Cam, gear, folding device and folding electronic equipment

Abstract

The utility model discloses a cam, a gear, a folding device and folding electronic equipment, the cam comprises a first concave-convex part, the first concave-convex part comprises a first substrate layer and a first wear-resistant layer covering the first substrate layer, the first substrate layer and the first wear-resistant layer are integrally formed, and the first wear-resistant layer is a concave-convex surface of the cam. Wherein the hardness of the first wear-resistant layer is greater than that of the first substrate layer. The hardness of the first wear-resistant layer of the cam is increased, and the wear resistance is improved. In the folding or unfolding process of the folding device, the abrasion degree of the first abrasion-resistant layer of the cam caused by friction force of the cam and the gear in the relative movement process of the cam and the gear is reduced, so that the risk that the structure of the first abrasion-resistant layer is changed due to abrasion is reduced, and then the risk that damping force provided by the damping assembly is reduced in the folding or unfolding process of the folding device is reduced; the folding type electronic equipment is good in hand feeling in the folding or unfolding process, and the user experience is improved.

Description

Technical Field

[0001] The present application relates to the technical field of electronic equipment, and in particular to a cam, a gear, a folding device and a foldable electronic equipment. Background Art

[0002] The folding device is a key component for realizing the folding function of a foldable electronic device. The cooperation between the synchronous gear assembly and the damping assembly in the folding device is the main structural component to ensure the user's opening and closing experience and maintain the opening and closing posture of the mobile phone. Specifically, the damping assembly includes a cam, and the synchronous gear assembly includes a gear. The concave and convex parts of the cam mesh with the concave and convex parts of the gear. During the folding or unfolding of the folding device, the concave and convex parts of the cam move relative to the concave and convex parts of the gear. The concave and convex parts of the gear and the concave and convex parts of the cam are subject to wear, resulting in a decrease in the damping force of the folding device and a reduction in the user experience. Utility Model Content

[0003] The present application provides a cam, a gear, a folding device and a folding electronic device, which are used to solve the problem that the damping force of the folding device decreases due to long-term repeated opening and closing, thereby reducing the user experience.

[0004] In a first aspect, the present application provides a cam, the cam comprising a first concave-convex portion, the first concave-convex portion comprising a first base layer and a first wear-resistant layer covering the first base layer, the first base layer and the first wear-resistant layer being integrally formed, the first wear-resistant layer being the concave-convex surface of the cam, wherein the hardness of the first wear-resistant layer is greater than the hardness of the first base layer.

[0005] In this solution, the hardness of the first wear-resistant layer of the cam is increased, that is, the hardness of the first wear-resistant layer of the cam for meshing with the gear is increased, and the wear resistance is improved. During the folding or unfolding process of the folding device, the friction between the cam and the gear during the relative movement between the two reduces the degree of wear on the first wear-resistant layer of the cam, thereby reducing the risk of structural changes in the first wear-resistant layer due to wear, and further reducing the risk of a reduction in the damping force provided by the damping component during the folding or unfolding process of the folding device, so that the foldable electronic device has a better feel during the folding or unfolding process, and improves the user experience.

[0006] In this solution, the grains of the first wear-resistant layer are nanometer-scale, and the grain size of the first wear-resistant layer is smaller than the grain size of the first substrate layer.

[0007] In this solution, the grains and microstructure of the first wear-resistant layer are finer, and the dislocation density is greater, so that the first wear-resistant layer has a greater hardness, reducing the risk of wear of the first wear-resistant layer.

[0008] In this solution, the grains of the first substrate layer are in micron size.

[0009] In this solution, the first base layer has good fatigue resistance and good toughness, so as to prepare a more complex and precise cam structure, which is beneficial to improving the stability and reliability of the cam structure.

[0010] In this solution, the grain size of the first wear-resistant layer gradually increases from the first wear-resistant layer to the first base layer.

[0011] In this solution, the surface grains of the first wear-resistant layer are significantly refined and the dislocation density is increased, which is beneficial to improving the microhardness, wear resistance and fatigue strength of the concave and convex surface of the cam, and further improving the wear resistance of the first wear-resistant layer.

[0012] In this solution, along the thickness direction of the cam, the thickness L of the first wear-resistant layer satisfies 20um≤L≤500um.

[0013] In this solution, when 20um≤L≤500um, the thickness of the first wear-resistant layer is moderate, which can reduce the risk of the concave and convex surface of the cam being worn, resulting in a decrease in the feel of the foldable electronic device. At the same time, it can also avoid a significant impact on the concave and convex surface profile and part size when forming the first wear-resistant layer.

[0014] In this solution, the hardness of the first wear-resistant layer is 8%-15% higher than that of the first base layer.

[0015] In this solution, the hardness of the first wear-resistant layer is relatively large, so as to reduce the risk of wear caused by the friction force generated when the first wear-resistant layer is engaged.

[0016] In this solution, the roughness Ra of the first wear-resistant layer satisfies 0<Ra≤0.6.

[0017] In this solution, the roughness of the first wear-resistant layer is relatively small, which reduces the friction between the first wear-resistant layer and the synchronous gear assembly, and further reduces the risk of wear of the first wear-resistant layer.

[0018] In this solution, the material of the cam is steel material formed by metal injection molding or titanium alloy formed by metal injection molding.

[0019] In this solution, the material of the cam can be steel or titanium alloy. Both steel and titanium alloy have high strength, thereby increasing the hardness of the cam and further reducing the possibility of wear of the first wear-resistant layer. The first base layer of the cam can be formed by metal injection molding. The first base layer formed by metal injection molding has the advantages of high dimensional accuracy and high production efficiency.

[0020] In this solution, the first wear-resistant layer is formed by performing ultrasonic impact strengthening on the surface of the first concave-convex portion.

[0021] In this scheme, ultrasonic impact treatment vibrates the surface of the cam through ultrasonic impact, so that the surface grains of the cam are significantly refined and the dislocation density is increased, thereby forming a first wear-resistant layer on the first base layer with grains smaller than those of the first base layer. The hardness of the first wear-resistant layer is greater than that of the first base layer, and it has good compressive resistance and wear resistance.

[0022] The second aspect of the present application provides a gear, the gear comprising a tooth portion and a second concave-convex portion, the second concave-convex portion comprising a second base layer and a second wear-resistant layer covering the second base layer, the second base layer and the second wear-resistant layer are integrally formed, and the second wear-resistant layer is the concave-convex surface of the gear. The hardness of the second wear-resistant layer is greater than the hardness of the second base layer.

[0023] In this solution, the hardness of the second wear-resistant layer of the gear for meshing with the cam is increased, and the wear resistance is improved. During the folding or unfolding process of the folding device, the friction between the cam and the gear during the relative movement between the two reduces the degree of wear on the second wear-resistant layer of the gear, thereby reducing the risk of structural changes in the second wear-resistant layer due to wear, and further reducing the damping force provided by the damping component during the folding or unfolding process of the folding device, so that the foldable electronic device has a better feel during the folding or unfolding process, and improves the user experience.

[0024] In this solution, the grain size of the second wear-resistant layer gradually increases from the second wear-resistant layer to the second base layer.

[0025] In this solution, the grains and microstructure of the second wear-resistant layer are finer, and the dislocation density is greater, so that the second wear-resistant layer has a greater hardness, reducing the risk of wear of the second wear-resistant layer.

[0026] The grains of the second wear-resistant layer are of nanometer scale, and the grains of the second base layer are of micrometer scale.

[0027] In this solution, along the thickness direction of the gear, the thickness of the second wear-resistant layer is between 20um and 500um.

[0028] In this solution, when the thickness of the second wear-resistant layer is between 20um-500um, the thickness of the second wear-resistant layer is moderate, which can reduce the risk of wear of the concave and convex surface of the gear, resulting in a decrease in the feel of the foldable electronic device. At the same time, it can also avoid a significant impact on the concave and convex surface profile and part size when forming the second wear-resistant layer.

[0029] In this solution, the second wear-resistant layer is formed by performing ultrasonic impact strengthening on the surface of the second concave-convex portion.

[0030] In this scheme, ultrasonic impact treatment vibrates the surface of the gear through ultrasonic impact, so that the surface grains of the gear are significantly refined and the dislocation density is increased, thereby forming a second wear-resistant layer on the second base layer with grains smaller than those of the second base layer. The hardness of the second wear-resistant layer is greater than that of the second base layer, and it has good compressive resistance and wear resistance.

[0031] The third aspect of the present application provides a folding device, the folding device comprises a main shaft, a rotating arm, a synchronous gear assembly and a damping assembly, the synchronous gear assembly comprises a gear, and the damping assembly comprises a cam. The cam is the cam described above, and / or the gear is the gear described above. The first concave-convex portion of the cam meshes with the second concave-convex portion of the gear.

[0032] In this solution, during the folding or unfolding process of the folding device, the friction between the first convex-concave portion and the second convex-concave portion during relative movement reduces the wear degree of the first convex-concave portion of the cam and / or the second convex-concave portion of the gear, thereby reducing the risk of structural changes of the first convex-concave portion and / or the second convex-concave portion due to wear, and further reducing the risk of reduction in the damping force provided by the damping assembly during the folding or unfolding process of the folding device, which is beneficial to extending the service life of the folding device.

[0033] A fourth aspect of the present application provides a foldable electronic device, which includes a screen and the folding device described above.

[0034] In this solution, the folding device has good wear resistance, which reduces the damping force provided by the damping component during folding or unfolding of the folding device, so that the foldable electronic device has a better feel during folding or unfolding, thereby improving the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic diagram of the structure of a foldable electronic device in a specific embodiment of the present application;

[0036] Figure 2 This is a schematic structural diagram of a foldable electronic device provided by the present application in a specific embodiment, wherein the folding device is in an unfolded state;

[0037] Figure 3 This is a schematic structural diagram of a foldable electronic device provided by the present application in a specific embodiment, wherein the folding device is in a folded state;

[0038] Figure 4 A schematic diagram of a partial structure of a folding device provided in the present application in a specific embodiment;

[0039] Figure 5 for Figure 4 The structural diagram of the middle cam;

[0040] Figure 6 This is a schematic structural diagram of the cam provided in the present application in another specific embodiment;

[0041] Figure 7 for Figure 5 sectional view of

[0042] Figure 8 for Figure 7 A partial enlarged view of part A;

[0043] Fig. 9 for Figure 8 Schematic diagram of the grain structure of the first wear-resistant layer and the first base layer;

[0044] Fig.10 is a schematic structural diagram of an ultrasonic tool head in a specific embodiment;

[0045] Fig.11 It is a schematic diagram of the structure in which the head of the ultrasonic tool head in the figure cooperates with the first concave-convex part of the cam;

[0046] Fig.12 A schematic diagram of ultrasonic impact vibration on the concave and convex surface of a cam;

[0047] Fig.13 It is a schematic diagram of treating the first concave-convex part of the cam by using abrasive flow coupled with ultrasonic strengthening;

[0048] Fig.14 for Figure 4 Schematic diagram of the structure of the gears in the synchronous gear assembly.

[0049] Description of reference numerals:

[0050] 1- Flexible screen;

[0051] 21- first housing;

[0052] 22- second housing;

[0053] 3- Folding device;

[0054] 31-spindle;

[0055] 321-first rotating arm;

[0056] 322- second rotating arm;

[0057] 33-synchronous gear assembly;

[0058] 331-Gear;

[0059] 331a-tooth portion;

[0060] 331b- second concave-convex portion;

[0061] 34- elastic member;

[0062] 35- Cam;

[0063] 351- first concave-convex portion;

[0064] 351a - first basal layer;

[0065] 351b-first wear-resistant layer;

[0066] 352-concave;

[0067] 353-convex;

[0068] 4-Ultrasonic tool head;

[0069] 41-head;

[0070] 5-Abrasive fluid. DETAILED DESCRIPTION

[0071] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms of "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0072] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0073] It should be noted that the directional words such as "upper", "lower", "left", and "right" described in the embodiments of the present application are described at the angles shown in the accompanying drawings and should not be understood as limiting the embodiments of the present application. In addition, in the context, it is also necessary to understand that when it is mentioned that an element is connected to another element "upper" or "lower", it can not only be directly connected to another element "upper" or "lower", but also indirectly connected to another element "upper" or "lower" through an intermediate element.

[0074] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below in conjunction with the accompanying drawings. In a specific embodiment, the present application is further described in detail below through a specific embodiment and in conjunction with the accompanying drawings.

[0075] The present application provides a foldable electronic device. The present application provides a foldable electronic device. Figure 1-3The foldable electronic device shown includes any device with a foldable screen function, such as a mobile phone, a tablet computer, a personal digital assistant (PDA), a laptop computer, a car computer, a foldable display device, a foldable display screen, a wearable device, etc. The embodiment of the present application does not impose any special restrictions on the specific form of the above-mentioned foldable electronic device. For the convenience of description, the following description is made by taking the foldable electronic device as an example of a mobile phone. The foldable electronic device of the present application is introduced in the following specific embodiments.

[0076] like Figure 1 As shown, Figure 1 This is a schematic diagram of the structure of a foldable electronic device in a specific embodiment provided in an embodiment of the present application. The foldable electronic device includes a screen, which may be a flexible screen 1, and the flexible screen 1 is used to display images, videos, and the like. The specific type of the flexible screen 1 of the present application is not limited. For example, the flexible screen 1 may be an active-matrix organic light-emitting diode or an active-matrix organic light-emitting diode (AMOLED) display screen. As a self-luminous display screen, the AMOLED display screen does not require a backlight module (BLM). Therefore, when the substrate substrate in the AMOLED display screen is made of a flexible resin material, such as polyethylene terephthalate (PET), the AMOLED display screen can have a bendable property. Exemplarily, the flexible screen 1 can also be an organic light-emitting diode (OLED) display, a mini organic light emitting diode (Mini organic light emitting diode) display, a micro organic light-emitting diode (Micro organic light-emitting diode) display, a quantum dot light emitting diode (Quantum dot light emitting diodes, QLED) display, etc.

[0077] like Figure 1As shown, the first shell 21 and the second shell 22 are spaced apart, and the first shell 21 and the second shell 22 are used to install the battery, circuit board, camera, earphone, receiver, button, battery and other components of the foldable electronic device. Among them, the first shell 21 includes a first middle frame and a first back cover, and the second shell 22 includes a second middle frame and a second back cover, and the first middle frame and the second middle frame are used to carry the flexible screen 1, that is, the flexible screen 1 is fixedly connected (for example, pasted) to the first middle frame and the second middle frame, so that the flexible screen 1 is kept as flat as possible during use, and the non-display surface of the flexible screen 1 is protected. The first back cover and the second back cover are used to protect the components in the first shell 21 and the second shell 22. The folding device 3 is located between the first shell 21 and the second shell 22, and is connected to the first shell 21 and the second shell 22. In some embodiments, the first shell 21 is provided with a first groove, and the second shell 22 is provided with a second groove. A part of the folding device 3 is installed in the first groove, and another part is installed in the second groove. In some possible embodiments, the folding device 3 can be connected to the first groove and the second groove by screws or the like.

[0078] During the use of the foldable electronic device, the folding device 3 at least includes an unfolded state and a folded state. Figure 2 and Figure 3 As shown, Figure 2 This is a schematic structural diagram of a foldable electronic device provided in the present application in a specific embodiment, wherein the folding device 3 is in an unfolded state; Figure 3 This is a schematic diagram of the structure of a foldable electronic device provided in this application in a specific embodiment, wherein the folding device 3 is in a folded state. Figure 2 In the unfolded state shown, the first shell 21 and the second shell 22 are roughly located in the same plane, so that the flexible screen 1 is roughly flat. At this time, the flexible screen 1 is exposed, and the user can operate the flexible screen 1, and the flexible screen 1 can display information such as images or videos to achieve a large-screen display and improve the user's viewing experience. When the folding device 3 is in the unfolded state, the first shell 21 and the second shell 22 can rotate towards each other (that is, the first shell 21 and the second shell 22 rotate relative to each other), thereby driving the folding device 3 to fold. During the folding process, the first shell 21 and the second shell 22 are close to each other at the ends away from the folding device 3, so that the foldable electronic device is in a state of being unfolded. Figure 3 In the folded state shown. In this folded state, the flexible screen 1 is located in the space enclosed by the folded first and second middle frames. At this time, the flexible screen 1 is not exposed, and the user cannot operate the flexible screen 1. The foldable electronic device is easy to store and carry. When the folding device 3 is in the folded state, the first shell 21 and the second shell 22 can rotate (the rotation direction is opposite to the rotation direction when folded), thereby driving the folding device 3 to unfold, so that the foldable electronic device is in Figure 2The unfolded state shown. In this embodiment, the foldable electronic device is a flexible screen 1 folded inwardly.

[0079] Those skilled in the art will appreciate that the structures illustrated in the embodiments of the present application do not constitute specific limitations on the foldable electronic device. In other possible implementations of the present application, the foldable electronic device may include more components than shown in the figure, or combine certain components, or separate certain components, or arrange the components differently.

[0080] In a specific embodiment, Figure 4 As shown, Figure 4 The schematic diagram of the partial structure of the folding device 3 provided in the present application in a specific embodiment. The folding device 3 includes a main shaft 31, a rotating arm, a synchronous gear assembly 33 and a damping assembly, wherein the rotating arm includes a first rotating arm 321 and a second rotating arm 322 arranged along the width direction of the main shaft 31, and the first rotating arm 321 and the second rotating arm 322 can rotate relative to the main shaft 31 to put the folding device 3 in an unfolded state or a folded state. The first rotating arm 321 and the second rotating arm 322 are meshed by the synchronous gear assembly 33, and the synchronous gear assembly 33 is used to transmit the movement between the first rotating arm 321 and the second rotating arm 322, so that during the folding and unfolding process, the first rotating arm 321 and the second rotating arm 322 move synchronously, thereby improving the stability and reliability of the folding device 3 and the electronic device during the unfolding and folding process. The damping assembly and the synchronous gear assembly 33 are arranged along the length direction. The damping assembly includes an elastic member 34 and a cam 35. Along the length direction, the cam 35 is located between the elastic member 34 and the synchronous gear assembly 33, and the elastic member 34 is located between the two cams 35 and connected to the two cams 35. The elastic member 34 is in a compressed state, so that the two cams 35 can be driven to move away from each other along the length direction.

[0081] Among them, Figure 4 and Figure 5 As shown, Figure 5 for Figure 4Schematic diagram of the structure of the cam 35. The cam 35 includes a first concave-convex portion 351, and the first concave-convex portion 351 has a first concave-convex surface. The gear 331 of the synchronous gear assembly 33 has a second concave-convex portion 331b along the length direction. The second concave-convex portion 331b has a second concave-convex surface. The second concave-convex surface of the gear 331 can mesh with the first concave-convex surface of the cam 35. In the process of the second concave-convex surface meshing with the first concave-convex surface, at least the following three situations are included: the first one, the convex surface of the second concave-convex surface cooperates with the convex surface 353 of the first concave-convex surface. At this time, the cam 35 moves toward the direction of the corresponding elastic member 34 and compresses the elastic member 34 so that the elastic member 34 has a first deformation amount. At this time, the elastic member 34 in the compressed state can apply a first elastic force to the gear 331 through the cam 35; the second one, the convex surface of the second concave-convex surface cooperates with the concave surface 352 of the first concave-convex surface, or the concave surface of the second concave-convex surface cooperates with the convex surface 353 of the first concave-convex surface. At this time, the elastic member 34 in the compressed state can apply a first elastic force to the gear 331 through the cam 35. The elastic member 34 in the compressed state can apply a second elastic force to the gear 331 through the cam 35, wherein the elastic member 34 has a second deformation amount, and the second deformation amount is smaller than the first deformation amount, and the second elastic force is smaller than the first elastic force; the third type, the concave surface of the second concave-convex surface cooperates with the concave surface 352 of the first concave-convex surface. At this time, the elastic member 34 in the compressed state can apply a third elastic force to the gear 331 through the cam 35, wherein the elastic member 34 has a third deformation amount, and the third deformation amount is smaller than the first deformation amount and smaller than the second deformation amount, and the third elastic force is smaller than the first elastic force and smaller than the second elastic force.

[0082] In this embodiment, the magnitude of the damping force applied by the damping assembly is related to the magnitude of the elastic force of the elastic member 34, and when the first rotating arm 321 and the second rotating arm 322 rotate, the gear 331 can rotate accordingly, thereby changing the matching position of the second concave-convex surface and the first concave-convex surface, and the matching position of the two switches between the above three situations.

[0083] In the first specific embodiment, when the folding device 3 is in the folded state or the unfolded state, it can be the first case mentioned above. At this time, when the folding device 3 needs to switch between the folded state and the unfolded state, the external force applied needs to be able to overcome the first elastic force of the elastic member 34, and the folding device 3 can be in the second case or the third case mentioned above during the switching between the folded state and the unfolded state, that is, during the folding or unfolding process, the damping component can provide a damping force of the same magnitude as the second elastic force or the third elastic force. In the second specific embodiment, when the folding device 3 is in the folded state or the unfolded state, it can be in the second case mentioned above. At this time, when the folding device 3 needs to switch between the folded state and the unfolded state, the external force applied needs to be able to overcome the second elastic force of the elastic member 34, and the folding device 3 can be in the third case mentioned above during the switching between the folded state and the unfolded state, that is, during the folding or unfolding process, the damping component can provide a damping force of the same magnitude as the third elastic force. During the folding or unfolding process of the folding device 3, the damping force provided by the damping component can improve the hand feel of the folding device 3 during the folding or unfolding process.

[0084] In addition, during the process of meshing of the second concave-convex surface and the first concave-convex surface, the inclined surfaces of the two are matched, that is, the interaction force between the second concave-convex surface and the first concave-convex surface is along the inclined surface (concave surface 352 or convex surface 353) perpendicular to the two. The interaction force acting on the inclined surface (concave surface 352 or convex surface 353) can generate a component force that drives the gear 331 meshing with it to rotate, thereby generating a driving force that drives the first rotating arm 321 and the second rotating arm 322 to rotate toward or away from each other, so that the folding device 3 can be automatically folded or unfolded.

[0085] In such Figure 4 In the embodiment shown, the main shaft 31 of the folding device 3 may include four pins, and accordingly, the synchronous gear assembly 33 may include four gears 331, and the four gears 331 all have the above-mentioned second concave-convex surface. Figure 5 As shown, in this embodiment, the cam 35 of the damping assembly includes four first concave-convex parts 351, and four pins pass through four gears 331 and the four first concave-convex parts 351 respectively. The four first concave-convex parts 351 all have the above-mentioned first concave-convex surface.

[0086] In another specific embodiment, Figure 6 As shown, Figure 6 This is a schematic diagram of the structure of the cam 35 provided in the present application in another specific embodiment. The cam 35 includes two first concave-convex parts 351, the two first concave-convex parts 351 have the above-mentioned first concave-convex surface, and the two first concave-convex parts 351 are located at both ends of the cam 35 along the width direction. Correspondingly, the two gears 331 in the synchronous gear assembly 33 matched with the cam 35 have the above-mentioned second concave-convex surface.

[0087] During the folding or unfolding process of the folding device 3, the second concave-convex surface contacts and moves relative to the first concave-convex surface during the meshing process, resulting in wear between the second concave-convex surface and the first concave-convex surface, that is, the structural shape of the second concave-convex surface and / or the first concave-convex surface changes, thereby resulting in a reduction in the damping force provided by the damping component during the folding or unfolding process of the folding device 3, thereby reducing the feel of the foldable electronic device during the folding or unfolding process.

[0088] In order to solve this technical problem, the embodiment of the present application provides a cam 35, such as Figure 5-8 As shown, the cam 35 includes a first concave-convex portion 351, and the first concave-convex portion 351 is a portion provided with a first concave-convex surface. Figure 7 Shown and Figure 8 As shown, Figure 7 for Figure 5 A cross-sectional view of Figure 8 for Figure 7 A partial enlarged view of part A in the figure. The first concave-convex portion 351 includes a first base layer 351a and a first wear-resistant layer 351b covering the first base layer 351a. The first base layer 351a and the first wear-resistant layer 351b are integrally formed, and the surface of the first wear-resistant layer 351b is the first concave-convex surface of the cam 35. Among them, the hardness of the first wear-resistant layer 351b is greater than the hardness of the first base layer 351a. That is, the hardness of the first concave-convex surface of the cam 35 used for meshing with the second concave-convex surface of the gear 331 in this embodiment is increased, and the wear resistance is improved. During the folding or unfolding process of the folding device 3, the friction between the first concave-convex surface and the second concave-convex surface during the relative movement of the two reduces the degree of wear on the first concave-convex surface of the cam 35, thereby reducing the risk of changes in the structure of the first concave-convex surface due to wear, and further reducing the risk of reduction in the damping force provided by the damping component during the folding or unfolding process of the folding device 3, so that the foldable electronic device has a better feel during the folding or unfolding process, and improves the user experience.

[0089] In addition, since the first wear-resistant layer 351b of the cam 35 is integrally formed with the first base layer 351a, under the friction force of the relative movement between the first wear-resistant layer 351b of the cam 35 and the second concave-convex surface of the gear 331, the first wear-resistant layer 351b and the first base layer 351a are not easily separated, further improving the life of the cam 35.

[0090] In such Figure 8In the illustrated embodiment, the first wear-resistant layer 351b is formed by ultrasonic impact strengthening the first base layer 351a, so that the first base layer 351a and the first wear-resistant layer 351b are made of the same material. The ultrasonic impact treatment vibrates the surface of the cam 35 by ultrasonic impact, so that the surface grains of the cam 35 are significantly refined and the dislocation density is increased, thereby forming a first wear-resistant layer 351b on the first base layer 351a with grains smaller than those of the first base layer 351a. The hardness of the first wear-resistant layer 351b is greater than that of the first base layer 351a, and has good compressive and wear resistance. At the same time, the ultrasonic impact treatment can reduce the surface roughness of the first wear-resistant layer 351b, which is beneficial to improving the microhardness, wear resistance and fatigue resistance of the surface of the first wear-resistant layer 351b. In addition, through the ultrasonic impact strengthening method, the cam 35 made of a single material can achieve a structure in which the first wear-resistant layer 351b and the first base layer 351a have different tissues. Compared with the two-layer structure in which the first wear-resistant layer 351b and the first base layer 351a are made of different materials, it has the advantages of reducing the processing steps of the cam 35 and improving the structural stability of the cam 35.

[0091] In a possible implementation, Figure 8 As shown, the material of the cam 35 can be steel or titanium alloy. Both steel and titanium alloy have high strength, thereby improving the hardness of the cam 35 and further reducing the possibility of wear of the first wear-resistant layer 351b.

[0092] The first base layer 351a of the cam 35 can be formed by metal injection molding, which has the advantages of high dimensional accuracy and high production efficiency.

[0093] In a specific embodiment, Figure 8 As shown, the hardness of the first wear-resistant layer 351b is 8%-15% higher than that of the first base layer 351a. For example, the hardness of the first wear-resistant layer 351b is 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, etc. higher than that of the first base layer 351a. That is, the hardness of the first wear-resistant layer 351b is greater to reduce the risk of wear caused by the friction generated when the first wear-resistant layer 351b is engaged.

[0094] In a specific embodiment, Figure 8As shown, the roughness Ra of the first wear-resistant layer 351b satisfies 0<Ra≤0.6, that is, the roughness of the first wear-resistant layer 351b is small, which reduces the friction between the first wear-resistant layer 351b and the synchronous gear assembly 33, and further reduces the risk of wear of the first wear-resistant layer 351b. For example, the roughness of the first wear-resistant layer 351b can be 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, etc.

[0095] In a specific embodiment, Fig. 9 As shown, Fig. 9 for Figure 8 Schematic diagram of the grain structure of the first wear-resistant layer 351b and the first base layer 351a. After the ultrasonic impact strengthening treatment, the grains of the first wear-resistant layer 351b of the cam 35 are refined. Specifically, the grains of the first wear-resistant layer 351b of the cam 35 are nanometer-level, and the grain size of the first wear-resistant layer 351b is smaller than the grain size of the first base layer 351a, so that the grains and microstructure of the first wear-resistant layer 351b are finer, the dislocation density is larger, and the first wear-resistant layer 351b has a greater hardness, reducing the risk of wear of the first wear-resistant layer 351b.

[0096] In a specific embodiment, Fig. 9 As shown, the grains of the first substrate layer 351a are in micron level, so that the first substrate layer 351a has good fatigue resistance and good toughness, so as to prepare a more complex and precise cam 35 structure, which is beneficial to improving the stability and reliability of the cam 35 structure.

[0097] In a specific embodiment, during the ultrasonic impact strengthening process on the surface of the cam 35, the energy of the ultrasonic impact is gradually transferred from the surface of the cam 35 to the inside of the cam 35, and the energy of the ultrasonic impact is gradually reduced, so the ultrasonic energy acting on the surface of the cam 35 is greater than the ultrasonic energy acting on the inside of the cam 35, so that after the surface of the cam 35 is subjected to the ultrasonic impact strengthening process, the grain structure of the first concave-convex portion 351 of the cam 35 along its thickness direction changes stepwise, forming a first wear-resistant layer 351b and a first base layer 351a. Fig. 9 As shown, the grain size of the first concave-convex portion 351 gradually increases from the first wear-resistant layer 351b to the first base layer 351a, and thus the grains of the first wear-resistant layer 351b are smaller than those of the first base layer 351a, so that the first wear-resistant layer 351b has better wear resistance than the first base layer 351a.

[0098] In a specific embodiment, Figure 8As shown, along the thickness direction of the cam 35, the thickness L of the first wear-resistant layer 351b satisfies 20um≤L≤500um. The thickness L can be 20um, 40um, 60um, 80um, 100um, 120um, 140um, 160um, 180um, 200um, 220um, 240um, 260um, 280um, 300um, 320um, 340um, 360um, 380um, 400um, 420um, 440um, 460um, 480um, 500um, etc.

[0099] In this embodiment, when 20um≤L≤500um, the thickness of the first wear-resistant layer 351b is moderate, which can reduce the risk of the first concave-convex surface of the cam 35 being worn, resulting in a decrease in the feel of the foldable electronic device. At the same time, the formation of the first wear-resistant layer 351b has a significant impact on the concave-convex surface profile and part size.

[0100] It should be noted that since the first wear-resistant layer 351b is a structure formed by ultrasonic impact strengthening, the thickness of the first wear-resistant layer 351b is related to the energy during the ultrasonic treatment process. Therefore, the thickness of the first wear-resistant layer 351b is not necessarily the same at different locations, and there is no fixed boundary between the first wear-resistant layer 351b and the first base layer 351a.

[0101] In summary, the cams 35 in the above embodiments can be subjected to ultrasonic impact treatment to form the first wear-resistant layer 351b and the first base layer 351a. Specifically, the ultrasonic impact treatment can be implemented by the following two methods.

[0102] Method 1: Use the ultrasonic tool head 4 to perform ultrasonic impact treatment on the surface of the first concave-convex portion 351 of the cam 35. Fig.10 and Fig.11 As shown, Fig.10 is a schematic structural diagram of an ultrasonic tool head 4 in a specific embodiment, Fig.11 To adopt Fig.10 The schematic diagram of the structure of the head 41 of the ultrasonic tool head 4 cooperating with the first concave-convex part 351 of the cam 35. The ultrasonic tool head 4 includes a head 41 that is configured to conform to the surface of the first concave-convex part 351 of the cam 35. When ultrasonic impact strengthening is performed, the head 41 is meshed with the first concave-convex part 351 of the cam 35, so that the concave-convex surface of the head 41 contacts the surface of the first concave-convex part 351, and the tool head is pushed by ultrasonic waves to perform high-frequency impact motion (for example, an impact frequency of 2W Hz or more) on the surface of the metal part. Fig.12 As shown, Fig.12Schematic diagram of ultrasonic impact vibration on the concave-convex surface of the cam 35. The ultrasonic tool head 4 transmits pressure and ultrasonic impact vibration to the surface of the first concave-convex part 351 of the cam 35, causing elastic-plastic deformation, refining the grains on the surface of the first concave-convex part 351, and forming a first wear-resistant layer 351b with higher hardness.

[0103] In a specific embodiment, the cam 35 can be processed by the following method:

[0104] 1) Feeding preparation

[0105] Prepare Fe-Co-Cr-Ni-Mo high-strength steel powder with a powder particle size of 3 to 18 μm. Mix the high-strength steel powder with a binder (the main components of the binder are polyoxymethylene, ethylene-vinyl acetate copolymer, polyethylene, high-density polyethylene, and octadecyl acrylate) in a certain volume ratio, and then add it to an internal mixer for mixing at a temperature of 170 to 210°C for 2 to 4 hours and a blade speed of 20 r / min; move the mixed paste feed into a granulator, and the screw of the granulator extrude the gradually cooled feed through the die head, and the rotating blade cuts the strip feed into cylindrical particles of 2 to 3 mm in length to obtain feed particles that can be directly used for molding.

[0106] 2) Injection molding

[0107] The feed particles obtained in step 1) are added into the hopper of an injection molding machine, and injection molding is performed at a molding temperature of 170 to 220° C. and a molding pressure of 50 to 200 MPa to obtain a green body of the cam 35 .

[0108] 3) Catalytic degreasing

[0109] The green body obtained in step 2) is placed flat on an alumina ceramic plate and placed in a catalytic degreasing furnace for catalytic degreasing at a temperature of 110 to 130° C. The amount of fuming nitric acid introduced is 0.5 to 3.5 g / min, and the degreasing time is 2 to 4 hours.

[0110] 4) Sintering

[0111] The green body prepared by catalytic degreasing in step 3) is placed in a sintering furnace together with an alumina ceramic support plate, and sintered in a vacuum or Ar, H2 atmosphere at a sintering temperature of 1200-1370°C for 1.5-8 hours.

[0112] 5) Heat treatment

[0113] The sintered blank obtained in step 4) is placed in a vacuum heat treatment furnace for solution treatment at a temperature of 800-1100°C for 2 hours; and then subjected to vacuum aging treatment at a temperature of 480-550°C for 4 hours to obtain a cam 35 made of high-strength steel, the shape of which is shown in FIG. Figure 7 and Figure 8 structure.

[0114] 6) Surface strengthening

[0115] Use an ultrasonic tool head 4 with a cam surface profiling head 41 to perform ultrasonic impact treatment on the first concave-convex portion 351 of the cam 35 obtained in step 5), with an ultrasonic frequency of 20kHz to 40kHz, to obtain a cam 35 with a first wear-resistant layer 351b having a nanocrystalline structure and a gradient-changing organizational structure from the first wear-resistant layer 351b to the first base layer 351a.

[0116] The first wear-resistant layer 351b of the cam 35 processed by the processing method described in this embodiment is dense, has fine grains (nanoscale), has lower surface roughness, and the hardness of the first wear-resistant layer 351b is significantly improved compared to the first base layer 351a, thereby achieving the effect of improving the wear resistance of the first concave-convex surface of the cam 35.

[0117] Method 2: Fig.13 As shown, Fig.13 Schematic diagram of the first concave-convex part 351 of the cam 35 treated by abrasive flow coupled with ultrasonic strengthening. Since the cam surface is an open surface, a tooling device is designed to form a working chamber so that the abrasive fluid 5 can reciprocate in the working chamber and flow through the surface of the first concave-convex part 351 of the cam 35. The ultrasonic tool head 4 is placed in the working chamber, and the ultrasonic energy exerts a force on the abrasive flowing between the cam surface and the tool head through the ultrasonic tool head 4, so that the surface of the first concave-convex part 351 simultaneously obtains polishing and surface strengthening effects to form a first wear-resistant layer 351b.

[0118] In a specific embodiment,

[0119] The cam 35 can be processed by the following method:

[0120] 1) Feeding preparation

[0121] Prepare Fe-Co-Cr-Ni-Mo high-strength steel powder with a powder particle size of 3 to 18 μm. Mix the high-strength steel powder with a binder (the main components of the binder are polyoxymethylene, ethylene-vinyl acetate copolymer, polyethylene, high-density polyethylene, and octadecyl acrylate) in a certain volume ratio, and then add it to an internal mixer for mixing at a temperature of 170 to 210°C for 2 to 4 hours and a blade speed of 20 r / min; move the mixed paste feed into a granulator, and the screw of the granulator extrude the gradually cooled feed through the die head, and the rotating blade cuts the strip feed into cylindrical particles of 2 to 3 mm in length to obtain feed particles that can be directly used for molding.

[0122] 2) Injection molding

[0123] The feed particles obtained in step 1) are added into the hopper of an injection molding machine, and injection molding is performed at a molding temperature of 170 to 220° C. and a molding pressure of 50 to 200 MPa to obtain a green body of the cam 35 .

[0124] 3) Catalytic degreasing

[0125] The green body obtained in step 2) is placed flat on an alumina ceramic plate and placed in a catalytic degreasing furnace for catalytic degreasing at a temperature of 110 to 130° C. The amount of fuming nitric acid introduced is 0.5 to 3.5 g / min, and the degreasing time is 2 to 4 hours.

[0126] 4) Sintering

[0127] The green body prepared by catalytic degreasing in step 3) is placed in a sintering furnace together with an alumina ceramic support plate, and sintered in a vacuum or Ar, H2 atmosphere at a sintering temperature of 1200-1370°C for 1.5-8 hours.

[0128] 5) Heat treatment

[0129] The sintered blank obtained in step 4) is placed in a vacuum heat treatment furnace for solution treatment at a temperature of 800-1100°C for 2 hours; and then subjected to vacuum aging treatment at a temperature of 480-550°C for 4 hours to obtain a cam 35 made of high-strength steel, the shape of which is shown in FIG. Figure 7 and Figure 8 structure.

[0130] 6) Surface strengthening

[0131] The first concavoconvex portion 351 of the cam 35 obtained in step 5) is subjected to abrasive flow coupled ultrasonic impact treatment so that the abrasive fluid 5 can flow on the surface of the first concavoconvex portion 351 to obtain a first wear-resistant layer 351b.

[0132] In addition, in a possible implementation, the blank cam 35 may be prepared by 3D printing technology, and the cam surface may be processed by laser shock peening to form the first wear-resistant layer 351b.

[0133] In a specific embodiment, the present application also provides a gear 331 of a synchronous gear assembly 33, such as Fig.14 As shown, Fig.14 for Figure 4 A schematic diagram of the structure of the gear 331 of the synchronous gear assembly 33, Fig.14, two gears 331 are shown to be meshed with each other. The gear 331 includes a tooth portion 331a and a second concave-convex portion 331b, wherein the tooth portion 331a is used to mesh with other gears 331 of the synchronous gear assembly 33, or the tooth portion 331a is used to mesh with a tooth portion 331a provided on the rotating arm. The second concave-convex portion 331b is connected to one or both ends of the tooth portion 331a along the length direction of the folding device 3, and the second concave-convex portion 331b has a second concave-convex surface for meshing with the first concave-convex surface of the cam 35. The second concave-convex portion 331b includes a second base layer (not shown in the figure) and a second wear-resistant layer (not shown in the figure) covering the second base layer, the second base layer and the second wear-resistant layer are integrally formed, and the surface of the second wear-resistant layer is the second concave-convex surface of the gear 331. The hardness of the second wear-resistant layer is greater than the hardness of the second base layer. That is, the hardness of the second concave-convex surface of the gear 331 for meshing with the first concave-convex surface of the cam 35 in this embodiment is increased, and the wear resistance is improved. During the folding or unfolding process of the folding device 3, the friction between the first concave-convex surface and the second concave-convex surface during the relative movement between the two reduces the degree of wear on the second concave-convex surface of the gear 331, thereby reducing the risk of structural changes of the second concave-convex surface due to wear, and further reducing the risk of reduction in the damping force provided by the damping component during the folding or unfolding process of the folding device 3, so that the foldable electronic device has a better feel during the folding or unfolding process, thereby improving the user experience.

[0134] The second wear-resistant layer of the gear 331 can be formed by ultrasonic impact strengthening the surface of the gear 331. The structure and forming method thereof can be referred to in the above embodiments and will not be described again here.

[0135] In a specific embodiment, the first concave-convex portion 351 of the cam 35 of the folding device 3 may include the above-mentioned first base layer 351a and the first wear-resistant layer 351b, and the second concave-convex portion 331b of the gear 331 may only include the above-mentioned second base layer, that is, the first concave-convex portion 351 of the cam 35 is ultrasonically strengthened, and the second concave-convex portion 331b of the gear 331 is not ultrasonically strengthened. In another specific embodiment, the first concave-convex portion 351 of the cam 35 of the folding device 3 may only include the above-mentioned first base layer 351a, and the second concave-convex portion 331b of the gear 331 may include the above-mentioned second base layer and the second wear-resistant layer, that is, the first concave-convex portion 351 of the cam 35 is not ultrasonically strengthened, and the second concave-convex portion 331b of the gear 331 is ultrasonically strengthened. In another specific embodiment, the first concave-convex portion 351 of the cam 35 of the folding device 3 includes the above-mentioned first base layer 351a and the first wear-resistant layer 351b, and the second concave-convex portion 331b of the gear 331 includes the above-mentioned second base layer and the second wear-resistant layer, that is, the first concave-convex portion 351 of the cam 35 and the second concave-convex portion 331b of the gear 331 are both ultrasonically strengthened.

Claims

1. A cam, characterized in that: The cam includes a first concavoconvex portion, the first concavoconvex portion includes a first base layer and a first wear-resistant layer covering the first base layer, the first base layer and the first wear-resistant layer are integrally formed, and the first wear-resistant layer is a concavoconvex surface of the cam; Wherein, the hardness of the first wear-resistant layer is greater than the hardness of the first base layer.

2. The cam according to claim 1, characterized in that: The grains of the first wear-resistant layer are nanometer-scale, and the grain size of the first wear-resistant layer is smaller than the grain size of the first substrate layer.

3. The cam according to claim 2, characterized in that: The grains of the first substrate layer are in micron order.

4. The cam according to claim 2, characterized in that: In a direction from the first wear-resistant layer to the first base layer, the grain size of the first wear-resistant layer gradually increases.

5. The cam according to any one of claims 1 to 4, characterized in that: Along the thickness direction of the cam, the thickness (L) of the first wear-resistant layer satisfies 20um≤(L)≤500um.

6. The cam according to any one of claims 1 to 4, characterized in that: The hardness of the first wear-resistant layer is 8%-15% higher than that of the first base layer.

7. The cam according to any one of claims 1 to 4, characterized in that: The roughness Ra of the first wear-resistant layer satisfies 0<Ra≤0.

6.

8. The cam according to any one of claims 1 to 4, characterized in that: The material of the cam is steel material formed by metal injection molding or titanium alloy formed by metal injection molding.

9. The cam according to any one of claims 1 to 4, characterized in that: The first wear-resistant layer is formed by performing ultrasonic impact strengthening on the surface of the first concave-convex portion.

10. A gear, characterized in that: The gear comprises a tooth portion and a second concave-convex portion, the second concave-convex portion comprises a second base layer and a second wear-resistant layer covering the second base layer, the second base layer and the second wear-resistant layer are integrally formed, and the second wear-resistant layer is a concave-convex surface of the gear; Wherein, the hardness of the second wear-resistant layer is greater than the hardness of the second base layer.

11. The gear according to claim 10, characterized in that The grain size of the second wear-resistant layer gradually increases from the second wear-resistant layer to the second base layer.

12. The gear according to claim 10, characterized in that Along the thickness direction of the gear, the thickness of the second wear-resistant layer is between 20um and 500um.

13. The gear according to claim 10, characterized in that The second wear-resistant layer is formed by performing ultrasonic impact strengthening on the surface of the second concave-convex portion.

14. A folding device, characterized in that: The folding device comprises: Spindle; Swivel arm; A synchronous gear assembly, the synchronous gear assembly comprising a gear; a damping assembly, the damping assembly comprising a cam; Wherein, the cam is the cam according to any one of claims 1 to 9, and / or the gear is the gear according to any one of claims 10 to 13; The first concavo-convex portion of the cam meshes with the second concavo-convex portion of the gear.

15. A foldable electronic device, characterized in that: The foldable electronic device comprises a screen and the folding device described in claim 14.

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