Foldable electronic device including hinge assembly having friction wheels

Abstract

This foldable electronic device comprises: a foldable housing including a first housing part and a second housing part; and a hinge assembly rotatably connecting the first housing part and the second housing part. The hinge assembly includes: a hinge bracket; a first rotator rotatably coupled to the hinge bracket; a first arm configured to rotate together with the first housing part; a second rotator rotatably coupled to the hinge bracket; a second arm configured to rotate together with the second housing part; and friction wheels configured to synchronize the rotation of the first arm and the rotation of the second arm. One of the friction wheels includes a protrusion that is in contact with a protrusion of another friction wheel adjacent to the one friction wheel when the foldable electronic device is in an unfolded state.

Description

Foldable electronic device including a hinge assembly including friction wheels

[0001] The present disclosure relates to a foldable electronic device comprising a hinge assembly including friction wheels.

[0002] An electronic device may include a foldable housing comprising a plurality of housing parts that are rotatably connected to each other. The electronic device may include a hinge assembly for rotatably connecting the plurality of housing parts. For example, the electronic device may include a first housing part and a second housing part that are rotatably connected to each other through the hinge assembly. The hinge assembly may be configured to synchronize the rotation of the first housing part with the rotation of the second housing part.

[0003] The information described above may be provided as related art for the purpose of aiding understanding of the present disclosure. No claim or determination is made as to whether any of the foregoing may be applied as prior art in relation to the present disclosure.

[0004] A foldable electronic device is disclosed. The foldable electronic device may include a foldable housing comprising a first housing part and a second housing part. The foldable electronic device may include a hinge assembly rotatably connecting the first housing part and the second housing part. The hinge assembly may include a hinge bracket, a first rotator rotatably coupled to the hinge bracket to guide the rotation of the first housing part, a first arm configured to rotate together with the rotation of the first housing part, a second rotator rotatably coupled to the hinge bracket to guide the rotation of the second housing part, a second arm configured to rotate together with the rotation of the second housing part, and friction wheels configured to synchronize the rotation of the first arm with the rotation of the second arm. One (a) of the friction wheels may include a protrusion that contacts a protrusion of another friction wheel adjacent to the one friction wheel among the friction wheels when the foldable electronic device is in an unfolded state.

[0005] A foldable electronic device is disclosed. The foldable electronic device may include a foldable housing comprising a first housing part and a second housing part. The foldable electronic device may include a flexible display. The flexible display may include a first part corresponding to the first housing part, a second part corresponding to the second housing part, and a third part extending from the first part to the second part and configured to be at least partially bent based on the rotation of the first housing part and the rotation of the second housing part. The foldable electronic device may include a hinge assembly rotatably connecting the first housing part and the second housing part. The hinge assembly may include friction wheels configured to synchronize the rotation of the first housing part and the rotation of the second housing part. The friction wheels may include a first friction wheel configured to rotate with the rotation of the first housing part, a second friction wheel configured to rotate with the rotation of the second housing part, a third friction wheel in contact with the first friction wheel, and a fourth friction wheel in contact with the second friction wheel and in contact with the third friction wheel. The friction wheels do not include these.

[0006] FIG. 1 is a block diagram of an electronic device in a network environment according to various embodiments.

[0007] FIG. 2a illustrates an example of an unfolded state of a foldable electronic device.

[0008] FIG. 2b illustrates an example of a folded state of a foldable electronic device.

[0009] FIG. 2c is an exploded view of a foldable electronic device.

[0010] FIG. 3 illustrates a foldable housing and a hinge assembly of a foldable electronic device.

[0011] FIG. 4 is an exploded perspective view of a part of the hinge assembly of FIG. 3.

[0012] Fig. 5 illustrates spur gears.

[0013] FIG. 6 is a cross-sectional view of a foldable electronic device in an unfolded state, cut along the AA' line of FIG. 3.

[0014] Figure 7 is a cross-sectional view of a foldable electronic device in a folded state.

[0015] FIG. 8 illustrates the unfolded state of a foldable electronic device when slip is induced in the friction wheels.

[0016] FIG. 9 illustrates the folded state of a foldable electronic device when slip is caused on the friction wheels.

[0017] Figure 10 illustrates the process of removing slip from friction wheels.

[0018] FIGS. 11 and 12 illustrate a hinge assembly of a foldable electronic device according to one embodiment.

[0019] FIG. 13 is a cross-sectional view of the hinge assembly of FIG. 12 cut along the BB' line.

[0020] FIG. 14 illustrates the friction wheels of a hinge assembly.

[0021] FIG. 1 is a block diagram of an electronic device in a network environment according to various embodiments.

[0022] Referring to FIG. 1, in a network environment (100), an electronic device (101) may communicate with an electronic device (102) through a first network (198) (e.g., a short-range wireless communication network) or with an electronic device (104) or a server (108) through a second network (199) (e.g., a long-range wireless communication network). According to one embodiment, the electronic device (101) may communicate with the electronic device (104) through a server (108). According to one embodiment, the electronic device (101) may include a processor (120), memory (130), input module (150), sound output module (155), display module (160), audio module (170), sensor module (176), interface (177), connection terminal (178), haptic module (179), camera module (180), power management module (188), battery (189), communication module (190), subscriber identification module (196), or antenna module (197). In some embodiments, at least one of these components (e.g., connection terminal (178)) may be omitted from the electronic device (101), or one or more other components may be added. In some embodiments, some of these components (e.g., sensor module (176), camera module (180), or antenna module (197)) may be integrated into a single component (e.g., display module (160)).

[0023] The processor (120) can control at least one other component (e.g., hardware or software component) of the electronic device (101) connected to the processor (120) by executing software (e.g., program (140)), for example, and can perform various data processing or operations. According to one embodiment, as at least part of the data processing or operations, the processor (120) can store commands or data received from other components (e.g., sensor module (176) or communication module (190)) in volatile memory (132), process the commands or data stored in volatile memory (132), and store the resulting data in non-volatile memory (134). According to one embodiment, the processor (120) may include a main processor (121) (e.g., central processing unit or application processor) or an auxiliary processor (123) that can operate independently or together with it (e.g., graphics processing unit, neural processing unit (NPU), image signal processor, sensor hub processor, or communication processor). For example, if the electronic device (101) includes a main processor (121) and an auxiliary processor (123), the auxiliary processor (123) may be configured to use less power than the main processor (121) or to be specialized for a designated function. The auxiliary processor (123) may be implemented separately from the main processor (121) or as part thereof.

[0024] The auxiliary processor (123) may control at least some of the functions or states associated with at least one component of the electronic device (101) (e.g., display module (160), sensor module (176), or communication module (190)) on behalf of the main processor (121) while the main processor (121) is in an inactive (e.g., sleep) state, or together with the main processor (121) while the main processor (121) is in an active (e.g., application execution) state. According to one embodiment, the auxiliary processor (123) (e.g., image signal processor or communication processor) may be implemented as part of another functionally related component (e.g., camera module (180) or communication module (190)). According to one embodiment, the auxiliary processor (123) (e.g., neural network processing unit) may include a hardware structure specialized for processing an artificial intelligence model. The artificial intelligence model may be generated through machine learning. Such learning may be performed, for example, on the electronic device (101) itself where the artificial intelligence is performed, or through a separate server (e.g., server (108)). The learning algorithm may include, for example, supervised learning, unsupervised learning, semi-supervised learning, or reinforcement learning, but is not limited to the examples described above. The artificial intelligence model may include a plurality of artificial neural network layers.An artificial neural network may be a deep neural network (DNN), a convolutional neural network (CNN), a recurrent neural network (RNN), a restricted Boltzmann machine (RBM), a deep belief network (DBN), a bidirectional recurrent deep neural network (BRDNN), a deep Q-network, or a combination of two or more of the above, but is not limited to the examples described above. In addition to the hardware structure, the artificial intelligence model may include a software structure, either additionally or substantially.

[0025] The memory (130) can store various data used by at least one component of the electronic device (101) (e.g., processor (120) or sensor module (176)). The data may include, for example, input data or output data for software (e.g., program (140)) and related commands. The memory (130) may include volatile memory (132) or non-volatile memory (134).

[0026] The program (140) may be stored as software in memory (130) and may include, for example, an operating system (142), middleware (144), or an application (146).

[0027] The input module (150) can receive commands or data to be used for a component of the electronic device (101) (e.g., processor (120)) from outside the electronic device (101) (e.g., user). The input module (150) may include, for example, a microphone, a mouse, a keyboard, a key (e.g., a button), or a digital pen (e.g., a stylus pen).

[0028] The sound output module (155) can output a sound signal to the outside of the electronic device (101). The sound output module (155) may include, for example, a speaker or a receiver. The speaker may be used for general purposes, such as multimedia playback or recording playback. The receiver may be used to receive incoming calls. According to one embodiment, the receiver may be implemented separately from the speaker or as part thereof.

[0029] The display module (160) can visually provide information to an external (e.g., user) of the electronic device (101). The display module (160) may include, for example, a display, a holographic device, or a projector and a control circuit for controlling said device. According to one embodiment, the display module (160) may include a touch sensor configured to detect a touch, or a pressure sensor configured to measure the intensity of the force generated by said touch.

[0030] The audio module (170) can convert sound into an electrical signal or, conversely, convert an electrical signal into sound. According to one embodiment, the audio module (170) can acquire sound through the input module (150) or output sound through the sound output module (155) or an external electronic device (e.g., electronic device (102)) (e.g., speaker or headphones) connected directly or wirelessly to the electronic device (101).

[0031] The sensor module (176) can detect the operating state of the electronic device (101) (e.g., power or temperature) or the external environmental state (e.g., user state) and generate an electrical signal or data value corresponding to the detected state. According to one embodiment, the sensor module (176) may include, for example, a gesture sensor, a gyroscope sensor, a barometric pressure sensor, a magnetic sensor, an accelerometer sensor, a grip sensor, a proximity sensor, a color sensor, an IR (infrared) sensor, a biosensor, a temperature sensor, a humidity sensor, or an illuminance sensor.

[0032] The interface (177) may support one or more specified protocols that can be used for the electronic device (101) to be connected directly or wirelessly to an external electronic device (e.g., electronic device (102)). According to one embodiment, the interface (177) may include, for example, a high definition multimedia interface (HDMI), a universal serial bus (USB) interface, an SD card interface, or an audio interface.

[0033] The connection terminal (178) may include a connector through which the electronic device (101) can be physically connected to an external electronic device (e.g., electronic device (102)). According to one embodiment, the connection terminal (178) may include, for example, an HDMI connector, a USB connector, an SD card connector, or an audio connector (e.g., a headphone connector).

[0034] The haptic module (179) can convert an electrical signal into a mechanical stimulus (e.g., vibration or movement) or an electrical stimulus that the user can perceive through tactile or kinesthetic senses. According to one embodiment, the haptic module (179) may include, for example, a motor, a piezoelectric element, or an electric stimulation device.

[0035] The camera module (180) can capture still images and video. According to one embodiment, the camera module (180) may include one or more lenses, image sensors, image signal processors, or flashes.

[0036] The power management module (188) can manage power supplied to the electronic device (101). According to one embodiment, the power management module (188) can be implemented, for example, as at least part of a power management integrated circuit (PMIC).

[0037] The battery (189) can supply power to at least one component of the electronic device (101). According to one embodiment, the battery (189) may include, for example, a non-rechargeable primary battery, a rechargeable secondary battery, or a fuel cell.

[0038] The communication module (190) can support the establishment of a direct (e.g., wired) communication channel or a wireless communication channel between an electronic device (101) and an external electronic device (e.g., electronic device (102), electronic device (104), or server (108)), and the performance of communication through the established communication channel. The communication module (190) may include one or more communication processors that operate independently of the processor (120) (e.g., application processor) and support direct (e.g., wired) communication or wireless communication. According to one embodiment, the communication module (190) may include a wireless communication module (192) (e.g., cellular communication module, short-range wireless communication module, or GNSS (global navigation satellite system) communication module) or a wired communication module (194) (e.g., LAN (local area network) communication module, or power line communication module). The corresponding communication module among these communication modules can communicate with an external electronic device (104) through a first network (198) (e.g., a short-range communication network such as Bluetooth, WiFi (wireless fidelity) direct, or IrDA (infrared data association)) or a second network (199) (e.g., a legacy cellular network, a 5G network, a next-generation communication network, the Internet, or a computer network (e.g., a LAN or WAN). These various types of communication modules may be integrated into a single component (e.g., a single chip) or implemented as multiple separate components (e.g., multiple chips). The wireless communication module (192) can identify or authenticate the electronic device (101) within a communication network such as the first network (198) or the second network (199) using subscriber information (e.g., International Mobile Subscriber Identifier (IMSI)) stored in the subscriber identification module (196).

[0039] The wireless communication module (192) can support 5G networks and next-generation communication technologies following 4G networks, for example, new radio access technology. NR access technology can support high-speed transmission of high-capacity data (enhanced mobile broadband (eMBB)), minimization of terminal power and connection of multiple terminals (massive machine type communications (mMTC)), or high reliability and low latency (ultra-reliable and low-latency communications (URLLC)). The wireless communication module (192) can support a high-frequency band (e.g., mmWave band) to achieve a high data transmission rate, for example. The wireless communication module (192) can support various technologies for securing performance in the high-frequency band, such as beamforming, massive MIMO (multiple-input and multiple-output), full-dimensional MIMO (FD-MIMO), array antenna, analog beam-forming, or large-scale antenna. The wireless communication module (192) can support various requirements specified in the electronic device (101), external electronic device (e.g., electronic device (104)), or network system (e.g., second network (199)). According to one embodiment, the wireless communication module (192) may support a Peak data rate (e.g., 20 Gbps or more) for eMBB realization, loss coverage (e.g., 164 dB or less) for mMTC realization, or U-plane latency (e.g., downlink (DL) and uplink (UL) each 0.5 ms or less, or round trip 1 ms or less) for URLLC realization.

[0040] An antenna module (197) can transmit a signal or power to or from an external source (e.g., an external electronic device). According to one embodiment, the antenna module (197) may include an antenna comprising a radiator made of a conductor or a conductive pattern formed on a substrate (e.g., a PCB). According to one embodiment, the antenna module (197) may include a plurality of antennas (e.g., an array antenna). In this case, at least one antenna suitable for a communication method used in a communication network, such as a first network (198) or a second network (199), may be selected from the plurality of antennas, for example, by a communication module (190). A signal or power may be transmitted or received between the communication module (190) and an external electronic device through the selected at least one antenna. According to some embodiments, in addition to the radiator, other components (e.g., a radio frequency integrated circuit (RFIC)) may be additionally formed as part of the antenna module (197).

[0041] According to one embodiment, the antenna module (197) may form a mmWave antenna module. According to one embodiment, the mmWave antenna module may include a printed circuit board, an RFIC disposed on or adjacent to a first surface (e.g., bottom surface) of the printed circuit board and capable of supporting a specified high frequency band (e.g., mmWave band), and a plurality of antennas (e.g., array antennas) disposed on or adjacent to a second surface (e.g., top surface or side surface) of the printed circuit board and capable of transmitting or receiving a signal of the specified high frequency band.

[0042] At least some of the above components can be connected to each other via a communication method between peripheral devices (e.g., bus, GPIO (general purpose input and output), SPI (serial peripheral interface), or MIPI (mobile industry processor interface)) and exchange signals (e.g., commands or data) with each other.

[0043] According to one embodiment, commands or data may be transmitted or received between the electronic device (101) and an external electronic device (104) through a server (108) connected to a second network (199). Each of the external electronic devices (102, or 104) may be the same or a different type of device as the electronic device (101). According to one embodiment, all or part of the operations performed on the electronic device (101) may be performed on one or more of the external electronic devices (102, 104, or 108). For example, if the electronic device (101) needs to perform a function or service automatically or in response to a request from a user or another device, the electronic device (101) may request one or more external electronic devices to perform at least part of the function or service instead of performing the function or service itself or additionally. One or more external electronic devices that receive the above request may execute at least part of the requested function or service, or additional function or service related to the request, and transmit the result of the execution to the electronic device (101). The electronic device (101) may provide the result as is or additionally processed as at least part of the response to the request. For this purpose, for example, cloud computing, distributed computing, mobile edge computing (MEC), or client-server computing technology may be used. The electronic device (101) may provide ultra-low latency services using, for example, distributed computing or mobile edge computing. In another embodiment, the external electronic device (104) may include an Internet of Things (IoT) device. The server (108) may be an intelligent server using machine learning and / or neural networks. According to one embodiment, the external electronic device (104) or the server (108) may be included within a second network (199).The electronic device (101) can be applied to intelligent services (e.g., smart home, smart city, smart car, or healthcare) based on 5G communication technology and IoT-related technology.

[0044] FIG. 2a illustrates an example of an unfolded state of a foldable electronic device. FIG. 2b illustrates an example of a folded state of a foldable electronic device. FIG. 2c is an exploded view of a foldable electronic device.

[0045] The electronic device (101) of FIG. 1 may include a foldable electronic device (200). Referring to FIG. 2a, FIG. 2b, and FIG. 2c, a foldable electronic device (200) according to one embodiment may include a foldable housing (201), a flexible display (230), one or more cameras (240), and a hinge assembly (250).

[0046] According to one embodiment, the foldable housing (201) may define the exterior surface of the foldable electronic device (200). For example, the foldable housing (201) may accommodate components disposed inside the foldable electronic device (200) as the physical exterior of the foldable electronic device (200) exposed to the outside. At least some of the components for implementing the functions of the foldable electronic device (200) may be disposed within the foldable housing (201). According to one embodiment, the foldable housing (201) may include a first housing part (210) and a second housing part (220).

[0047] According to one embodiment, the first housing part (210) may include a first surface (211), a second surface (212) opposite to the first surface (211), and a first side (213) (side exterior surface) that at least partially covers the edge of the first surface (211) and the edge of the second surface (212). For example, the first surface (211) may be referred to as the front exterior surface of the first housing part (210), and the second surface (212) may be referred to as the rear exterior surface of the first housing part (210). The first side (213) may be connected to the periphery of the first surface (211) and the edge of the second surface (212). The first surface (211), the second surface (212), and the first side (213) may form an internal space of the first housing part (210). For example, at least one component may be placed within the space enclosed by the first surface (211), the second surface (212), and the first side (213).

[0048] According to one embodiment, the second housing part (220) may include a third surface (221), a fourth surface (222) opposite to the third surface (221), and a second side (223) that at least partially covers the edge of the third surface (221) and the edge of the fourth surface (222). For example, the third surface (221) may be referred to as the front of the second housing part (220), and the fourth surface (222) may be referred to as the rear of the second housing part (220). The second side (223) may be connected to the edge of the third surface (221) and the edge of the fourth surface (222). The third surface (221), the fourth surface (222), and the second side (223) may form an internal space of the second housing part (220). For example, at least one component may be placed within the space enclosed by the third side (221), the fourth side (222), and the second side (223).

[0049] According to one embodiment, the flexible display (230) may be configured to display visual information. For example, the flexible display (230) may include a display area comprising a plurality of pixels. For example, the active area may be referred to as an active area that displays visual information.

[0050] According to one embodiment, the flexible display (230) may include a first part (231), a second part (232), and a third part (233) disposed between the first part (231) and the second part (232). The foldable electronic device (200) may further include a cover display (235) distinct from the flexible display (230). The cover display (235) may be referred to as a sub-display.

[0051] According to one embodiment, the first part (231) may be supported by the first housing part (210). The second part (232) may be supported by the second housing part (220). The first part (231) and the second part (232) may be substantially flat independently of the state of the foldable electronic device (200). The third part (233) may be configured to bend based on the rotation of the first housing part (210) or the second housing part (220). For example, within the unfolded state where the first housing part (210) and the second housing part (220) are unfolded, the third part (233) may be substantially flat. In a folded state or partially folded state (or partially unfolded state) in which the first housing part (210) and the second housing part (220) are folded, the third part (233) may be at least partially bent. The flexible display (230) may be a flexible display including the bendable third part (233).

[0052] According to one embodiment, one or more cameras (240) may be configured to acquire an image or video based on receiving light from an object outside the foldable electronic device (200). For example, one or more cameras (240) may include first cameras (241), a second camera (242), and / or a third camera (243). For example, the first cameras (241) may be disposed within a first housing part (210). For example, the first housing part (210) may include at least one opening (241a) that overlaps the first cameras (241) when the foldable electronic device (200) is viewed from above. The first cameras (241) may acquire an image based on receiving light from outside the foldable electronic device (200) through the at least one opening (241a). The first cameras (241) can face the rear side of the foldable electronic device (200).

[0053] According to one embodiment, the second camera (242) may be disposed within the second housing part (220). The second housing part (220) may include at least one opening (242a) that overlaps the second camera (242) when the foldable electronic device (200) is viewed from above. The second camera (242) may acquire an image based on receiving light from outside the foldable electronic device (200) through the at least one opening (242a).

[0054] According to one embodiment, the third camera (243) may be disposed within the first housing part (210). For example, the first part (231) of the flexible display (230) may include at least one opening that overlaps the third camera (243) when the flexible display (230) is viewed from above. The third camera (243) may acquire an image based on receiving light from outside the flexible display (230) through the at least one opening.

[0055] According to one embodiment, the second camera (242) and the third camera (243) may be positioned below the flexible display (230) or the cover display (235) (e.g., in the -z direction). For example, the second camera (242) and / or the third camera (243) may include an under display camera (UDC) and / or a punch hole camera.

[0056] According to one embodiment, the first housing part (210) and the second housing part (220) can be rotatably coupled. For example, the second housing part (220) can be rotatably coupled to the first housing part (210) through a hinge assembly (250).

[0057] According to one embodiment, the hinge assembly (250) can rotatably connect the first housing part (210) and the second housing part (220). The hinge assembly (250) can be positioned between the first housing part (210) and the second housing part (220) of the foldable electronic device (200) so that the foldable electronic device (200) can be folded. The hinge assembly (250) can change the foldable electronic device (200) from an unfolded state to a folded state. The hinge assembly (250) can change the foldable electronic device (200) from a folded state to an unfolded state. For example, the hinge assembly (250) can maintain the foldable electronic device (200) in a partially folded state (or partially unfolded state) between the unfolded state and the folded state.

[0058] According to one embodiment, the unfolded state may be referred to as a state in which the first direction in which the first part (231) faces and the second direction in which the second part (232) faces are substantially the same. The folded state may be referred to as a state in which the first direction is substantially opposite to the second direction. When the foldable electronic device (200) is in the folded state, the first housing part (210) and the second housing part (220) may be stacked or overlapped.

[0059] According to one embodiment, when the foldable electronic device (200) is in a folded state and a partially folded state, the first direction and the second direction may be different from each other. For example, when the foldable electronic device (200) is in a folded state, the first direction and the second direction may be opposite to each other. For example, when the foldable electronic device (200) is in a partially folded state, the first direction may form an angle with respect to the second direction.

[0060] For example, the foldable electronic device (200) may include at least one conductive portion (214a, 224a) and at least one non-conductive portion (214b, 224b) included within the first side (213) and / or the third side (223). For example, the at least one conductive portion (214a, 224a) may be separated from other conductive portions within the first side (213) and / or the third side (223) by contacting the at least one non-conductive portion (214b, 224b). In one embodiment, the at least one conductive portion (214a, 224a) may operate as an antenna radiator to be used for communication with an external electronic device.

[0061] Referring to FIG. 2c, the hinge assembly (250) may include a hinge cover (251), a first hinge plate (252), a second hinge plate (253), and a plurality of hinge modules (254). The hinge cover (251) may at least partially cover the components of the hinge assembly (250) and form the outer surface of the hinge assembly (250). The hinge cover (251) may be at least partially exposed to the outside of the foldable electronic device (200) through the space between the first housing part (210) and the second housing part (220) when the foldable electronic device (200) is in a folded state. When the foldable electronic device (200) is in an unfolded state, the hinge cover (251) may be covered by the first housing part (210) and the second housing part (220) so as not to be exposed to the outside of the foldable electronic device (200). The hinge cover (251) may be referred to as a hinge housing part.

[0062] According to one embodiment, the first hinge plate (252) and the second hinge plate (253) are each operatively coupled to the first housing part (210) and the second housing part (220), respectively, thereby allowing the first housing part (210) and the second housing part (220) to be rotatably connected. For example, the first hinge plate (252) may be coupled to the first support member (215) of the first housing part (210), and the second hinge plate (253) may be coupled to the second support member (227) of the second housing part (220). As the first hinge plate (252) and the second hinge plate (253) are operatively coupled to the first support member (215) and the second support member (227), respectively, the first housing part (210) and the second housing part (220) may be rotatable according to the rotation of the first hinge plate (252) and the second hinge plate (253).

[0063] According to one embodiment, a plurality of hinge modules (254) can rotate a first hinge plate (252) and a second hinge plate (253). For example, the plurality of hinge modules (254) may include gears that are rotatably engaged with each other (e.g., friction wheels (400) of FIG. 3). The first hinge plate (252) and the second hinge plate (253) can be rotated based on the rotational movement of the gears of the plurality of hinge modules (254).

[0064] According to one embodiment, the first housing part (210) may include a first support member (215) and a rear cover (216). The first support member (215) is disposed inside the first housing part (210) and may support at least one component disposed inside the first housing part (210). The rear cover (216) may at least partially form a second surface (212) of the first housing part (210). For example, the second housing part (220) may include a second support member (227). The second support member (227) is disposed inside the second housing part (220) and may support at least one component disposed inside the second housing part (220). For example, a cover display (235) may be disposed below (e.g., in the -z direction) the second support member (227). According to one embodiment, a flexible display (e.g., the flexible display (230) of FIG. 2a) can define the front side of the foldable electronic device (200), and a rear cover (216) opposite to the flexible display can define the rear side of the foldable electronic device (200).

[0065] A foldable electronic device (200) according to one embodiment may include a plurality of electronic components for implementing various functions in addition to the one or more cameras (240) described above. For example, the foldable electronic device (200) may include a first printed circuit board (261), a second printed circuit board (262), a flexible printed circuit board (263), and / or a battery (189). The electronic components described above are exemplary and are not limited thereto.

[0066] For example, the first printed circuit board (261) and the second printed circuit board (262) can each provide electrical connections between components within the foldable electronic device (200). For example, the first printed circuit board (261) can be placed within the first housing part (210), and the second printed circuit board (262) can be placed within the second housing part (220). The first printed circuit board (261) can provide electrical connections between electronic components placed within the first housing part (210). The second printed circuit board (262) can provide electrical connections between electronic components placed within the second housing part (220). A flexible printed circuit board (263) can electrically connect the first printed circuit board (261) and the second printed circuit board (262). For example, the flexible printed circuit board (263) may extend from the first printed circuit board (261) across the hinge assembly (250) to the second printed circuit board (262). For example, the flexible printed circuit board (263) may overlap at least partially with the hinge assembly (250).

[0067] According to one embodiment, the battery (189) is a device for supplying power to at least one component of the foldable electronic device (200), and may include, for example, a non-rechargeable primary battery and / or a rechargeable secondary battery.

[0068] According to one embodiment, the foldable electronic device (200) may include a plurality of antennas (ANT1, ANT2, ANT3, or ANT4) to be used for communication with an external electronic device. For example, the foldable electronic device (200) may include a main antenna (ANT1), a sub-antenna (ANT2), an ultra-wide band (UWB) antenna (ANT3), and / or an antenna (ANT4) for short-range wireless communication. However, it is not limited thereto. For example, the main antenna (ANT1) may include one or more conductive portions forming at least a portion of the first housing part (210) or the second housing part (220). For example, the main antenna (ANT1) may include a plurality of conductive portions forming an edge portion of the first housing part (210). For example, the main antenna (ANT1) may further include conductive portions forming an upper edge or a side edge of the first housing part (210). The main antenna (ANT1) can be configured to transmit and / or receive signals of various frequency bands through each of the plurality of conductive parts or a combination of the plurality of conductive parts.

[0069] One or more components to be described below with reference to the drawings may be implemented together with the components of the foldable electronic device (200) described with reference to FIG. 2a, FIG. 2b, and FIG. 2c.

[0070] FIG. 3 illustrates a foldable housing and a hinge assembly of a foldable electronic device. FIG. 4 is an exploded perspective view of a part of the hinge assembly of FIG. 3.

[0071] Referring to FIG. 3, a foldable electronic device (200) according to one embodiment may include a foldable housing (201) and a hinge assembly (300) (e.g., the hinge assembly (250) of FIG. 2c).

[0072] According to one embodiment, the foldable housing (201) may include a first housing part (210) and a second housing part (220). A hinge assembly (300) may be configured to rotatably connect the first housing part (210) and the second housing part (220). For example, the first housing part (210) and the second housing part (220) may be configured to rotate relative to each other through the hinge assembly (300).

[0073] According to one embodiment, the hinge assembly (300) may include components for rotatably connecting a first housing part (210) and a second housing part (220). When an external force is applied to the first housing part (210) and / or the second housing part (220), the components of the hinge assembly (300) may operate in response to the external force. The external force may be referred to as a torque provided by a user to the first housing part (210) and / or the second housing part (220) to change the state of the foldable electronic device (200).

[0074] According to one embodiment, the first housing part (210) may include a first support member (215). The first support member (215) may support components disposed within the first housing part (210). The second housing part (220) may include a second support member (227). The second support member (227) may support components disposed within the second housing part (220). A hinge assembly (300) may rotatably connect the first support member (215) and the second support member (227).

[0075] According to one embodiment, the hinge assembly (300) may include a first hinge module (301) and a second hinge module (302). The first hinge module (301) may be spaced apart from the second hinge module (302). For example, the first hinge module (301) may be positioned adjacent to the upper part (e.g., +y direction) of the foldable electronic device (200), and the second hinge module (302) may be positioned adjacent to the lower part (e.g., -y direction) of the foldable electronic device (200). For example, the first hinge module (301) and the second hinge module (302) may be positioned symmetrically with respect to an imaginary line perpendicular to the rotation axis of the foldable electronic device (200). The second hinge module (302) may substantially correspond to the first hinge module (301). In the following description, the descriptions of the hinge assembly (300) may be applied substantially the same way to the first hinge module (301) and the second hinge module (302).

[0076] Referring to FIGS. 3 and 4, the hinge assembly (300) may include a hinge bracket (310), rotators (e.g., a first rotator (321) and a second rotator (322)), arms (e.g., a first arm (331) and a second arm (332)), friction wheels (400), and coupling brackets (e.g., a first coupling bracket (341), a second coupling bracket (342), a third coupling bracket (343), and a fourth coupling bracket (344)).

[0077] According to one embodiment, rotators (321, 322) may be rotatably coupled to a hinge bracket (310). For example, the hinge bracket (310) may include a first rail (311) and a second rail (312). The first rail (311) may have an arc shape to guide the rotational movement of the first housing part (210). The second rail (312) may have an arc shape to guide the rotational movement of the second housing part (220). The rotators (321, 322) may include a first rotator (321) and a second rotator (322). The first rotator (321) may include a rail portion (321a) that is rotatably coupled to the first rail (311) of the hinge bracket (310). The second rotator (322) may include a rail portion (322a) that is rotatably coupled to the second rail (312) of the hinge bracket (310). The first rotator (321) may rotate along the first rail (311), and the second rotator (322) may rotate along the second rail (312).

[0078] According to one embodiment, rotators (321, 322) may be coupled to a foldable housing (201). For example, a first rotator (321) may be coupled to a first housing part (210), and a second rotator (322) may be coupled to a second housing part (220). According to one embodiment, a hinge assembly (300) may include a first coupling bracket (341) and a second coupling bracket (342) for coupling the rotators (321, 322) to the foldable housing (201). For example, the first coupling bracket (341) can mechanically connect the first rotator (321) and the first housing part (210) by being coupled to the first support member (215) of the first housing part (210) and the first rotator (321). The first rotator (321), configured to rotate along the first rail (311) of the hinge bracket (310), can guide the rotation of the first housing part (210). For example, the second coupling bracket (342) can mechanically connect the second rotator (322) and the second housing part (220) by being coupled to the second support member (227) of the second housing part (220) and the second rotator (322). A second rotator (322) configured to rotate along the second rail (312) of the hinge bracket (310) can guide the rotation of the second housing part (220).

[0079] According to one embodiment, the arms (331, 332) and friction wheels (400) may be configured to synchronize the rotation of the first housing part (210) and the rotation of the second housing part (220) with each other. As the rotation of the first housing part (210) and the rotation of the second housing part (220) are synchronized with each other, the rotation of either the first housing part (210) or the second housing part (220) may cause the rotation of the other.

[0080] According to one embodiment, the arms (331, 332) may include a first arm (331) and a second arm (332). The hinge assembly (300) may include a third coupling bracket (343) and a fourth coupling bracket (344) for coupling the arms (331, 332) to a foldable housing (201). For example, the third coupling bracket (343) may mechanically connect the first arm (331) and the first housing part (210) by being coupled to the first arm (331) and the first support member (215) of the first housing part (210). For example, the fourth coupling bracket (344) can mechanically connect the second arm (332) and the second housing part (220) by being coupled to the second support member of the second arm (332) and the second housing part (220).

[0081] According to one embodiment, the hinge assembly (300) may include a first shaft (351) and a second shaft (352) for synchronizing the rotation of the arms (331, 332). For example, the first shaft (351) may be coupled to the first arm (331) and the hinge bracket (310). For example, the second shaft (352) may be coupled to the second arm (332) and the hinge bracket (310). The hinge cover may include a guide member (251a) for supporting the first shaft (351) and the second shaft (352). For example, the first shaft (351) and the second shaft (352) may be inserted into a recess of the guide member (251a) and supported by the guide member (251a).

[0082] According to one embodiment, the friction wheels (400) may include four friction wheels. For example, the friction wheels (400) may include a first friction wheel (410), a second friction wheel (420), a third friction wheel (430), and a fourth friction wheel (440). The first friction wheel (410) may be coupled to a first shaft (351) coupled to a first arm (331). For example, by inserting the first shaft (351) into the first friction wheel (410), the first friction wheel (410) may be positioned to surround the outer surface of the first shaft (351). The second friction wheel (420) may be coupled to a second shaft (352) coupled to a second arm (332). For example, by inserting the second shaft (352) into the second friction wheel (420), the second friction wheel (420) may be positioned to surround the outer surface of the second shaft (352). The third friction wheel (430) and the fourth friction wheel (440) may be positioned between the first friction wheel (410) and the second friction wheel (420). For example, the third friction wheel (430) may be in contact with the first friction wheel (410) and the fourth friction wheel (440), respectively. For example, the fourth friction wheel (440) may be in contact with the second friction wheel (420) and the third friction wheel (430), respectively.

[0083] According to one embodiment, a first shaft (351) coupled to a first arm (331) can rotate together with the rotation of the first arm (331), and when the first shaft (351) rotates, a first friction wheel (410) coupled to the first arm (331) can also rotate. A second shaft (352) coupled to a second arm (332) can rotate together with the rotation of the second arm (332), and when the second shaft (352) rotates, a second friction wheel (420) coupled to the second arm (332) can also rotate. The first friction wheel (410) and the second friction wheel (420) may be referred to as driving wheels in that they rotate directly by the torque that causes the rotation of the foldable electronic device (200). The third friction wheel (430) and the fourth friction wheel (440) may be configured to rotate based on the rotation of the first friction wheel (410) and the rotation of the second friction wheel (420). The third friction wheel (430) and the fourth friction wheel (440) may be referred to as idle wheels in that they rotate by the first friction wheel (410) and the second friction wheel (420). The friction wheels (400) in contact with each other may be configured to synchronize the rotation of the first housing part (210) and the rotation of the second housing part (220) using frictional force. The friction wheels (400) may be referred to as friction gears. The rotational movements of the friction wheels (400) will be described later.

[0084] According to one embodiment, the hinge assembly (300) may include spur gears including teeth. For example, the spur gears may include a first spur gear (361) coupled to a third friction wheel (430) and a second spur gear (362) coupled to a fourth friction wheel (440). For example, the first spur gear (361) may be coupled to a third shaft (353) of the third friction wheel (430) and configured to rotate in conjunction with the rotation of the third friction wheel (430). For example, the second spur gear (362) may be coupled to a fourth shaft (354) of the fourth friction wheel (440) and configured to rotate in conjunction with the rotation of the fourth friction wheel (440). The first spur gear (361) and the second spur gear (362) may be engaged with each other. The first spur gear (361) and the second spur gear (362) meshed with each other can be configured to reduce slip of the third friction wheel (430) and slip of the fourth friction wheel (440).

[0085] According to one embodiment, the hinge assembly (300) may include an elastic sheet (370). The elastic sheet (370) may have a restoring force by including an elastic material. For example, the elastic sheet (370) may be configured to apply force to the friction wheels (400) in a direction in which the friction wheels (400) come into close contact with each other. For example, the elastic sheet (370) may be coupled to a first shaft (351) coupled to a first friction wheel (410) and a second shaft (352) coupled to a second friction wheel (420). The elastic sheet (370) may at least partially wrap around the first shaft (351) and the second shaft (352). Due to the restoring force of the elastic sheet (370), the first shaft (351) and the second shaft (352) may receive a force in a direction in which they come closer to each other. For example, the elastic sheet (370) can apply a force to the first shaft (351) in a direction toward the second shaft (352), and can apply a force to the second shaft (352) in a direction toward the first shaft (351). By the force, the friction wheels (400) can maintain a state of contact with each other.

[0086] According to one embodiment, the hinge assembly (300) may be configured to synchronize the rotation of the first housing part (210) and the rotation of the second housing part (220). For example, the hinge assembly (300) may be configured to synchronize the rotation of the first housing part (210) and the rotation of the second housing part (220) by the rotation of the first arm (331) according to the rotation of the first arm (331), the rotation of the first shaft (351) according to the rotation of the first shaft (351), the rotation of the first friction wheel (410) according to the rotation of the first friction wheel (410), the rotation of the third friction wheel (430) according to the rotation of the third friction wheel (430), the rotation of the second friction wheel (420) according to the rotation of the fourth friction wheel (440), the rotation of the second shaft (352) according to the rotation of the second friction wheel (420), and the rotation of the second arm (332) according to the rotation of the second shaft (352).

[0087] For example, when an external force (e.g., torque) is applied to the first housing part (210), rotation of the first arm (331) coupled to the first support member (215) of the first housing part (210) may be caused by said external force. Depending on the rotation of the first arm (331), rotation of the first shaft (351) coupled to the first arm (331) may be caused. Depending on the rotation of the first shaft (351), rotation of the first friction wheel (410) coupled to the first shaft (351) may be caused. Depending on the rotation of the first friction wheel (410), rotation of the third friction wheel (430) in contact with the first friction wheel (410) may be caused. Depending on the rotation of the third friction wheel (430), rotation of the fourth friction wheel (440) in contact with the third friction wheel (430) may be caused. Depending on the rotation of the fourth friction wheel (440), rotation of the second friction wheel (420) in contact with the fourth friction wheel (440) may be induced. Depending on the rotation of the second friction wheel (420), rotation of the second shaft (352) coupled to the second friction wheel (420) may be induced. Depending on the rotation of the second shaft (352), rotation of the second arm (332) may be induced. Since the second arm (332) is coupled to the second support member (227) of the second housing part (220), rotation of the second housing part (220) may be induced depending on the rotation of the second arm (332). By synchronizing the rotation of the first housing part (210) and the rotation of the second housing part (220), the folding and unfolding operations of the foldable electronic device (200) can be performed stably.

[0088] Fig. 5 illustrates spur gears.

[0089] Referring to FIG. 5, spur gears (510, 520) can be used to transmit power. Spur gears (510, 520) include. For example, as illustrated in FIG. 5, spur gears (510, 520) can transmit power through first teeth (511) and second teeth (521) meshed with the first teeth (511). There may be a certain gap (backlash) between the teeth meshed with each other. The backlash can compensate for errors due to the tolerances of the spur gears (510, 520) and provide natural rotation of the spur gears (510, 520). The spur gears (510, 520) can be manufactured so that backlash is formed within an intended range. If the first teeth (511) and the second teeth (521) wear out, backlash may increase. If backlash exceeds the intended range, the precision of the rotational movement of the spur gears (510, 520) may be reduced.

[0090] For example, when spur gears (510, 520) are used to synchronize the rotation of a first housing part (e.g., the first housing part (210) of FIG. 3) and the rotation of a second housing part (e.g., the second housing part (220) of FIG. 3), an error may be caused by backlash. For example, if the first teeth (511) and / or the second teeth (521) wear out, the backlash increases, which may cause slip of the spur gears (510, 520). Due to this slip, the rotation of the first housing part (210) and the rotation of the second housing part (220) may not be synchronized. If the rotation of the first housing part (210) and the rotation of the second housing part (220) are not synchronized, structural problems may occur. For example, the foldable housing (e.g., the foldable housing (201) of FIG. 3) may not be fully folded or fully unfolded.

[0091] FIG. 6 is a cross-sectional view of a foldable electronic device in an unfolded state, cut along the AA' line of FIG. 3.

[0092] Referring to FIG. 6, a hinge assembly (300) of a foldable electronic device (200) according to one embodiment may include friction wheels (400). As illustrated in FIG. 6, the friction wheels (400) may be configured to transmit rotational force through the frictional force of the contact surface between the friction wheels (400) without including those that interlock with each other. Since the friction wheels (400) do not include those that interlock with each other, problems caused by backlash can be eliminated.

[0093] According to one embodiment, the friction wheels (400) may be configured to synchronize the rotation of the first arm (331) and the rotation of the second arm (332). As illustrated in FIG. 6, the first arm (331) may be coupled to a first support member (215) of the first housing part (210), and the second arm (332) may be coupled to a second support member (227) of the second housing part (220). For example, the first arm (331) may be coupled to the first support member (215) via a third coupling bracket (e.g., the third coupling bracket (343) of FIG. 3), and the second arm (332) may be coupled to the second support member (227) via a fourth coupling bracket (e.g., the fourth coupling bracket (344) of FIG. 3). Since the first arm (331) is coupled to the first housing part (210) and the second arm (332) is coupled to the second housing part (220), the rotation of the first arm (331) and the rotation of the second arm (332) are synchronized, so the rotation of the first housing part (210) and the rotation of the second housing part (220) can be synchronized.

[0094] According to one embodiment, each of the friction wheels (400) may include a protrusion. The protrusion may be configured to limit the rotation of the friction wheels (400) according to the unfolding movement of the foldable electronic device (200) when the foldable electronic device (200) is in an unfolded state. For example, the first friction wheel (410) may include a protrusion (e.g., first protrusion (411)) that contacts a protrusion (e.g., third protrusion (421)) of the second friction wheel (420) adjacent to the first friction wheel (410). For example, the second friction wheel (420) may include a protrusion (e.g., third protrusion (421)) that contacts a protrusion (e.g., seventh protrusion (441)) of the fourth friction wheel (440) adjacent to the second friction wheel (420). For example, the third friction wheel (430) may include a projection (e.g., a sixth projection (432)) that contacts a projection (e.g., an eighth projection (442)) of the fourth friction wheel (440) adjacent to the third friction wheel (430).

[0095] For example, one (a) friction wheel among the friction wheels (400) may include a projection that contacts a projection of another friction wheel adjacent to the one friction wheel among the friction wheels (400) when the foldable electronic device (200) is in an unfolded state. The projection of the one friction wheel and the projection of the other friction wheel may be configured to restrict the rotation of the friction wheel and the rotation of the other friction wheel according to the unfolding operation of the foldable electronic device (200) when the foldable electronic device (200) is in an unfolded state. The projection of the one friction wheel and the projection of the other friction wheel may be configured not to restrict, but to allow, the rotation of the friction wheel and the rotation of the other friction wheel according to the folding operation of the foldable electronic device (200) when the foldable electronic device (200) is in an unfolded state.

[0096] In the present disclosure, the unfolding operation of the foldable electronic device (200) may be referred to as a rotational operation of the first housing part (210) and a rotational operation of the second housing part (220) to provide an unfolded state of the foldable electronic device (200). For example, the unfolding operation of the foldable electronic device (200) may be referred to as a rotational operation of the first housing part (210) in a first rotational direction (601) (e.g., clockwise) and a rotational operation of the second housing part (220) in a second rotational direction (602) (e.g., counterclockwise) opposite to the first rotational direction (601). The foldable electronic device (200) may change from a folded state to an unfolded state according to the unfolding operation of the foldable electronic device (200).

[0097] For example, the first friction wheel (410) may include a first projection (411) and a second projection (412) spaced apart from the first projection (411). The second friction wheel (420) may include a third projection (421) and a fourth projection (422) spaced apart from the third projection (421). The third friction wheel (430) may include a fifth projection (431) and a sixth projection (432) spaced apart from the fifth projection (431). The fourth friction wheel (440) may include a seventh projection (441) and an eighth projection (442) spaced apart from the seventh projection (441). As illustrated in FIG. 6, when the foldable electronic device (200) is in an unfolded state, the first projection (411) of the first friction wheel (410) may come into contact with the fifth projection (431) of the third friction wheel (430). When the foldable electronic device (200) is in an unfolded state, the third projection (421) of the second friction wheel (420) may come into contact with the seventh projection (441) of the fourth friction wheel (440). When the foldable electronic device (200) is in an unfolded state, the sixth projection (432) of the third friction wheel (430) may come into contact with the eighth projection (442) of the fourth friction wheel (440).

[0098] According to one embodiment, the first projection (411) of the first friction wheel (410) and the fifth projection (431) of the third friction wheel (430) in contact with each other, the third projection (421) of the second friction wheel (420) and the seventh projection (441) of the fourth friction wheel (440) in contact with each other, and the sixth projection (432) of the third friction wheel (430) and the eighth projection (442) of the fourth friction wheel (440) in contact with each other may be configured to limit the rotation of the friction wheels (400) according to the unfolding operation of the foldable electronic device (200) when the foldable electronic device (200) is in an unfolded state.

[0099] For example, when the foldable electronic device (200) is in an unfolded state, the first projection (411) of the first friction wheel (410) comes into contact with the fifth projection (431) of the third friction wheel (430), so the rotation of the first friction wheel (410) in the first rotational direction (601) (e.g., clockwise) may be restricted. For example, even if an external force in the first rotational direction (601) is applied to the first friction wheel (410) within the unfolded state of the foldable electronic device (200), the first friction wheel (410) may not rotate in the first rotational direction (601) because of the first projection (411) of the first friction wheel (410) that is in contact with the fifth projection (431) of the third friction wheel (430). The fifth projection (431) of the third friction wheel (430) in contact with the first projection (411) of the first friction wheel (410) may be configured to limit the rotation of the first friction wheel (410) in the first rotational direction (601).

[0100] For example, when the foldable electronic device (200) is in an unfolded state, the third projection (421) of the second friction wheel (420) comes into contact with the seventh projection (441) of the fourth friction wheel (440), so the rotation of the second friction wheel (420) in the second rotational direction (602) (e.g., counterclockwise) may be restricted. For example, even if an external force in the second rotational direction (602) is applied to the second friction wheel (420) within the unfolded state of the foldable electronic device (200), the second friction wheel (420) may not rotate in the second rotational direction (602) because of the third projection (421) of the second friction wheel (420) that is in contact with the seventh projection (441) of the fourth friction wheel (440). The seventh projection (441) of the fourth friction wheel (440) in contact with the third projection (421) of the second friction wheel (420) may be configured to limit the rotation of the second friction wheel (420) in the second rotational direction (602).

[0101] For example, when the foldable electronic device (200) is in an unfolded state, the fifth projection (431) of the third friction wheel (430) comes into contact with the first projection (411) of the first friction wheel (410), and the sixth projection (432) of the third friction wheel (430) comes into contact with the eighth projection (442) of the fourth friction wheel (440), so the rotation of the third friction wheel (430) in the second rotation direction (602) (e.g., counterclockwise) may be restricted. The first projection (411) of the first friction wheel (410) in contact with the fifth projection (431) of the third friction wheel (430) and the eighth projection (442) of the fourth friction wheel (440) in contact with the sixth projection (432) of the third friction wheel (430) may be configured to limit the rotation of the third friction wheel (430) in the second rotational direction (602).

[0102] For example, when the foldable electronic device (200) is in an unfolded state, the seventh projection (441) of the fourth friction wheel (440) contacts the third projection (421) of the second friction wheel (420), and the eighth projection (442) of the fourth friction wheel (440) contacts the sixth projection (432) of the third friction wheel (430), so the rotation of the fourth friction wheel (440) in the first rotational direction (601) (e.g., clockwise) may be restricted. The third projection (421) of the second friction wheel (420) in contact with the seventh projection (441) of the fourth friction wheel (440) and the sixth projection (432) of the third friction wheel (430) in contact with the eighth projection (442) of the fourth friction wheel (440) may be configured to limit the rotation of the fourth friction wheel (440) in the first rotational direction (601).

[0103] According to one embodiment, when the foldable electronic device (200) changes from an unfolded state to a folded state, the friction wheels (400) may be configured to rotate. The friction wheels (400) in contact with each other may be configured to transmit rotational force through the frictional force of the contact surface between the friction wheels (400). The first projection (411) of the first friction wheel (410) and the fifth projection (431) of the third friction wheel (430) that are in contact with each other, the third projection (421) of the second friction wheel (420) and the seventh projection (441) of the fourth friction wheel (440) that are in contact with each other, and the sixth projection (432) of the third friction wheel (430) and the eighth projection (442) of the fourth friction wheel (440) that are in contact with each other can be configured to allow, without restricting, the rotation of the friction wheels (400) according to the folding operation of the foldable electronic device (200) when the foldable electronic device (200) is in an unfolded state.

[0104] For example, when the foldable electronic device (200) is in an unfolded state, if an external force in a second rotational direction (602) is applied to the first housing part (210), the first friction wheel (410) may be configured to rotate in the second rotational direction (602) based on the external force. As described above, the rotation of the first housing part (210) caused by the external force applied to the first housing part (210) may cause the rotation of the first arm (331) and the rotation of the first shaft (351). The first friction wheel (410) coupled to the first shaft (351) may be configured to rotate according to the rotation of the first shaft (351). When the foldable electronic device (200) is in an unfolded state, rotation of the first friction wheel (410) in the first rotational direction (601) is restricted, but rotation of the first friction wheel (410) in the second rotational direction (602) may not be restricted. The first friction wheel (410) may be rotated in the second rotational direction (602) based on the external force.

[0105] For example, a third friction wheel (430) in contact with a first friction wheel (410) may be rotated in a first rotation direction (601) opposite to the second rotation direction (602) based on the rotation of the first friction wheel (410) in the second rotation direction (602). The rotational force of the first friction wheel (410) may be transmitted to the third friction wheel (430) through the frictional force between the first friction wheel (410) and the third friction wheel (430). When the foldable electronic device (200) is in an unfolded state, the rotation of the third friction wheel (430) in the second rotation direction (602) is restricted, but the rotation of the third friction wheel (430) in the first rotation direction (601) may not be restricted. The third friction wheel (430) can be rotated in the first rotation direction (601) based on the rotation of the first friction wheel (410) in the second rotation direction (602).

[0106] For example, the fourth friction wheel (440) in contact with the third friction wheel (430) may be rotated in a second rotation direction (602) opposite to the first rotation direction (601) based on the rotation of the third friction wheel (430) in the first rotation direction (601). The rotational force of the third friction wheel (430) may be transmitted to the fourth friction wheel (440) through the frictional force between the third friction wheel (430) and the fourth friction wheel (440). When the foldable electronic device (200) is in an unfolded state, the rotation of the fourth friction wheel (440) in the first rotation direction (601) is restricted, but the rotation of the fourth friction wheel (440) in the second rotation direction (602) may not be restricted. The fourth friction wheel (440) can be rotated in a second rotation direction (602) based on the rotation of the third friction wheel (430) in a first rotation direction (601).

[0107] For example, the second friction wheel (420) in contact with the fourth friction wheel (440) may be rotated in a first rotation direction (601) opposite to the second rotation direction (602) based on the rotation of the fourth friction wheel (440) in the second rotation direction (602). The rotational force of the fourth friction wheel (440) may be transmitted to the second friction wheel (420) through the frictional force between the second friction wheel (420) and the fourth friction wheel (440). When the foldable electronic device (200) is in an unfolded state, the rotation of the second friction wheel (420) in the second rotation direction (602) is restricted, but the rotation of the second friction wheel (420) in the first rotation direction (601) may not be restricted. The second friction wheel (420) can be rotated in a first rotation direction (601) based on the rotation of the fourth friction wheel (440) in a second rotation direction (602). Based on the rotation of the second friction wheel (420) in a first rotation direction (601), rotation of the second shaft (352) and rotation of the second arm (332) may be induced, and rotation of the second housing part (220) in a first rotation direction (601) may be induced according to the rotation of the second arm (332). According to one embodiment, when the foldable electronic device (200) is in an unfolded state, rotation of the second housing part (220) in a first rotation direction (601) may be induced according to the rotation of the first housing part (210) in a second rotation direction (602). The foldable electronic device (200) can be changed from the unfolded state of the foldable electronic device (200) shown in FIG. 6 to the folded state of the foldable electronic device (200) shown in FIG. 7 through the above process.

[0108] Figure 7 is a cross-sectional view of a foldable electronic device in a folded state.

[0109] Referring to FIG. 7, each of the friction wheels (400) may include another protrusion. The other protrusion may be configured to limit the rotation of the friction wheels (400) according to the folding movement of the foldable electronic device (200) when the foldable electronic device (200) is in a folded state.

[0110] For example, one (a) friction wheel among the friction wheels (400) may include another protrusion that contacts another protrusion of another friction wheel adjacent to the one friction wheel among the friction wheels (400) when the foldable electronic device (200) is in a folded state. The other protrusion of the one friction wheel and the other protrusion of the other friction wheel may be configured to restrict the rotation of the friction wheel and the rotation of the other friction wheel according to the folding operation of the foldable electronic device (200) when the foldable electronic device (200) is in a folded state. The other protrusion of the one friction wheel and the other protrusion of the other friction wheel may be configured not to restrict, but to allow, the rotation of the friction wheel and the rotation of the other friction wheel according to the unfolding operation of the foldable electronic device (200) when the foldable electronic device (200) is in a folded state.

[0111] For example, the second friction wheel (420) may include a projection (e.g., a fourth projection (422)) that contacts a projection (e.g., an eighth projection (442)) of the fourth friction wheel (440) adjacent to the second friction wheel (420). For example, the third friction wheel (430) may include a projection (e.g., a fifth projection (431)) that contacts a projection (e.g., a seventh projection (441)) of the fourth friction wheel (440) adjacent to the third friction wheel (430).

[0112] In the present disclosure, the folding operation of the foldable electronic device (200) may be referred to as a rotational operation of the first housing part (210) and a rotational operation of the second housing part (220) to provide a folded state of the foldable electronic device (200). For example, the folding operation of the foldable electronic device (200) may be referred to as a rotational operation of the first housing part (210) in a second rotational direction (602) (e.g., counterclockwise) and a rotational operation of the second housing part (220) in a first rotational direction (601) (e.g., clockwise). The foldable electronic device (200) may change from an unfolded state to a folded state according to the folding operation of the foldable electronic device (200).

[0113] As illustrated in FIG. 7, when the foldable electronic device (200) is in a folded state, the second projection (412) of the first friction wheel (410) may come into contact with the sixth projection (432) of the third friction wheel (430). When the foldable electronic device (200) is in a folded state, the fourth projection (422) of the second friction wheel (420) may come into contact with the eighth projection (442) of the fourth friction wheel (440). When the foldable electronic device (200) is in a folded state, the fifth projection (431) of the third friction wheel (430) may come into contact with the seventh projection (441) of the fourth friction wheel (440).

[0114] According to one embodiment, the second projection (412) of the first friction wheel (410) and the sixth projection (432) of the third friction wheel (430) in contact with each other, the fourth projection (422) of the second friction wheel (420) and the eighth projection (442) of the fourth friction wheel (440) in contact with each other, and the fifth projection (431) of the third friction wheel (430) and the seventh projection (441) of the fourth friction wheel (440) in contact with each other may be configured to limit the rotation of the friction wheels (400) according to the folding operation of the foldable electronic device (200) when the foldable electronic device (200) is in a folded state.

[0115] For example, when the foldable electronic device (200) is in a folded state, the second projection (412) of the first friction wheel (410) comes into contact with the sixth projection (432) of the third friction wheel (430), so the rotation of the first friction wheel (410) in the second rotational direction (602) (e.g., counterclockwise) may be restricted. For example, even if an external force in the second rotational direction (602) is applied to the first friction wheel (410) within the folded state of the foldable electronic device (200), the first friction wheel (410) may not rotate in the second rotational direction (602) because of the second projection (412) of the first friction wheel (410) that is in contact with the sixth projection (432) of the third friction wheel (430). The sixth projection (432) of the third friction wheel (430) in contact with the second projection (412) of the first friction wheel (410) may be configured to limit the rotation of the first friction wheel (410) in the second rotational direction (602).

[0116] For example, when the foldable electronic device (200) is in a folded state, the fourth projection (422) of the second friction wheel (420) comes into contact with the eighth projection (442) of the fourth friction wheel (440), so the rotation of the second friction wheel (420) in the first rotational direction (601) (e.g., clockwise) may be restricted. For example, even if an external force in the first rotational direction (601) is applied to the second friction wheel (420) within the folded state of the foldable electronic device (200), the second friction wheel (420) may not rotate in the first rotational direction (601) because of the fourth projection (422) of the second friction wheel (420) that is in contact with the eighth projection (442) of the fourth friction wheel (440). The eighth projection (442) of the fourth friction wheel (440) in contact with the fourth projection (422) of the second friction wheel (420) may be configured to limit the rotation of the second friction wheel (420) in the first rotational direction (601).

[0117] For example, when the foldable electronic device (200) is in a folded state, the sixth projection (432) of the third friction wheel (430) contacts the second projection (412) of the first friction wheel (410), and the fifth projection (431) of the third friction wheel (430) contacts the seventh projection (441) of the fourth friction wheel (440), so the rotation of the third friction wheel (430) in the first rotational direction (601) (e.g., clockwise) may be restricted. The second projection (412) of the first friction wheel (410) in contact with the sixth projection (432) of the third friction wheel (430) and the seventh projection (441) of the fourth friction wheel (440) in contact with the fifth projection (431) of the third friction wheel (430) may be configured to limit the rotation of the third friction wheel (430) in the first rotational direction (601).

[0118] For example, when the foldable electronic device (200) is in a folded state, the eighth projection (442) of the fourth friction wheel (440) contacts the fourth projection (422) of the second friction wheel (420), and the seventh projection (441) of the fourth friction wheel (440) contacts the fifth projection (431) of the third friction wheel (430), so the rotation of the fourth friction wheel (440) in the second rotational direction (602) (e.g., counterclockwise) may be restricted. The fourth projection (422) of the second friction wheel (420) in contact with the eighth projection (442) of the fourth friction wheel (440) and the fifth projection (431) of the third friction wheel (430) in contact with the seventh projection (441) of the fourth friction wheel (440) may be configured to limit the rotation of the fourth friction wheel (440) in the second rotational direction (602).

[0119] According to one embodiment, when the foldable electronic device (200) changes from a folded state to an unfolded state, the friction wheels (400) may be configured to rotate. The friction wheels (400) in contact with each other may be configured to transmit rotational force through the frictional force of the contact surface between the friction wheels (400). The second projection (412) of the first friction wheel (410) and the sixth projection (432) of the third friction wheel (430) in contact with each other, the fourth projection (422) of the second friction wheel (420) and the eighth projection (442) of the fourth friction wheel (440) in contact with each other, and the fifth projection (431) of the third friction wheel (430) and the seventh projection (441) of the fourth friction wheel (440) in contact with each other can be configured to allow, without restricting, the rotation of the friction wheels (400) according to the unfolding operation of the foldable electronic device (200) when the foldable electronic device (200) is in a folded state.

[0120] For example, when the foldable electronic device (200) is in a folded state, if an external force in the first rotational direction (601) is applied to the first housing part (210), the first friction wheel (410) may be configured to rotate in the first rotational direction (601) based on the external force. As described above, the rotation of the first housing part (210) caused by the external force applied to the first housing part (210) may cause the rotation of the first arm (331) and the rotation of the first shaft (351). The first friction wheel (410) coupled to the first shaft (351) may be configured to rotate according to the rotation of the first shaft (351). When the foldable electronic device (200) is in a folded state, rotation of the first friction wheel (410) in the second rotation direction (602) is restricted, but rotation of the first friction wheel (410) in the first rotation direction (601) may not be restricted. The first friction wheel (410) may be rotated in the first rotation direction (601) based on the external force.

[0121] For example, a third friction wheel (430) in contact with a first friction wheel (410) may be rotated in a second rotation direction (602) opposite to the first rotation direction (601) based on the rotation of the first friction wheel (410) in the first rotation direction (601). The rotational force of the first friction wheel (410) may be transmitted to the third friction wheel (430) through the frictional force between the first friction wheel (410) and the third friction wheel (430). When the foldable electronic device (200) is in a folded state, the rotation of the third friction wheel (430) in the first rotation direction (601) is restricted, but the rotation of the third friction wheel (430) in the second rotation direction (602) may not be restricted. The third friction wheel (430) can be rotated in a second rotation direction (602) based on the rotation of the first friction wheel (410) in a first rotation direction (601).

[0122] For example, the fourth friction wheel (440) in contact with the third friction wheel (430) may be rotated in a first rotation direction (601) opposite to the second rotation direction (602) based on the rotation of the third friction wheel (430) in the second rotation direction (602). The rotational force of the third friction wheel (430) may be transmitted to the fourth friction wheel (440) through the frictional force between the third friction wheel (430) and the fourth friction wheel (440). When the foldable electronic device (200) is in a folded state, the rotation of the fourth friction wheel (440) in the second rotation direction (602) is restricted, but the rotation of the fourth friction wheel (440) in the first rotation direction (601) may not be restricted. The fourth friction wheel (440) can be rotated in the first rotation direction (601) based on the rotation of the third friction wheel (430) in the second rotation direction (602).

[0123] For example, the second friction wheel (420) in contact with the fourth friction wheel (440) may be rotated in a second rotation direction (602) opposite to the first rotation direction (601) based on the rotation of the fourth friction wheel (440) in the first rotation direction (601). The rotational force of the fourth friction wheel (440) may be transmitted to the second friction wheel (420) through the frictional force between the second friction wheel (420) and the fourth friction wheel (440). When the foldable electronic device (200) is in a folded state, the rotation of the second friction wheel (420) in the first rotation direction (601) is restricted, but the rotation of the second friction wheel (420) in the second rotation direction (602) may not be restricted. The second friction wheel (420) can be rotated in a second rotation direction (602) based on the rotation of the fourth friction wheel (440) in a first rotation direction (601). Based on the rotation of the second friction wheel (420) in a second rotation direction (602), rotation of the second shaft (352) and rotation of the second arm (332) may be induced, and rotation of the second housing part (220) in a second rotation direction (602) may be induced according to the rotation of the second arm (332). According to one embodiment, when the foldable electronic device (200) is in a folded state, rotation of the second housing part (220) in a second rotation direction (602) may be induced according to the rotation of the first housing part (210) in a first rotation direction (601). The foldable electronic device (200) can be changed from the folded state of the foldable electronic device (200) shown in FIG. 7 to the unfolded state of the foldable electronic device (200) shown in FIG. 6 through the above process.

[0124] As described with reference to FIGS. 6 and 7, the friction wheels (400) may be configured to synchronize the rotation of the first housing part (210) and the rotation of the second housing part (220). Since the friction wheels (400) transmit rotational force through the frictional force of the contact surface without including these, they may not cause problems caused by backlash.

[0125] According to one embodiment, the protrusions of the friction wheel may be opposite to other protrusions of the friction wheel. For example, the first protrusion (411) of the first friction wheel (410) may be opposite to the second protrusion (412) of the first friction wheel (410). For example, the third protrusion (421) of the second friction wheel (420) may be opposite to the fourth protrusion (422) of the second friction wheel (420). For example, the fifth protrusion (431) of the third friction wheel (430) may be opposite to the sixth protrusion (432) of the third friction wheel (430). For example, the seventh protrusion (441) of the fourth friction wheel (440) may be opposite to the eighth protrusion (442) of the fourth friction wheel (440).

[0126] According to one embodiment, the first friction wheel (410) may be paired with the second friction wheel (420). For example, the first size of the first friction wheel (410) may correspond to the second size of the second friction wheel (420). According to one embodiment, the third friction wheel (430) may correspond to the fourth friction wheel (440). For example, the size of the third friction wheel (430) may correspond to the size of the fourth friction wheel (440). The first friction wheel (410) and the second friction wheel (420) for providing rotational force may be larger than the third friction wheel (430) and the fourth friction wheel (440) for transmitting rotational force. For example, the first size and the second size may be larger than the third size and the fourth size.

[0127] FIG. 8 illustrates the unfolded state of a foldable electronic device when slip is caused in the friction wheels. FIG. 9 illustrates the folded state of a foldable electronic device when slip is caused in the friction wheels. FIG. 10 illustrates the process of removing slip from the friction wheels.

[0128] Referring to FIGS. 8 and 9, slip may occur in the friction wheels (400) of the foldable electronic device (200). For example, if the relative rotational movements of the friction wheels (400) in contact with each other do not match, the rotation of the first housing part (210) and the rotation of the second housing part (220) may not be synchronized. If the rotation of the first housing part (210) and the rotation of the second housing part (220) are not synchronized, when the foldable electronic device (200) is unfolded, the first housing part (210) or the second housing part (220) may not be fully unfolded. For example, among the friction wheels (400), if there is insufficient frictional force on the contact surface between one friction wheel (a) in contact with each other and another friction wheel adjacent to said friction wheel, the one friction wheel may slip against said other friction wheel, thereby causing slip of the friction wheels (400). Alternatively, slip of the friction wheels (400) may be caused by an external force applied to the foldable electronic device (200).

[0129] As illustrated in FIG. 8, when slip is caused by the friction wheels (400), the foldable housing (201) may not be substantially flat and may be at least partially tilted when the foldable electronic device (200) is in an unfolded state. For example, when the foldable electronic device (200) is unfolded with slip caused between the first friction wheel (410) and the third friction wheel (430), the first housing part (210) may not be fully unfolded and may be tilted relative to the hinge cover. As the first housing part (210) is tilted relative to the hinge cover, the visibility of the flexible display (e.g., the flexible display (230) of FIG. 2a) placed on the foldable housing (201) may be degraded, and the usability of the foldable electronic device (200) may be degraded.

[0130] As illustrated in FIG. 9, when slippage of the friction wheels (400) is caused, the first housing part (210) and the second housing part (220) may tilt relative to the hinge cover when the foldable electronic device (200) is in a folded state. When the first housing part (210) and the second housing part (220) tilt relative to the hinge cover, the portability of the foldable electronic device (200) may be degraded, and the foldable electronic device (200) may be easily damaged by external force.

[0131] Referring to FIG. 10, the protrusions of the friction wheels (400) can be used to eliminate slip. For example, the first state (1001) of FIG. 10 illustrates a state in which slip of the friction wheels (400) is caused. The second state (1002) of FIG. 10 illustrates a state in which slip of the friction wheels (400) is eliminated.

[0132] Referring to the first state (1001) of FIG. 10, when slip of the friction wheels (400) is caused, the foldable housing (201) may not be substantially flat when the foldable electronic device (200) is in an unfolded state. For example, due to the slip of the friction wheels (400), the first housing part (210) or the second housing part (220) may not be fully unfolded. Because the first housing part (210) or the second housing part (220) is not fully unfolded, the foldable housing (201) may not be substantially flat within the unfolded state of the foldable electronic device (200). For example, when the foldable electronic device (200) is unfolded in which slip is caused between the first friction wheel (410) and the third friction wheel (430), the first housing part (210) may tilt relative to the hinge cover. When the foldable electronic device (200) is unfolded, if the foldable housing (201) is not substantially flat, the user may apply force in a direction that causes an unfolding motion to the tilted housing part to eliminate slip. For example, if the first housing part (210) is not fully unfolded and is tilted relative to the hinge cover, the user may apply force to the first housing part (210) in a direction (e.g., clockwise) that causes an unfolding motion of the first housing part (210).

[0133] For example, when the foldable electronic device (200) in which the first friction wheel (410) slips is caused is unfolded, the first projection (411) of the first friction wheel (410) may not come into contact with the fifth projection (431) of the third friction wheel (430). When the foldable electronic device (200) in which the first friction wheel (410) slips is caused is unfolded, the third projection (421) of the second friction wheel (420) may come into contact with the seventh projection (441) of the fourth friction wheel (440), and the sixth projection (432) of the third friction wheel (430) may come into contact with the eighth projection (442) of the fourth friction wheel (440).

[0134] In a first state (1001) in which slip of the friction wheels (400) is caused (e.g., a state in which slip of the first friction wheel (410) is caused), if a force is applied from the user to the tilted first housing part (210) in a direction that causes the first housing part (210) to unfold, the second friction wheel (420), the third friction wheel (430), and the fourth friction wheel (440) may not rotate due to the third projection (421) of the second friction wheel (420), the sixth projection (432) of the third friction wheel (430), the seventh projection (441) of the fourth friction wheel (440), and the eighth projection (442) of the fourth friction wheel (440) which limit the rotation of the friction wheels (400) in the unfolded state of the foldable electronic device (200). As described above, when the foldable electronic device (200) is in an unfolded state, the third projection (421) of the second friction wheel (420), the sixth projection (432) of the third friction wheel (430), the seventh projection (441) of the fourth friction wheel (440), and the eighth projection (442) of the fourth friction wheel (440) may be configured to limit the rotation of the second friction wheel (420), the rotation of the third friction wheel (430), and the rotation of the fourth friction wheel (440) according to the unfolding operation. Since the first projection (411) of the first friction wheel (410) does not come into contact with the fifth projection (431) of the third friction wheel (430), the rotation of the first friction wheel (410) according to the unfolding operation may not be limited.

[0135] When the above force is applied, rotation of the first friction wheel (410) (e.g., rotation in the first rotational direction) may be induced. As the second friction wheel (420), the third friction wheel (430), and the fourth friction wheel (440) are not rotated and only the first friction wheel (410) rotates, slip of the first friction wheel (410) may be eliminated. Due to the above external force, the first friction wheel (410) may be rotated so that the first projection (411) of the first friction wheel (410) comes into contact with the fifth projection (431) of the third friction wheel (430). When the first projection (411) of the first friction wheel (410) comes into contact with the fifth projection (431) of the third friction wheel (430), the rotation of the first friction wheel (410) may be restricted by the first projection (411) and the fifth projection (431). When the first projection (411) of the first friction wheel (410) comes into contact with the fifth projection (431) of the third friction wheel (430), the foldable electronic device (200) can be changed from the first state (1001) to a second state (1002) in which the slip of the friction wheels (400) is removed. According to one embodiment, the slip of the first friction wheel (410) can be easily removed by the force.

[0136] Although not illustrated, if slip is caused between the second friction wheel (420) and the fourth friction wheel (440), said slip can be removed through substantially the same process. For example, in the unfolded state of the foldable electronic device (200) in which slip is caused by the second friction wheel (420), the second housing part (220) may not be fully unfolded. When the foldable electronic device (200) in which slip is caused between the second friction wheel (420) and the fourth friction wheel (440) is unfolded, the third projection (421) of the second friction wheel (420) may not come into contact with the seventh projection (441) of the fourth friction wheel (440). When the foldable electronic device (200) is unfolded, slip is caused between the second friction wheel and the fourth friction wheel (440), the first projection (411) of the first friction wheel (410) may come into contact with the fifth projection (431) of the third friction wheel (430), and the sixth projection (432) of the third friction wheel (430) may come into contact with the eighth projection (442) of the fourth friction wheel (440). In this case, when a force is applied from the user to the tilted second housing part (220) in a direction that causes the second housing part (220) to unfold, the first friction wheel (410), the third friction wheel (430), and the fourth friction wheel (440) may not rotate. Since the third projection (421) of the second friction wheel (420) does not come into contact with the seventh projection (441) of the fourth friction wheel (440), rotation of the second friction wheel (420) (e.g., rotation in the second rotation direction) can be caused by the said force. As the first friction wheel (410), the third friction wheel (430), and the fourth friction wheel (440) are not rotated and only the second friction wheel (420) is rotated, slip of the second friction wheel (420) can be eliminated. Due to the said external force, the second friction wheel (420) can be rotated so that the third projection (421) of the second friction wheel (420) comes into contact with the seventh projection (441) of the fourth friction wheel (440).When the third projection (421) of the second friction wheel (420) comes into contact with the seventh projection (441) of the fourth friction wheel (440), the rotation of the second friction wheel (420) can be restricted by the third projection (421) and the seventh projection (441). When the third projection (421) of the second friction wheel (420) comes into contact with the seventh projection (441) of the fourth friction wheel (440), the slip of the second friction wheel (420) can be eliminated.

[0137] A foldable electronic device (200) according to one embodiment can resolve problems caused by backlash through friction wheels (400). Even if slip occurs on the friction wheels (400), the slip can be easily removed by using protrusions.

[0138] FIGS. 11 and 12 illustrate a hinge assembly of a foldable electronic device according to one embodiment. FIG. 13 is a cross-sectional view of the hinge assembly of FIG. 12 cut along the BB' line.

[0139] Referring to FIGS. 11 and 12, the hinge assembly (300) may include a first spur gear (361) and a second spur gear (362).

[0140] As described above, slip of the friction wheels (400) can be eliminated through the protrusions of the friction wheels (400). Since the first friction wheel (410) can receive a force applied to the first housing part (210) through the first arm (331) and the first shaft (351), slip of the first friction wheel (410) can be eliminated by the force applied to the first housing part (210). For example, if slip of the first friction wheel (410) is caused, slip of the first friction wheel (410) can be eliminated by the force applied to the first housing part (210). Since the second friction wheel (420) can receive the force applied to the second housing part (220) through the second arm (332) and the second shaft (352), the slip of the second friction wheel (420) can be eliminated by the force applied to the second housing part (220). For example, if slip of the second friction wheel (420) is caused, the slip of the second friction wheel (420) can be eliminated by the force applied to the second housing part (220).

[0141] The third friction wheel (430) and the fourth friction wheel (440), which are positioned between the first friction wheel (410) and the second friction wheel (420), cannot directly receive the force applied to the first housing part (210) and / or the force applied to the second housing part (220), but can receive said forces through the first friction wheel (410) or the second friction wheel (420). If slip is caused in the third friction wheel (430) and / or the fourth friction wheel (440), said slip cannot be removed by the force applied to the first housing part (210) and / or the force applied to the second housing part (220). A hinge assembly (300) according to one embodiment may include a first spur gear (361) and a second spur gear (362) to prevent and / or reduce slip of the third friction wheel (430) and slip of the fourth friction wheel (440).

[0142] According to one embodiment, the hinge assembly (300) may include a first spur gear (361) coupled to a third friction wheel (430) and a second spur gear (362) coupled to a fourth friction wheel (440). For example, the first spur gear (361) may be coupled to a third shaft (353) coupled to the third friction wheel (430). The first spur gear (361) coupled to the third friction wheel (430) may be configured to rotate in conjunction with the rotation of the third friction wheel (430). For example, the second spur gear (362) may be coupled to a fourth shaft (354) coupled to the fourth friction wheel (440). The second spur gear (362) coupled to the fourth friction wheel (440) may be configured to rotate in conjunction with the rotation of the fourth friction wheel (440).

[0143] According to one embodiment, the first spur gear (361) and the second spur gear (362) can be engaged with each other. For example, the teeth of the first spur gear (361) can be engaged with the teeth of the second spur gear (362). Because the first spur gear (361) and the second spur gear (362) are engaged with each other, the third friction wheel (430) coupled to the first spur gear (361) and the fourth friction wheel (440) coupled to the second spur gear (362) can be coupled with each other. Since the first spur gear (361) and the second spur gear (362) can be firmly engaged through them, slip of the third friction wheel (430) and slip of the fourth friction wheel (440) can be prevented and / or reduced.

[0144] Referring to FIGS. 11 and 12, the hinge assembly (300) may include an elastic sheet (370). For example, the elastic sheet (370) may have a restoring force. The elastic sheet (370) may be positioned to at least partially wrap around a first shaft (351) coupled to a first friction wheel (410) and a second shaft (352) coupled to a second friction wheel (420).

[0145] Referring to FIG. 13, the first shaft (351) can be inserted into the first arm (331) and the first friction wheel (410) and can protrude toward the elastic sheet (370). The second shaft (352) can be inserted into the second arm (332) and the second friction wheel (420) and can protrude toward the elastic sheet (370). The elastic sheet (370) can wrap the portion of the first shaft (351) protruding from the first arm (331) and the first friction wheel (410) and the portion of the second shaft (352) protruding from the second arm (332) and the second friction wheel (420). For example, the elastic sheet (370) can be press-fitted onto the first shaft (351) and the second shaft (352) so as to at least partially wrap the outer surface of the first shaft (351) and the outer surface of the second shaft (352).

[0146] According to one embodiment, the elastic sheet (370) may be configured to press the friction wheels (400) in a direction in which the friction wheels (400) come into close contact with each other. For example, the elastic sheet (370) may have a restoring force. For example, the restoring force of the elastic sheet (370) may be referred to as a force that maintains the original shape of the elastic sheet (370). The original shape of the elastic sheet (370) may be a state in which the first shaft (351) and the second shaft (352) press against each other. For example, the elastic sheet (370) may apply a force to the first shaft (351) in a direction toward the second shaft (352), and may apply a force to the second shaft (352) in a direction toward the first shaft (351). The force applied to the first shaft (351) and the second shaft (352) can be transmitted to the first friction wheel (410) coupled to the first shaft (351) and the second friction wheel (420) coupled to the second shaft (352). By the force, the first friction wheel (410) can receive force in a direction toward the second friction wheel (420), and the second friction wheel (420) can receive force in a direction toward the first friction wheel (410). By the force, the friction wheels (400) (e.g., the first friction wheel (410), the second friction wheel (420), the third friction wheel (430), and the fourth friction wheel (440)) can maintain a state of close contact with each other. For example, even if a force is applied to the friction wheels (400) in a direction that moves the friction wheels (400) away from each other, contact between the friction wheels (400) can be maintained by the restoring force of the elastic sheet (370).

[0147] FIG. 14 illustrates the friction wheels of a hinge assembly.

[0148] In the examples described above, the friction wheels (e.g., the friction wheels (400) of FIG. 3) are described as comprising four friction wheels, but the present disclosure is not limited thereto. Referring to FIG. 14, the hinge assembly (e.g., the hinge assembly (300) of FIG. 3) may comprise two friction wheels.

[0149] For example, the hinge assembly (300) may include a first friction wheel (1410) and a second friction wheel (1420) in contact with the first friction wheel (1410). The first friction wheel (1410) may be configured to rotate with the rotation of the first housing part (e.g., the first housing part (210) of FIG. 3). The second friction wheel (1420) may be configured to rotate with the rotation of the second housing part (e.g., the second housing part (220) of FIG. 3).

[0150] For example, the first friction wheel (1410) may include a first projection (1411) and a second projection (1412) spaced apart from the first projection (1411). The second friction wheel (1420) may include a third projection (1421) and a fourth projection (1422) spaced apart from the third projection (1421). For example, when the foldable electronic device (e.g., the foldable electronic device (200) of FIG. 3) is in an unfolded state, the first projection (1411) of the first friction wheel (1410) may come into contact with the third projection (1421) of the second friction wheel (1420). For example, when the foldable electronic device (200) is in a folded state, the second projection (1412) of the first friction wheel (1410) may come into contact with the fourth projection (1422) of the second friction wheel (1420).

[0151] The technical problems to be solved in this disclosure are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which this disclosure pertains.

[0152] A foldable electronic device (101, 200) is disclosed. The foldable electronic device (101, 200) may include a foldable housing (201) comprising a first housing part (210) and a second housing part (220). The foldable electronic device (101, 200) may include a hinge assembly (300) that rotatably connects the first housing part (210) and the second housing part (220). The hinge assembly (300) may include a hinge bracket (310), a first rotator (321) rotatably coupled to the hinge bracket (310) to guide the rotation of the first housing part (210), a first arm (331) configured to rotate together with the rotation of the first housing part (210), a second rotator (322) rotatably coupled to the hinge bracket (310) to guide the rotation of the second housing part (220), a second arm (332) configured to rotate together with the rotation of the second housing part (220), and friction wheels (400) configured to synchronize the rotation of the first arm (331) with the rotation of the second arm (332). One (a) friction wheel among the friction wheels (400) may include a projection that contacts a projection of another friction wheel adjacent to the one friction wheel among the friction wheels (400) when the foldable electronic device (101, 200) is in an unfolded state. For example, the first friction wheel (410) may include a projection (e.g., first projection (411)) that contacts a projection (e.g., third projection (421)) of the second friction wheel (420) adjacent to the first friction wheel (410). For example, the second friction wheel (420) may include a projection (e.g., third projection (421)) that contacts a projection (e.g., seventh projection (441)) of the fourth friction wheel (440) adjacent to the second friction wheel (420).For example, the third friction wheel (430) may include a projection (e.g., a sixth projection (432)) that contacts a projection (e.g., an eighth projection (442)) of the fourth friction wheel (440) adjacent to the third friction wheel (430).

[0153] As an example not limited to, the projection of one friction wheel and the projection of the other friction wheel may be configured to restrict the rotation of the friction wheel and the rotation of the other friction wheel in accordance with the unfolding operation of the foldable electronic device (101, 200) when the foldable electronic device (101, 200) is in the unfolded state. As the rotation of the friction wheel and the rotation of the other friction wheel are restricted in accordance with the unfolding operation, slip of the friction wheels may be eliminated.

[0154] As an example not limited to, among the friction wheels (400), the friction wheel may include another protrusion that contacts another protrusion of the other friction wheel among the friction wheels (400) when the foldable electronic device (101, 200) is in a folded state. For example, the first friction wheel (410) may include a protrusion (e.g., second protrusion (412)) that contacts a protrusion (e.g., fourth protrusion (421)) of the second friction wheel (420) adjacent to the first friction wheel (410). For example, the second friction wheel (420) may include a protrusion (e.g., fourth protrusion (422)) that contacts a protrusion (e.g., eighth protrusion (442)) of the fourth friction wheel (440) adjacent to the second friction wheel (420). For example, the third friction wheel (430) may include a projection (e.g., a fifth projection (431)) that contacts a projection (e.g., a seventh projection (441)) of the fourth friction wheel (440) adjacent to the third friction wheel (430).

[0155] As an example not limited to, the other protrusion of the one friction wheel and the other protrusion of the other friction wheel may be configured to limit the rotation of the friction wheel and the rotation of the other friction wheel according to the folding operation of the foldable electronic device (101, 200) when the foldable electronic device (101, 200) is in the folded state.

[0156] As a non-limiting example, the projection of the friction wheel may be opposite to the other projection of the friction wheel.

[0157] As an example not limited to, the hinge assembly (300) may include a first shaft (351) coupled to the first arm (331) and a second shaft (352) coupled to the second arm (332). The friction wheels (400) may include a first friction wheel (410) coupled to the first shaft (351), a second friction wheel (420) coupled to the second shaft (352), a third friction wheel (430) in contact with the first friction wheel (410), and a fourth friction wheel (440) in contact with the second friction wheel (420) and in contact with the third friction wheel (430).

[0158] As an example not limited to, the first friction wheel (410) may include a first projection (411) and a second projection (412) spaced apart from the first projection (411). The second friction wheel (420) may include a third projection (421) and a fourth projection (422) spaced apart from the third projection (421). The third friction wheel (430) may include a fifth projection (431) and a sixth projection (432) spaced apart from the fifth projection (431). The fourth friction wheel (440) may include a seventh projection (441) and an eighth projection (442) spaced apart from the seventh projection (441). When the foldable electronic device (101, 200) is in the unfolded state, the first projection (411) of the first friction wheel (410) may come into contact with the fifth projection (431) of the third friction wheel (430). When the foldable electronic device (101, 200) is in the unfolded state, the third projection (421) of the second friction wheel (420) may come into contact with the seventh projection (441) of the fourth friction wheel (440). When the foldable electronic device (101, 200) is in the unfolded state, the sixth projection (432) of the third friction wheel (430) may come into contact with the eighth projection (442) of the fourth friction wheel (440).

[0159] As a non-limiting example, when the foldable electronic device (101, 200) is in a folded state, the second projection (412) of the first friction wheel (410) may come into contact with the sixth projection (432) of the third friction wheel (430). When the foldable electronic device (101, 200) is in a folded state, the fourth projection (422) of the second friction wheel (420) may come into contact with the eighth projection (442) of the fourth friction wheel (440). When the foldable electronic device (101, 200) is in a folded state, the fifth projection (431) of the third friction wheel (430) may come into contact with the seventh projection (441) of the fourth friction wheel (440).

[0160] As an example not limited to, the hinge assembly (300) is such that, by the rotation of the first arm (331) according to the rotation of the first housing part (210), the rotation of the first shaft (351) according to the rotation of the first arm (331), the rotation of the first friction wheel (410) according to the rotation of the first shaft (351), the rotation of the third friction wheel (430) according to the rotation of the first friction wheel (410), the rotation of the fourth friction wheel (440) according to the rotation of the third friction wheel (430), the rotation of the second friction wheel (420) according to the rotation of the fourth friction wheel (440), the rotation of the second shaft (352) according to the rotation of the second friction wheel (420), and the rotation of the second arm (332) according to the rotation of the second shaft (352), the rotation of the first arm (331) and the second The above rotation of the arm (332) can be configured to synchronize.

[0161] As an example not limited to, the first size of the first friction wheel (410) may correspond to the second size of the second friction wheel (420). The third size of the third friction wheel (430) may correspond to the fourth size of the fourth friction wheel (440).

[0162] As an example not limited to, the hinge assembly (300) may include an elastic sheet (370) configured to at least partially wrap the first shaft (351) and the second shaft (352) and to press the friction wheels (400) in a direction in which the friction wheels (400) come into close contact with each other.

[0163] As an example not limited to, the hinge assembly (300) may include a third shaft (353) coupled to the third friction wheel (430), a fourth shaft (354) coupled to the fourth friction wheel (440), a first spur gear (361) coupled to the third shaft (353) and configured to rotate with the rotation of the third friction wheel (430) through the third shaft (353), and a second spur gear (362) coupled to the fourth shaft (354), engaged with the first spur gear (361), and configured to rotate with the rotation of the fourth friction wheel (440) through the fourth shaft (354). The first spur gear (361) and the second spur gear (362) can prevent and / or reduce slip of the third friction wheel (430) and slip of the fourth friction wheel (440).

[0164] As an example not limited to, the hinge assembly (300) may include a first coupling bracket (341) for coupling the first rotator (321) to the first housing part (210), a second coupling bracket (342) for coupling the second rotator (322) to the second housing part (220), a third coupling bracket (343) for coupling the first arm (331) to the first housing part (210), and a fourth coupling bracket (344) for coupling the second arm (332) to the second housing part (220).

[0165] The foldable electronic device (101, 200) may further include a flexible display (230). The flexible display (230) may include a first part (231) corresponding to the first housing part (210), a second part (232) corresponding to the second housing part (220), and a third part (233) extending from the first part (231) of the flexible display (230) to the second part (232) of the flexible display (230) and configured to be at least partially bent based on the rotation of the first housing part (210) and the rotation of the second housing part (220).

[0166] As a non-limiting example, the friction wheels (400) may not include teeth.

[0167] A foldable electronic device (101, 200) is disclosed. The foldable electronic device (101, 200) may include a foldable housing (201) comprising a first housing part (210) and a second housing part (220). The foldable electronic device (101, 200) may include a flexible display (230). The flexible display (230) may include a first part (231) corresponding to the first housing part (210), a second part (232) corresponding to the second housing part (220), and a third part (233) extending from the first part (231) to the second part (232) and configured to be at least partially bent based on the rotation of the first housing part (210) and the rotation of the second housing part (220). The foldable electronic device (101, 200) may include a hinge assembly (300) that rotatably connects the first housing part (210) and the second housing part (220). The hinge assembly (300) may include friction wheels (400) configured to synchronize the rotation of the first housing part (210) with the rotation of the second housing part (220). The friction wheels (400) may include a first friction wheel (410) configured to rotate together with the rotation of the first housing part (210), a second friction wheel (420) configured to rotate together with the rotation of the second housing part (220), a third friction wheel (430) in contact with the first friction wheel (410), and a fourth friction wheel (440) in contact with the second friction wheel (420) and in contact with the third friction wheel (430). The above friction wheels (400) do not include these.

[0168] As an example not limited to, the first friction wheel (410) may include a first projection (411) and a second projection (412) spaced apart from the first projection (411). The second friction wheel (420) may include a third projection (421) and a fourth projection (422) spaced apart from the third projection (421). The third friction wheel (430) may include a fifth projection (431) and a sixth projection (432) spaced apart from the fifth projection (431). The fourth friction wheel (440) may include a seventh projection (441) and an eighth projection (442) spaced apart from the seventh projection (441). When the foldable electronic device (101, 200) is in the unfolded state, the first projection (411) of the first friction wheel (410) may come into contact with the fifth projection (431) of the third friction wheel (430). When the foldable electronic device (101, 200) is in the unfolded state, the third projection (421) of the second friction wheel (420) may come into contact with the seventh projection (441) of the fourth friction wheel (440). When the foldable electronic device (101, 200) is in the unfolded state, the sixth projection (432) of the third friction wheel (430) may come into contact with the eighth projection (442) of the fourth friction wheel (440).

[0169] As a non-limiting example, when the foldable electronic device (101, 200) is in a folded state, the second projection (412) of the first friction wheel (410) may come into contact with the sixth projection (432) of the third friction wheel (430). When the foldable electronic device (101, 200) is in a folded state, the fourth projection (422) of the second friction wheel (420) may come into contact with the eighth projection (442) of the fourth friction wheel (440). When the foldable electronic device (101, 200) is in a folded state, the fifth projection (431) of the third friction wheel (430) may come into contact with the seventh projection (441) of the fourth friction wheel (440).

[0170] As an example not limited to, the first projection (411) of the first friction wheel (410), the third projection (421) of the second friction wheel (420), the fifth projection (431) of the third friction wheel (430), the sixth projection (432) of the third friction wheel (430), the seventh projection (441) of the fourth friction wheel (440), and the eighth projection (442) of the fourth friction wheel (440) may be configured to limit the rotation of the friction wheels according to the unfolding operation of the foldable electronic device (101, 200) when the foldable electronic device (101, 200) is in the unfolded state.

[0171] As an example not limited to, the second projection (412) of the first friction wheel (410), the fourth projection (422) of the second friction wheel (420), the fifth projection (431) of the third friction wheel (430), the sixth projection (432) of the third friction wheel (430), the seventh projection (441) of the fourth friction wheel (440), and the eighth projection (442) of the fourth friction wheel (440) may be configured to limit the rotation of the friction wheels according to the unfolding operation of the foldable electronic device (101, 200) when the foldable electronic device (101, 200) is in the unfolded state.

[0172] The effects obtainable from the present disclosure are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present disclosure belongs.

[0173] The electronic devices according to the various embodiments disclosed in this document may be of various forms. The electronic devices may include, for example, portable communication devices (e.g., smartphones), computer devices, portable multimedia devices, portable medical devices, cameras, electronic devices, or consumer electronics. The electronic devices according to the embodiments of this document are not limited to the devices described above.

[0174] The various embodiments of this document and the terms used therein are not intended to limit the technical features described in this document to specific embodiments, and should be understood to include various modifications, equivalents, or substitutions of said embodiments. In connection with the description of the drawings, similar reference numerals may be used for similar or related components. The singular form of a noun corresponding to an item may include one or more of said items unless the relevant context clearly indicates otherwise. In this document, phrases such as "A or B," "at least one of A and B," "at least one of A or B," "A, B or C," "at least one of A, B and C," and "at least one of A, B, or C" may each include any one of the items listed together in the corresponding phrase, or all possible combinations thereof. Terms such as "first," "second," or "first" or "second" may be used simply to distinguish said components from other said components and do not limit said components in any other aspect (e.g., importance or order). Where any (e.g., 1st) component is referred to as "coupled" or "connected" to another (e.g., 2nd) component, with or without the terms "functionally" or "communicationly," it means that said any component may be connected to said other component directly (e.g., via a wire), wirelessly, or through a third component.

[0175] The term “module” as used in the various embodiments of this document may include a unit implemented in hardware, software, or firmware, and may be used interchangeably with terms such as logic, logic block, component, or circuit, for example. A module may be a component formed integrally, or a minimum unit of said component or a part thereof that performs one or more functions. For example, according to one embodiment, a module may be implemented in the form of an application-specific integrated circuit (ASIC).

[0176] Various embodiments of the present document may be implemented as software (e.g., program (140)) comprising one or more instructions stored in a storage medium (e.g., internal memory (136) or external memory (138)) readable by a machine (e.g., electronic device (101)). For example, a processor (120) of the machine (e.g., electronic device (101)) may call at least one of the one or more instructions stored from the storage medium and execute it. This enables the machine to operate to perform at least one function according to the at least one called instruction. The one or more instructions may include code generated by a compiler or code that can be executed by an interpreter. The storage medium readable by the machine may be provided in the form of a non-transitory storage medium. Here, 'non-temporary' simply means that the storage medium is a tangible device and does not contain a signal (e.g., electromagnetic waves), and the term does not distinguish between cases where data is stored semi-permanently and cases where it is stored temporarily.

[0177] According to one embodiment, the method according to the various embodiments disclosed herein may be provided as included in a computer program product. The computer program product may be traded between a seller and a buyer as a product. The computer program product may be distributed in the form of a device-readable storage medium (e.g., compact disc read-only memory (CD-ROM)), or distributed online (e.g., download or upload) through an application store (e.g., Play Store™) or directly between two user devices (e.g., smartphones). In the case of online distribution, at least a portion of the computer program product may be temporarily stored or temporarily created in a device-readable storage medium such as a manufacturer's server, an application store's server, or a relay server's memory (130).

[0178] According to various embodiments, each component (e.g., module or program) of the components described above may include a singular or multiple entities, and some of the multiple entities may be separated and placed in other components. According to various embodiments, one or more of the components or operations of the aforementioned components may be omitted, or one or more other components or operations may be added. Generally or additionally, multiple components (e.g., module or program) may be integrated into a single component. In this case, the integrated component may perform one or more functions of each of the multiple components in the same or similar manner as those performed by the corresponding component among the multiple components prior to integration. According to various embodiments, operations performed by the module, program, or other components may be executed sequentially, in parallel, iteratively, or heuristically, or one or more of the operations may be executed in a different order, omitted, or one or more other operations may be added.

Claims

1. In a foldable electronic device, A foldable housing comprising a first housing part and a second housing part; and It includes a hinge assembly that rotatably connects the first housing part and the second housing part, and The above hinge assembly is, Hinge bracket, A first rotator rotatably coupled to the hinge bracket to guide the rotation of the first housing part, A first arm configured to rotate together with the rotation of the first housing part, A second rotator rotatably coupled to the hinge bracket to guide the rotation of the second housing part, A second arm configured to rotate together with the rotation of the second housing part, and It includes friction wheels configured to synchronize the rotation of the first arm and the rotation of the second arm, and One (a) of the above friction wheels is, When the above-mentioned foldable electronic device is in an unfolded state, it includes a projection that contacts a projection of another friction wheel adjacent to one of the friction wheels. Foldable electronic device.

2. In Paragraph 1, The projection of the above-mentioned friction wheel and the projection of the above-mentioned friction wheel are, When the foldable electronic device is in the unfolded state, the device is configured to restrict the rotation of the friction wheel and the rotation of the other friction wheel according to the unfolding operation of the foldable electronic device. Foldable electronic device.

3. In Paragraph 1 or 2, Among the above friction wheels, the friction wheel is, When the above-mentioned foldable electronic device is in a folded state, it includes another protrusion among the friction wheels that contacts another protrusion of the other friction wheel. Foldable electronic device.

4. In Paragraph 3, The other protrusion of the above-mentioned friction wheel and the other protrusion of the above-mentioned friction wheel are, When the foldable electronic device is in the folded state, the device is configured to restrict the rotation of the friction wheel and the rotation of the other friction wheel according to the folding operation of the foldable electronic device. Foldable electronic device.

5. In Paragraph 3 or 4, The protrusion of the above friction wheel is, Opposite to the other protrusion of the friction wheel, Foldable electronic device.

6. In any one of paragraphs 1 through 5, The above hinge assembly is, It includes a first shaft coupled to the first arm and a second shaft coupled to the second arm, The above friction wheels are, A first friction wheel coupled to the first shaft, A second friction wheel coupled to the second shaft, A third friction wheel in contact with the first friction wheel, and A fourth friction wheel that is in contact with the second friction wheel and in contact with the third friction wheel, Foldable electronic device.

7. In Paragraph 6, The first friction wheel mentioned above is, It includes a first projection and a second projection spaced apart from the first projection, and The above second friction wheel is, It includes a third projection and a fourth projection spaced apart from the third projection, and The above third friction wheel is, It includes a fifth projection and a sixth projection spaced apart from the fifth projection, The above-mentioned fourth friction wheel is, It includes a seventh projection and an eighth projection spaced apart from the seventh projection, When the above foldable electronic device is in the above unfolded state, The first projection of the first friction wheel is, Contacted with the fifth projection of the third friction wheel, The third projection of the second friction wheel is, Contacted with the seventh projection of the fourth friction wheel, The sixth projection of the third friction wheel is, contacting the eighth projection of the fourth friction wheel, Foldable electronic device.

8. In Paragraph 7, When the above-mentioned foldable electronic device is in a folded state, The second projection of the first friction wheel is, Contact with the sixth projection of the third friction wheel, The fourth projection of the second friction wheel is, Contacted with the eighth projection of the fourth friction wheel, The fifth projection of the third friction wheel is, contacting the seventh projection of the fourth friction wheel, Foldable electronic device.

9. In any one of paragraphs 6 through 8, The above hinge assembly is, Rotation of the first arm according to the rotation of the first housing part, Rotation of the first shaft according to the rotation of the first arm, Rotation of the first friction wheel according to the rotation of the first shaft, Rotation of the third friction wheel according to the rotation of the first friction wheel, Rotation of the fourth friction wheel according to the rotation of the third friction wheel, Rotation of the second friction wheel according to the rotation of the fourth friction wheel, Rotation of the second shaft according to the rotation of the second friction wheel, and By the rotation of the second arm according to the rotation of the second shaft, Configured to synchronize the rotation of the first arm and the rotation of the second arm, Foldable electronic device.

10. In any one of paragraphs 6 through 9, The first size of the first friction wheel above is, Corresponding to the second size of the second friction wheel above, The third size of the above third friction wheel is, Corresponding to the fourth size of the above fourth friction wheel, Foldable electronic device.

11. In any one of paragraphs 6 through 10, The above hinge assembly is, A elastic sheet comprising at least partially wrapping the first shaft and the second shaft, and configured to press the friction wheels in a direction in which the friction wheels come into close contact with each other, Foldable electronic device.

12. In any one of paragraphs 6 through 11, The above hinge assembly is, A third shaft coupled to the third friction wheel, A fourth shaft coupled to the above-mentioned fourth friction wheel, A first spur gear coupled to the third shaft and configured to rotate together with the rotation of the third friction wheel through the third shaft, and A second spur gear coupled to the fourth shaft, engaged with the first spur gear, and configured to rotate together with the rotation of the fourth friction wheel through the fourth shaft, Foldable electronic device.

13. In any one of paragraphs 1 through 12, The above hinge assembly is, A first coupling bracket for coupling the first rotator to the first housing part, A second coupling bracket that connects the second rotator to the second housing part, A third coupling bracket for coupling the first arm to the first housing part, and A fourth coupling bracket for coupling the second arm to the second housing part, Foldable electronic device.

14. In any one of paragraphs 1 through 13, It further includes a flexible display, The above flexible display is, A first part corresponding to the first housing part above, A second part corresponding to the second housing part above, and A third part extending from the first part of the flexible display to the second part of the flexible display and configured to be at least partially bent based on the rotation of the first housing part and the rotation of the second housing part, Foldable electronic device.

15. In any one of paragraphs 1 through 14, The above friction wheels are, Not including these (teeth), Foldable electronic device.

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