A foldable electronic device

Abstract

This application provides a foldable electronic device, including: a shaft cover, a body rotatable about a rotation axis within the shaft cover, a first cam component, and a second cam component; the first cam component and the second cam component are disposed within the shaft cover along the rotation axis direction, forming pressure contact; the first cam component is connected to the body via a swing arm and is configured to rotate about its central axis; the second cam component is configured to slide along the central axis direction; the contact surface between the first cam component and the second cam component includes at least one mutually cooperating cam profile, and the cam profile includes a locking section, the angle between the normal direction of the locking section and the central axis is less than or equal to the arctangent function of μ, where μ is the friction coefficient between the first cam component and the second cam component, and the resultant force on the wheel drive component in its rotation direction is 0, therefore the body will not automatically unfold or close, achieving the freestop characteristic.

Description

[0001] This application is a divisional application. The original application has the application number 202111647992.3 and the original application date is December 30, 2021. The entire contents of the original application are incorporated herein by reference. Technical Field

[0002] This application relates to the field of terminal technology, and more particularly to a foldable electronic device. Background Technology

[0003] In recent years, with the continuous development of screen technology, especially the emergence of flexible screens, electronic devices have been able to develop more product forms, and foldable screen phones are a new type of product form. Foldable screen phones generally include a hinge cover and a body located on both sides of the hinge cover. Each side of the body can be connected to the hinge cover through at least one swing arm. The swing arm can rotate around a rotation axis inside the hinge cover. When the user applies force to the body to rotate it, the body can rotate around the rotation axis, realizing unfolding and folding.

[0004] In order to provide a certain damping force when the user opens and closes the body to improve the feel, a damping component connected to the swing arm is also provided inside the shaft cover. The damping component includes a pair of cam components that make pressure contact along the rotation axis. The damping force is provided by the surface design of the cam components and the friction generated by the pressure contact. The pressure that enables the cam components to make pressure contact is provided by the elastic force generated by the deformation of the spring set in the shaft cover.

[0005] Currently, engineers hope that foldable phones will possess a freestop feature, meaning the phone's body can remain in its current position without external force, thus improving the user experience. One feasible way to achieve freestop is to increase the coefficient of friction of the damping system. The coefficient of friction is related to the number and size of the springs: more springs result in a higher coefficient of friction, and vice versa; larger springs also result in a higher coefficient of friction, and vice versa. Therefore, current foldable phones typically achieve freestop by increasing the number and diameter of springs. However, with the increase in the number and size of springs, the springs occupy more space in the body, leading to an increase in the overall thickness and weight of the foldable phone, which is detrimental to achieving a slim and lightweight design. Summary of the Invention

[0006] This application provides a foldable electronic device that achieves freestop functionality while maintaining a slim and lightweight design. The foldable electronic device includes: a shaft cover, a body, a swing arm, a first cam component, a second cam component, and an elastomer; the first cam component and the second cam component are coaxially disposed within the shaft cover; the first cam component is connected to the body via the swing arm and is configured to rotate about its central axis, allowing the body to fold or unfold about the central axis under external force; the first cam component includes a first end face facing the second cam component, and the second cam component includes a second end face facing the first cam component, both the first and second end faces including at least one cam profile; the second cam component is configured to slide along the central axis; the elastomer is connected to the second cam component and configured to apply an elastic force to the second cam component, causing the first end face of the first cam component to remain in contact with the second end face of the second cam component under the action of the elastic force; when the body is unfolded or folded to a position between fully unfolded and fully folded, the first cam component and the second cam component contact a locking section of the cam profile, the angle between the normal direction of the locking section and the central axis being less than or equal to arctanμ, where μ is the coefficient of friction between the first cam component and the second cam component.

[0007] The foldable electronic device provided in this application embodiment has a contact surface between the first cam component and the second cam component, which includes at least one mutually cooperating cam profile. The cam profile includes a locking section. The angle between the normal direction of the locking section and the central axis is less than or equal to the arctangent function of μ, where μ is the friction coefficient between the first cam component and the second cam component. The resultant force on the wheel drive component in its rotation direction is 0, so the body will not automatically unfold or close, thus achieving the freestop characteristic.

[0008] In one implementation, the first end face and the second end face are mating annular end faces; both the first end face and the second end face include an equal number of cam profiles, and the multiple cam profiles are distributed in a circular array. This results in a more uniform force distribution on the first cam component and the second cam component along the central axis C1, improving the service life of the components.

[0009] In one implementation, the angle β through which the locking segment rotates about the central axis C1 is greater than or equal to 90°. Since the angle of rotation of each side of the foldable phone from fully folded to fully unfolded is 90°, if the angle β through which the locking segment rotates about the central axis C1 is greater than or equal to 90°, the first cam component and the second cam component can always be in contact with the locking segment during the folding or unfolding process of the phone, so that the phone has freestop characteristics at any position.

[0010] In one implementation, the cam profile includes a push-stroke section and a return section, with a locking section being a part of the push-stroke section. The locking section includes multiple locking planes along the lifting direction of the push-stroke section, and the angle between the normal direction of any locking plane and the central axis is less than or equal to arctanμ. Thus, as the fuselage rotates to different positions, the first cam component and the second cam component can achieve surface contact on different locking planes. While possessing freestop characteristics, this surface contact also reduces the contact stress between the first and second cam components, thereby improving their service life.

[0011] In one implementation, the angles between the normal directions of multiple locking planes and the central axis decrease sequentially along the lifting direction of the push stroke. This allows the slope of the push stroke to gradually flatten along its lifting direction, ultimately achieving a smooth transition between the top of the push stroke and the return stroke.

[0012] In one implementation, the lengths of multiple locking planes decrease sequentially in the lifting direction of the push stroke. This allows the locking planes to be divided more finely as the slope of the push stroke gradually flattens in its lifting direction, resulting in a smoother slope change at the top of the push stroke and improving the user's feel when rotating the machine.

[0013] In one implementation, adjacent locking planes are connected by a curved transition. This allows the contact surfaces of the first and second cam components to smoothly transition between the locking planes when the user rotates the device, preventing vibrations when sliding between adjacent locking planes and improving the user's feel when rotating the device.

[0014] In one implementation, the locking section begins in the lower middle part of the push-stroke section and extends along the lifting direction of the push-stroke section to the top of the cam profile, where it connects with the return section. Thus, compared to conventional solutions, the locking section effectively covers most of the push-stroke section and the entire stop section. When the electronic device's body rotates from a fully folded state to a fully unfolded state, the first and second cam components can maintain full contact with the locking section, achieving the freestop characteristic.

[0015] In one implementation, the locking section and the return section are connected by a curved surface. This allows the contact surfaces of the first and second cam components to smoothly transition between the locking and return sections when the user rotates the machine body, preventing vibration during the transition and improving the user's feel when rotating the machine body.

[0016] In one implementation, the length of the locking segment is greater than half that of the push segment.

[0017] In one implementation, the elastic body is a spring, which is coaxially arranged with the second cam component and is in a compressed state along the central axis direction to apply an elastic force to the second cam component along the central axis direction.

[0018] In one implementation, the locking segment is disposed on at least one cam profile of the first end face and / or the second end face. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a current form factor for foldable screen phones;

[0020] Figure 2 This is a schematic diagram of the internal structure of a current foldable screen phone;

[0021] Figure 3 This is a schematic diagram of a current cam profile;

[0022] Figure 4 This is a force analysis diagram of the driving and driven components of the cam.

[0023] Figure 5 This is a partial structural schematic diagram of the foldable electronic device provided in the embodiments of this application;

[0024] Figure 6 This is a schematic diagram of the contact surface structure shown in an embodiment of this application;

[0025] Figure 7 This is a schematic diagram of the cam profile structure shown in the embodiments of this application;

[0026] Figure 8 This is a schematic diagram showing the contact between the cam drive member and the cam follower member in the locking section, as illustrated in an embodiment of this application.

[0027] Figure 9 This is a force analysis diagram of the cam driving element and the cam driven element when they are in contact with the locking section;

[0028] Figure 10 This is a schematic diagram illustrating the distribution of the cam profile on the annular end face according to an embodiment of this application.

[0029] Illustration:

[0030] Wherein: 10-body, 11-display screen, 20-shaft cover, 30-swing arm, 40-damping component, 41-cam drive component, 42-cam follower component, 43-spring, 50-cam profile, 51-push stroke section, 52-stop section, 53-return section, 100-first cam component, 200-second cam component, 300-elastic body, 400-cam profile, 410-push stroke section, 411-locking section, 412-locking plane, 420-return section, 413-curved surface, 414-curved surface. Detailed Implementation

[0031] In recent years, with the continuous development of screen technology, especially the emergence of flexible screens that can be bent at will, electronic devices have been able to develop more product forms, among which foldable screen phones are a new type of product form.

[0032] Figure 1 This is a schematic diagram of a current form factor for foldable screen phones. (For example...) Figure 1 As shown, foldable phones can currently be categorized into inward-folding and outward-folding phones based on their screen bending direction. Among them, inward-folding phones include... Figure 1 As shown in structure a, outward-folding screen phones are like... Figure 1 As shown in structure b, the body 10 of the inward-folding screen phone can fold towards the display screen 11. After the body 10 is folded, the display screen 11 is hidden inside the body 10, thus creating the effect that the display screen 11 is hidden when the body 10 is folded and is displayed when the body 10 is unfolded. The body 10 of the outward-folding screen phone can fold towards the back of the display screen 11. After the body 10 is folded, the display screen 11 wraps around the outside of the body 10, thus creating a wraparound screen when the body 10 is folded and a normal flat screen when the body 10 is unfolded.

[0033] Figure 2 This is a schematic diagram of the internal structure of a current foldable screen phone. Below is a combination of... Figure 2 This provides an example of how the body of a current foldable phone folds or unfolds. For example... Figure 2 As shown, the foldable screen phone includes a hinge cover 20 and a body 10. For a foldable screen phone capable of folding in half, the body 10 may include two parts, respectively disposed on both sides of the hinge cover 20. Each side of the body 10 can be connected to the hinge cover 20 via at least one swing arm 30. One end of the swing arm 30 is located inside the hinge cover 20 and is configured to rotate about a rotation axis within the hinge cover 20. The other end of the swing arm 30 extends to one side of the body 10 and connects to it. Thus, when a user applies force to the body 10 to rotate it, the body 10 can rotate about the rotation axis, achieving unfolding and folding.

[0034] In addition, to provide a certain damping force when the user opens and closes the body 10 to improve the feel, a damping component 40 connected to the swing arm 30 is also provided inside the shaft cover 20. This damping component 40 can be, for example, a cam damping component or a gear damping component, and is used to apply a damping force opposite to the direction of rotation to the swing arm 30 when the body 10 drives the swing arm 30 to rotate. This damping force can be transmitted to the user's hand through the swing arm 30 and the body 10, thereby improving the user's feel and the premium feel of the device.

[0035] Figure 2 The specific structure of the damping component is also illustrated by way of example. For example... Figure 2 As shown, the damping component 40 includes a cam drive member 41, a cam follower member 42, and a spring 43. The rocker arm 30 rotates around the central axis C1 of the cam drive member 41. The cam drive member 41 and the cam follower member 42 are arranged side-by-side and coaxially along the central axis C1. The cam drive member 41 is connected to one end of the rocker arm 30 located within the shaft cover 20, and is configured to be fixed along the central axis C1 but rotatable about it. The cam follower member 42 is configured not to rotate about the central axis C1 but can slide along it. Spring 43 is connected to cam follower 42 and is configured to apply elastic force Ft to cam follower 42. The direction of elastic force Ft can be parallel to the central axis C1 and toward cam drive 41. In this way, cam follower 42 can maintain pressure contact with cam drive 41 along the central axis C1 under the action of elastic force Ft. When the user rotates the body 10, the swing arm 30 drives cam drive 41 to rotate around the central axis C1, thereby generating relative sliding between cam follower 42 and cam drive 42 on their contact surface.

[0036] To provide damping force, the contact surfaces of the cam drive member 41 and the cam follower member 42 may include mutually mating cam profiles 50. Figure 3 This is a schematic diagram of a current cam profile 50. In Figure 3 In the process, when the body of the foldable screen device unfolds from the folded state, the cam drive member 41 moves relative to the cam follower member 42 towards... Figure 3 Sliding to the left, the cam follower 42 moves relative to the cam driver 41 towards Figure 3 Slide to the right in the middle. For example... Figure 3As shown, the cam profile 50 includes, in sequence along the sliding direction of the cam drive member 41 or the cam follower member 42: push stroke section 51, stop section 52 and return stroke section 53. The push segment, stop segment, and return segment are technical terms used in the mechanical field to describe cam structures. Specifically: the push segment 51 refers to the section where the cam follower 42 moves away from the cam drive member 41 when the cam drive member 41 slides relative to the cam follower 42. Therefore, the push segment 51 has a certain upward angle in the sliding direction of the cam drive member 41 / cam follower 42. The stop segment 52 refers to the section where the distance between the cam follower 42 and the cam drive member 41 remains unchanged when the cam drive member 41 slides relative to the cam follower 42. Therefore, the stop segment 52 is perpendicular to the central axis C1. The return segment 53 refers to the section where the cam follower 42 moves closer to the cam drive member 41 when the cam drive member 41 slides relative to the cam follower 42. Therefore, the return segment 53 has a certain downward angle in the sliding direction of the cam drive member 41 / cam follower 42. Generally, when the body of a foldable phone rotates between a fully folded state and a fully unfolded state, the cam drive member 41 and the cam follower member 42 will form pressure contact and slide in the push section 51 or stop section 52 of the cam profile.

[0037] Figure 4 This is a force analysis diagram of the cam drive member and the cam follower member. When the cam drive member 41 and the cam follower member 42 contact the push section 51 of the cam profile, the cam follower member 42 will apply a pressure Fn to the cam drive member 41 under the action of the elastic force Ft. This pressure Fn acts in the normal direction of the push section 51 of the cam drive member 41, and Fn = Ft × cosα, where Ft is the elastic force of the spring, and α is the angle between the normal direction of the push section 51 and the elastic force Ft. In this way, Fn will generate a component Fn × sinα in the opposite direction of the sliding of the cam drive member 41. This component is part of the damping force. When the user rotates the machine body, the force applied to the machine body needs to overcome this component to make the cam drive member 41 rotate.

[0038] Further as Figure 4As shown, when the cam drive member 41 and the cam follower member 42 contact the push stroke section 51, the elastic force Ft acting on the cam follower member 42 has a component of Ft×sinα in the tangential direction of the push stroke section 51, and a component of Ft in the normal direction of the push stroke section is Ft×cosα. Therefore, under the action of Ft×sinα, the cam follower member 42 will have a tendency to slide along the tangential direction of the push stroke section 51. At this time, under the action of Ft×cosα, the cam follower member 42 will be subjected to a frictional force Fm in the opposite direction to Ft×sinα. This frictional force Fm is used to prevent the cam follower member 42 from sliding along the tangential direction of the push stroke section. According to mechanics, the magnitude of the frictional force Fm is related to the coefficient of friction μ between the cam drive member 41 and the cam follower member 42 (the coefficient of friction μ here integrates the system friction of the overall shaft structure used to realize the rotation of the body in the foldable screen phone) and the motion state of the cam drive member 41 and the cam follower member 42. When the cam follower member 42 is stationary relative to the cam drive member 41, the frictional force Fm exists in the form of static friction, its magnitude is equal to Ft×sinα and its direction is opposite, but not greater than μ×Fn (i.e., μ×Ft×cosα). When the cam follower member 42 slides relative to the cam drive member 41, the frictional force Fm exists in the form of sliding friction, its magnitude is equal to μ×Ft×cosα, and its direction is opposite to the sliding direction of the cam follower member 42.

[0039] Currently, engineers hope that foldable screen phones can possess the freestop characteristic, meaning that the foldable screen phone's body can remain in its current position when no external force is applied. According to mechanics, when Ft×sinα>μ×Ft×cosα, it means that the maximum static friction between the cam drive member 41 and the cam follower member 42 in the push stroke section 51 is less than Ft×sinα, insufficient to allow the cam follower member 42 to achieve force balance along the tangential direction of the push stroke section 51. Therefore, the cam follower member 42 will slide relative to the cam drive member 41, failing to achieve the freestop characteristic. When Ft×sinα≤μ×Ft×cosα, the maximum static friction between the cam drive member 41 and the cam follower member 42 in the push stroke section 51 is greater than or equal to Ft×sinα, allowing the cam follower member 42 to achieve force balance along the tangential direction of the push stroke section 51. Therefore, the cam drive member 41 and the cam follower member 42 will remain relatively stationary, achieving the freestop characteristic.

[0040] Based on the conditions for achieving the FreeStop characteristic mentioned above, increasing the coefficient of friction μ to ensure that Ft×sinα ≤ μ×Ft×cosα is a feasible approach. In damping components, the coefficient of friction μ is related to the number and size of the springs: more springs result in a higher coefficient of friction, and fewer springs result in a lower coefficient of friction; larger spring sizes result in a higher coefficient of friction, and smaller spring sizes result in a lower coefficient of friction. Therefore, current foldable phones typically increase the number and diameter of springs to achieve a higher coefficient of friction μ and thus the FreeStop characteristic. However, with the increase in the number and size of springs, the space occupied by the springs increases, leading to an increase in the overall thickness and weight of the foldable phone, which is detrimental to achieving a slim and lightweight design.

[0041] This application provides an improved foldable electronic device that achieves FreeStop functionality while maintaining a slim and lightweight design. This electronic device can be, for example, a foldable phone, tablet, laptop, e-reader, wireless earphone case, wearable device (e.g., virtual reality VR glasses, smartwatch, smart bracelet, head-mounted display), an electronic device with two or more parts connected by a hinge structure, or other electronic devices of various forms; no specific limitations are imposed here.

[0042] Figure 5 This is a partial structural schematic diagram of the foldable electronic device provided in an embodiment of this application. For example... Figure 5As shown, the electronic device includes: a body 10, a shaft cover 20, a swing arm 30, a first cam component 100, a second cam component 200, and an elastic body 300. The first cam component 100 and the second cam component 200 can be cylindrical structures, coaxially and side-by-side arranged within the shaft cover 20. The first cam component 100 can be, for example, a cam drive, and the second cam component 200 can be, for example, a cam follower. The first cam component 100 is configured to be fixed along its central axis C1, but can rotate around its central axis C1. The first cam component 100 is connected to the body 10, which is located on one side of the shaft cover 20, via the swing arm 30. Thus, when a user applies a certain bending force to the body 10, the body 10 can drive the swing arm 30 to rotate around the central axis C1 of the first cam component 100, thereby enabling the body 10 to unfold or fold around the central axis C1. The second cam component 200 is configured to be fixed in a direction perpendicular to the central axis C1, but can slide along the central axis C1. The elastic body 300 is connected to the second cam component 200 and is configured to apply an elastic force Ft to the second cam component 200. The direction of the elastic force Ft is parallel to the central axis C1 and toward the first cam component 100. In this way, the second cam component 200 can maintain pressure contact with the first cam component 100 along the central axis C1 under the action of the elastic force Ft. When the first cam component 100 rotates around the central axis C1, the first cam component 100 and the second cam component 200 will slide relative to each other on their contact surfaces.

[0043] Further as Figure 5 As shown, the contact surfaces of the first cam component 100 and the second cam component 200 may include at least one mating cam profile 400, which includes a locking section 411. Figure 5 (The section with thickened lines in the middle), and the angle α between the normal direction of the locking section 411 and the central axis C1 is less than or equal to the arctangent function of μ, that is, α≤arctanμ, where μ refers to the friction coefficient between the first cam component 100 and the second cam component 200, which integrates the system friction of the overall shaft structure used to realize the rotation of the body in the electronic device.

[0044] Thus, when the first cam component 100 and the second cam component 200 are in contact at the locking section 411, since α≤arctanμ, the tangential component Ft×sinα and the normal component Ft×cosα of the elastic force Ft at the locking section 411 can satisfy Ft×sinα≤μ×Ft×cosα. The maximum static friction force between the first cam component 100 and the second cam component 200 at the locking section 411 is greater than or equal to Ft×sinα, so that the second cam component 200 reaches force balance along the tangential direction of the locking section 411. Therefore, the first cam component 100 and the second cam component 200 will remain relatively stationary, realizing the freestop characteristic.

[0045] In this embodiment, the elastic body 300 can be a spring, a sheet spring, or other component that can generate elastic force through deformation. When the elastic body 300 is implemented using a spring, the spring is disposed at the end of the second cam component 200 opposite to the first cam component 100 and is coaxially disposed with the second cam component 200. One end of the spring is in contact with the second cam component 200 and is configured in a compressed state along the central axis C1. In this way, the spring can apply an elastic force Ft to the second cam component 200 along the central axis C1. The elastic force Ft is proportional to the compression of the spring, i.e., Ft = kx, where k is the spring constant and x is the compression of the spring.

[0046] Figure 6 This is a schematic diagram of the contact surface structure shown in an embodiment of this application. For example... Figure 6 As shown, the first cam component 100 and the second cam component 200 may include mating annular end faces. For ease of description, the annular end face of the first cam component 100 is referred to as the first end face 110, and the annular end face of the second cam component 200 is referred to as the second end face 210. The first end face 110 and the second end face 210 may include an equal number of cam profiles 400. Figure 6 (Represented by shading of different depths), and multiple cam surfaces 400 are connected end to end in sequence and arranged in a circular array around the central axis C1. When the first end face 110 and the second end face 210 include an equal number of cam surfaces 400, the multiple cam surfaces 400 located on the first end face 110 can form pressure contact with the multiple cam surfaces 400 located on the second end face 210 in a one-to-one correspondence. When the first cam component 400 rotates around the central axis C1, the first cam component 100 and the second cam component 200 will undergo relative torsion around the central axis C1, thereby generating relative sliding.

[0047] Further as Figure 6As shown, in one implementation, the first end face 110 and the second end face 210 can each include three cam profiles 400, with an included angle of 120° between two adjacent cam profiles 400. Thus, the projection of each cam profile 400 along the central axis C1 is an arc with a central angle of 120°, and each cam profile 400 constitutes one-third of the annular end face. The first end face 110 and the second end face 210 can uniformly form three pressure contacts around the central axis C1, making the force on the first cam component 100 and the second cam component 200 more uniform along the central axis C1, thereby improving the service life of the components.

[0048] Figure 7 This is a schematic diagram of the structure of the cam profile 400 shown in the embodiment of this application.

[0049] Figure 8 This is a schematic diagram showing the first cam component 100 and the second cam component 200 contacting the locking section 411, as illustrated in an embodiment of this application.

[0050] To facilitate the description of the structure of the cam profile 400, Figure 7 and Figure 8 The cam profile 400 was expanded from an arc shape.

[0051] Combination Figure 7 and Figure 8 As shown, in one implementation, the cam profile 400 sequentially includes a push-stroke section 410 and a return section 420 along the sliding direction of the first cam component 100 or the second cam component 200. Specifically: the push-stroke section 410 refers to the section where the second cam component 200 moves away from the first cam component 100 when the first cam component 100 slides relative to the second cam component 200; the push-stroke section 410 has a certain upward angle along the sliding direction of the second cam component 200 relative to the first cam component 100. The return section 420 refers to the section where the second cam component 200 moves closer to the first cam component 100 when the first cam component 100 slides relative to the second cam component 200; the return section 420 has a certain downward angle along the sliding direction of the second cam component 200 relative to the first cam component 100.

[0052] and Figure 3 Compared to the cam profile shown, the embodiments of this application... Figure 7 and Figure 8 The cam profile 400 shown includes only the push section 410 and the return section 420, but not the stop section. The push section 410 is directly connected to the return section 420. Figure 7 and Figure 8 The cam profile 400 shown can be considered as being in Figure 3Based on the cam profile 400 shown, the push segment 410 is extended into the area of ​​the original stop segment, replacing the original stop segment, thereby increasing the length of the push segment 410. While keeping the lifting height of the push segment 410 unchanged, increasing the length of the push segment 410 helps to make the slope of the push segment 410 gentler and reduces the angle α between the normal direction of the push segment 410 and the central axis C1.

[0053] In this embodiment of the application, the locking segment 411 (in) Figure 7 The middle is indicated by shading, in Figure 8 (Indicated by a solid line) can extend along the lifting direction of the thrust segment 410, starting from the lower middle part of the thrust segment 410 and continuing to the top of the thrust segment 410, and connecting with the return segment 420 at the top of the thrust segment 410. Compared to Figure 3 In the structure shown, the locking section 411 covers most of the push section 51 and the entire stop section 52. Thus, when the body of the electronic device rotates from a fully folded state to a fully unfolded state, the first cam component 100 and the second cam component 200 can be in contact with the locking section 411 almost throughout the entire process.

[0054] Further integration Figure 7 and Figure 8 As shown, in one implementation, the locking section 411 includes multiple locking planes 412 along the lifting direction of the push section 410. The angle α between the normal direction of different locking planes 412 and the central axis C1 is different, but the angle α between the normal direction of any locking plane 412 and the central axis C1 is less than or equal to arctanμ. In this way, as the fuselage rotates to different positions, the first cam component 100 and the second cam component 200 can achieve surface contact on different locking planes 412. While possessing the freestop characteristic, the surface contact can also reduce the contact stress between the first cam component 100 and the second cam component 200, thereby improving the service life of the first cam component 100 and the second cam component 200.

[0055] Further as Figure 7 and Figure 8 As shown, in one implementation, in the lifting direction of the push segment 410, the angle α between the normal directions of multiple locking planes 412 and the central axis C1 decreases sequentially. This allows the slope of the push segment 410 to gradually flatten in its lifting direction, ultimately achieving a smooth transition between the top of the push segment 410 and the return segment 420. For example, if the locking segment 411 includes four locking planes 412a, 412b, 412c, and 412d sequentially in the lifting direction of the push segment 410, corresponding to angles α1, α2, α3, and α4 respectively, then arctanμ>α1>α2>α3>α4≥0°.

[0056] Further as Figure 7 and Figure 8 As shown, in one implementation, the lengths of multiple locking planes 412 decrease sequentially in the lifting direction of the push segment 410. Thus, as the slope of the push segment 410 gradually flattens in its lifting direction, the division of the locking planes 412 becomes more refined, resulting in a smoother slope change at the top of the push segment 410, which improves the user's feel when rotating the machine.

[0057] Further as Figure 7 and Figure 8 As shown, in one implementation, adjacent locking planes 412 are connected by a curved surface 413. This allows the contact surfaces of the first cam component 100 and the second cam component 200 to smoothly transition between the locking planes 412 when the user rotates the device, causing relative sliding between them. This avoids vibration when sliding between adjacent locking planes 412 and improves the user's feel when rotating the device.

[0058] Further as Figure 7 and Figure 8 As shown, in one implementation, the locking section 411 and the return section 420 are connected by a curved surface 414. This allows the contact surfaces of the first cam component 100 and the second cam component 200 to smoothly transition between the locking section 411 and the return section 420 when the user rotates the device, causing relative sliding between them. This prevents vibration and improves the user's feel when rotating the device.

[0059] Figure 9 This is a force analysis diagram when the first cam component 100 and the second cam component 200 are in contact with the locking section 411.

[0060] like Figure 9 As shown, when the first cam component 100 and the second cam component 200 contact the locking section 411, on the one hand, the second cam component 200 applies a pressure Fn to the first cam component 100 in the direction perpendicular to the locking section 411 along the elastic force Ft = k × x, where Fn = Ft × cosα; the pressure Fn generates a component Fd1 in the rotation direction of the first cam component 100 (i.e., the direction perpendicular to the rotation axis C1), where Fd1 = Fn × sinα = Ft × cosα × sinα, and this component Fd1 causes the first cam component 100 to rotate towards... Figure 9The tendency to rotate to the right; on the other hand, under the action of pressure Fn, the first cam component 100 will also be subjected to a frictional force Fm at its contact surface with the second cam component 200. The direction of the frictional force Fm is parallel to the tangential direction of the locking section 411, which is used to prevent the first cam component 100 from sliding along the tangential direction of the locking section 411. The frictional force Fm will generate a component Fd2 opposite to the direction of component Fd1, Fd2=Fm×cosα.

[0061] According to mechanics, for the first cam component 100 to remain stationary without being subjected to bending force from the user, i.e., to achieve the freestop characteristic, then Fd1 = Fd2, that is, Fn × sinα = Fm × cosα. In this case, the frictional force Fm is static friction, and its maximum value is μ × Ft × cosα. Therefore, the condition for Fd1 = Fd2 to hold is Ft × cosα × sinα ≤ μ × Ft × cosα × cosα, i.e., tanα ≤ μ. In other words:

[0062] When α≤arctanμ, the net force on the first cam component 100 in its rotation direction is 0, so the fuselage will not automatically unfold or close, thus achieving the freestop characteristic;

[0063] When α > arctanμ, Fd1 > Fd2, the resultant force on the first cam component 100 in its rotation direction is greater than 0, so it will rotate, causing the body to automatically open or close, and it does not have the freestop characteristic.

[0064] In this embodiment of the application, θ = arctanμ is defined as the self-locking angle, and when μ≈0.2, θ≈10°.

[0065] Figure 10 This is a schematic diagram illustrating the distribution of the cam profile on the annular end face according to an embodiment of this application.

[0066] like Figure 10 As shown, in one implementation, when the annular end face includes multiple cam profiles 400, the locking segment 411 can be disposed on at least one cam profile 400 of the annular end face. Taking the first end face 110 as an example, when it includes multiple cam profiles 400: as... Figure 10 As shown in method a, the locking section 411 can be provided on a portion of the cam-shaped surface 400, while the remaining cam-shaped surfaces 400 do not have the locking section 411; for example Figure 10 As shown in method b, the locking section 411 can also be set on each cam profile 400.

[0067] In addition, it is understandable that for Figure 1 For the foldable phone shown, each side of the body rotates 90° from fully folded to fully unfolded. Based on this, as... Figure 10 As shown, in this embodiment of the application, the angle β through which each locking segment 411 rotates about the central axis C1 is greater than or equal to 90°, or close to 90°, for example, any angle between 45° and 90°. In this way, when the fuselage is folded or unfolded, the first cam component and the second cam component can always or mostly be in contact with the locking segment 411, so that the fuselage has freestop characteristics in any position or most positions.

[0068] As can be seen from the above technical solutions, the electronic device provided in this application embodiment has at least one mutually cooperating cam profile surface on the contact surface between the first cam component and the second cam component, and the cam profile surface includes a locking section. The angle between the normal direction of the locking section and the central axis is less than or equal to the arctangent function of μ, where μ is the friction coefficient between the first cam component and the second cam component. The resultant force on the wheel drive component in its rotation direction is 0, so the body will not automatically unfold or close, thus realizing the freestop characteristic.

[0069] It is readily understood that, based on the several embodiments provided in this application, those skilled in the art can combine, split, or reorganize the embodiments of this application to obtain other embodiments, none of which exceed the protection scope of this application.

[0070] The above specific embodiments further illustrate the purpose, technical solution and beneficial effects of this application. It should be understood that the above are only specific embodiments of this application and are not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made on the basis of the technical solution of this application should be included within the scope of protection of this application.

Claims

1. A foldable electronic device, characterized in that, include: The components include a first cam component (100), a second cam component (200), an elastomer (300), and a rocker arm (30); The first cam component (100) and the second cam component (200) are coaxially arranged along a preset central axis (C1); The first cam component (100) includes a first end face (110) facing the second cam component (200), and the second cam component (200) includes a second end face (210) facing the first cam component (100); The elastic body (300) abuts against the end of the second cam member (200) away from the first cam member (100) and is configured to apply an elastic force to the second cam member (200) so that the first end face (110) and the second end face (210) remain in contact. Both the first end face (110) and the second end face (210) include at least one cam profile (400), and the cam profile (400) includes a plurality of locking planes (412) in sequence along its lifting direction. The normal direction of different locking planes (412) has a different angle with the central axis (C1). The swing arm (30) is connected to the first cam component (100) and is configured to drive the first cam component (100) to rotate around the central axis (C1), so that the first cam component (100) and the second cam component (200) contact the locking plane (412); The angle between the normal direction of any of the locking planes (412) and the central axis (C1) is less than or equal to arctanμ, where μ is the coefficient of friction between the first cam component (100) and the second cam component (200).

2. The electronic device according to claim 1, characterized in that, The first end face (110) and the second end face (210) are mating annular end faces; Both the first end face (110) and the second end face (210) include an equal number of the cam profiles (400), and the cam profiles (400) are arranged in a ring array.

3. The electronic device according to claim 1 or 2, characterized in that, The cam profile (400) includes a push section (410) and a return section (420); The push-stroke section (410) includes a locking section (411), wherein the locking section (411) rotates about the central axis (C1) by an angle β greater than or equal to 90°; The plurality of locking planes (412) are located on the locking segment (411).

4. The electronic device according to claim 3, characterized in that, In the lifting direction of the push segment (410), the angle between the normal direction of the plurality of locking planes (412) and the central axis (C1) decreases sequentially.

5. The electronic device according to claim 3, characterized in that, In the lifting direction of the push segment (410), the lengths of the plurality of locking planes (412) decrease sequentially.

6. The electronic device according to claim 3, characterized in that, The first cam component (100) and the second cam component (200) form surface contact on the locking plane (412).

7. The electronic device according to claim 3, characterized in that, The two adjacent locking planes (412) are connected by a curved surface transition.

8. The electronic device according to claim 3, characterized in that, The locking section (411) starts at the lower middle part of the push section (410) and extends along the lifting direction of the push section (410) to the top of the cam profile (400), and connects to the return section (420) at the top of the cam profile (400).

9. The electronic device according to claim 8, characterized in that, The locking section (411) and the return section (420) are connected by a curved surface.

10. The electronic device according to claim 3, characterized in that, The length of the locking section (411) is greater than half that of the pushing section (410).

11. The electronic device according to claim 1 or 2, characterized in that, The elastic body (300) is a spring, which is coaxially arranged with the second cam component (200) and is in a compressed state along the central axis (C1) to apply the elastic force to the second cam component (200) along the central axis (C1).

12. The electronic device according to claim 3, characterized in that, The locking section (411) is disposed on at least one of the cam profiles (400) of the first end face (110) and / or the second end face (210).

13. The electronic device according to claim 1 or 2, characterized in that, Also includes: A shaft cover (20) is provided inside the first cam component (100) and the second cam component (200); The fuselage (10), connected to the swing arm (30), is configured to drive the swing arm (30) to rotate around the central axis (C1) under the action of an external force.

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