagram of an electronic device provided in an embodiment of the present application in an unfolded state;

[0046] Figure 4 yes Figure 1 A schematic diagram of a partial structure of a rotating shaft mechanism of an electronic device shown;

[0047] Figure 5 yes Figure 4 An exploded schematic diagram of a portion of the structure of the rotating shaft mechanism shown;

[0048] Figure 6a yes Figure 4 A schematic structural diagram of a central beam of the rotating shaft mechanism at one angle is shown;

[0049] Figure 6b yes Figure 4 A schematic structural diagram of the center beam of the rotating shaft mechanism shown in FIG.

[0050] Figure 7 yes Figure 6a An exploded schematic diagram of the center beam is shown;

[0051] Figure 8 yes Figure 4 A partial structural diagram of the first rotating assembly and the second rotating assembly of the rotating shaft mechanism shown;

[0052] Figure 9 yes Figure 4 A schematic structural diagram of the support plate assembly of the rotating shaft mechanism shown;

[0053] Figure 10 It is along Figure 4 The schematic cross-sectional view obtained by cutting along the cutting line AA shown;

[0054] Figure 11 yes Figure 4 A partial structural diagram of a synchronization component of the rotating shaft mechanism shown;

[0055] Figure 12 yes Figure 4 A partial structural diagram of a synchronization component of the first embodiment of the rotating shaft mechanism shown;

[0056] Figure 13 yes Figure 12 A partial structural diagram of the synchronization component shown;

[0057] Figure 14a yes Figure 13 A schematic structural diagram of a synchronization component at one angle is shown;

[0058] Figure 14b yes Figure 13 A schematic structural diagram of the synchronization component from another angle is shown;

[0059] Figure 15a yes Figure 4 A schematic diagram of a first tooth tip thickness variation trend of a first embodiment of a synchronous gear shown;

[0060] Figure 15b yes Figure 4 A schematic diagram of a second tooth tip thickness variation trend of the first embodiment of the synchronous gear shown;

[0061] Figure 15c yes Figure 4 A schematic diagram of a third tooth tip thickness variation trend of the first embodiment of the synchronous gear shown;

[0062] Figure 15d yes Figure 4 A schematic diagram of a fourth tooth tip thickness variation trend of the first embodiment of the synchronous gear shown;

[0063] Figure 16 yes Figure 12 A schematic structural diagram of an angle of the first gear of the synchronous gear shown;

[0064] Figure 17 yes Figure 12 A schematic structural diagram of an angle of the second gear of the synchronous gear shown;

[0065] Figure 18 yes Figure 12 The schematic structural diagram of the first and second limiting members of the synchronization assembly at an angle is shown;

[0066] Figure 19 yes Figure 4 A partial structural diagram of a synchronization component of a second embodiment of the rotating shaft mechanism shown;

[0067] Figure 20a yes Figure 19 A schematic structural diagram of a synchronization component at one angle is shown;

[0068] Figure 20b yes Figure 19 A schematic structural diagram of the synchronization component from another angle is shown;

[0069] Figure 21 yes Figure 19 A schematic structural diagram of an angle of the first gear of the synchronous gear shown;

[0070] Figure 22 yes Figure 19 A schematic structural diagram of an angle of the second gear of the synchronous gear shown;

[0071] Figure 23a yes Figure 19A schematic diagram of a first tooth tip thickness variation trend of a second embodiment of a synchronous gear shown;

[0072] Figure 23b yes Figure 19 A schematic diagram of a second tooth tip thickness variation trend of a second embodiment of a synchronous gear shown;

[0073] Figure 23c yes Figure 19 A schematic diagram of a third tooth tip thickness variation trend of the second embodiment of the synchronous gear shown;

[0074] Figure 23d yes Figure 19 FIG. 1 is a schematic diagram showing a fourth tooth tip thickness variation trend of the second embodiment of the synchronous gear shown. DETAILED DESCRIPTION

[0075] For ease of understanding, the terms involved in the embodiments of the present application are first explained.

[0076] And / or: It is just a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone.

[0077] Multiple: refers to two or more than two.

[0078] Connection: should be understood in a broad sense. For example, A and B are connected, which can be either directly connected or indirectly connected through an intermediary.

[0079] The specific implementation of the present application will be clearly described below with reference to the accompanying drawings.

[0080] Embodiments of the present application provide an electronic device. The electronic device can be any foldable device that can be unfolded and closed by a user. The electronic device includes, but is not limited to, a mobile phone, a notebook computer, a tablet computer, a laptop computer, a handheld game console, a personal digital assistant, a wearable device, or an in-vehicle device.

[0081] It is understood that when the electronic device is a mobile phone with foldable performance, the mobile phone can include inward-folding mobile phones and outward-folding mobile phones. Among them, because the folding of the flexible screen of the outward-folding mobile phone is smaller than the inward-folding, the damage to the flexible screen is relatively weak. After the mobile phone is flattened, there is almost no crease at the folding point, making the entire screen appear very smooth, thereby greatly improving the texture of the mobile phone and increasing the service life of the mobile phone screen.

[0082] The following description will take the electronic device as an external folding mobile phone as an example. Of course, in other embodiments, the electronic device may also include but is not limited to an internal folding mobile phone, a tablet computer, a handheld game console, an e-reader, a wearable device, etc., and this is not strictly limited.

[0083] Please refer to Figure 1 、 Figure 2 and Figure 3 , Figure 1 is a schematic structural diagram of the electronic device 200 provided in an embodiment of the present application when in a folded state. Figure 2 is a schematic structural diagram of the electronic device 200 provided in an embodiment of the present application when it is in an intermediate state. Figure 3 It is a structural diagram of the electronic device 200 provided in an embodiment of the present application when it is in an unfolded state.

[0084] For ease of description, the length direction of the electronic device 200 is defined as the X direction, the width direction of the electronic device 200 is defined as the Y direction, and the thickness direction of the electronic device 200 is defined as the Z direction. The X direction, the Y direction, and the Z direction are perpendicular to each other.

[0085] The electronic device 200 may include a flexible display 210, a first housing 220, a second housing 230 and a hinge mechanism 100. The hinge mechanism 100 is connected between the first housing 220 and the second housing 230 to achieve a rotational connection between the first housing 220 and the second housing 230. The first housing 220 and the second housing 230 can rotate relative to each other through the hinge mechanism 100, so that the electronic device 200 can switch between a folded state, an intermediate state and an unfolded state to meet the user's usage needs in different scenarios. The first housing 220 and the second housing 230 are also provided with a storage space (not shown), which is used to accommodate electronic components and structural elements such as the processor, circuit board, camera module, etc. of the electronic device 200. The flexible display 210 is connected to the first housing 220, the second housing 230 and the hinge mechanism 100. The flexible display 210 can be unfolded or folded by the first housing 220, the second housing 230 and the hinge mechanism 100.

[0086] The flexible display 210 is an external folding screen, that is, when the electronic device 200 is in the folded state, the flexible display 210 can constitute the external display surface of the electronic device 200. The flexible display 210 can be a flexible screen that is foldable in its entirety, or the flexible display 210 can also be a combination of a foldable flexible screen in the middle area and rigid screens at both ends, without strict limitation. Of course, in other embodiments, the flexible display 210 can also be an internal folding screen, that is, when the electronic device 200 is in the folded state, the flexible display 210 is sandwiched between the first shell 220 and the second shell 230.

[0087] Exemplarily, the flexible display 210 can be an organic light-emitting diode (OLED) display, an active-matrix organic light-emitting diode or an active-matrix organic light-emitting diode (AMOLED) display, a mini organic light-emitting diode (MID) display, a micro organic light-emitting diode (MID) display, a micro organic light-emitting diode (MID) display, or a quantum dot light-emitting diode (QLED) display.

[0088] Specifically, the flexible display 210 may include a first portion 2110, a second portion 2120, and a foldable portion 2130. The foldable portion 2130 of the flexible display 210 is connected between the first portion 2110 and the second portion 2120 of the flexible display 210 and can be bent to accommodate the unfolding and folding of the electronic device 200. The first portion 2110 of the flexible display 210 is connected to the first housing 220, the second portion 2120 of the flexible display 210 is connected to the second housing 230, and the foldable portion 2130 of the flexible display 210 is disposed opposite the hinge mechanism 100 in the Z direction.

[0089] The electronic device 200 shown in the embodiment of the present application is an electronic device 200 that can be folded once. In other embodiments, the electronic device 200 can also be an electronic device 200 that can be folded multiple times (more than twice). In this case, the electronic device 200 can include multiple parts, and two adjacent parts can be folded relatively close together until the electronic device 200 is in a folded state, and the two adjacent parts can be unfolded relatively far apart until the electronic device 200 is in an unfolded state.

[0090] The following description will use the example of the first housing 220 and the second housing 230 being arranged left and right, so that the electronic device 200 can be folded left and right. However, it should be understood that in other embodiments, the first housing 220 and the second housing 230 can also be arranged up and down, so that the electronic device 200 can be folded up and down.

[0091] like Figure 1As shown, the relative rotation of the first shell 220 and the second shell 230 causes the electronic device 200 to be in a folded state, which means that the first shell 220 and the second shell 230 are rotated by the hinge mechanism 100 and are close to each other until they fit together. When the electronic device 200 is in a folded state, the first shell 220 and the second shell 230 may be partially in contact or completely in contact. At this time, the flexible display 210 is located on the outside of the electronic device 200, the foldable part 2130 of the flexible display 210 is bent, and the first part 2110 of the flexible display 210 and the second part 2120 of the flexible display 210 are arranged back to back. The electronic device 200 not only has a smaller volume, which makes it easier for users to store and carry it. The electronic device 200 can also use half of the flexible display 210 to display information and provide user operation at the same time.

[0092] like Figure 2 As shown, the relative rotation of the first housing 220 and the second housing 230 causes the electronic device 200 to be in an intermediate state. This means that the first housing 220 and the second housing 230 rotate via the hinge mechanism 100 and move away from each other, causing the angle between the first housing 220 and the second housing 230 to increase. Alternatively, this means that the first housing 220 and the second housing 230 rotate via the hinge mechanism 100 and move toward each other, causing the angle between the first housing 220 and the second housing 230 to decrease. At this time, the foldable portion 2130 of the flexible display 210 is still bent, but the bending amplitude of the foldable portion 2130 of the flexible display 210 in the intermediate state is smaller than the bending amplitude of the foldable portion 2130 of the flexible display 210 in the folded state.

[0093] like Figure 3 As shown, the relative rotation of the first shell 220 and the second shell 230 puts the electronic device 200 in the unfolded state, which means that the first shell 220 and the second shell 230 rotate through the hinge mechanism 100 and move away from each other, and the angle between the first shell 220 and the second shell 230 continues to increase, which can be close to 180 degrees or equal to 180 degrees (allowable tolerance range). At this time, the foldable portion 2130 of the flexible display 210 is flattened, and the first portion 2110 of the flexible display 210 and the second portion 2120 of the flexible display 210 are relatively unfolded. The electronic device 200 can achieve a large-screen display, which can provide users with richer information and bring users a better user experience.

[0094] When the electronic device 200 is in the folded state, the hinge mechanism 100 is also in the folded state. When the electronic device 200 is in the intermediate state, the hinge mechanism 100 is also in the intermediate state. When the electronic device 200 is in the unfolded state, the hinge mechanism 100 is also in the unfolded state.

[0095] Please refer to Figure 4 and Figure 5 , Figure 4 yes Figure 1 The schematic diagram of the partial structure of the rotating shaft mechanism 100 of the electronic device 200 is shown. Figure 5 yes Figure 4 FIG. 1 is a schematic exploded view of a partial structure of the rotating shaft mechanism 100 .

[0096] The hinge mechanism 100 can extend from one end of the electronic device 200 to the other end of the electronic device 200 along the Y direction. However, for ease of understanding, the following text and the accompanying drawings only illustrate a portion of the hinge mechanism 100 extending along the Y direction. However, it should be understood that this is not a limitation. In addition, the following description uses the hinge mechanism 100 as an example of an outward folding device. However, the improvements made to the hinge mechanism 100 below can also be applied to a hinge mechanism 100 capable of inward folding, unless there is a conflict.

[0097] The hinge mechanism 100 may include a center beam 10, a first rotating assembly 20, a second rotating assembly 30, a synchronization assembly 40, and a support plate assembly 50. The first rotating assembly 20 and the second rotating assembly 30 are respectively located on either side of the center beam 10 in the width direction (i.e., the X direction). The first rotating assembly 20 is rotationally connected to the center beam 10, and the end of the first rotating assembly 20 away from the center beam 10 is fixedly connected to the first shell 220. The second rotating assembly 30 is rotationally connected to the center beam 10, and the end of the second rotating assembly 30 away from the center beam 10 is fixedly connected to the second shell 230. The synchronization assembly 40 is mounted on the center beam 10 and connected between the first rotating assembly 20 and the second rotating assembly 30. It is capable of achieving synchronized rotation of the first rotating assembly 20 and the second rotating assembly 30, thereby enabling synchronized rotation of the first shell 220 and the second shell 230. The support plate assembly 50 may include a first support plate 51 and a second support plate 52. The first support plate 51 and the second support plate 52 are respectively located on either side of the center beam 10 in the width direction. The first support plate 51 is connected between the center beam 10 and the first rotating assembly 20 and is rotatable relative to the center beam 10. The second support plate 52 is connected between the center beam 10 and the second rotating assembly 30 and is rotatable relative to the center beam 10. The first support plate 51 and the second support plate 52 can support the flexible display 210 in the folded state, intermediate state, and unfolded state of the hinge mechanism 100.

[0098] The rotation direction of the first rotating assembly 20 is opposite to that of the second rotating assembly 30, allowing the center beam 10 to remain stationary during the relative folding and unfolding of the first and second shells 220, 230. In other words, during the relative folding and unfolding of the first and second shells 220, 230, the center beam 10 can maintain its position unchanged, i.e., the center beam 10 remains relatively stationary, while both the first and second shells 220, 230 can rotate relative to the center beam 10. When the first shell 220 rotates relative to the center beam 10, it drives the first rotating assembly 20 to rotate relative to the center beam 10, thereby causing the first rotating assembly 20 to drive the second rotating assembly 30 to rotate relative to the center beam 10 via the synchronization assembly 40, thereby achieving synchronized rotation of the first and second rotating assemblies 20, 30, and thus synchronized rotation of the first and second shells 220, 230. When the second housing 230 rotates relative to the center beam 10, it can drive the second rotating assembly 30 to rotate relative to the center beam 10, thereby causing the second rotating assembly 30 to drive the first rotating assembly 20 to rotate relative to the center beam 10 through the synchronization assembly 40, thereby achieving synchronous rotation of the second rotating assembly 30 and the first rotating assembly 20, that is, achieving synchronous rotation of the second housing 230 and the first housing 220. At the same time, during the process of the first rotating assembly 20 and the second rotating assembly 30 rotating relative to the center beam 10, they can also drive the first support plate 51 and the second support plate 52 to rotate relative to the center beam 10, so that the first rotating assembly 20, the first support plate 51, the second rotating assembly 30, the second support plate 52, and the center beam 10 can cooperate to jointly support the flexible display screen 210 in the folded state, the intermediate state, and the unfolded state of the hinge mechanism 100.

[0099] Please refer to Figure 6a and Figure 6b , Figure 6a yes Figure 4 The structural diagram of the middle beam 10 of the rotating shaft mechanism 100 is shown at an angle. Figure 6b yes Figure 4 The structure diagram of the center beam 10 of the rotating shaft mechanism 100 is shown at another angle.

[0100] The center beam 10 can extend along the Y direction, extending from one end of the rotating shaft mechanism 100 to the other end of the rotating shaft mechanism 100 in the Y direction. The center beam 10 is the most important load-bearing component in the rotating shaft mechanism 100. It can form a kinematic connection with the first main swing arm of the first rotating assembly 20 and the second main swing arm of the second rotating assembly 30. It also provides a certain load-bearing space for the synchronization assembly 40 that realizes the synchronous movement of the first shell 220 and the second shell 230, and the damping mechanism that realizes the good damping feel of the electronic device 200.

[0101] The center beam 10 can be a one-piece structure, for example, the center beam 10 can be formed into a one-piece structure by an integral molding method. It is understood that the center beam 10 formed by the one-piece structure has fewer parts, which is conducive to simplifying the manufacturing process of the center beam 10 and improving the production and assembly efficiency of the center beam 10.

[0102] Alternatively, the center beam 10 may also be a split structure. It is understood that when the center beam 10 is a split structure, the center beam 10 can be split into multiple structures in the Z direction, and the same structural member can also be split into multiple structures in the Y direction. This simplifies the center beam 10 by layering, avoids the problem of reduced strength due to excessive extension of the same structural member, and facilitates positioning and assembly.

[0103] The following description will be made using the split-type center beam 10 as an example, but it should be understood that the description is not limited to this. In addition, the following description of the split-type center beam 10 can also be applied to the integrated center beam 10 unless there is any conflict.

[0104] Please continue reading Figure 6a and Figure 6b The center beam 10 may have a first rotation slot 11 and a second rotation slot 12. The first rotation slot 11 of the center beam 10 can be used to mount the first main swing arm of the first rotation assembly 20 and provide space for its rotation relative to the center beam 10. The second rotation slot 12 of the center beam 10 can be used to mount the second main swing arm of the second rotation assembly 30 and provide space for its rotation relative to the center beam 10.

[0105] The first rotation groove 11 and the second rotation groove 12 of the center beam 10 can be arranged relative to each other in the X-direction and relative to or staggered in the Y-direction. The staggered arrangement of the first rotation groove 11 and the second rotation groove 12 of the center beam 10 in the Y-direction means that the first rotation groove 11 and the second rotation groove 12 of the center beam 10 can be arranged in a completely staggered and spaced manner in the Y-direction, or can be arranged in a partially staggered and overlapping manner in the Y-direction. When the first rotation groove 11 and the second rotation groove 12 are partially staggered in the Y-direction, not only can the structures of the first rotation groove 11 and the second rotation groove 12 be independent of each other and not interfere with each other, but the size of the center beam 10 along the X-direction can also be minimized, which is conducive to miniaturization and thinness of the electronic device 200.

[0106] The opening of the first rotation slot 11 of the center beam 10 is located on one side of the center beam 10 along the X-direction, allowing the first main swing arm of the first rotation assembly 20 to extend into the slot. The opening of the second rotation slot 12 of the center beam 10 is located on the other side of the center beam 10 along the X-direction, allowing the second main swing arm of the second rotation assembly 30 to extend into the slot. The first rotation slot 11 of the center beam 10 extends in a direction opposite to that of the second rotation slot 12 of the center beam 10. For example, both the first rotation slot 11 and the second rotation slot 12 can be arcuate slots.

[0107] A first rotation groove 11 can be used to mount a first main swing arm of the first rotation assembly 20. A second rotation groove 12 can be used to mount a second main swing arm of the second rotation assembly 30. A first rotation groove 11 and a second rotation groove 12 can form a set of rotation groove structures. Depending on the actual application requirements of the rotating shaft mechanism 100, one or more sets of rotation groove structures can be provided on the center beam 10. The placement of one or more sets of rotation groove structures can be selected based on actual application requirements and is not strictly limited.

[0108] Furthermore, the first rotation groove 11 and the second rotation groove 12 of the center beam 10 can be an integral structure located on the center beam 10, or can be an assembled structure formed by splicing multiple components of the center beam 10. The following description will be based on an example in which the first rotation groove 11 and the second rotation groove 12 of the center beam 10 are assembled structures formed by splicing multiple components of the center beam 10, but it should be understood that this is not a limitation.

[0109] Please refer to Figure 6a 、 Figure 6b and Figure 7 , Figure 7 yes Figure 6a The exploded schematic diagram of the center beam 10 is shown. The center beam 10 may include a center beam seat 13 and a center beam cover plate 14.

[0110] The center beam 13 can extend along the Y-direction, extending from one end of the rotating shaft mechanism 100 to the other end of the rotating shaft mechanism 100 in the Y-direction. The center beam 13 can include a top and a bottom. The bottom and top of the center beam 13 are arranged opposite each other in the Z-direction. The top of the center beam 13 faces away from the flexible display 210, while the bottom of the center beam 13 faces the flexible display 210. The center beam 13 can be a one-piece structure or an assembled structure. The center beam 13 can be used to provide a mounting base for the first rotating assembly 20 and the second rotating assembly 30.

[0111] When the center beam seat 13 is an integrated structure, the center beam seat 13 can be a separate structural member, which can independently extend from one end of the rotation axis mechanism 100 to the other end of the rotation axis mechanism 100 along the Y direction. For example, the center beam seat 13 can be formed into an integrated structure by integral molding.

[0112] It is understandable that the center beam seat 13 formed by the integrated structure has fewer parts, which is conducive to simplifying the manufacturing process of the center beam seat 13 and improving the production and assembly efficiency of the center beam seat 13.

[0113] When the center beam 13 is an assembled structure, it can include multiple sub-base bodies. These sub-base bodies can be arranged along the Y direction. Each sub-base body extends along the Y direction, and its extension length is less than the total extension length of the center beam 13. The multiple sub-base bodies can be connected end to end to form a center beam 13 that extends from one end of the rotating shaft mechanism 100 to the other end.

[0114] It is understood that, on the one hand, splitting the long center beam 13 into multiple shorter sub-base bodies can effectively prevent the center beam 13 from being damaged or broken during processing, transportation, and assembly due to its excessive extension, thereby increasing reliability. On the other hand, splitting the long center beam 13 into multiple shorter sub-base bodies allows that if damage occurs in the center beam 13, only the sub-base body at the damaged portion needs to be replaced without replacing the entire center beam 13, which helps avoid material waste and effectively reduces the maintenance cost of the center beam 13.

[0115] The center beam cover plate 14 is connected to the top of the center beam seat 13 and extends along the Y direction. The center beam cover plate 14 can be spliced ​​with the center beam seat 13 to form the first rotation groove 11 and the second rotation groove 12 of the center beam 10. The center beam cover plate 14 can partially shield the structural components disposed in the center beam 10, achieving a good appearance for the electronic device 200. There can be one or more center beam cover plates 14. If there are multiple center beam cover plates 14, the multiple center beam cover plates 14 can be spaced apart in the Y direction.

[0116] Please continue reading Figure 6a and Figure 6b The center beam 10 may further include a first mounting slot 15, a second mounting slot 16, a first axial hole 17, and a second axial hole 18. The first mounting slot 15 and the second mounting slot 16 are located on either side of the width direction (i.e., the Z direction) of the center beam 10. The first axial hole 17 and the second axial hole 18 are located on either side of the width direction of the center beam 10.

[0117] The first mounting groove 15 can be disposed on the same side of the center beam 10 as the first rotation groove 11 and spaced apart from the first rotation groove 11 along the Y direction. The first mounting groove 15 can be used to mount a portion of the synchronization assembly 40. For example, the first mounting groove 15 can be located on the center beam seat 13.

[0118] The number of the first mounting grooves 15 can be one or more. When there are multiple first mounting grooves 15, the multiple first mounting grooves 15 can be spaced apart in the length direction (i.e., the Y direction) of the center beam 10, and each first mounting groove 15 can be used to install a partial structure of the synchronization assembly 40.

[0119] The second mounting slot 16 can be disposed on the same side of the center beam 10 as the second rotation slot 12 and spaced apart from the second rotation slot 12 along the Y direction. The second mounting slot 16 can be used to mount a portion of the synchronization assembly 40. For example, the second mounting slot 16 can be located on the center beam seat 13.

[0120] The number of the second mounting grooves 16 can be one or more. When there are multiple second mounting grooves 16, the multiple second mounting grooves 16 can be spaced apart in the length direction of the center beam 10, and each second mounting groove 16 can be used to install a partial structure of the synchronization assembly 40.

[0121] The first axial hole 17 can be located on the same side of the center beam 10 as the first rotation slot 11 and the first mounting slot 15, and spaced apart from both the first rotation slot 11 and the first mounting slot 15. The first axial hole 17 can extend in the same direction as the length of the center beam 10 (i.e., the Y direction) and can penetrate the center beam 10 along the length of the center beam 10. The first axial hole 17 can be used to mount the first shaft 512 of the first support plate 51.

[0122] The number of the first shaft holes 17 can be one or more. When there are multiple first shaft holes 17, the multiple first shaft holes 17 can be spaced apart in the length direction of the center beam 10, and each first shaft hole 17 can be used to install a first shaft body 512 of the first support plate 51.

[0123] For example, the first shaft hole 17 may be located at the bottom of the center beam seat 13. The number of the first shaft holes 17 may be two, and the two first shaft holes 17 may be spaced apart in the length direction of the center beam seat 13.

[0124] The second axial hole 18 can be disposed on the same side of the center beam 10 as the second rotation slot 12 and the second mounting slot 16, and spaced apart from the second rotation slot 12 and the second mounting slot 16. The second axial hole 18 can extend in the same direction as the length of the center beam 10 (i.e., the Y direction) and can penetrate the center beam 10 along the length of the center beam 10. The second axial hole 18 can be used to mount the second shaft 522 of the second support plate 52.

[0125] The number of the second shaft holes 18 can be one or more. When there are multiple second shaft holes 18, the multiple second shaft holes 18 can be spaced apart in the length direction of the center beam 10, and each second shaft hole 18 can be used to install a second shaft body 522 of the second support plate 52.

[0126] For example, the second shaft hole 18 may be located at the bottom of the center beam seat 13. The number of the second shaft holes 18 may be two, and the two second shaft holes 18 may be spaced apart in the length direction of the center beam seat 13.

[0127] Please refer to Figure 4 and Figure 8 , Figure 8 yes Figure 4 The schematic diagram of the partial structure of the first rotating assembly 20 and the second rotating assembly 30 of the rotating shaft mechanism 100 is shown. Figure 8 In the figure, the first main swing arm of the first rotating assembly 20 and the second main swing arm of the second rotating assembly 30 are not shown. The structures of the first rotating assembly 20 and the second rotating assembly 30 can be the same or different.

[0128] The first rotating assembly 20 may include a first main swing arm (not shown) and a first fixing frame 21. The first fixing frame 21 is located on one side of the center beam 10 in the width direction (i.e., the X direction) and is fixedly connected to the first housing 220. The first main swing arm is connected between the center beam 10 and the first fixing frame 21. The second rotating assembly 30 may include a second main swing arm and a second fixing frame 31. The second fixing frame 31 is located on the other side of the center beam 10 in the width direction and is fixedly connected to the second housing 230. The second main swing arm is connected between the center beam 10 and the second fixing frame 31.

[0129] When the first shell 220 and the second shell 230 rotate relative to each other, the first shell 220 can drive the first fixing frame 21 to rotate relative to the center beam 10, and drive the first main swing arm to rotate synchronously relative to the center beam 10. The second shell 230 can drive the second fixing frame 31 to rotate relative to the center beam 10, and drive the second main swing arm to rotate synchronously relative to the center beam 10, thereby realizing the rotation of the rotating shaft mechanism 100, so that the rotating shaft mechanism 100 can be expanded or folded.

[0130] It should be noted that the entire hinge mechanism 100 can have multiple first main swing arms, multiple second main swing arms, multiple first fixed frames 21, and multiple second fixed frames 31. When the hinge mechanism 100 has multiple first main swing arms, multiple second main swing arms, multiple first fixed frames 21, and multiple second fixed frames 31, the multiple first main swing arms can be spaced apart along the Y direction, the multiple second main swing arms can be spaced apart along the Y direction, the multiple first fixed frames 21 can be spaced apart along the Y direction, and the multiple second fixed frames 31 can be spaced apart along the Y direction. The following description of the connection relationship of the hinge mechanism 100 will be described using one first fixed frame 21 and one second fixed frame 31 as an example. The following description of one first fixed frame 21 and one second fixed frame 31 can be applied to other first fixed frames 21 and other second fixed frames 31 unless there is any conflict.

[0131] Please continue reading Figure 4 and Figure 8 The first fixing frame 21 and the second fixing frame 31 are respectively located on both sides of the center beam 10 along the X direction. The first fixing frame 21 and the second fixing frame 31 can both rotate relative to the center beam 10 to realize the folded state and the unfolded state of the hinge mechanism 100. Specifically, the rotation directions of the first fixing frame 21 and the second fixing frame 31 are opposite. When the electronic device 200 is in the unfolded state, the hinge mechanism 100 is also in the unfolded state. The first fixing frame 21 and the second fixing frame 31 can be relatively flattened and jointly support the flexible display screen 210, making the flexible display screen 210 more flat and less likely to be damaged by external force, which is beneficial to improving the reliability of the flexible display screen 210. When the electronic device 200 is in the folded state, the hinge mechanism 100 is also in the folded state. The first fixing frame 21 and the second fixing frame 31 can be folded to be parallel to each other, thereby providing better support performance for the flexible display screen 210.

[0132] The first fixing frame 21 can extend along the Y direction and be connected to the first housing 220 to achieve linkage with the first housing 220. In other words, when the first housing 220 rotates, the first fixing frame 21 is driven to rotate synchronously. This can ensure that the electronic device 200 as a whole has better mechanical resistance to tension and compression.

[0133] The first fixing frame 21 is provided with a first slide groove 211, a third slide groove 212, and a third axial hole 213. The first slide groove 211 allows the first main swing arm to slide therein. The first slide groove 211 can extend parallel to the width of the first fixing frame 21 (i.e., the X-direction). The shape of the first slide groove 211 can be adapted to the shape of the first main swing arm sliding therein, thereby ensuring a smooth and fluid sliding motion of the first main swing arm within the first slide groove 211.

[0134] There may be one or more first chute 211. When there are multiple first chute 211, the multiple first chute 211 may be spaced apart in the length direction of the first fixing frame 21, and each first chute 211 may be used for a first main swing arm to slide therein.

[0135] The third slot 212 can be spaced apart from the first slot 211 in the lengthwise direction (i.e., the Y-direction) of the first fixed frame 21 and can accommodate the sliding movement of the first swing arm 41 of the synchronization assembly 40 therein. The third slot 212 can extend parallel to the widthwise direction (i.e., the X-direction) of the first fixed frame 21. The shape of the third slot 212 can be adapted to the shape of the first swing arm 41 of the synchronization assembly 40 that slides therein, thereby ensuring smooth and fluid sliding of the first swing arm 41 of the synchronization assembly 40 within the third slot 212.

[0136] The number of the third sliding grooves 212 can be one or more. When there are multiple third sliding grooves 212, the multiple third sliding grooves 212 can be spaced apart in the length direction of the first fixing frame 21, and each third sliding groove 212 can be used for a first swing arm 41 of the synchronization assembly 40 to slide therein.

[0137] The third axial hole 213 can be spaced apart from the first slide groove 211 and the third slide groove 212 in the longitudinal direction of the first fixing frame 21. The third axial hole 213 can extend parallel to the longitudinal direction of the first fixing frame 21 and can penetrate the first fixing frame 21 along the longitudinal direction of the first fixing frame 21. The third axial hole 213 can be used to mount the third shaft 513 of the first support plate 51.

[0138] The number of the third shaft holes 213 can be one or more. When there are multiple third shaft holes 213, the multiple third shaft holes 213 can be spaced apart in the length direction of the first fixing frame 21, and each third shaft hole 213 can be used to install a third shaft body 513 of the first support plate 51.

[0139] For example, the third shaft hole 213 may be located on a side of the first fixing frame 21 facing the center beam seat 13. There may be two third shaft holes 213, which may be spaced apart in the length direction of the first fixing frame 21.

[0140] Please continue reading Figure 8The second fixing frame 31 can be mirror-symmetrical to the first fixing frame 21. The second fixing frame 31 can extend along the Y direction and be connected to the second housing 230 to achieve linkage with the second housing 230. In other words, when the second housing 230 rotates, the second fixing frame 31 is driven to rotate synchronously. This can ensure that the electronic device 200 as a whole has better mechanical tensile strength and mechanical compression resistance.

[0141] The second fixing frame 31 is provided with a second slide groove 311, a fourth slide groove 312, and a fourth axial hole 313. The second slide groove 311 allows the second main swing arm to slide therein. The second slide groove 311 can extend parallel to the width of the second fixing frame 31 (i.e., the X-direction). The shape of the second slide groove 311 can be adapted to the shape of the second main swing arm sliding therein, thereby ensuring a smooth and fluid sliding motion of the second main swing arm within the second slide groove 311.

[0142] There may be one or more second chute grooves 311. When there are multiple second chute grooves 311, the multiple second chute grooves 311 may be spaced apart in the length direction of the second fixing frame 31, and each second chute groove 311 may be used for a second main swing arm to slide therein.

[0143] The fourth slot 312 can be spaced apart from the second slot 311 in the lengthwise direction (i.e., the Y-direction) of the second fixed frame 31 and can accommodate the sliding movement of the second swing arm 42 of the synchronizer assembly 40 therein. The fourth slot 312 can extend parallel to the widthwise direction (i.e., the X-direction) of the second fixed frame 31. The shape of the fourth slot 312 can be adapted to the shape of the second swing arm 42 of the synchronizer assembly 40 sliding therein, thereby ensuring smooth and fluid sliding of the second swing arm 42 of the synchronizer assembly 40 within the fourth slot 312.

[0144] The number of the fourth sliding grooves 312 can be one or more. When there are multiple fourth sliding grooves 312, the multiple fourth sliding grooves 312 can be spaced apart in the length direction of the second fixing frame 31, and each fourth sliding groove 312 can be used for a second swing arm 42 of the synchronization assembly 40 to slide therein.

[0145] The fourth axial hole 313 can be spaced apart from the second slide groove 311 and the fourth slide groove 312 in the longitudinal direction of the second fixing frame 31. The fourth axial hole 313 can extend parallel to the longitudinal direction of the second fixing frame 31 and can penetrate the second fixing frame 31 along the longitudinal direction of the second fixing frame 31. The fourth axial hole 313 can be used to mount the fourth shaft 523 of the second support plate 52.

[0146] The number of the fourth shaft holes 313 can be one or more. When there are multiple fourth shaft holes 313, the multiple fourth shaft holes 313 can be spaced apart in the length direction of the second fixing frame 31, and each fourth shaft hole 313 can be used to install a fourth shaft body 523 of the second support plate 52.

[0147] For example, the fourth shaft hole 313 may be located on a side of the second fixing frame 31 facing the center beam seat 13. There may be two fourth shaft holes 313, which may be located at the head and tail ends of the second fixing frame 31 along the Y direction.

[0148] Based on the above description, when the first shell 220 and the second shell 230 rotate relative to the center beam 10 and approach each other, the first fixing frame 21 and the second fixing frame 31 also rotate relative to the center beam 10 and approach each other, thereby achieving the folding of the electronic device 200. When the first shell 220 and the second shell 230 rotate relative to the center beam 10 and move away from each other, the first fixing frame 21 and the second fixing frame 31 also rotate relative to the center beam 10 and move away from each other, thereby achieving the unfolding of the electronic device 200.

[0149] The first and second main swing arms are located on either side of the center beam 10 in the X direction, respectively. The first and second main swing arms rotate in opposite directions. These arms control the swinging position of the hinge mechanism 100, supporting the flexible display 210 and enhancing the strength of the entire hinge mechanism 100.

[0150] One end of the first main swing arm is rotatably connected to the center beam 10, and the other end of the first main swing arm is slidably connected to the first fixing frame 21. When the first housing 220 rotates relative to the center beam 10, the first housing 220 drives the first fixing frame 21 to rotate relative to the center beam 10. The rotation of the first fixing frame 21 relative to the center beam 10 drives the first main swing arm to rotate relative to the center beam 10 and slide relative to the first fixing frame 21.

[0151] Specifically, one end of the first main swing arm is mounted in the first rotation groove 11 of the center beam 10, and the one end of the first main swing arm is capable of sliding within the first rotation groove 11 of the center beam 10. It will be appreciated that the sliding movement of the one end of the first main swing arm within the first rotation groove 11 of the center beam 10 enables rotational movement of the first main swing arm relative to the center beam 10, thereby achieving a rotational connection between the first main swing arm and the center beam 10. For example, the one end of the first main swing arm can be arc-shaped.

[0152] The other end of the first main swing arm is mounted in the first slot 211 of the first fixed frame 21 and is capable of sliding within the first slot 211 of the first fixed frame 21. When the user folds the first housing 220, the first housing 220 drives the first fixed frame 21 to rotate. The first fixed frame 21, in turn, drives the first main swing arm to slide within the first slot 211 via the first slot 211, thereby achieving linkage between the first fixed frame 21 and the first main swing arm, allowing the first main swing arm to rotate relative to the center beam 10. In other words, the first fixed frame 21 is capable of rotating relative to the center beam 10, driving the first main swing arm to rotate relative to the center beam 10, thereby forming a "first fixed frame 21-first main swing arm-center beam 10" rotation chain, enabling the hinge mechanism 100 to rotate smoothly and fluently.

[0153] One end of the second main swing arm is rotatably connected to the center beam 10, and the other end of the second main swing arm is slidably connected to the second fixing bracket 31. When the second housing 230 rotates relative to the center beam 10, the second housing 230 drives the second fixing bracket 31 to rotate relative to the center beam 10. The rotation of the second fixing bracket 31 relative to the center beam 10 drives the second main swing arm to rotate relative to the center beam 10 and slide relative to the second fixing bracket 31.

[0154] Specifically, one end of the second main swing arm is mounted in the second rotation groove 12 of the center beam 10, and one end of the second main swing arm is capable of sliding within the second rotation groove 12 of the center beam 10. It will be appreciated that the sliding movement of one end of the second main swing arm within the second rotation groove 12 of the center beam 10 enables rotational movement of the second main swing arm relative to the center beam 10, thereby achieving a rotational connection between the second main swing arm and the center beam 10. For example, one end of the second main swing arm can be arcuate.

[0155] The other end of the second main swing arm is mounted in the second slot 311 of the second fixing frame 31 and is capable of sliding within the second slot 311 of the second fixing frame 31. When the user folds the second housing 230, the second housing 230 drives the second fixing frame 31 to rotate. The second fixing frame 31, in turn, drives the second main swing arm to slide within the second slot 311 via the second slot 311. This achieves a linkage between the second fixing frame 31 and the second main swing arm, enabling the second main swing arm to rotate relative to the center beam 10. In other words, the second fixing frame 31 is capable of rotating relative to the center beam 10, driving the second main swing arm to rotate relative to the center beam 10, forming a "second fixing frame 31-second main swing arm-center beam 10" rotation chain, enabling the hinge mechanism 100 to rotate smoothly and fluently.

[0156] Please refer to Figure 9 and Figure 10 , Figure 9 yes Figure 4 The structural diagram of the support plate assembly 50 of the rotating shaft mechanism 100 is shown in FIG. Figure 10 It is along Figure 4 The schematic cross-sectional view is shown along the cutting line AA.

[0157] The first support plate 51 and the second support plate 52 are respectively located on both sides of the center beam 10 along the X direction. The first support plate 51 and the second support plate 52 can both rotate relative to the center beam 10 to realize the folded state and the unfolded state of the hinge mechanism 100. Specifically, the first support plate 51 and the second support plate 52 rotate in opposite directions. When the electronic device 200 is in the unfolded state, the hinge mechanism 100 is also in the unfolded state. The first support plate 51 and the second support plate 52 can be relatively flattened and jointly support the flexible display 210, making the flexible display 210 more flat and less likely to be damaged by external touch force, which is conducive to improving the reliability of the flexible display 210. When the electronic device 200 is in the folded state, the hinge mechanism 100 is also in the folded state. The first support plate 51 and the second support plate 52 can be closed, thereby providing better support performance for the flexible display 210.

[0158] The first support plate 51 can extend along the Y direction and extend from one end of the rotating shaft mechanism 100 along the Y direction to the other end along the Y direction. The first support plate 51 can be connected between the center beam 10 and the first fixing frame 21. The first support plate 51 can be linked with the first fixing frame 21 and can rotate relative to the center beam 10. In other words, when the first fixing frame 21 rotates relative to the center beam 10, the first support plate 51 is driven to rotate synchronously relative to the center beam 10. As a result, the electronic device 200 as a whole can have better mechanical tensile strength and mechanical compression resistance.

[0159] The first support plate 51 may include a first body 511, a first shaft 512, and a third shaft 513. The first body 511 may extend along the Y-direction, extending from one end of the hinge mechanism 100 along the Y-direction to the other end thereof. The first body 511 is positioned between the center beam 10 and the first fixing frame 21. The first body 511 can work together with the center beam 10 and the first fixing frame 21 to support the flexible display 210 in the folded, intermediate, and unfolded states of the hinge mechanism 100, thereby providing a larger support area for the flexible display 210 and improving the support stability of the flexible display 210.

[0160] The first shaft body 512 can be connected to the side of the first body 511 close to the center beam 10, and the extension direction of the first shaft body 512 can be arranged parallel to the length direction (i.e., the Y direction) of the first body 511. The first shaft body 512 can be installed in the first shaft hole 17 of the center beam 10 to realize the rotational connection between the first support plate 51 and the center beam 10. The number of the first shaft bodies 512 can be one or more. When the number of the first shaft bodies 512 is multiple, the multiple first shaft bodies 512 can be spaced apart in the length direction (i.e., the Y direction) of the first body 511, and each first shaft body 512 is used to connect to a first shaft hole 17 of the center beam 10. Exemplarily, the number of the first shaft bodies 512 can be two, and the two first shaft bodies 512 are both connected to the first body 511 and spaced apart in the length direction of the first body 511.

[0161] The third shaft 513 can be connected to a side of the first body 511 near the first fixing frame 21, and the extension direction of the third shaft 513 can be arranged parallel to the length direction of the first body 511. The third shaft 513 can be arranged opposite to the first shaft 512 in the width direction of the first body 511 (i.e., the X direction). The third shaft 513 can be installed in the third shaft hole 213 of the first fixing frame 21 to achieve a rotational connection between the first support plate 51 and the first fixing frame 21. The number of third shafts 513 can be one or more. When the number of third shafts 513 is multiple, the multiple third shafts 513 can be spaced apart in the length direction of the first body 511, and each third shaft 513 is used to connect to a third shaft hole 213 of the first fixing frame 21. For example, the number of third shafts 513 can be two, and both third shafts 513 are connected to the first body 511 and spaced apart in the length direction of the first body 511.

[0162] When the user folds the first housing 220, the first housing 220 drives the first fixing frame 21 to rotate, which in turn rotates in conjunction with the first support plate 51, allowing the first support plate 51 to rotate relative to the center beam 10. In other words, the first fixing frame 21 can rotate relative to the center beam 10, driving the first support plate 51 to rotate relative to the center beam 10, forming a "first fixing frame 21-first support plate 51-center beam 10" rotation chain, allowing the hinge mechanism 100 to rotate smoothly.

[0163] The second support plate 52 can be mirror-symmetrical with the first support plate 51. The second support plate 52 can extend along the Y direction and extend from one end of the rotating shaft mechanism 100 along the Y direction to the other end along the Y direction. The second support plate 52 can be connected between the central beam 10 and the second fixing frame 31. The second support plate 52 can be linked with the second fixing frame 31 and can rotate relative to the central beam 10. That is, when the second fixing frame 31 rotates relative to the central beam 10, the second support plate 52 will be driven and synchronously rotated relative to the central beam 10. As a result, the electronic device 200 as a whole can have better mechanical tensile strength and mechanical anti-extrusion capabilities.

[0164] The second support plate 52 may include a second body 521, a second shaft 522, and a fourth shaft 523. The second body 521 may extend along the Y direction, extending from one end of the hinge mechanism 100 along the Y direction to the other end along the Y direction. The second body 521 is positioned between the center beam 10 and the second fixing frame 31. The second body 521 can work together with the center beam 10 and the second fixing frame 31 to support the flexible display 210 in the folded, intermediate, and unfolded states of the hinge mechanism 100, providing a larger support area for the flexible display 210 and improving the support stability of the flexible display 210.

[0165] The second shaft body 522 can be connected to a side of the second body 521 close to the center beam 10, and the extension direction of the second shaft body 522 can be arranged parallel to the length direction of the second body 521 (i.e., the Y direction). The second shaft body 522 can be installed in the second shaft hole 18 of the center beam 10 to achieve a rotational connection between the second support plate 52 and the center beam 10. The number of the second shaft bodies 522 can be one or more. When the number of the second shaft bodies 522 is multiple, the multiple second shaft bodies 522 can be spaced apart in the length direction of the second body 521, and each second shaft body 522 is used to connect to a second shaft hole 18 of the center beam 10. Exemplarily, the number of the second shaft bodies 522 can be two, and the two second shaft bodies 522 are both connected to the second body 521 and spaced apart in the length direction of the second body 521.

[0166] The fourth shaft 523 can be connected to a side of the second body 521 near the second fixing frame 31, and the extension direction of the fourth shaft 523 can be arranged parallel to the length direction of the second body 521. The fourth shaft 523 can be arranged opposite to the second shaft 522 in the width direction of the second body 521 (i.e., the X direction). The fourth shaft 523 can be installed in the fourth shaft hole 313 of the second fixing frame 31 to achieve a rotational connection between the second support plate 52 and the second fixing frame 31. The number of the fourth shaft 523 can be one or more. When the number of the fourth shaft 523 is multiple, the multiple fourth shafts 523 can be spaced apart in the length direction of the second body 521, and each fourth shaft 523 is used to connect to a fourth shaft hole 313 of the second fixing frame 31. For example, the number of the fourth shaft 523 can be two, and the two fourth shafts 523 are respectively connected to the first and last ends of the second body 521 along the Y direction.

[0167] When the user folds the second housing 230, the second housing 230 drives the second fixing frame 31 to rotate, which in turn rotates in conjunction with the second support plate 52, allowing the second support plate 52 to rotate relative to the center beam 10. In other words, the second fixing frame 31 can rotate relative to the center beam 10, driving the second support plate 52 to rotate relative to the center beam 10, forming a "second fixing frame 31 - second support plate 52 - center beam 10" rotation chain, allowing the hinge mechanism 100 to rotate smoothly.

[0168] See also Figure 11 , Figure 11 yes Figure 4 FIG. 1 is a partial structural diagram of the synchronization component 40 of the rotating shaft mechanism 100 .

[0169] The synchronization assembly 40 may include a first swing arm 41, a second swing arm 42, and a synchronization gear 43. The first and second swing arms 41, 42 are located on either side of the width of the center beam 10 and are connected to either side of the synchronization gear 43. When the first swing arm 41 rotates, it drives the synchronization gear 43 to rotate, which in turn drives the second swing arm 42 to rotate, thereby achieving synchronized rotation of the first and second swing arms 41, 42.

[0170] The first swing arm 41 may include a first swing arm body 411, a first rotating portion 412, and a first sliding portion 413. The first rotating portion 412 is connected to one end of the first swing arm body 411 and may be connected to one side of the synchronous gear 43 to achieve a fixed connection between the first swing arm 41 and the synchronous gear 43, thereby enabling the first swing arm 41 and the synchronous gear 43 to achieve synchronous movement. The connection between the first rotating portion 412 and the synchronous gear 43 may be as follows: Figure 11The first rotating portion 412 is shown to be directly connected to the synchronous gear 43, or the first rotating portion 412 may be connected to a rotating shaft passing through the synchronous gear 43 and indirectly connected to the synchronous gear 43. The first sliding portion 413 is connected to the other end of the first swing arm body 411. The first sliding portion 413 can also be mounted to the third slide groove 212 of the first fixed frame 21, and the first sliding portion 413 can slide within the third slide groove 212 of the first fixed frame 21. Specifically, the first sliding portion 413 may include two first sliders 414, the two first sliders 414 are respectively located on both sides of the width direction of the first swing arm body 411, and the two first sliders 414 are arranged opposite to each other along the Y direction. The two first sliders 414 are respectively mounted to both sides of the third slide groove 212 of the first fixed frame 21 along the Y direction.

[0171] The second swing arm 42 can be mirror-symmetrical with the first swing arm 41. The second swing arm 42 can include a second swing arm body 421, a second rotating portion 422 and a second sliding portion 423. The second rotating portion 422 is connected to one end of the second swing arm body 421 and can be connected to the other side of the synchronous gear 43 to achieve a fixed connection between the second swing arm 42 and the synchronous gear 43, so that the second swing arm 42 and the synchronous gear 43 can achieve synchronous movement. The connection between the second rotating portion 422 and the synchronous gear 43 can be as follows: Figure 11 The second rotating portion 422 is directly connected to the synchronous gear 43, or the second rotating portion 422 is indirectly connected to the synchronous gear 43 by being connected to a rotating shaft passing through the synchronous gear 43. The second sliding portion 423 is connected to the other end of the second swing arm body 421. The second sliding portion 423 can also be mounted to the fourth slide groove 312 of the second fixed frame 31, and the second sliding portion 423 can slide within the fourth slide groove 312 of the second fixed frame 31. Specifically, the second sliding portion 423 can include two second sliders 424, the two second sliders 424 are respectively located on both sides of the width direction of the second swing arm body 421, and the two second sliders 424 are arranged opposite to each other along the Y direction. The two second sliders 424 are respectively mounted to both sides of the fourth slide groove 312 of the second fixed frame 31 along the Y direction.

[0172] The following will describe in detail the synchronization gear 43 and other structures of the synchronization assembly 40 through two different embodiments.

[0173] First embodiment:

[0174] See also Figure 12 , Figure 12 yes Figure 4 A partial structural diagram of the synchronization component 40 of the first embodiment of the rotating shaft mechanism 100 is shown. Figure 12 In the figure, for the sake of easy understanding, the first swing arm 41 and the second swing arm 42 of the synchronization assembly 40 are not shown.

[0175] The synchronization assembly 40 may also include a first rotating shaft 44 and a second rotating shaft 45. The first rotating shaft 44 and the second rotating shaft 45 are both mounted on the center beam 10, and are arranged opposite to and spaced apart along the width direction (i.e., the X direction) of the center beam 10. Specifically, the first rotating shaft 44 can be mounted on the first mounting groove 15 of the center beam 10, extend along the Y direction, and be able to rotate relative to the center beam 10. The second rotating shaft 45 can be mounted on the second mounting groove 16 of the center beam 10, extend along the Y direction, and be able to rotate relative to the center beam 10. The first rotating shaft 44 and the second rotating shaft 45 can be passed through the synchronization gear 43 and form a gear shaft structure with the synchronization gear 43, so that the first rotating shaft 44, the second rotating shaft 45 and the synchronization gear 43 can rotate synchronously.

[0176] Please refer to Figure 13 、 Figure 14a and Figure 14b , Figure 13 yes Figure 12 A partial structural diagram of the synchronization component 40 is shown. Figure 14a yes Figure 13 The schematic structural diagram of the synchronization component 40 is shown at an angle. Figure 14b yes Figure 13 FIG. 4 is a schematic structural diagram of the synchronization assembly 40 from another angle.

[0177] The synchronization gear 43 may include a first gear 46 and a second gear 47. The first gear 46 may be mounted on the outer periphery of the first rotating shaft 44, fixedly connected to the first rotating shaft 44, and coaxially arranged with the first rotating shaft 44. The coaxial arrangement of the first gear 46 and the first rotating shaft 44 means that the rotation centerline of the first gear 46 coincides with the rotation centerline of the first rotating shaft 44. The second gear 47 may be mounted on the outer periphery of the second rotating shaft 45, fixedly connected to the second rotating shaft 45, and coaxially arranged with the second rotating shaft 45. The coaxial arrangement of the second gear 47 and the second rotating shaft 45 means that the rotation centerline of the second gear 47 coincides with the rotation centerline of the second rotating shaft 45. When the first rotating shaft 44 with the first gear 46 mounted thereon and the second rotating shaft 45 with the second gear 47 mounted thereon are mounted on the center beam 10, the first gear 46 and the second gear 47 are also mounted on the center beam 10, arranged sequentially in the width direction (i.e., the X direction) of the center beam 10, and meshing with each other.

[0178] It is understood that when the first rotating shaft 44 rotates relative to the center beam 10, it drives the first gear 46 to rotate together. Due to the meshing relationship between the first gear 46 and the second gear 47, the rotation of the first gear 46 drives the second gear 47 to rotate together, and the second gear 47 drives the second rotating shaft 45 to rotate relative to the base, thereby achieving synchronous rotation of the first gear 46 and the second gear 47, as well as synchronous rotation of the first rotating shaft 44 and the second rotating shaft 45.

[0179] The first gear 46 is also fixedly connected to the first swing arm 41, so as to be in motion with the first swing arm 41. The second gear 47 is also fixedly connected to the second swing arm 42, so as to be in motion with the second swing arm 42. As a result, due to the mutual meshing relationship between the first gear 46 and the second gear 47, when one rotates, the other can also rotate synchronously, thereby achieving the opening and closing of the first swing arm 41 and the second swing arm 42, that is, achieving the expansion and folding of the hinge mechanism 100, and thus the expansion and folding of the electronic device 200.

[0180] Please continue reading Figure 13 、 Figure 14a and Figure 14b The first gear 46 may include a first gear body 461 and a plurality of first teeth 462. The first gear body 461 may be annular. The inner edge of the first gear body 461 is connected to the outer periphery of the first rotating shaft 44, and the outer edge of the first gear body 461 is connected to the plurality of first teeth 462. The plurality of first teeth 462 may be spaced apart along the circumferential direction of the first gear body 461, wherein the circumferential direction of the first gear body 461 is a direction that circles the rotation centerline of the first gear 46. That is, the plurality of first teeth 462 may be spaced apart along the circumferential direction of the first gear 46, wherein the circumferential direction of the first gear 46 is a direction that circles the rotation centerline of the first gear 46. A first tooth groove W1 may be formed between two adjacent first teeth 462, and the plurality of first teeth 462 may form a plurality of first tooth grooves W1. Each first tooth groove W1 may be used to accommodate a second tooth 472 of the second gear 47.

[0181] The tooth root of the first tooth 462 can be connected to the first gear body 461, and the tooth top of the first tooth 462 can be away from the first gear body 461. The extension direction of the first tooth 462 can be set parallel to the axial direction of the first gear 46, wherein the axial direction of the first gear 46 is the direction of the rotation centerline of the first gear 46. The first tooth 462 may include a first end 4621 and a second end 4622, and the first end 4621 and the second end 4622 may be arranged relative to each other in the tooth width direction of the first tooth 462 (i.e., the Y direction). The tooth width of the first tooth 462 refers to the length of the first tooth 462 in the axial direction of the first gear 46, and the tooth width direction of the first tooth 462 refers to the axial direction of the first gear 46, i.e., the thickness direction of the first tooth 462, i.e., the direction from one end face of the first tooth 462 to the other end face of the first tooth 462.

[0182] The second gear 47 may include a second gear body 471 and a plurality of second teeth 472. The second gear body 471 may be annular. The inner edge of the second gear body 471 is connected to the outer circumference of the second rotating shaft 45, and the outer edge of the second gear body 471 is connected to the plurality of second teeth 472. The plurality of second teeth 472 may be spaced apart along the circumference of the second gear body 471, where the circumference of the second gear body 471 is the direction circling the rotational centerline of the second gear body 471. In other words, the plurality of second teeth 472 may be spaced apart along the circumference of the second gear 47, where the circumference of the second gear 47 is the direction circling the rotational centerline of the second gear 47. The plurality of second teeth 472 may be configured to mesh with the plurality of first teeth 462. A second tooth groove W2 may be formed between two adjacent second teeth 472, and the plurality of second teeth 472 may form a plurality of second tooth grooves W2. Each second tooth groove W2 may be configured to accommodate a first tooth 462 of the first gear 46.

[0183] The tooth root of the second tooth 472 can be connected to the second gear body 471, and the tooth top of the second tooth 472 can be away from the second gear body 471. The extension direction of the second tooth 472 can be arranged parallel to the axial direction of the second gear 47, wherein the axial direction of the second gear 47 is the direction of the rotation centerline of the second gear 47. The second tooth 472 may include a third end 4721 and a fourth end 4722, and the third end 4721 and the fourth end 4722 may be arranged relative to each other in the tooth width direction (i.e., the Y direction) of the second tooth 472. The tooth width of the second tooth 472 refers to the length of the second tooth 472 in the axial direction of the second gear 47, and the tooth width direction of the second tooth 472 refers to the axial direction of the second gear 47, i.e., the thickness direction of the second tooth 472, i.e., the direction from one end face of the second tooth 472 to the other end face of the second tooth 472.

[0184] The third end 4721 of the second tooth 472 can be located on the same side as the first end 4621 of the first tooth 462, and the fourth end 4722 of the second tooth 472 can be located on the same side as the second end 4622 of the first tooth 462. That is, the third end 4721 of the second tooth 472 can be located on one side of the synchronous gear 43 with the first end 4621 of the first tooth 462, and the fourth end 4722 of the second tooth 472 can be located on the other side of the synchronous gear 43 with the second end 4622 of the first tooth 462. The tooth tip thickness of the first tooth 462 gradually changes from the first end 4621 to the second end 4622, while the tooth tip thickness of the second tooth 472 gradually changes from the third end 4721 to the fourth end 4722, with the changing trend of the tooth tip thickness of the second tooth 472 being opposite to that of the first tooth 462.

[0185] The tooth tip thickness of the first tooth 462 refers to the arc length of the tooth tip circle between the tooth profiles on both sides of the first tooth 462 within the end plane of the first gear 46 (i.e., a plane parallel to the XZ plane), that is, the arc length between the tooth profiles on both sides of the first tooth tip surface 4623 of the first tooth 462 that are arranged opposite each other along the circumferential direction of the first gear 46. The tooth tip thickness of the second tooth 472 refers to the arc length of the tooth tip circle between the tooth profiles on both sides of the second tooth 472 within the end plane of the second gear 47 (i.e., a plane parallel to the XZ plane), that is, the arc length between the tooth profiles on both sides of the second tooth tip surface 4723 of the second tooth 472 that are arranged opposite each other along the circumferential direction of the second gear 47.

[0186] Please refer to Figure 15a 、 Figure 15b 、 Figure 15c and Figure 15d , Figure 15a yes Figure 4 A schematic diagram of a first tooth tip thickness variation trend of a first embodiment of the synchronous gear 43 is shown, Figure 15b yes Figure 4 A schematic diagram of the second tooth tip thickness variation trend of the first embodiment of the synchronous gear 43 is shown, Figure 15c yes Figure 4 A schematic diagram of the third tooth tip thickness variation trend of the first embodiment of the synchronous gear 43 is shown, Figure 15d yes Figure 4 The schematic diagram of the fourth tooth top thickness variation trend of the first embodiment of the synchronous gear 43 shown in FIG. Figure 15a-Figure 15d In the figure, the changing trend of the tooth top thickness of the first tooth 462 is illustrated by taking the changing trend of the tooth top thickness of the first tooth top surface 4623 of the first tooth 462 as an example, and the changing trend of the tooth top thickness of the second tooth 472 is illustrated by taking the changing trend of the tooth top thickness of the second tooth top surface 4723 of the second tooth 472 as an example, but it is not limited to this.

[0187] It should be understood that the variation trend of the tooth top thickness of the second tooth 472 is opposite to the variation trend of the tooth top thickness of the first tooth 462, including at least the following situations:

[0188] 1. Such as Figure 15a As shown, the tooth top thickness of the first tooth 462 may gradually increase from the first end 4621 to the second end 4622 , and the tooth top thickness of the second tooth 472 may gradually decrease from the third end 4721 to the fourth end 4722 .

[0189] For example, the tooth top thickness D1 of the first end 4621 may be smaller than the tooth top thickness D2 of the second end 4622. The tooth top thickness D3 of the third end 4721 may be larger than the tooth top thickness D4 of the fourth end 4722. The tooth top thickness D1 of the first end 4621 may be the same as the tooth top thickness D4 of the fourth end 4722. The tooth top thickness D2 of the second end 4622 may be the same as the tooth top thickness D3 of the third end 4721. Of course, in other application scenarios, the tooth top thickness D1 of the first end 4621 may be different from the tooth top thickness D4 of the fourth end 4722. The tooth top thickness D2 of the second end 4622 may be different from the tooth top thickness D3 of the third end 4721.

[0190] 2. If Figure 15b As shown, the tooth top thickness of the first tooth 462 may gradually decrease from the first end 4621 to the second end 4622 , and the tooth top thickness of the second tooth 472 may gradually increase from the third end 4721 to the fourth end 4722 .

[0191] For example, the tooth top thickness D1 of the first end 4621 may be greater than the tooth top thickness D2 of the second end 4622. The tooth top thickness D3 of the third end 4721 may be less than the tooth top thickness D4 of the fourth end 4722. The tooth top thickness D1 of the first end 4621 may be the same as the tooth top thickness D4 of the fourth end 4722. The tooth top thickness D2 of the second end 4622 may be the same as the tooth top thickness D3 of the third end 4721. Of course, in other application scenarios, the tooth top thickness D1 of the first end 4621 may be different from the tooth top thickness D4 of the fourth end 4722. The tooth top thickness D2 of the second end 4622 may be different from the tooth top thickness D3 of the third end 4721.

[0192] 3. If Figure 15c As shown, the tooth top thickness of the first tooth 462 first increases and then decreases from the first end 4621 to the second end 4622 , and the tooth top thickness of the second tooth 472 first decreases and then increases from the third end 4721 to the fourth end 4722 .

[0193] For example, the tooth top thickness D1 of the first end 4621 may be equal to the tooth top thickness D2 of the second end 4622. The tooth top thickness D3 of the third end 4721 may be equal to the tooth top thickness D4 of the fourth end 4722. The tooth top thickness D1 of the first end 4621 may be different from the tooth top thickness D4 of the fourth end 4722. The tooth top thickness D2 of the second end 4622 may be different from the tooth top thickness D3 of the third end 4721. Of course, in other application scenarios, the tooth top thickness D1 of the first end 4621 may be smaller than or larger than the tooth top thickness D2 of the second end 4622. The tooth top thickness D3 of the third end 4721 may be larger than or smaller than the tooth top thickness D4 of the fourth end 4722. The tooth top thickness D1 of the first end 4621 may be the same as the tooth top thickness D4 of the fourth end 4722. The tooth top thickness D2 of the second end 4622 may be the same as the tooth top thickness D3 of the third end 4721.

[0194] 4. If Figure 15d As shown, the tooth top thickness of the first tooth 462 first decreases and then increases from the first end 4621 to the second end 4622 , and the tooth top thickness of the second tooth 472 first increases and then decreases from the third end 4721 to the fourth end 4722 .

[0195] For example, the tooth tip thickness D1 at the first end 4621 may be equal to the tooth tip thickness D2 at the second end 4622. The tooth tip thickness D3 at the third end 4721 may be equal to the tooth tip thickness D4 at the fourth end 4722. The tooth tip thickness D1 at the first end 4621 may be different from the tooth tip thickness D4 at the fourth end 4722. The tooth tip thickness D2 at the second end 4622 may be different from the tooth tip thickness D3 at the third end 4721.

[0196] It should be noted that the changing trend of the tooth top thickness of the first tooth 462 and the changing trend of the tooth top thickness of the second tooth 472 are not limited to the several cases listed above. The implementation methods that can satisfy the opposite trend of the changing trend of the tooth top thickness of the second tooth 472 and the changing trend of the tooth top thickness of the first tooth 462 are all within the scope of protection requested by this embodiment, and no strict restrictions are imposed on this.

[0197] It is understood that in a foldable electronic device 200, the contact ratio of the gears in the synchronization assembly 40 is a key factor affecting the synchronization of movement between the two housings of the electronic device 200. To improve the synchronization of movement between the two housings of the electronic device 200, the contact ratio of the gears in the synchronization assembly 40 must be increased to ensure the transmission efficiency and stability of the synchronization assembly 40.

[0198] Among them, the overlap of the gears refers to the ratio of the actual meshing line length to the normal tooth pitch. The overlap greater than 1 is a condition for the gears to be able to mesh continuously. The overlap represents the ratio of the frequency of two teeth meshing simultaneously to the frequency of one tooth meshing during the meshing process. The higher the frequency of two teeth meshing simultaneously, the higher the overlap, the better the synchronization performance of the synchronous gear 43, the smaller the load on a single tooth, the more stable the meshing structure of the gear, the less likely it is to bend, and the less noise during the gear rotation process. In addition, the greater the overlap of the gears, the higher the transmission efficiency and stability of the gears.

[0199] In the related art, when designing the synchronous gear and the center beam, a clearance must be left between them to ensure that the synchronous gear can be smoothly installed on the center beam. This clearance prevents the synchronous gear from getting stuck when installed on the center beam due to the clearance between the synchronous gear and the center beam being too small or too large. However, in the actual operation of the synchronous gear, the two meshing gears are prone to loose fit, resulting in one gear moving closer to the center beam below it, reducing or eliminating the clearance between it and the center beam. The other gear also moves closer to the center beam below it, reducing or eliminating the clearance between it and the center beam. This causes the two gears to expand outwards away from each other, causing the involute surfaces of the two gears to change from tangent to offset, resulting in an increase in the tooth side clearance between the two gears and preventing complete meshing, which reduces the overlap and meshing effect of the synchronous gears.

[0200] Based on this, in this embodiment, by gradually changing the tooth top thickness of the first tooth 462 from the first end 4621 to the second end 4622, and gradually changing the tooth top thickness of the second tooth 472 from the third end 4721 to the fourth end 4722, and the changing trend of the tooth top thickness of the second tooth 472 is opposite to the changing trend of the tooth top thickness of the first tooth 462, the tooth shape of the first tooth 462 and the tooth shape of the second tooth 472 can both have an inclined surface, and the inclination trends of the inclined surfaces can be set in opposite directions.

[0201] Under this arrangement, when the first teeth 462 and the second teeth 472 are engaged, the tooth profiles of the first teeth 462 and the second teeth 472, which are opposite to each other, can be arranged in an intersecting manner, and the mating surfaces of the first teeth 462 and the second teeth 472 can be changed from a flat mating surface to an inclined mating surface, thereby effectively increasing the relative mating area between the first teeth 462 and the second teeth 472. The increase in the mating area between the first teeth 462 and the second teeth 472 allows the tooth profiles of the first teeth 462 and the second teeth 472 to fit more closely together, allowing the tooth grooves of the first teeth 462 and the second teeth 472 to further engage with each other when the tooth profiles of the first teeth 462 and the second teeth 472 contact each other. This facilitates the engagement of the tooth profiles of the next pair of first teeth 462 and the second teeth 472 before the meshing of the tooth profiles of the previous pair of first teeth 462 and the second teeth 472 is completed (at least simultaneously), so that the involute surfaces of the first teeth 462 and the second teeth 472 remain tangent to each other, effectively improving the overlap and meshing effect, and ensuring the continuity and smoothness of the transmission. In addition, since the overlap is improved, the synchronization effect between the first gear 46 and the second gear 47 will be better, so that the structures on both sides of the rotating shaft mechanism 100 can achieve synchronous rotation.

[0202] The following description of the structure of the first tooth 462 and the second tooth 472 will be described in detail using an example in which the tooth top thickness of the first tooth 462 gradually increases from the first end 4621 to the second end 4622, and the tooth top thickness of the second tooth 472 gradually decreases from the third end 4721 to the fourth end 4722. The following description of the structure of the first tooth 462 and the second tooth 472 can be applied to other first teeth 462 and other second teeth 472 unless there is any conflict.

[0203] See also Figure 16 , Figure 16 yes Figure 12 The schematic diagram of the structure of the first gear 46 of the synchronous gear 43 at one angle is shown.

[0204] The first tooth 462 may further include a first tooth top surface 4623, a first side surface 4624, a second side surface 4625, a first end surface 4626, and a second end surface 4627. The first end surface 4626 is the end surface of the first end 4621 of the first tooth 462. The second end surface 4627 is the end surface of the second end 4622 of the first tooth 462. The first end surface 4626 and the second end surface 4627 may be arranged relative to each other in the tooth width direction (i.e., the Y direction) of the first tooth 462. The first tooth top surface 4623 is the surface of the first tooth 462 that faces away from the first gear body 461. The first tooth top surface 4623 is connected between the first end 4621 and the second end 4622, that is, connected between the first end surface 4626 and the second end surface 4627. First side surface 4624 is a surface of first tooth 462 that connects between first tooth top surface 4623 and first gear body 461. First side surface 4624 may also connect between first end 4621 and second end 4622, that is, between first end surface 4626 and second end surface 4627. Second side surface 4625 is another surface of first tooth 462 that connects between first tooth top surface 4623 and first gear body 461. Second side surface 4625 may also connect between first end 4621 and second end 4622, that is, between first end surface 4626 and second end surface 4627. First side surface 4624 may be the surface on the left side of first tooth 462, and second side surface 4625 may be the surface on the right side of second tooth 472. In other embodiments, first side surface 4624 may be the surface on the right side of first tooth 462, and second side surface 4625 may be the surface on the left side of second tooth 472.

[0205] The first tooth top surface 4623 may include a first top edge A1 located at the first end 4621 and a second top edge A2 located at the second end 4622. The first top edge A1 may be the intersection of the first tooth top surface 4623 and the first end surface 4626, and the second top edge A2 may be the intersection of the first tooth top surface 4623 and the second end surface 4627. The length of the first top edge A1 may be different from the length of the second top edge A2. Specifically, the length of the first top edge A1 may be less than or greater than the length of the second top edge A2. For example, the shape of the first tooth top surface 4623 may be an inverted trapezoid.

[0206] It can be understood that by making the length of the second top edge A2 different from the length of the first top edge A1, the tooth width of the first tooth 462 can gradually change in the axial direction of the first gear 46, so that the first tooth 462 is a gear tooth with a certain radial displacement, so that the mating surface of the first tooth 462 that cooperates with the second tooth 472 can be a bevel, which is beneficial to increase the mating area between the second tooth 472, optimize the meshing effect between the first tooth 462 and the second tooth 472, and increase the overlap of the synchronous gear 43.

[0207] In one possible implementation, Figure 16 As shown, the length of the first top side A1 can be less than the length of the second top side A2. The first tooth 462 has a first draft angle θ1, a length of the first top side A1 of S1, a length of the second top side A2 of S2, and a tooth width of the first tooth 462 of B1, wherein the tooth width B1 of the first tooth 462 is the length of the first tooth 462 along the axial direction of the first gear 46. The first draft angle θ1, the length S1 of the first top side A1, the length S2 of the second top side A2, and the tooth width B1 of the first tooth 462 satisfy the relationship:

[0208] tanθ1=(S1-S2) / B1

[0209] It is understood that by providing the first tooth 462 with the first draft angle θ1, the machining allowance of the first gear 46 can be ensured during the production of the first gear 46, thereby reducing the frictional resistance between the mold and the workpiece surface and improving the quality of the produced first gear 46. Furthermore, the finished first gear 46 can be ejected smoothly and quickly from the mold, saving the cost and time of removing the first gear 46 from the mold, thereby reducing the difficulty and cost of machining the first gear 46.

[0210] For example, the first draft angle θ1 can be within the range of 3° to 30° (including the endpoints 3° and 30°). It will be appreciated that by setting the first draft angle θ1 within the aforementioned range, the draft angle can be adjusted to facilitate demolding of the first gear 46 from the mold. The greater the first draft angle θ1, the less force is required to remove the first gear 46 from the mold, and the shorter the time it takes to remove the first gear 46 from the mold.

[0211] Please refer to Figure 14a and Figure 16 In this embodiment, the first side surface 4624 may include a first side edge C1 located at the first end 4621 and a second side edge C2 located at the second end 4622. The first side edge C1 may be an intersection line between the first end surface 4626 and the first side surface 4624, and the second side edge C2 may be an intersection line between the second end surface 4627 and the first side surface 4624.

[0212] The second side surface 4625 may include a third side C3 located at the first end 4621 and a fourth side C4 located at the second end 4622. The third side C3 may be an intersection line of the first end surface 4626 and the second side surface 4625, and the fourth side C4 may be an intersection line of the second end surface 4627 and the second side surface 4625.

[0213] In the circumferential direction of the first gear 46, the first side C1 and the second side C2 of the first side surface 4624 can be staggered, and the third side C3 and the fourth side C4 of the second side surface 4625 can be staggered, and the minimum distance between the first side C1 of the first side surface 4624 and the third side C3 of the second side surface 4625 is less than or greater than the minimum distance between the second side C2 of the first side surface 4624 and the fourth side C4 of the second side surface 4625.

[0214] The first side C1 and the second side C2 of the first side surface 4624 are staggered in the circumferential direction of the first gear 46, which means that the first side C1 and the second side C2 of the first side surface 4624 do not overlap in the circumferential direction of the first gear 46, but are arranged in sequence. The third side C3 and the fourth side C4 of the second side surface 4625 are staggered in the circumferential direction of the first gear 46, which means that the third side C3 and the fourth side C4 of the second side surface 4625 do not overlap in the circumferential direction of the first gear 46, but are arranged in sequence. For example, Figure 14a As shown, the minimum distance between the first side C1 and the third side C3 is smaller than the minimum distance between the second side C2 and the fourth side C4.

[0215] It can be understood that by staggering the first side C1 and the second side C2 of the first side surface 4624 in the circumferential direction of the first gear 46, and staggering the third side C3 and the fourth side C4 of the second side surface 4625 in the circumferential direction of the first gear 46, both the first side surface 4624 and the second side surface 4625 can be inclined surfaces with a certain inclination angle. Furthermore, by ensuring that the minimum distance between the first side C1 of the first side surface 4624 and the third side C3 of the second side surface 4625 is smaller than or larger than the minimum distance between the second side C2 of the first side surface 4624 and the fourth side C4 of the second side surface 4625, the extension direction of the first side surface 4624 and the extension direction of the second side surface 4625 can intersect, facilitating the first gear 46 to present a structural configuration with a larger tooth thickness at one end and a smaller tooth thickness at the other end. This allows the first gear 46 to present a bilaterally radially displaced configuration of the first side surface 4624 and the second side surface 4625. By setting the first gear 46 to bilateral radial displacement, not only can the first gear 46 be easily demolded, but the load-bearing capacity, wear resistance, processing accuracy and installation accuracy of the first gear 46 can also be improved, and the transmission ratio and speed adaptability of the gear can be optimized, which is conducive to making the synchronous gear 43 have a better overlap and a good meshing effect.

[0216] Additionally, the addendum radius R1 of the first end 4621 can be different from the addendum radius R2 of the second end 4622. That is, in the radial direction of the first gear 46, the first top edge A1 and the second top edge A2 are offset. The radial direction of the first gear 46 is perpendicular to the rotational centerline of the first gear 46. For example, the addendum radius R1 of the first end 4621 can be smaller than the addendum radius R2 of the second end 4622.

[0217] It can be understood that by making the tooth top circle radius R1 of the first end 4621 different from the tooth top circle radius R2 of the second end 4622, the first tooth top surface 4623 can be an inclined surface with a certain inclination. Under this setting, the first gear 46 can be easily demolded from the mold.

[0218] See also Figure 17 , Figure 17 yes Figure 12 The schematic diagram of the structure of the second gear 47 of the synchronous gear 43 at one angle is shown.

[0219] The second tooth 472 may further include a second tooth top surface 4723, a third side surface 4724, a fourth side surface 4725, a third end surface 4726, and a fourth end surface 4727. The third end surface 4726 is the end surface of the third end 4721 of the second tooth 472. The fourth end surface 4727 is the end surface of the fourth end 4722 of the second tooth 472. The third end surface 4726 and the fourth end surface 4727 may be arranged relative to each other in the tooth width direction (i.e., the Y direction) of the second tooth 472. The second tooth top surface 4723 is the surface of the second tooth 472 that faces away from the second gear body 471. The second tooth top surface 4723 is connected between the third end 4721 and the fourth end 4722, that is, connected between the third end surface 4726 and the fourth end surface 4727. The third side surface 4724 is a surface of the second tooth 472 that connects between the second tooth top surface 4723 and the second gear body 471. The third side surface 4724 may also connect between the third end 4721 and the fourth end 4722, that is, between the third end surface 4726 and the fourth end surface 4727. The fourth side surface 4725 is another surface of the second tooth 472 that connects between the second tooth top surface 4723 and the second gear body 471. The fourth side surface 4725 may also connect between the third end 4721 and the fourth end 4722, that is, between the third end surface 4726 and the fourth end surface 4727. The third side surface 4724 may be the surface on the left side of the second tooth 472, and the fourth side surface 4725 may be the surface on the right side of the second tooth 472. Of course, in other embodiments, the third side surface 4724 may be the surface on the right side of the second tooth 472, and the fourth side surface 4725 may be the surface on the left side of the second tooth 472.

[0220] The second tooth top surface 4723 may include a third top edge A3 located at the third end 4721 and a fourth top edge A4 located at the fourth end 4722. The third top edge A3 may be the intersection of the second tooth top surface 4723 and the third end surface 4726, and the fourth top edge A4 may be the intersection of the second tooth top surface 4723 and the fourth end surface 4727. The length of the third top edge A3 may differ from the length of the fourth top edge A4. Specifically, the length of the third top edge A3 may be greater than or less than the length of the fourth top edge A4. For example, the shape of the second tooth top surface 4723 may be an inverted trapezoid.

[0221] It can be understood that by making the length of the third top edge A3 different from the length of the fourth top edge A4, the tooth width of the second tooth 472 can gradually change in the axial direction of the second gear 47, so that the second tooth 472 is a gear tooth with a certain radial displacement, so that the mating surface of the second tooth 472 that cooperates with the first tooth 462 can be a bevel, which is beneficial to increase the mating area between the first tooth 462, optimize the meshing effect between the first tooth 462 and the second tooth 472, and increase the overlap of the synchronous gear 43.

[0222] In this embodiment, the length relationship between the third top side A3 and the fourth top side A4 is opposite to the length relationship between the first top side A1 and the second top side A2. For example, the length of the third top side A3 is greater than the length of the fourth top side A4, and the length of the first top side A1 is less than the length of the second top side A2. Alternatively, the length of the third top side A3 is less than the length of the fourth top side A4, and the length of the first top side A1 is greater than the length of the second top side A2.

[0223] The length of the third top side A3 may be the same as or different from the length of the first top side A1. The length of the fourth top side A4 may be the same as or different from the length of the second top side A2. For example, the length of the third top side A3 may be the same as the length of the first top side A1, and the length of the fourth top side A4 may be the same as the length of the second top side A2.

[0224] It is understood that by making the length relationship between the third top side A3 and the fourth top side A4 opposite to the length relationship between the first top side A1 and the second top side A2, the mating surfaces of the first tooth 462 and the second tooth 472 can be changed from a flat fit to an inclined fit, thereby effectively increasing the relative mating area between the first tooth 462 and the second tooth 472. The increased mating area between the first tooth 462 and the second tooth 472 allows the tooth profiles of the first tooth 462 and the second tooth 472 to fit well at any cross-section, achieving a tight fit between the first tooth 462 and the second tooth 472. A tight fit between the first tooth 462 and the second tooth 472 means that the fit between the first tooth 462 and the second tooth 472 is within a certain range, allowing the first gear 46 and the second gear 47 to operate normally without relative sliding or jumping. This mating method ensures the transmission accuracy and stability of the gear pair and avoids vibration, noise, and wear caused by improper mating.

[0225] In one possible implementation, Figure 17 As shown, the length of the third top side A3 can be greater than the length of the fourth top side A4. The second tooth 472 has a second draft angle θ2, the length of the third top side A3 is S3, the length of the fourth top side A4 is S4, and the tooth width of the second tooth 472 is B2, wherein the tooth width B2 of the second tooth 472 is the length of the second tooth 472 along the axial direction of the second gear 47. The second draft angle θ2, the length S3 of the third top side A3, the length S4 of the fourth top side A4, and the tooth width B2 of the second tooth 472 satisfy the relationship:

[0226] tanθ2=(S3-S4) / B2

[0227] It is understood that by providing the second tooth 472 with the second draft angle θ2, it is possible to ensure the machining allowance of the second gear 47 during the production of the second gear 47, reduce the frictional resistance between the mold and the workpiece surface, and improve the quality of the produced second gear 47. It also allows the finished second gear 47 to be ejected smoothly and quickly from the mold, saving the cost and time of removing the second gear 47 from the mold, thereby reducing the difficulty and cost of machining the second gear 47.

[0228] For example, the second draft angle θ2 can be within the range of 3° to 30° (including the endpoints 3° and 30°). It will be appreciated that by setting the second draft angle θ2 within the aforementioned range, the draft angle can be adjusted to facilitate demolding of the second gear 47 from the mold. The greater the second draft angle θ2, the less force is required to remove the second gear 47 from the mold, and the shorter the time it takes to remove the second gear 47 from the mold.

[0229] Please refer to Figure 14b and Figure 17 In this embodiment, the third side surface 4724 may include a fifth side C5 located at the third end 4721 and a sixth side C6 located at the fourth end 4722. The fifth side C5 may be an intersection line between the third end surface 4726 and the third side surface 4724, and the sixth side C6 may be an intersection line between the fourth end surface 4727 and the third side surface 4724.

[0230] The fourth side surface 4725 may include a seventh side C7 located at the first end 4621 and an eighth side C8 located at the second end 4622. The seventh side C7 may be an intersection line of the first end surface 4626 and the fourth side surface 4725, and the eighth side C8 may be an intersection line of the second end surface 4627 and the fourth side surface 4725.

[0231] In the circumferential direction of the second gear 47, the fifth side C5 and the sixth side C6 of the third side 4724 can be staggered, and the seventh side C7 and the eighth side C8 of the fourth side 4725 can be staggered, and the minimum distance between the fifth side C5 of the third side 4724 and the seventh side C7 of the fourth side 4725 is less than or greater than the minimum distance between the sixth side C6 of the third side 4724 and the eighth side C8 of the fourth side 4725.

[0232] The fifth side C5 and the sixth side C6 of the third side surface 4724 are staggered in the circumferential direction of the second gear 47, which means that the fifth side C5 and the sixth side C6 of the third side surface 4724 do not overlap in the circumferential direction of the second gear 47, but are arranged in sequence. The seventh side C7 and the eighth side C8 of the fourth side surface 4725 are staggered in the circumferential direction of the second gear 47, which means that the seventh side C7 and the eighth side C8 of the fourth side surface 4725 do not overlap in the circumferential direction of the second gear 47, but are arranged in sequence. For example, Figure 14b As shown, the minimum distance between the fifth side C5 and the seventh side C7 is greater than the minimum distance between the sixth side C6 and the eighth side C8.

[0233] It can be understood that by staggering the fifth side C5 and the sixth side C6 of the third side surface 4724 in the circumferential direction of the second gear 47, and staggering the seventh side C7 and the eighth side C8 of the fourth side surface 4725 in the circumferential direction of the second gear 47, both the third side surface 4724 and the fourth side surface 4725 can be inclined surfaces with a certain inclination angle. Furthermore, by ensuring that the minimum distance between the fifth side C5 of the third side surface 4724 and the seventh side C7 of the fourth side surface 4725 is smaller than or larger than the minimum distance between the sixth side C6 of the third side surface 4724 and the eighth side C8 of the fourth side surface 4725, the extension direction of the third side surface 4724 and the extension direction of the fourth side surface 4725 intersect, thereby facilitating the second gear 47 to exhibit a structural configuration with a larger tooth thickness at one end and a smaller tooth thickness at the other end. Consequently, the second gear 47 can exhibit a bilaterally radially offset configuration of the third side surface 4724 and the fourth side surface 4725. By setting the second gear 47 to bilateral radial displacement, not only can the second gear 47 be easily demolded, but the load-bearing capacity, wear resistance, processing accuracy and installation accuracy of the second gear 47 can also be improved, and the transmission ratio and speed adaptability of the gear can be optimized, which is conducive to making the synchronous gear 43 have a better overlap and a good meshing effect.

[0234] Additionally, the addendum radius R3 of the third end 4721 may be different from the addendum radius R4 of the fourth end 4722. That is, in the radial direction of the second gear 47, the third top edge A3 and the fourth top edge A4 are offset from each other, where the radial direction of the second gear 47 is perpendicular to the rotational centerline of the second gear 47. For example, the addendum radius R3 of the third end 4721 may be greater than the addendum radius R4 of the fourth end 4722.

[0235] It can be understood that by making the tooth top circle radius R3 of the third end 4721 different from the tooth top circle radius R4 of the fourth end 4722, the second tooth top surface 4723 can be an inclined surface with a certain inclination. Under this setting, the second gear 47 can be easily demolded from the mold.

[0236] Please refer to Figure 12 and Figure 18 , Figure 18 yes Figure 12 The structure diagram of the first limiting member 48 and the second limiting member 49 of the synchronization assembly 40 is shown at an angle.

[0237] The synchronization assembly 40 may further include a first stopper 48 and a second stopper 49. The first stopper 48 is mounted on one end of the first rotating shaft 44 and one end of the second rotating shaft 45, and is elastically connected between one end of the synchronization gear 43 and the center beam 10. The second stopper 49 is mounted on the other ends of the first rotating shaft 44 and the other ends of the second rotating shaft 45, and is elastically connected between the other ends of the synchronization gear 43 and the center beam 10. The first stopper 48 and the second stopper 49 may be structural members with a certain degree of elasticity, capable of rebounding when subjected to pressure and returning to their original position when the pressure is removed.

[0238] Exemplarily, the first limiting member 48 and the second limiting member 49 can be a spring, a retaining spring or a disc spring, etc. Among them, the disc spring can be an ordinary disc spring, and the cross-section of the ordinary disc spring is rectangular. They can have a support surface or no support surface. Alternatively, the disc spring can be a disc spring with radial grooves. On the basis of an ordinary disc spring, this spring has a plurality of evenly distributed grooves opened in the radial direction. These grooves can be opened from the inner hole to the outer circle, or from the outer circle to the inner hole. Alternatively, the disc spring can also be a disc spring with a trapezoidal cross-section. The cross-section of this spring is trapezoidal, and can be specifically divided into two types: the inner edge thickness is greater than the outer edge thickness and the inner edge thickness is less than the outer edge thickness.

[0239] Under this setting, the first limit member 48 and the second limit member 49 can cooperate to press the two ends of the first gear 46 along the axial direction and the two ends of the second gear 47 along the axial direction, so that the first gear 46 and the second gear 47 can always maintain engagement, avoiding axial movement of the first gear 46 and the second gear 47 during the engagement process, which may cause the engagement of the first gear 46 and the second gear 47 to fail. This is conducive to achieving axial tight fit between the first gear 46 and the second gear 47, improving the engagement effect of the first gear 46 and the second gear 47, and having good reliability.

[0240] Specifically, the first limiting member 48 may include a first connecting portion 481, a first elastic portion 482 and a second elastic portion 483. The first connecting portion 481 may be connected between the first elastic portion 482 and the second elastic portion 483. The first elastic portion 482 is arranged around the first rotating shaft 44 and extends spirally along the axial direction of the first rotating shaft 44. The second elastic portion 483 is arranged around the second rotating shaft 45 and extends spirally along the axial direction of the second rotating shaft 45. The rotation direction of the second elastic portion 483 is opposite to that of the first elastic portion 482. The rotation direction of the first elastic portion 482 refers to the direction in which the spiral line of the first elastic portion 482 rotates around the rotation center line of the first rotating shaft 44, and the rotation direction of the second elastic portion 483 refers to the direction in which the spiral line of the second elastic portion 483 rotates around the rotation center line of the second rotating shaft 45.

[0241] For example, the rotation direction of the first elastic portion 482 can be left-handed, i.e., the first elastic portion 482 rotates counterclockwise around the first rotation axis 44. The rotation direction of the second elastic portion 483 can be right-handed, i.e., the second elastic portion 483 rotates clockwise around the second rotation axis 45. Of course, in other embodiments, the rotation direction of the first elastic portion 482 can be right-handed, i.e., the first elastic portion 482 rotates clockwise around the first rotation axis 44. The rotation direction of the second elastic portion 483 can be left-handed, i.e., the second elastic portion 483 rotates counterclockwise around the second rotation axis 45.

[0242] It can be understood that by having the first elastic portion 482 wound around the first rotating shaft 44 and extending spirally along the axial direction of the first rotating shaft 44, and the second elastic portion 483 wound around the second rotating shaft 45 and extending spirally along the axial direction of the second rotating shaft 45, and the rotation direction of the second elastic portion 483 is opposite to that of the first elastic portion 482, the opposite rotation directions of the first elastic portion 482 and the second elastic portion 483 can be adapted to the opposite tooth profile change trends of the first tooth 462 and the second tooth 472, so that the first gear 46 and the second gear 47 can always maintain meshing, avoiding the problem of axial movement of the first gear 46 and the second gear 47 during the meshing process, which may cause the meshing failure of the first gear 46 and the second gear 47, and further facilitating the axial tight fit of the first gear 46 and the second gear 47, thereby improving the meshing effect of the first gear 46 and the second gear 47 and improving reliability.

[0243] The second stopper 49 may include a second connecting portion 491, a third elastic portion 492, and a fourth elastic portion 493. The second connecting portion 491 may be connected between the third elastic portion 492 and the fourth elastic portion 493. The third elastic portion 492 is wound around the second rotating shaft 45 and extends helically along the axial direction of the second rotating shaft 45. The fourth elastic portion 493 is wound around the second rotating shaft 45 and extends helically along the axial direction of the second rotating shaft 45. The rotation direction of the fourth elastic portion 493 is opposite to that of the third elastic portion 492.

[0244] Among them, the rotation direction of the third elastic part 492 refers to the direction in which the helix of the third elastic part 492 rotates around the rotation center line of the first rotating shaft 44, and the rotation direction of the fourth elastic part 493 refers to the direction in which the helix of the fourth elastic part 493 rotates around the rotation center line of the second rotating shaft 45.

[0245] For example, the rotation direction of the third elastic portion 492 can be right-handed, i.e., the third elastic portion 492 rotates clockwise around the first rotation axis 44. The rotation direction of the fourth elastic portion 493 can be left-handed, i.e., the fourth elastic portion 493 rotates counterclockwise around the second rotation axis 45. Of course, in other embodiments, the rotation direction of the third elastic portion 492 can be left-handed, i.e., the third elastic portion 492 rotates counterclockwise around the first rotation axis 44. The rotation direction of the fourth elastic portion 493 can be right-handed, i.e., the fourth elastic portion 493 rotates clockwise around the second rotation axis 45.

[0246] It is understandable that by having the third elastic portion 492 wound around the first rotating shaft 44 and extending helically along the axial direction of the first rotating shaft 44, and the fourth elastic portion 493 wound around the second rotating shaft 45 and extending helically along the axial direction of the second rotating shaft 45, and the rotation direction of the fourth elastic portion 493 is opposite to that of the third elastic portion 492, the opposite rotation directions of the third elastic portion 492 and the fourth elastic portion 493 can be adapted to the opposite tooth profile change trends of the first tooth 462 and the second tooth 472, so that the first gear 46 and the second gear 47 can always maintain engagement, avoiding the problem of axial movement of the first gear 46 and the second gear 47 during the engagement process, which may cause the engagement of the first gear 46 and the second gear 47 to fail, and further facilitating the axial tight fit of the first gear 46 and the second gear 47, thereby improving the meshing effect of the first gear 46 and the second gear 47 and improving reliability.

[0247] In addition, in this embodiment, the rotation direction of the first elastic portion 482 can be opposite to the rotation direction of the third elastic portion 492. The rotation direction of the second elastic portion 483 can be opposite to the rotation direction of the fourth elastic portion 493. For example, the rotation direction of the first elastic portion 482 can be left-handed, the rotation direction of the third elastic portion 492 can be right-handed, the rotation direction of the second elastic portion 483 can be right-handed, and the rotation direction of the fourth elastic portion 493 can be left-handed. Alternatively, the rotation direction of the first elastic portion 482 can be right-handed, the rotation direction of the third elastic portion 492 can be left-handed, the rotation direction of the second elastic portion 483 can be left-handed, and the rotation direction of the fourth elastic portion 493 can be right-handed.

[0248] Second embodiment:

[0249] Please refer to Figure 19 、 Figure 20a and Figure 20b , Figure 19 yes Figure 4 A partial structural diagram of the synchronization component 40 of the second embodiment of the rotating shaft mechanism 100 is shown. Figure 20a yes Figure 19 The schematic structural diagram of the synchronization component 40 is shown at an angle. Figure 20b yes Figure 19 The schematic structural diagram of the synchronization component 40 from another angle is shown. Figure 19 In the figure, for the sake of easy understanding, the first swing arm 41 and the second swing arm 42 of the synchronization assembly 40 are not shown.

[0250] In this embodiment, the details common to the first embodiment are omitted. Unlike the first embodiment, both the first gear 46 and the second gear 47 are unilaterally radially displaced, as will be described below. Furthermore, the following description of the synchronizer assembly 40 applies to the first embodiment above, unless otherwise specified.

[0251] Specifically, in the circumferential direction of the first gear 46, the first side C1 and the second side C2 of the first side surface 4624 may be staggered, and the third side C3 and the fourth side C4 of the second side surface 4625 may be overlapped. Alternatively, in the circumferential direction of the first gear 46, the first side C1 and the second side C2 of the first side surface 4624 may be overlapped, and the third side C3 and the fourth side C4 of the second side surface 4625 may be staggered.

[0252] The first side C1 and the second side C2 of the first side surface 4624 are staggered in the circumferential direction of the first gear 46, meaning that the first side C1 and the second side C2 of the first side surface 4624 do not overlap in the circumferential direction of the first gear 46, but are arranged sequentially. The third side C3 and the fourth side C4 of the second side surface 4625 are staggered in the circumferential direction of the first gear 46, meaning that the third side C3 and the fourth side C4 of the second side surface 4625 do not overlap in the circumferential direction of the first gear 46, but are arranged sequentially.

[0253] In one possible implementation, please refer to Figure 20a and Figure 21 , Figure 21 yes Figure 19 The diagram shows an angled structural diagram of the first gear 46 of the synchronous gear 43. In the circumferential direction of the first gear 46, the first side C1 and the second side C2 of the first side surface 4624 are overlapped, and the third side C3 and the fourth side C4 of the second side surface 4625 are staggered.

[0254] It can be understood that by aligning the first side C1 and second side C2 of the first side surface 4624 in the circumferential direction of the first gear 46, and staggering the third side C3 and fourth side C4 of the second side surface 4625 in the circumferential direction of the first gear 46, the first side surface 4624 can be made flat, while the second side surface 4625 can be made into an inclined surface with a certain inclination angle. This arrangement facilitates the first gear 46 to exhibit a structure with a thicker tooth at one end and a thinner tooth at the other end, thereby enabling the first gear 46 to exhibit a single radial displacement of a single side of the second side surface 4625. The single radial displacement of the first gear 46 not only facilitates demolding, but also improves its load-bearing capacity, wear resistance, machining accuracy, and installation precision, optimizes the gear ratio and speed adaptability, and facilitates a good overlap and meshing effect for the synchronous gear 43.

[0255] In addition, the addendum radius R1 of the first end 4621 can be the same as the addendum radius R2 of the second end 4622. That is, in the radial direction of the first gear 46, the first top edge A1 and the second top edge A2 are arranged to coincide with each other, wherein the radial direction of the first gear 46 is a direction perpendicular to the rotational centerline of the first gear 46.

[0256] It can be understood that by making the tooth top circle radius R1 of the first end 4621 and the tooth top circle radius R2 of the second end 4622 the same, the first tooth top surface 4623 can be made flat, and the first tooth top surface 4623 has better flatness.

[0257] In this embodiment, in the circumferential direction of the second gear 47, the fifth side C5 and the sixth side C6 of the third side surface 4724 may be staggered, and the seventh side C7 and the eighth side C8 of the fourth side surface 4725 may be overlapped. Alternatively, in the circumferential direction of the second gear 47, the fifth side C5 and the sixth side C6 of the third side surface 4724 may be overlapped, and the seventh side C7 and the eighth side C8 of the fourth side surface 4725 may be staggered.

[0258] The fifth side C5 and the sixth side C6 of the third side surface 4724 are staggered in the circumferential direction of the second gear 47, meaning that the fifth side C5 and the sixth side C6 of the third side surface 4724 do not overlap in the circumferential direction of the second gear 47, but are arranged sequentially. The seventh side C7 and the eighth side C8 of the fourth side surface 4725 are staggered in the circumferential direction of the second gear 47, meaning that the seventh side C7 and the eighth side C8 of the fourth side surface 4725 do not overlap in the circumferential direction of the second gear 47, but are arranged sequentially.

[0259] In one possible implementation, please refer to Figure 20b and Figure 22 , Figure 22 yes Figure 19 The diagram shows an angled structural diagram of the second gear 47 of the synchronous gear 43. In the circumferential direction of the second gear 47, the fifth side C5 and the sixth side C6 of the third side surface 4724 can be arranged to overlap, and the seventh side C7 and the eighth side C8 of the fourth side surface 4725 can be arranged to be staggered.

[0260] It can be understood that by aligning the fifth and sixth sides C5 and C6 of the third side surface 4724 circumferentially with the second gear 47, and staggering the seventh and eighth sides C7 and C8 of the fourth side surface 4725 circumferentially with the second gear 47, the third side surface 4724 can be flat, while the fourth side surface 4725 can be inclined at a predetermined angle. This arrangement facilitates the second gear 47 to exhibit a structure with a thicker tooth at one end and a thinner tooth at the other end, thereby enabling the second gear 47 to exhibit a single radial displacement of a single side of the fourth side surface 4725. This single radial displacement of the second gear 47 not only facilitates demolding, but also improves its load-bearing capacity, wear resistance, machining accuracy, and installation precision, optimizes the gear ratio and speed adaptability, and facilitates a good overlap and meshing effect for the synchronous gear 43.

[0261] In addition, the addendum radius R3 of the third end 4721 can be the same as the addendum radius R4 of the fourth end 4722. That is, in the radial direction of the second gear 47, the third top edge A3 and the fourth top edge A4 are arranged to coincide with each other, wherein the radial direction of the second gear 47 is a direction perpendicular to the rotation centerline of the second gear 47.

[0262] It can be understood that by making the tooth top circle radius R3 of the third end 4721 different from the tooth top circle radius R4 of the fourth end 4722, the second tooth top surface 4723 can be made flat, and the second tooth top surface 4723 has better flatness.

[0263] Please refer to Figure 23a 、 Figure 23b 、 Figure 23c and Figure 23d , Figure 23a yes Figure 19 A schematic diagram of a first tooth tip thickness variation trend of the second embodiment of the synchronous gear 43 is shown, Figure 23b yes Figure 19 A schematic diagram of a second tooth tip thickness variation trend of the second embodiment of the synchronous gear 43 is shown, Figure 23c yes Figure 19 A schematic diagram of the third tooth tip thickness variation trend of the second embodiment of the synchronous gear 43 is shown, Figure 23d yes Figure 19 The fourth tooth top thickness variation trend of the second embodiment of the synchronous gear 43 is shown in FIG. Figure 23a-23d In the figure, the changing trend of the tooth top thickness of the first tooth 462 is illustrated by taking the changing trend of the tooth top thickness of the first tooth top surface 4623 of the first tooth 462 as an example, and the changing trend of the tooth top thickness of the second tooth 472 is illustrated by taking the changing trend of the tooth top thickness of the second tooth top surface 4723 of the second tooth 472 as an example, but it is not limited to this.

[0264] It should be understood that in this embodiment, the variation trend of the tooth top thickness of the second tooth 472 is opposite to the variation trend of the tooth top thickness of the first tooth 462, including at least the following situations:

[0265] 1. Such as Figure 23a As shown, the tooth top thickness of the first tooth 462 may gradually increase from the first end 4621 to the second end 4622 , and the tooth top thickness of the second tooth 472 may gradually decrease from the third end 4721 to the fourth end 4722 .

[0266] For example, the tooth top thickness D1 of the first end 4621 may be smaller than the tooth top thickness D2 of the second end 4622. The tooth top thickness D3 of the third end 4721 may be larger than the tooth top thickness D4 of the fourth end 4722. The tooth top thickness D1 of the first end 4621 may be the same as the tooth top thickness D4 of the fourth end 4722. The tooth top thickness D2 of the second end 4622 may be the same as the tooth top thickness D3 of the third end 4721. Of course, in other application scenarios, the tooth top thickness D1 of the first end 4621 may be different from the tooth top thickness D4 of the fourth end 4722. The tooth top thickness D2 of the second end 4622 may be different from the tooth top thickness D3 of the third end 4721.

[0267] 2. If Figure 23b As shown, the tooth top thickness of the first tooth 462 may gradually decrease from the first end 4621 to the second end 4622 , and the tooth top thickness of the second tooth 472 may gradually increase from the third end 4721 to the fourth end 4722 .

[0268] For example, the tooth top thickness D1 of the first end 4621 may be greater than the tooth top thickness D2 of the second end 4622. The tooth top thickness D3 of the third end 4721 may be less than the tooth top thickness D4 of the fourth end 4722. The tooth top thickness D1 of the first end 4621 may be the same as the tooth top thickness D4 of the fourth end 4722. The tooth top thickness D2 of the second end 4622 may be the same as the tooth top thickness D3 of the third end 4721. Of course, in other application scenarios, the tooth top thickness D1 of the first end 4621 may be different from the tooth top thickness D4 of the fourth end 4722. The tooth top thickness D2 of the second end 4622 may be different from the tooth top thickness D3 of the third end 4721.

[0269] 3. If Figure 23cAs shown, the tooth top thickness of the first tooth 462 first increases and then decreases from the first end 4621 to the second end 4622 , and the tooth top thickness of the second tooth 472 first decreases and then increases from the third end 4721 to the fourth end 4722 .

[0270] For example, the tooth top thickness D1 of the first end 4621 may be equal to the tooth top thickness D2 of the second end 4622. The tooth top thickness D3 of the third end 4721 may be equal to the tooth top thickness D4 of the fourth end 4722. The tooth top thickness D1 of the first end 4621 may be different from the tooth top thickness D4 of the fourth end 4722. The tooth top thickness D2 of the second end 4622 may be different from the tooth top thickness D3 of the third end 4721. Of course, in other application scenarios, the tooth top thickness D1 of the first end 4621 may be smaller than or larger than the tooth top thickness D2 of the second end 4622. The tooth top thickness D3 of the third end 4721 may be larger than or smaller than the tooth top thickness D4 of the fourth end 4722. The tooth top thickness D1 of the first end 4621 may be the same as the tooth top thickness D4 of the fourth end 4722. The tooth top thickness D2 of the second end 4622 may be the same as the tooth top thickness D3 of the third end 4721.

[0271] 4. If Figure 23d As shown, the tooth top thickness of the first tooth 462 first decreases and then increases from the first end 4621 to the second end 4622 , and the tooth top thickness of the second tooth 472 first increases and then decreases from the third end 4721 to the fourth end 4722 .

[0272] For example, the tooth tip thickness D1 at the first end 4621 may be equal to the tooth tip thickness D2 at the second end 4622. The tooth tip thickness D3 at the third end 4721 may be equal to the tooth tip thickness D4 at the fourth end 4722. The tooth tip thickness D1 at the first end 4621 may be different from the tooth tip thickness D4 at the fourth end 4722. The tooth tip thickness D2 at the second end 4622 may be different from the tooth tip thickness D3 at the third end 4721.

[0273] It should be noted that the changing trend of the tooth top thickness of the first tooth 462 and the changing trend of the tooth top thickness of the second tooth 472 are not limited to the several cases listed above. The implementation methods that can satisfy the opposite trend of the changing trend of the tooth top thickness of the second tooth 472 and the changing trend of the tooth top thickness of the first tooth 462 are all within the scope of protection requested by this embodiment, and no strict restrictions are imposed on this.

[0274] With reference to the above two embodiments, it should be understood that the structural improvement of the synchronization component 40 of the rotating shaft mechanism 100 provided in the embodiment of the present application is not only applicable to the scenario where the electronic device 200 is folded outward, but also applicable to the scenario where the electronic device 200 is folded inward. When the synchronization component 40 is used in the scenario where the electronic device 200 is folded inward, the synchronization component 40 may include more gears than the two gears described above. For example, the synchronization component 40 may include four gears, namely, two first gears 46 and two second gears 47, wherein the first gears 46 and the second gears 47 are alternately arranged and meshed in sequence. The structural arrangement of the first gear 46 and the second gear 47 can be referred to the above description and will not be repeated here. Of course, in other embodiments, the synchronization component 40 may also include six gears, namely, three first gears 46 and three second gears 47, wherein the first gears 46 and the second gears 47 are alternately arranged and meshed in sequence.

[0275] It should be noted that the embodiment of the present application does not limit the number of gears in the synchronization assembly 40. It only requires that the synchronization assembly 40 includes an even number of gears, and the first gear 46 and the second gear 47 are alternately arranged and meshed in sequence.

[0276] The above is a detailed introduction to the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for those skilled in the art, according to the idea of ​​the present application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A rotating shaft mechanism, characterized in that: The rotating shaft mechanism comprises: middle beam; a synchronous gear, comprising a first gear and a second gear, wherein the first gear and the second gear are both mounted on the center beam and arranged in sequence along the width direction of the center beam, and the first gear is meshed with the second gear; The first gear includes a plurality of first teeth, the plurality of first teeth are spaced apart along a circumferential direction of the first gear, the first teeth include a first end and a second end, the first end and the second end are oppositely arranged in a tooth width direction of the first teeth; The second gear includes a plurality of second teeth, the plurality of second teeth being spaced apart along a circumferential direction of the second gear, the plurality of second teeth being configured to mesh with the plurality of first teeth, the second teeth including a third end and a fourth end, the third end and the fourth end being arranged opposite to each other in a tooth width direction of the second teeth, the third end and the first end being located on one side of the synchronous gear, and the fourth end and the second end being located on the other side of the synchronous gear; The tooth tip thickness of the first tooth gradually changes from the first end to the second end, the tooth tip thickness of the second tooth gradually changes from the third end to the fourth end, and the changing trend of the tooth tip thickness of the second tooth is opposite to the changing trend of the tooth tip thickness of the first tooth; and A first swing arm and a second swing arm, wherein the first swing arm and the second swing arm are respectively located on both sides of the width direction of the center beam, the first swing arm is fixedly connected to the first gear, and the second swing arm is fixedly connected to the second gear.

2. The rotating shaft mechanism according to claim 1, wherein: The first tooth further includes a first tooth top surface connected between the first end and the second end, the first tooth top surface including a first top edge located at the first end and a second top edge located at the second end, and the length of the first top edge is different from the length of the second top edge; The second tooth includes a second tooth top surface, which is connected between the third end and the fourth end. The second tooth top surface includes a third top edge located at the third end and a fourth top edge located at the fourth end. The length of the third top edge is different from the length of the fourth top edge. The relationship between the length of the first top edge and the length of the second top edge is opposite to the relationship between the length of the third top edge and the length of the fourth top edge.

3. The rotating shaft mechanism according to claim 2, wherein: The length of the first top side is greater than the length of the second top side, the first tooth has a first draft angle θ1, the length of the first top side is S1, the length of the second top side is S2, the tooth width of the first tooth is B1, and the first draft angle θ1, the length of the first top side S1, the length of the second top side S2, and the tooth width B1 of the first tooth satisfy the relationship: tanθ1 = (S1-S2) / B1.

4. The rotating shaft mechanism according to claim 3, wherein: The first draft angle θ1 may be in the range of 3° to 30°.

5. The rotating shaft mechanism according to any one of claims 1 to 4, characterized in that: The first tooth further includes a first side surface and a second side surface, the first side surface and the second side surface are both connected between the first end and the second end and are arranged opposite to each other in the circumferential direction of the first gear, the first side surface includes a first side edge located at the first end and a second side edge located at the second end, and the second side surface includes a third side edge located at the first end and a fourth side edge located at the second end; In the circumferential direction of the first gear, the first side and the second side are staggered, and the third side and the fourth side are overlapped, or, in the circumferential direction of the first gear, the first side and the second side are overlapped, and the third side and the fourth side are staggered.

6. The rotating shaft mechanism according to any one of claims 1 to 4, characterized in that: The first tooth further includes a first side surface and a second side surface, the first side surface and the second side surface are both connected between the first end and the second end and are arranged opposite to each other in the circumferential direction of the first gear, the first side surface includes a first side edge located at the first end and a second side edge located at the second end, and the second side surface includes a third side edge located at the first end and a fourth side edge located at the second end; In the circumferential direction of the first gear, the first side and the second side are staggered, the third side and the fourth side are staggered, and the minimum distance between the first side and the third side is less than or greater than the minimum distance between the second side and the fourth side.

7. The rotating shaft mechanism according to any one of claims 1 to 4, characterized in that: The addendum radius of the first end is different from the addendum radius of the second end.

8. The rotating shaft mechanism according to any one of claims 1 to 4, characterized in that: The synchronous gear includes a first rotating shaft, a second rotating shaft, a first limiting member and a second limiting member; The first rotating shaft and the second rotating shaft are both mounted on the center beam and are arranged opposite to each other along the width direction of the center beam and are capable of rotating relative to the center beam. The first gear is sleeved on the outer periphery of the first rotating shaft and is fixedly connected to the first rotating shaft. The second gear is sleeved on the outer periphery of the second rotating shaft and is fixedly connected to the second rotating shaft. The first limiting member is sleeved on one end of the first rotating shaft and one end of the second rotating shaft, and is elastically connected between the middle beam and one end of the first gear and one end of the second gear; The second limiting member is sleeved on the other end of the second rotating shaft and the other end of the second rotating shaft, and is elastically connected between the middle beam and the other end of the first gear and the other end of the second gear.

9. The rotating shaft mechanism according to claim 8, wherein: The first limiting member includes a first connecting portion, a first elastic portion and a second elastic portion, the first connecting portion is connected between the first elastic portion and the second elastic portion, the first elastic portion is wound around the first rotating shaft and extends spirally along the axial direction of the first rotating shaft, the second elastic portion is wound around the second rotating shaft and extends spirally along the axial direction of the second rotating shaft, and the rotation direction of the second elastic portion is opposite to that of the first elastic portion.

10. An electronic device, characterized in that: The electronic device includes a first shell, a second shell, and the hinge mechanism according to any one of claims 1 to 9, wherein the hinge mechanism is connected between the first shell and the second shell.

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