Patent Description:
This application relates to the field of foldable terminals, and in particular, to a rotating mechanism and a foldable terminal.

With the advancement of science and technology, an era of large-screen intelligent terminals is coming. Foldable terminals are favored by users because of large screens and high portability. Currently, a foldable terminal usually uses a rotating mechanism to implement folding and unfolding. However, an existing rotating mechanism tends to stretch a display during folding, resulting in wrinkles on the display under a stress, which affects use reliability of the foldable terminal.

<CIT> discloses a foldable electronic with a hinge comprising a main body, a first folding component and a second folding component, wherein the first folding component and the second folding component are symmetrically arranged on the main body. When the first folding assembly and the second folding assembly rotate oppositely, the length of the first folding assembly and the second folding assembly can be extended.

Another foldable device shown in <CIT> includes a hinge mechanism with a plurality of hinge segments, arranged in a plurality of rows. Adjacent hinge segments may be movably coupled by one or more pins of the hinge segment being slidably received in a corresponding arcuate slot formed in the adjacent hinge segment. Positioning of the one or more pins abutting a first end of the respective one or more arcuate slots may restrict further folding movement of the foldable device beyond a minimum bending radius. Positioning of the one or more pins abutting a second end of the respective one or more arcuate slots may restrict further unfolding movement of the foldable device beyond a maximum bending radius.

<CIT> discloses a flexural rotating shaft mechanism comprising a multi-section rotating shaft unit. The neighboring rotating shaft units are connected by a dowel. The rotating shaft unit can slide in an arc relative to the rotating shaft unit. The multi-section rotating shaft unit provided generates bending movements by a slide between the neighboring rotating shaft units and a rotation axis thereof can be adjusted arbitrarily, so that relative slippage between a screen and a housing is removed.

<CIT> discloses a flexible screen supporting device including a first shell and a second shell connected with the rotating assembly. A fixing piece is positioned on one side of the first shell and the second shell, which are distant from the rotating assembly. The first shell and the second shell rotate around the rotating assembly to drive the fixing sheet to bend or flatten. The horizontal length of the side surface of the fixing piece perpendicular to the rotating shaft in the flattening state is equal to the length of the curved surface of the side surface in the bending state.

<CIT> discloses a folding device and flexible display screen equipped with a first connecting portion connected to a second connecting portion. A flexible member is laminated between the first and second connecting portions and respective first and second backup pad to enable relative movement of the foldable device. The foldable device further includes a synchronous driving assembly.

This application provides a rotating mechanism and a foldable terminal, so as to reduce stretching of the rotating mechanism on a display during folding of the foldable terminal, and avoid the problem that the display has wrinkles under a stress, thereby ensuring use reliability of the foldable terminal. Advantageous aspects and features are defined in the dependent claims.

According to a first aspect, this application provides a rotating mechanism, used in a foldable terminal. The foldable terminal includes a display, and the display includes a neutral layer. It should be noted that because the display includes a plurality of structural layers, and the structural layers are made of different materials, stretching deformation amounts of the structural layers also vary. During folding of the foldable terminal, some structural layers are stretched, and some structural layers are compressed. The neutral layer may include one or more structural layers. During folding of the foldable terminal, the neutral layer is a layer structure that is neither stretched nor compressed in the display, or the neutral layer is a layer structure that has a small stretching deformation amount and a small compression deformation amount in the display.

The rotating mechanism includes a limit base, a first swing arm, and a second swing arm. The limit base is provided with a first arc-shaped groove and a second arc-shaped groove.

The first swing arm includes a first rotating shaft portion, and the first rotating shaft portion is slidably mounted in the first arc-shaped groove and is configured to rotate with respect to the limit base. The second swing arm includes a second rotating shaft portion, and the second rotating shaft portion is slidably mounted in the second arc-shaped groove and is configured to rotate with respect to the limit base. The first rotating shaft portion and the second rotating shaft portion rotate in opposite directions with respect to the limit base.

For example, the first rotating shaft portion rotates clockwise with respect to the limit base, and the second rotating shaft portion rotates counterclockwise with respect to the limit base. In this case, the first swing arm and the second swing arm rotate with respect to the limit base to be relatively folded. Alternatively, the first rotating shaft portion rotates counterclockwise with respect to the limit base, the second rotating shaft portion rotates clockwise with respect to the limit base, and the first swing arm and the second swing arm rotate with respect to the limit base to be relatively unfolded.

The first rotating shaft portion includes a first arc-shaped part and a second arc-shaped part that are distributed in a circumferential direction of the first rotating shaft portion, the first arc-shaped part and the second arc-shaped part are fixedly connected, an axle center of the first arc-shaped part and an axle center of the second arc-shaped part are both located at the neutral layer and coincide with each other, and a radius of the first arc-shaped part is different from a radius of the second arc-shaped part.

When the rotating mechanism according to this application is used in the foldable terminal, during folding of the foldable terminal, because the axle center of the first arc-shaped part and the axle center of the second arc-shaped part are both located at the neutral layer of the display, a center of rotation of the first swing arm is located at the neutral layer of the display when rotating with respect to the limit base, so that rotation of the first swing arm with respect to the limit base can match a change in the neutral layer. Therefore, a rotation process of the first swing arm can match a bending process of the display, so as to reduce stretching of the rotating mechanism on the display, and avoid the problem that the display has wrinkles due to stretching, thereby ensuring use reliability of the foldable terminal.

In an implementation, a difference between the radius of the first arc-shaped part and the radius of the second arc-shaped part is <NUM>~<NUM>, so as to reduce an amplitude of a curvature change between the first arc-shaped part and the second arc-shaped part when the first swing arm rotates with respect to the limit base, thereby ensuring smoothness of rotation of the first rotating shaft portion with respect to the limit base.

According to the invention, the second rotating shaft portion includes a third arc-shaped part and a fourth arc-shaped part that are distributed in a circumferential direction of the second rotating shaft portion, the third arc-shaped part and the fourth arc-shaped part are fixedly connected, an axle center of the third arc-shaped part and an axle center of the fourth arc-shaped part are both located at the neutral layer and coincide with each other, and a radius of the third arc-shaped part is different from a radius of the fourth arc-shaped part.

When the rotating mechanism according to this application is used in the foldable terminal, during folding of the foldable terminal, because the axle center of the third arc-shaped part and the axle center of the fourth arc-shaped part are both located at the neutral layer of the display, a center of rotation of the second swing arm is located at the neutral layer of the display when rotating with respect to the limit base, so that rotation of the second swing arm with respect to the limit base can match a change in the neutral layer. Therefore, a rotation process of the second swing arm can match a bending process of the display, so as to reduce stretching of the rotating mechanism on the display, and avoid the problem that the display has wrinkles due to stretching, thereby ensuring use reliability of the foldable terminal.

In an implementation, a difference between the radius of the third arc-shaped part and the radius of the fourth arc-shaped part is <NUM>~<NUM>, so as to reduce an amplitude of a curvature change between the third arc-shaped part and the fourth arc-shaped part when the second swing arm rotates with respect to the limit base, thereby ensuring smoothness of rotation of the second rotating shaft portion with respect to the limit base.

In an implementation, the first rotating shaft portion further includes a fifth arc-shaped part distributed in the circumferential direction of the first rotating shaft portion, the fifth arc-shaped part is fixedly connected to one end that is of the second arc-shaped part and that is away from the first arc-shaped part, an axle center of the fifth arc-shaped part coincides with the axle center of the second arc-shaped part, and a radius of the fifth arc-shaped part is different from the radius of the second arc-shaped part.

When the rotating mechanism according to this application is used in the foldable terminal, during folding of the foldable terminal, because the axle center of the fifth arc-shaped part is located at the neutral layer of the display, a center of rotation of the first swing arm is always located at the neutral layer of the display when rotating with respect to the limit base, so that rotation of the first swing arm with respect to the limit base can match a change in the neutral layer. Therefore, a rotation process of the first swing arm can match a bending process of the display, so as to reduce stretching of the rotating mechanism on the display, and avoid the problem that the display has wrinkles due to stretching, thereby ensuring use reliability of the foldable terminal.

In an implementation, a difference between the radius of the fifth arc-shaped part and the radius of the second arc-shaped part is <NUM>~<NUM>, so as to reduce an amplitude of a curvature change between the fifth arc-shaped part and the second arc-shaped part when the first rotating shaft portion rotates with respect to the limit base, thereby ensuring smoothness of the rotation of the first rotating shaft portion with respect to the limit base.

In an implementation, the second rotating shaft portion further includes a sixth arc-shaped part distributed in the circumferential direction of the second rotating shaft portion, the sixth arc-shaped part is fixedly connected to the fourth arc-shaped part, an axle center of the sixth arc-shaped part coincides with an axle center of the fourth arc-shaped part, and a radius of the sixth arc-shaped part is different from the radius of the fourth arc-shaped part.

When the rotating mechanism according to this application is used in the foldable terminal, during folding of the foldable terminal, because the axle center of the sixth arc-shaped part is located at the neutral layer of the display, a center of rotation of the second swing arm is always located at the neutral layer of the display when rotating with respect to the limit base, so that rotation of the second swing arm with respect to the limit base can match a change in the neutral layer. Therefore, a rotation process of the second swing arm can match a bending process of the display, so as to reduce stretching of the rotating mechanism on the display, and avoid the problem that the display has wrinkles due to stretching, thereby ensuring use reliability of the foldable terminal.

In an implementation, a difference between the radius of the sixth arc-shaped part and the radius of the fourth arc-shaped part is <NUM>~<NUM>, so as to reduce an amplitude of a curvature change between the sixth arc-shaped part and the fourth arc-shaped part when the second rotating shaft portion rotates with respect to the limit base, thereby ensuring smoothness of the rotation of the second rotating shaft portion with respect to the limit base.

In an implementation, the first swing arm further includes a first swing portion fixedly connected to the first rotating shaft portion, and the first swing portion extends relative to the first arc-shaped groove. When rotating with respect to the limit base, the first swing portion drives the first rotating shaft portion to slide in the first arc-shaped groove, so that the first rotating shaft portion rotates with respect to the limit base, and then the first swing arm rotates with respect to the limit base.

The second swing arm further includes a second swing portion fixedly connected to the second rotating shaft portion, and the second swing portion extends relative to the second arc-shaped groove. When rotating with respect to the limit base, the second swing portion drives the second rotating shaft portion to slide in the second arc-shaped groove, so that the second rotating shaft portion rotates with respect to the limit base, and then the second swing arm rotates with respect to the limit base.

In an implementation, the limit base is provided with two first arc-shaped grooves and two second arc-shaped grooves. In a Y-axis direction, the two first arc-shaped grooves are spaced apart, and the two second arc-shaped grooves are spaced apart.

The rotating mechanism includes two first swing arms and two second swing arms. Two first rotating shaft portions are slidably mounted in the two first arc-shaped grooves respectively, and two second rotating shaft portions are slidably mounted in the two second arc-shaped grooves respectively, so as to improve rotation stability of the rotating mechanism.

In an implementation, the rotating mechanism has a symmetry plane, and the rotating mechanism is mirror-symmetrical with respect to the symmetry plane to ensure rotation stability of the rotating mechanism.

In an implementation, the limit base includes a lower limit block and an upper limit block, and the upper limit block is mounted on the lower limit block and encloses with the lower limit block to form the first arc-shaped groove and the second arc-shaped groove.

The upper limit block and the lower limit block may be integrally formed, or the upper limit block and the lower limit block may be assembled to form an integrated structure, so as to ensure an overall strength of the rotating mechanism.

In an implementation, the rotating mechanism further includes a housing, and the limit base, the first swing arm, and the second swing arm are mounted on an inner side of the housing.

According to a second aspect, this application provides a rotating mechanism, used in a foldable terminal. The foldable terminal includes a display, and the display includes a neutral layer. It should be noted that because the display includes a plurality of structural layers, and the structural layers are made of different materials, stretchability of the structural layers also varies. During folding of the foldable terminal, stretchability of the structural layers of the display varies: Some structural layers are stretched, and some structural layers are compressed. The neutral layer may include one or more structural layers. During folding of the foldable terminal, the neutral layer is a layer structure that is neither stretched nor compressed in the display, or the neutral layer is a layer structure that has a low stretching rate and a low compression rate in the display.

The rotating mechanism includes a limit base, a first swing arm, and a second swing arm. The limit base is provided with a first arc-shaped groove and a second arc-shaped groove. The first swing arm includes a first rotating shaft portion, and the first rotating shaft portion is slidably mounted in the first arc-shaped groove and is configured to rotate with respect to the limit base. The second swing arm includes a second rotating shaft portion, and the second rotating shaft portion is slidably mounted in the second arc-shaped groove and is configured to rotate with respect to the limit base. The first rotating shaft portion and the second rotating shaft portion rotate in opposite directions with respect to the limit base.

The first rotating shaft portion includes a first arc-shaped part and a second arc-shaped part that are distributed in a circumferential direction of the first rotating shaft portion, the first arc-shaped part and the second arc-shaped part are fixedly connected, and an axle center of the first arc-shaped part and an axle center of the second arc-shaped part are both located at the neutral layer and are spaced apart from each other.

In an implementation, a radius of the first arc-shaped part is the same as a radius of the second arc-shaped part, or a difference between the radius of the first arc-shaped part and the radius of the second arc-shaped part is <NUM>~<NUM>, so as to reduce an amplitude of a curvature change between the first arc-shaped part and the second arc-shaped part when the first rotating shaft portion rotates with respect to the limit base, thereby ensuring smoothness of the rotation of the first rotating shaft portion with respect to the limit base.

According to the invention, the second rotating shaft portion includes a third arc-shaped part and a fourth arc-shaped part that are distributed in a circumferential direction of the second rotating shaft portion, the third arc-shaped part and the fourth arc-shaped part are fixedly connected, and an axle center of the third arc-shaped part and an axle center of the fourth arc-shaped part are both located at the neutral layer and are spaced apart from each other.

In an implementation, a radius of the third arc-shaped part is the same as a radius of the fourth arc-shaped part, or a difference between the radius of the third arc-shaped part and the radius of the fourth arc-shaped part is <NUM>~<NUM>, so as to reduce an amplitude of a curvature change between the third arc-shaped part and the fourth arc-shaped part when the second swing arm rotates with respect to the limit base, thereby ensuring smoothness of rotation of the second rotating shaft portion with respect to the limit base.

In an implementation, the first rotating shaft portion further includes a fifth arc-shaped part distributed in the circumferential direction of the first rotating shaft portion, the fifth arc-shaped part is fixedly connected to one end that is of the second arc-shaped part and that is away from the first arc-shaped part, and an axle center of the fifth arc-shaped part is located at the neutral layer and is spaced apart from the axle center of the second arc-shaped part.

In an implementation, a radius of the fifth arc-shaped part is the same as the radius of the second arc-shaped part, or the radius of the fifth arc-shaped part is different from the radius of the second arc-shaped part, and a difference between the radius of the fifth arc-shaped part and the radius of the second arc-shaped part is <NUM>~<NUM>, so as to reduce an amplitude of a curvature change between the fifth arc-shaped part and the second arc-shaped part when the first rotating shaft portion rotates with respect to the limit base, thereby ensuring smoothness of the rotation of the first rotating shaft portion with respect to the limit base.

In an implementation, the second rotating shaft portion further includes a sixth arc-shaped part distributed in the circumferential direction of the second rotating shaft portion, the sixth arc-shaped part is fixedly connected to the fourth arc-shaped part, and an axle center of the sixth arc-shaped part is located at the neutral layer and is spaced apart from the axle center of the fourth arc-shaped part.

In an implementation, a radius of the sixth arc-shaped part is the same as the radius of the fourth arc-shaped part, or the radius of the sixth arc-shaped part is different from the radius of the fourth arc-shaped part, and a difference between the radius of the sixth arc-shaped part and the radius of the fourth arc-shaped part is <NUM>~<NUM>, so as to reduce an amplitude of a curvature change between the sixth arc-shaped part and the fourth arc-shaped part when the second rotating shaft portion rotates with respect to the limit base, thereby ensuring smoothness of the rotation of the second rotating shaft portion with respect to the limit base.

According to a third aspect, this application provides a rotating mechanism, used in a foldable terminal. The foldable terminal includes a display, and the display includes a first structural layer and a second structural layer that are laminated. During folding of the foldable terminal, a stretching deformation amount of the first structural layer is greater than that of the second structural layer.

The first rotating shaft portion includes a first arc-shaped part and a second arc-shaped part that are distributed in a circumferential direction of the first rotating shaft portion, the first arc-shaped part and the second arc-shaped part are fixedly connected, an axle center of the first arc-shaped part is located at the first structural layer, an axle center of the second arc-shaped part is located at the second structural layer, and the axle center located in the first arc-shaped part is away from one side of the second swing arm.

When the rotating mechanism according to this application is used in the foldable terminal, during folding of the foldable terminal, because the axle center of the first arc-shaped part is located at the first structural layer, the axle center of the second arc-shaped part is located at the second structural layer, and the axle center located in the first arc-shaped part is away from one side of the second swing arm, a stretching deformation amount of the first structural layer may be reduced to match that of the second structural layer, so that a degree of matching between the first structural layer and the second structural layer may be improved. Therefore, a rotation process of the first swing arm with respect to the limit base can match a bending process of the display <NUM>, so as to reduce stretching of the rotating mechanism on the display, and avoid the problem that the display has wrinkles due to stretching, thereby ensuring use reliability of the foldable terminal.

In an implementation, a radius of the first arc-shaped part is the same as a radius of the second arc-shaped part, or the radius of the first arc-shaped part is different from the radius of the second arc-shaped part, and a difference between the radius of the first arc-shaped part and the radius of the second arc-shaped part is <NUM>~<NUM>, so as to reduce an amplitude of a curvature change between the first arc-shaped part and the second arc-shaped part when the first rotating shaft portion rotates with respect to the limit base, thereby ensuring smoothness of the rotation of the first rotating shaft portion with respect to the limit base.

According to the invention, the second rotating shaft portion includes a third arc-shaped part and a fourth arc-shaped part that are distributed in a circumferential direction of the second rotating shaft portion, the third arc-shaped part and the fourth arc-shaped part are fixedly connected, an axle center of the third arc-shaped part is located at the first structural layer, an axle center of the fourth arc-shaped part is located at the second structural layer, and the axle center located in the third arc-shaped part is away from one side of the first swing arm.

When the rotating mechanism according to this application is used in the foldable terminal, during folding of the foldable terminal, because the axle center of the third arc-shaped part is located at the first structural layer, the axle center of the fourth arc-shaped part is located at the second structural layer, and the axle center located in the third arc-shaped part is away from one side of the first swing arm, a stretching deformation amount of the first structural layer may be reduced to match that of the second structural layer, so that a degree of matching between the first structural layer and the second structural layer may be improved. Therefore, a rotation process of the second swing arm with respect to the limit base can match a bending process of the display, so as to reduce excessive stretching on the first structural layer during rotation of the second swing arm, and then reduce stretching of the rotating mechanism on the display, and avoid the problem that the display has wrinkles due to stretching, thereby ensuring use reliability of the foldable terminal.

In an implementation, the display further includes a third structural layer; the third structural layer, the first structural layer, and the second structural layer are laminated; and during folding of the foldable terminal, a stretching deformation amount of the third structural layer is less than that of the second structural layer.

The first rotating shaft portion further includes a fifth arc-shaped part distributed in the circumferential direction of the first rotating shaft portion, the fifth arc-shaped part is fixedly connected to one end that is of the second arc-shaped part and that is away from the first arc-shaped part, an axle center of the fifth arc-shaped part is located at the third structural layer, and the axle center located in the second arc-shaped part is away from one side of the second swing arm.

When the rotating mechanism according to this application is used in the foldable terminal, during folding of the foldable terminal, because the axle center of the fifth arc-shaped part is located at the third structural layer, and the axle center located in the second arc-shaped part is away from one side of the second swing arm, a stretching deformation amount of the first structural layer and a stretching deformation amount of the second structural layer may be reduced to match a stretching deformation amount of the third structural layer, so that a degree of matching among the first structural layer, the second structural layer, and the third structural layer may be improved. Therefore, a rotation process of the first swing arm with respect to the limit base can match a bending process of the display, so as to reduce stretching of the rotating mechanism on the display, and avoid the problem that the display has wrinkles due to stretching, thereby ensuring use reliability of the foldable terminal.

In an implementation, the second rotating shaft portion further includes a sixth arc-shaped part distributed in the circumferential direction of the second rotating shaft portion, the sixth arc-shaped part is fixedly connected to the fourth arc-shaped part, an axle center of the sixth arc-shaped part is located at the third structural layer, and the axle center located in the fourth arc-shaped part is away from one side of the first swing arm.

When the rotating mechanism according to this application is used in the foldable terminal, during folding of the foldable terminal, because the axle center of the sixth arc-shaped part is located at the third structural layer, and the axle center located in the fourth arc-shaped part is away from one side of the first swing arm, a stretching deformation amount of the first structural layer and a stretching deformation amount of the second structural layer may be reduced to match a stretching deformation amount of the third structural layer, so that a degree of matching among the first structural layer, the second structural layer, and the third structural layer may be improved. Therefore, a rotation process of the second swing arm with respect to the limit base can match a bending process of the display, so as to reduce stretching of the rotating mechanism on the display, and avoid the problem that the display has wrinkles due to stretching, thereby ensuring use reliability of the foldable terminal.

According to a fourth aspect, this application provides a foldable terminal, including a first housing, a second housing, a display, and any rotating mechanism according to the first aspect or the second aspect. The first swing arm is fixedly connected to the first housing, the second swing arm is fixedly connected to the second housing, the display includes a neutral layer, an axle center of the first arc-shaped part and an axle center of the second arc-shaped part are both located at the neutral layer and coincide with each other, and a radius of the first arc-shaped part is different from a radius of the second arc-shaped part.

The first swing portion is fixedly connected to the first housing, and the second swing portion is fixedly connected to the second housing.

During folding of the foldable terminal according to this application, because the axle center of the first arc-shaped part and the axle center of the second arc-shaped part are both located at the neutral layer of the display, a center of rotation of the first swing arm is located at the neutral layer of the display when rotating with respect to the limit base, so that rotation of the first swing arm with respect to the limit base can match a change in the neutral layer. Therefore, a rotation process of the first swing arm can match a bending process of the display, so as to reduce stretching of the rotating mechanism on the display, and avoid the problem that the display has wrinkles due to stretching, thereby ensuring use reliability of the foldable terminal.

In an implementation, the display includes a plurality of structural layers, and the neutral layer includes one or more structural layers.

In an implementation, the display includes a substrate layer, a display functional layer, a polarizer, a bonding layer, and a protective layer, and the display functional layer, the polarizer, the bonding layer, and the protective layer are sequentially laminated on a top surface of the substrate layer.

In an implementation, the neutral layer includes the display functional layer, an axle center of the first arc-shaped part and an axle center of the second arc-shaped part are both located at the display functional layer, so as to prevent the display functional layer from being split due to excessive stretching during folding of the foldable terminal, thereby ensuring use reliability of the foldable terminal.

In an implementation, the neutral layer includes the polarizer, and the axle center of the first arc-shaped part and the axle center of the second arc-shaped part are both located in the polarizer.

In some other implementations, the neutral layer includes the display functional layer and the polarizer, and the axle center of the first arc-shaped part and the axle center of the second arc-shaped part are both located in the display functional layer or the polarizer.

In an implementation, the display includes a first display part, a second display part, and a bendable part, the bendable part is connected between the first display part and the second display part, the first display part is mounted on the first housing, the second display part is mounted on the second housing, and the bendable part is disposed opposite to the rotating mechanism.

According to a fifth aspect, this application provides a foldable terminal, including a first housing, a second housing, a display, and any rotating mechanism according to the third aspect. The first swing arm is fixedly connected to the first housing, and the second swing arm is fixedly connected to the second housing. The first swing portion is fixedly connected to the first housing, and the second swing portion is fixedly connected to the second housing. The display is mounted on the first housing and the second housing, and the display includes the first structural layer and the second structural layer.

During folding of the foldable terminal according to this application, because the axle center of the first arc-shaped part is located at the first structural layer, the axle center of the second arc-shaped part is located at the second structural layer, and the axle center located in the first arc-shaped part is away from one side of the second swing arm, a stretching deformation amount of the first structural layer may be reduced to match that of the second structural layer, so that a degree of matching between the first structural layer and the second structural layer may be improved, so as to reduce excessive stretching on the first structural layer during rotation of the first swing arm, and then reduce stretching of the rotating mechanism on the display, and avoid the problem that the display has wrinkles due to stretching, thereby ensuring use reliability of the foldable terminal.

During folding of the foldable terminal according to this application, because the axle center of the fifth arc-shaped part is located at the third structural layer, and the axle center located in the second arc-shaped part is away from one side of the second swing arm, a stretching deformation amount of the first structural layer and a stretching deformation amount of the second structural layer may be reduced to match a stretching deformation amount of the third structural layer, so that a degree of matching among the first structural layer, the second structural layer, and the third structural layer may be improved. Therefore, a rotation process of the first swing arm with respect to the limit base can match a bending process of the display, so as to reduce stretching of the rotating mechanism on the display, and avoid the problem that the display has wrinkles due to stretching, thereby ensuring use reliability of the foldable terminal.

In an implementation, the display includes a substrate layer, a display functional layer, a polarizer, a bonding layer, and a protective layer that are sequentially laminated, the substrate layer is the first structural layer, the display functional layer is the second structural layer, and the polarizer is the third structural layer.

To describe technical solutions in embodiments of this application more clearly, the following describes accompanying drawings required in embodiments of this application.

The following clearly and completely describes technical solutions in embodiments of this application with reference to accompanying drawings in embodiments of this application.

Referring to <FIG> is a schematic diagram of a structure of a foldable terminal <NUM> in a first state according to an embodiment of this application; and <FIG> is a schematic diagram of a structure of the foldable terminal <NUM> shown in <FIG> in a second state.

For ease of description, a width direction of the foldable terminal <NUM> shown in <FIG> is defined as an X-axis direction, a length direction of the foldable terminal <NUM> is defined as a Y-axis direction, and a thickness direction of the foldable terminal <NUM> is defined as a Z-axis direction. The X-axis direction, the Y-axis direction, and the Z-axis direction are perpendicular to each other.

The foldable terminal <NUM> may be a foldable electronic product such as a mobile phone, a tablet computer, a personal computer, a multimedia player, an e-book reader, a notebook computer, a vehicle-mounted device, or a wearable device. In this embodiment, the foldable terminal <NUM> is a foldable phone. That is, the foldable terminal <NUM> is a mobile phone that can be switched between a folded state and an unfolded state. In this embodiment of this application, an example in which the foldable terminal <NUM> can be folded or unfolded in the X-axis direction is used for description.

The foldable terminal <NUM> shown in <FIG> is in a folded state, and the foldable terminal <NUM> shown in <FIG> is in an unfolded state. For example, an unfolding angle α of the foldable terminal <NUM> shown in <FIG> is <NUM>°. That is, the foldable terminal <NUM> shown in <FIG> is in a flattened state.

It should be noted that the angle illustrated in this embodiment of this application is allowed to have a little deviation. For example, that the unfolding angle α of the foldable terminal <NUM> shown in <FIG> is <NUM>° means that α may be <NUM>° or about <NUM>°, such as <NUM>°, <NUM>°, <NUM>° or <NUM>°. The angle illustrated later can be understood in the same way.

It should be understood that the foldable terminal <NUM> shown in this embodiment of this application is a terminal that can be folded once. In some other embodiments, the foldable terminal <NUM> may be a terminal that can be folded for multiple times (twice or more). In this case, the foldable terminal <NUM> may include a plurality of parts, two adjacent parts may be folded relatively close to each other until the foldable terminal <NUM> in the folded state, or two adjacent parts may be unfolded relatively away from each other until the foldable terminal <NUM> in the unfolded state.

Also referring to <FIG> is an exploded view of a structure of the foldable terminal <NUM> shown in <FIG>.

The foldable terminal <NUM> includes a foldable apparatus <NUM> and a display <NUM>. The display <NUM> is mounted on the foldable apparatus <NUM>, and is configured to display information such as text, images, or videos. In this embodiment, the display <NUM> includes a first display part <NUM>, a second display part <NUM>, and a bendable part <NUM>, and the bendable part <NUM> is connected between the first display part <NUM> and the second display part <NUM>. The bendable portion <NUM> may be bent in the X-axis direction.

As shown in <FIG>, when the foldable terminal <NUM> is in a folded state, the first display part <NUM> and the second display part <NUM> are oppositely disposed, and the bendable part <NUM> is bent. In this case, the display <NUM> is in a folded state, and an exposed area of the display <NUM> is small, so as to greatly reduce a probability of damage to the display <NUM>, and effectively protect the display <NUM>. As shown in <FIG>, the foldable terminal <NUM> is in an unfolded state, the first display part <NUM> and the second display part <NUM> are relatively unfolded, and the bendable part <NUM> is flattened without bending. In this case, included angles between the first display part <NUM>, the second display part <NUM>, and the bendable part <NUM> are all α, and the display <NUM> has a large display area to implement large-screen display of the foldable terminal <NUM> and improve user experience.

In this embodiment, the foldable apparatus <NUM> includes a first housing <NUM>, a second housing <NUM>, and a rotating mechanism <NUM>. The rotating mechanism <NUM> is connected between the first housing <NUM> and the second housing <NUM> to implement a rotatable connection between the first housing <NUM> and the second housing <NUM>. Specifically, the first housing <NUM> carries the first display part <NUM>, and the second housing <NUM> carries the second display part <NUM>. In other words, the first display part <NUM> is mounted on the first housing <NUM>, and the second display part <NUM> is mounted on the second housing <NUM>. The rotating mechanism <NUM> is disposed opposite to the bendable part <NUM>.

The first housing <NUM> and the second housing <NUM> may be relatively rotated by using the rotating mechanism <NUM>, so that the foldable apparatus <NUM> can be switched between a folded state and an unfolded state. Specifically, the first housing <NUM> and the second housing <NUM> may be relatively rotated to be oppositely disposed, so as to allow the foldable apparatus <NUM> to be in a folded state, as shown in <FIG>. The first housing <NUM> and the second housing <NUM> may alternatively be relatively rotated to be relatively unfolded, so as to allow the foldable apparatus <NUM> to be in an unfolded state, as shown in <FIG>. For example, the foldable terminal <NUM> shown in <FIG> is in an unfolded state, and an included angle between the first housing <NUM> and the second housing <NUM> is α.

The first housing <NUM> is provided with a first accommodating groove <NUM>, and the first accommodating groove <NUM> is located on one side that is of the first housing <NUM> and that faces the second housing <NUM>. An opening of the first accommodating groove <NUM> is located on a top surface of the first housing <NUM>. The first accommodating groove <NUM> is recessed in a direction from the top surface to a bottom surface of the first housing <NUM>, and runs through a side face that is of the first housing <NUM> and that faces the second housing <NUM>. A first step <NUM> protrudes from a bottom wall of the first accommodating groove <NUM>, and a step surface of the first step <NUM> is located between the top surface of the first housing <NUM> and the bottom wall of the first accommodating groove <NUM>.

The second housing <NUM> and the first housing <NUM> have a same structure and are mirror-symmetrical with respect to the rotating mechanism <NUM>. The second housing <NUM> is provided with a second accommodating groove <NUM>, and the second accommodating groove <NUM> is located on one side that is of the second housing <NUM> and that faces the first housing <NUM>. An opening of the second accommodating groove <NUM> is located on a top surface of the second housing <NUM>. The second accommodating groove <NUM> is recessed in a direction from the top surface to a bottom surface of the second housing <NUM>, and runs through a side face that is of the second housing <NUM> and that faces the first housing <NUM>. A second step <NUM> protrudes from a bottom wall of the second accommodating groove <NUM>, and a step surface of the second step <NUM> is located between the top surface of the second housing <NUM> and the bottom wall of the second accommodating groove <NUM>. As shown in <FIG>, when the foldable apparatus <NUM> is in a flattened state, that is, when the included angle between the first housing <NUM> and the second housing <NUM> is α, the first accommodating groove <NUM> and the second accommodating groove <NUM> enclose to form an accommodating space <NUM>, and the rotating mechanism <NUM> is accommodated in the accommodating space <NUM>.

It should be noted that orientation words such as "top" and "bottom" used in this embodiment of this application to describe the foldable terminal <NUM> are mainly described based on a display orientation of the foldable terminal <NUM> shown in <FIG>, with the "top" facing a positive direction of a Z axis and the "bottom" facing a negative direction of the Z axis, which does not limit an orientation of the foldable terminal <NUM> in an actual application scenario.

Referring to <FIG> is a schematic diagram of a sectional structure of a display <NUM> of the foldable terminal <NUM> shown in <FIG> taken along I-I. It should be noted that, in accompanying drawings of this application, "taken along I-I" means taken along a plane where an I-I line is located, and the following description of accompanying drawings may be understood in a same way.

In this embodiment, the display <NUM> includes five structural layers, and the five structural layers are laminated. The five structural layers are a first structural layer <NUM>, a second structural layer <NUM>, a third structural layer <NUM>, a fourth structural layer <NUM>, and a fifth structural layer <NUM>. The second structural layer <NUM>, the third structural layer <NUM>, the fourth structural layer <NUM>, and the fifth structural layer <NUM> are sequentially laminated on a top surface of the first structural layer <NUM>. In some other embodiments, the display <NUM> may further include two, three, four or more than five structural layers, which is not specifically limited in this application.

Specifically, the first structural layer <NUM> is a substrate layer, the second structural layer <NUM> is a display functional layer, the third structural layer <NUM> is a polarizer, the fourth structural layer <NUM> is a bonding layer, and the fifth structural layer <NUM> is a protective layer. The substrate layer is a structural layer with a support function in the display <NUM>. For example, the substrate layer may be a steel sheet substrate. In some other embodiments, the substrate layer may include one or more support structural layers (not shown in the figure), and each support structural layer may be made of foam, polyimide (PI, polyimide), or a metal support plate, so that the substrate layer has some strength and rigidity to support the display functional layer.

The display functional layer is a structural layer with a display function in the display <NUM>. The polarizer is laminated on a top surface of the display functional layer. Because the substrate layer, the display functional layer, and the polarizer are made of different materials, stretching deformation amounts of the substrate layer, the display functional layer, and the polarizer vary during folding of the foldable terminal <NUM>. A stretching deformation amount of the substrate layer is greater than that of the display functional layer, and a stretching deformation amount of the display functional layer is greater than that of the polarizer. That is, a stretching deformation amount of the first structural layer <NUM> is greater than that of the second structural layer <NUM>, and a stretching deformation amount of the second structural layer <NUM> is greater than that of the third structural layer <NUM>.

The protective layer is a structural layer with a protection function in the display <NUM>. The protective layer is located on a top side of the polarizer, and the bonding layer is connected between the protective layer and the polarizer. The protective layer may protect the display functional layer. The bonding layer may be a double-sided adhesive, a top surface of the bonding layer is bonded to a bottom surface of the protective layer, and a bottom surface of the bonding layer is bonded to a top surface of the polarizer.

In addition, the display <NUM> includes a neutral layer 200a, and the neutral layer 200a may include one or more structural layers. In this embodiment, the neutral layer 200a includes a third structural layer <NUM>. In some other embodiments, the neutral layer 200a may further include the second structural layer <NUM>, or the neutral layer 200a may further include the second structural layer <NUM> and the third structural layer <NUM>.

It should be noted that because the display <NUM> is of a multilayer laminated structure, and the structural layers are made of different materials, stretching deformation amounts of the structural layers also vary. During folding of the foldable terminal <NUM>, some structural layers are stretched, and some structural layers are compressed. During folding of the foldable terminal <NUM>, the neutral layer 200a is a layer structure that is neither stretched nor compressed in the display <NUM>, or the neutral layer 200a is a layer structure that has a small stretching deformation amount and a small compression deformation amount in the display <NUM>.

Referring to <FIG> and <FIG>, <FIG> is a schematic diagram of a structure of a rotating mechanism <NUM> of the foldable terminal <NUM> shown in <FIG>; and <FIG> is a schematic diagram of a sectional structure of the rotating mechanism <NUM> shown in <FIG> taken along II-II.

In this embodiment, the rotating mechanism <NUM> has a symmetry plane O, and the rotating mechanism <NUM> is mirror-symmetrical with respect to the symmetry plane O to ensure rotation stability of the rotating mechanism <NUM>. In some other embodiments, the rotating mechanism <NUM> may alternatively not have the symmetry plane O. Whether the rotating mechanism <NUM> has symmetry is not specifically limited in this application. Specifically, the rotating mechanism <NUM> includes a housing <NUM>, a limit base <NUM>, a first swing arm <NUM>, and a second swing arm <NUM>. The limit base <NUM>, the first swing arm <NUM>, and the second swing arm <NUM> are mounted on an inner side of the housing <NUM>. The limit base <NUM> is provided with a first arc-shaped groove <NUM> and a second arc-shaped groove <NUM>. The first swing arm <NUM> is slidably mounted in the first arc-shaped groove <NUM> and is configured to rotate with respect to the limit base <NUM>. The second swing arm <NUM> is slidably mounted in the second arc-shaped groove <NUM>, and is configured to rotate with respect to the limit base <NUM>.

The first swing arm <NUM> and the second swing arm <NUM> rotate in opposite directions with respect to the limit base <NUM>. For example, the first swing arm <NUM> rotates clockwise (a ω<NUM> direction shown in the figure) with respect to the limit base <NUM>, and the second swing arm <NUM> rotates counterclockwise (a ω<NUM> direction shown in the figure) with respect to the limit base <NUM>. In this case, the first swing arm <NUM> and the second swing arm <NUM> rotate with respect to the limit base <NUM> to be relatively folded. Alternatively, the first swing arm <NUM> rotates counterclockwise with respect to the limit base <NUM>, and the second swing arm <NUM> rotates clockwise with respect to the limit base <NUM>. In this case, the first swing arm <NUM> and the second swing arm <NUM> rotate with respect to the limit base <NUM> to be relatively unfolded.

For example, the limit base <NUM> is provided with two first arc-shaped grooves <NUM> and two second arc-shaped grooves <NUM>. The rotating mechanism <NUM> includes two first swing arms <NUM> and two second swing arms <NUM>. The two first arc-shaped grooves <NUM> are spaced apart from each other in the Y-axis direction, and the two second arc-shaped grooves <NUM> are spaced apart from each other in the Y-axis direction. The two first swing arms <NUM> are slidably mounted in the two first arc-shaped grooves <NUM> respectively, and are spaced apart from each other in the Y-axis direction. The two second swing arms <NUM> are slidably mounted in the two second arc-shaped grooves <NUM> respectively, and are spaced apart from each other in the Y-axis direction. In some other embodiments, a quantity of the first arc-shaped groove <NUM>, the second arc-shaped groove <NUM>, the first swing arm <NUM>, and the second swing arm <NUM> may alternatively be one or more than three respectively, which is not specifically limited in this embodiment of this application.

In this embodiment, the limit base <NUM> includes a lower limit block <NUM> and an upper limit block <NUM>, and the upper limit block <NUM> is mounted on the lower limit block <NUM> and encloses with the lower limit block <NUM> to form the first arc-shaped groove <NUM> and the second arc-shaped groove <NUM>. Specifically, the lower limit block <NUM> includes a first lower limit block <NUM> and a second lower limit block <NUM>. In the X-axis direction, the first lower limit block <NUM> and the second lower limit block <NUM> are spaced apart from each other. The upper limit block <NUM> includes a first upper limit block <NUM> and a second upper limit block <NUM>. The first upper limit block <NUM> is mounted on the first lower limit block <NUM>, and encloses with the first lower limit block <NUM> to form the first arc-shaped groove <NUM>. The second upper limit block <NUM> is mounted on the second lower limit block <NUM>, and encloses with the second lower limit block <NUM> to form the second arc-shaped groove <NUM>. In the X-axis direction, the first arc-shaped groove <NUM> and the second arc-shaped groove <NUM> are spaced apart from each other. The first arc-shaped groove <NUM> and the second arc-shaped groove <NUM> are all arranged in an overlapped manner in the Y-axis direction.

It should be noted that arrangement in an overlapped manner means that projections are overlapped. For example, that the first arc-shaped groove <NUM> and the second arc-shaped groove <NUM> are all arranged in an overlapped manner in the Y-axis direction means that projections of the first arc-shaped groove <NUM> and the second arc-shaped groove <NUM> on a Y-Z axis plane are all overlapped. The following description of arrangement in an overlapped manner may be understood in a same way.

In some other embodiments, the first arc-shaped groove <NUM> and the second arc-shaped groove <NUM> may alternatively be arranged in an overlapped manner in the X-axis direction, so as to reduce a size of the rotating mechanism <NUM> in the X-axis direction. Alternatively, the first arc-shaped groove <NUM> and the second arc-shaped groove <NUM> may be spaced apart from each other in the Y-axis direction.

The first lower limit block <NUM> is provided with a first chute <NUM>, and an opening of the first chute <NUM> is located on a top surface of the first lower limit block <NUM>. The first chute <NUM> is recessed in a direction from the top surface to a bottom surface of the first lower limit block <NUM>. The first chute <NUM> is a circular arc chute, and a bottom wall of the first chute <NUM> is a circular arc surface. For example, there are two first chutes <NUM>, and the two first chutes <NUM> are spaced apart from each other in the Y-axis direction.

The first upper limit block <NUM> is mounted on a top side of the first chute <NUM>. A bottom surface of the first upper limit block <NUM> is an arc-shaped surface matching the bottom wall of the first chute <NUM>, so that the first upper limit block <NUM> encloses with a first limit block <NUM> to form the first arc-shaped groove <NUM>. An axle center of the bottom surface of the first upper limit block <NUM> coincides with an axle center of the bottom wall of the first chute <NUM>. For example, there are two first upper limit blocks <NUM>, and the two first upper limit blocks <NUM> are spaced apart from each other in the Y-axis direction. The two first upper limit blocks <NUM> are respectively mounted on top sides of the two first chutes <NUM>, and respectively enclose with the two first chutes <NUM> to form two first arc-shaped grooves <NUM>.

In some other embodiments, the two first upper limit blocks <NUM> may be integrally formed with the first lower limit block <NUM>, or the two first upper limit blocks <NUM> may be assembled with the first lower limit block <NUM> to form an integrated structure, so as to enhance an overall strength of the rotating mechanism <NUM>.

The second lower limit block <NUM> is provided with a second chute <NUM>, and an opening of the second chute <NUM> is located on a top surface of the second lower limit block <NUM>. The second chute <NUM> is recessed in a direction from the top surface to a bottom surface of the second lower limit block <NUM>. The second chute <NUM> is a circular arc chute, and a bottom wall of the second chute <NUM> is an arc-shaped surface. For example, there are two second chutes <NUM>, and the two second chutes <NUM> are spaced apart from each other in the Y-axis direction.

The second upper limit block <NUM> is mounted on a top side of the second chute <NUM>. A bottom surface of the second upper limit block <NUM> is an arc-shaped surface matching the bottom wall of the second chute <NUM>, so that the second upper limit block <NUM> encloses with a second lower limit block <NUM> to form the second arc-shaped groove <NUM>. An axle center of the bottom surface of the second upper limit block <NUM> coincides with an axle center of the bottom wall of the second chute <NUM>. For example, there are two second upper limit blocks <NUM>, and the two second upper limit blocks <NUM> are spaced apart from each other in the Y-axis direction. The two second upper limit blocks <NUM> are respectively mounted on top sides of the two second chutes <NUM>, and respectively enclose with the two second chutes <NUM> to form two second arc-shaped grooves <NUM>.

In some other embodiments, the two second upper limit blocks <NUM> may be integrally formed with the second lower limit block <NUM>, or the two second upper limit blocks <NUM> may be assembled with the second lower limit block <NUM> to form an integrated structure, so as to enhance an overall strength of the rotating mechanism <NUM>.

The first swing arm <NUM> includes a first rotating shaft portion <NUM> and a first swing portion <NUM>, the first rotating shaft portion <NUM> is located at one end of the first swing arm <NUM>, and the first swing portion <NUM> is located on one side of the first rotating shaft portion <NUM> and is fixedly connected to the first rotating shaft portion <NUM>. The first rotating shaft portion <NUM> is in a shape of a circular arc plate, and the first swing portion <NUM> is in a shape of a flat plate. The first rotating shaft portion <NUM> protrudes in a direction away from a top surface of the first swing portion <NUM>, and matches the first arc-shaped groove <NUM>.

Specifically, the first rotating shaft portion <NUM> is slidably mounted in the first arc-shaped groove <NUM>, and is configured to rotate with respect to the limit base <NUM>. The first rotating shaft portion <NUM> is clamped between the first lower limit block <NUM> and the first upper limit block <NUM>. That is, in the Z-axis direction, the first lower limit block <NUM> and the first upper limit block <NUM> jointly limit the first rotating shaft portion <NUM>, to prevent the first rotating shaft portion <NUM> from sliding from the first arc-shaped groove <NUM>, so as to ensure rotation reliability of the first rotating shaft portion <NUM> with respect to the limit base <NUM>, and then ensure use reliability of the rotating mechanism <NUM>.

It should be noted that, that the first rotating shaft portion <NUM> matches the first arc-shaped groove <NUM> means that the first rotating shaft portion <NUM> may slide in the first arc-shaped groove <NUM>, to implement relative rotation between the first rotating shaft portion <NUM> and the limit base <NUM>. The following description of matching may be understood in a same way.

The first swing portion <NUM> extends relative to the first arc-shaped groove <NUM>. The first swing portion <NUM> extends relative to a left side of the first lower limit block <NUM>. When rotating with respect to the limit base <NUM>, the first swing portion <NUM> drives the first rotating shaft portion <NUM> to slide in the first arc-shaped groove <NUM>, so that the first rotating shaft portion <NUM> rotates with respect to the limit base <NUM>, and then the first swing arm <NUM> rotates with respect to the limit base <NUM>.

In this embodiment, a structure of the second swing arm <NUM> is roughly the same as that of the first swing arm <NUM>. The second swing arm <NUM> includes a second rotating shaft portion <NUM> and a second swing portion <NUM>, the second rotating shaft portion <NUM> is located at one end of the second swing arm <NUM>, and the second swing portion <NUM> is located on one side of the second rotating shaft portion <NUM> and is fixedly connected to the second rotating shaft portion <NUM>. The second rotating shaft portion <NUM> is in a shape of a circular arc plate, and the second swing portion <NUM> is in a shape of a flat plate. The second rotating shaft portion <NUM> protrudes in a direction away from a top surface of the second swing portion <NUM>, and matches the second arc-shaped groove <NUM>.

Specifically, the second rotating shaft portion <NUM> is slidably mounted in the second arc-shaped groove <NUM>, and is configured to rotate with respect to the limit base <NUM>. The second rotating shaft portion <NUM> is clamped between the second lower limit block <NUM> and the second upper limit block <NUM>. That is, in the Z-axis direction, the second lower limit block <NUM> and the second upper limit block <NUM> jointly limit the second rotating shaft portion <NUM>, to prevent the second rotating shaft portion <NUM> from sliding from the second arc-shaped groove <NUM>, so as to ensure rotation reliability of the second rotating shaft portion <NUM> with respect to the limit base <NUM>, and then ensure use reliability of the rotating mechanism <NUM>.

The second swing portion <NUM> extends relative to the second arc-shaped groove <NUM>. The second swing portion <NUM> extends relative to a right side of the second lower limit block <NUM>. When rotating with respect to the limit base <NUM>, the second swing portion <NUM> drives the second rotating shaft portion <NUM> to slide in the second arc-shaped groove <NUM>, so that the second rotating shaft portion <NUM> rotates with respect to the limit base <NUM>, and then the second swing arm <NUM> rotates with respect to the limit base <NUM>.

In this case, the included angle between the second swing portion <NUM> and the first swing portion <NUM> is α. In the X-axis direction, the first rotating shaft portion <NUM> and the second rotating shaft portion <NUM> are spaced apart. The first rotating shaft portion <NUM> and the second rotating shaft portion <NUM> are all arranged in an overlapped manner in the Y-axis direction, so as to reduce a size of the rotating mechanism <NUM> in the Y-axis direction, and implement a miniaturization design of the rotating mechanism <NUM>.

In some other embodiments, the first rotating shaft portion <NUM> and the second rotating shaft portion <NUM> may alternatively be partially or completely overlapped in the X-axis direction, so as to reduce a size of the rotating mechanism <NUM> in the X-axis direction, and implement a miniaturization design of the rotating mechanism <NUM>. Alternatively, the first rotating shaft portion <NUM> and the second rotating shaft portion <NUM> may be partially overlapped or spaced apart in the Y-axis direction, which is not specifically limited in this application.

Referring to <FIG> and <FIG> is a schematic diagram of a sectional structure of the foldable terminal <NUM> shown in <FIG> taken along III-III.

When the foldable apparatus <NUM> is in a flattened state, the rotating mechanism <NUM> is mounted in the accommodating space <NUM>. Apart of the rotating mechanism <NUM> is mounted in the first accommodating groove <NUM> of the first housing <NUM>, and another part of the rotating mechanism <NUM> is mounted in the second accommodating groove <NUM> of the second housing <NUM>. Specifically, the first swing arm <NUM> is fixedly connected to the first housing <NUM>, and the second swing arm <NUM> is fixedly connected to the second housing <NUM>. The first swing portion <NUM> is fixedly connected to the first housing <NUM>, and the second swing portion <NUM> is fixedly connected to the second housing <NUM>. For example, the first swing arm <NUM> may be fixedly connected to the first housing <NUM> by using a screw or a bolt, and the second swing arm <NUM> may be fixedly connected to the second housing <NUM> by using a screw or a bolt. When the first housing <NUM> and the second housing <NUM> are relatively folded or unfolded, the first housing <NUM> drives the first swing arm <NUM> to rotate with respect to the limit base <NUM>, and the second housing <NUM> drives the second swing arm <NUM> to rotate with respect to the limit base <NUM>.

In this case, the top surface of the first swing portion <NUM> is flush with the top surface of the second swing portion <NUM>. The top surface of the first swing portion <NUM> and the top surface of the second swing portion <NUM> jointly form a support surface <NUM>, and the support surface <NUM> may support the bendable part <NUM> of the display <NUM> to ensure good display of the display <NUM>. For example, the bendable part <NUM> may be mounted on the support surface <NUM> by using a bonding layer <NUM>. The top surface of the first swing portion <NUM> is flush with the top surface of the first housing <NUM>, and the top surface of the second swing portion <NUM> is flush with the top surface of the second housing <NUM>, so that the first swing portion <NUM> and the second swing portion <NUM> may support the display <NUM> together with the first housing <NUM> and the second housing <NUM>. Therefore, the foldable apparatus <NUM> in a flattened state can effectively support the display <NUM>.

In addition, the rotating mechanism <NUM> may further include a transmission member (not shown in the figure), and the transmission member is connected between the first swing arm <NUM> and the second swing arm <NUM> to drive the second swing arm <NUM> to rotate with respect to the limit base <NUM> while the first swing arm <NUM> rotates with respect to the limit base <NUM>, or to drive the first swing arm <NUM> to rotate with respect to the limit base <NUM> while the second swing arm <NUM> rotates with respect to the limit base <NUM>, so as to implement synchronous rotation of the first swing arm <NUM> and the second swing arm <NUM> with respect to the limit base <NUM>. For example, the transmission member may be a gear or another component that can implement transmission.

It should be noted that, in an existing rotating mechanism, rotating shaft portions of swing arms are in a shape of a continuous arc-shaped plate. During folding or unfolding of the rotating mechanism, a rotation process of each swing arm cannot match a bending process of a display, and the rotating mechanism tends to stretch the display, resulting in wrinkles on the display under a stress, which affects use reliability of the foldable terminal.

In the rotating mechanism <NUM> shown in this embodiment of this application, the first rotating shaft portion <NUM> and the second rotating shaft portion <NUM> are designed to be in a shape of a discontinuous arc-shaped plate. During folding of the foldable terminal <NUM>, rotation processes of the first swing arm <NUM> and the second swing arm <NUM> with respect to the limit base <NUM> can match a bending process of the display <NUM>, so as to prevent the rotating mechanism <NUM> from stretching the display <NUM>, and avoid the problem that the display <NUM> has wrinkles under a stress, thereby ensuring use reliability of the foldable terminal <NUM>.

Next, structures of the first swing arm <NUM> and the second swing arm <NUM> of the rotating mechanism <NUM> shown in this embodiment of this application are described in detail.

Referring to <FIG> is a schematic diagram of a structure of a first swing arm <NUM> of the foldable terminal <NUM> shown in <FIG> according to a first implementation.

The first rotating shaft portion <NUM> includes three arc-shaped parts distributed in a circumferential direction of the first rotating shaft portion <NUM>, and the three arc-shaped parts are sequentially connected. The three arc-shaped parts are a first arc-shaped part <NUM>, a second arc-shaped part <NUM>, and a fifth arc-shaped part <NUM>. The first arc-shaped part <NUM> is located at one end that is of the first rotating shaft portion <NUM> and that is away from the first swing portion <NUM>; the fifth arc-shaped part <NUM> is located at one end that is of the first rotating shaft portion <NUM> and that is close to the first swing portion <NUM>, and is fixedly connected to the first swing portion <NUM>; and the second arc-shaped part <NUM> is connected between the first arc-shaped part <NUM> and the fifth arc-shaped part <NUM>. In some other implementations, the first rotating shaft portion <NUM> may further include two or more than four arc-shaped parts, which is not specifically limited in this application.

In this implementation, an axle center of the first arc-shaped part <NUM> is C<NUM>, and the first arc-shaped part <NUM> has a radius of R<NUM>. An axle center of the second arc-shaped part <NUM> is C<NUM>, and the second arc-shaped part <NUM> has a radius of R<NUM>. An axle center of the fifth arc-shaped part <NUM> is C<NUM>, and the fifth arc-shaped part <NUM> has a radius of R<NUM>. Specifically, the axle center C<NUM> of the first arc-shaped part <NUM>, the axle center C<NUM> of the second arc-shaped part <NUM>, and the axle center C<NUM> of the fifth arc-shaped part <NUM> are spaced apart from each other. That is, the axle center C<NUM> of the first arc-shaped part <NUM>, the axle center C<NUM> of the second arc-shaped part <NUM>, and the axle center C<NUM> of the fifth arc-shaped part <NUM> do not coincide. The axle center C<NUM> of the first arc-shaped part <NUM> and the axle center C<NUM> of the second arc-shaped part <NUM> are located at a bottom side of the axle center C<NUM> of the fifth arc-shaped part <NUM>, and the axle center C<NUM> of the first arc-shaped part <NUM> is located at a bottom side of the axle center C<NUM> of the second arc-shaped part <NUM>.

In some other implementations, the axle center C<NUM> of the second arc-shaped part <NUM> may alternatively be located at a bottom side of the axle center C<NUM> of the first arc-shaped part <NUM>. Alternatively, the axle center C<NUM> of the first arc-shaped part <NUM> and the axle center C<NUM> of the fifth arc-shaped part <NUM> may be located at the bottom side of the axle center C<NUM> of the second arc-shaped part <NUM>, and the axle center C<NUM> of the fifth arc-shaped part <NUM> is located at the bottom side of the axle center C<NUM> of the first arc-shaped part <NUM>, or the axle center C<NUM> of the first arc-shaped part <NUM> is located at the bottom side of the axle center C<NUM> of the fifth arc-shaped part <NUM>. Alternatively, the axle center C<NUM> of the second arc-shaped part <NUM> and the axle center C<NUM> of the fifth arc-shaped part <NUM> may be located at the bottom side of the axle center C<NUM> of the first arc-shaped part <NUM>, and the axle center C<NUM> of the second arc-shaped part <NUM> is located at the bottom side of the axle center C<NUM> of the fifth arc-shaped part <NUM>, or the axle center C<NUM> of the fifth arc-shaped part <NUM> is located at the bottom side of the axle center C<NUM> of the second arc-shaped part <NUM>.

In addition, a radius R<NUM> of the first arc-shaped part <NUM>, a radius R<NUM> of the second arc-shaped part <NUM>, and a radius R<NUM> of the fifth arc-shaped part <NUM> are equal. In some other implementations, the radius R<NUM> of the first arc-shaped part <NUM> may be equal to the radius R<NUM> of the second arc-shaped part <NUM>, but not equal to the radius R<NUM> of the fifth arc-shaped part <NUM>; or the radius R<NUM> of the first arc-shaped part <NUM> may be equal to the radius R<NUM> of the fifth arc-shaped part <NUM>, but not equal to the radius R<NUM> of the fifth arc-shaped part <NUM>; or the radius R<NUM> of the second arc-shaped part <NUM> may be equal to the radius R<NUM> of the fifth arc-shaped part <NUM>, but not equal to the radius R<NUM> of the first arc-shaped part <NUM>; or the radius R<NUM> of the first arc-shaped part <NUM>, the radius R<NUM> of the second arc-shaped part <NUM>, and the radius R<NUM> of the fifth arc-shaped part <NUM> are not equal.

Referring to <FIG> and <FIG> is a schematic diagram of a partial structure of the foldable terminal <NUM> shown in <FIG> according to an example not covered by the claims. <FIG> shows only the display <NUM>, the axle center C<NUM> of the first arc-shaped part <NUM>, the axle center C<NUM> of the second arc-shaped part <NUM>, and the axle center C<NUM> of the fifth arc-shaped part <NUM>.

In this implementation, the axle center C<NUM> of the first arc-shaped part <NUM>, the axle center C<NUM> of the second arc-shaped part <NUM>, and the axle center C<NUM> of the fifth arc-shaped part <NUM> are located in the display <NUM>. Specifically, the axle center C<NUM> of the first arc-shaped part <NUM>, the axle center C<NUM> of the second arc-shaped part <NUM>, and the axle center C<NUM> of the fifth arc-shaped part <NUM> are respectively located at different layers of the display <NUM>. The axle center C<NUM> of the first arc-shaped part <NUM> is located at the third structural layer <NUM>, the axle center C<NUM> of the second arc-shaped part <NUM> is located at the second structural layer <NUM>, the axle center C<NUM> located in the first arc-shaped part <NUM> is away from one side of the second swing arm <NUM>, the axle center C<NUM> of the fifth arc-shaped part <NUM> is located at the first structural layer <NUM>, and the axle center C<NUM> located in the second arc-shaped part <NUM> is away from one side of the second swing arm <NUM>.

In some other implementations, the axle center C<NUM> of the first arc-shaped part <NUM> may alternatively be located in the fifth structural layer <NUM>, the fourth structural layer <NUM>, the second structural layer <NUM>, or the first structural layer <NUM> of the display <NUM>; or the axle center C<NUM> of the second arc-shaped part <NUM> may be located in the fifth structural layer <NUM>, the fourth structural layer <NUM>, the third structural layer <NUM> or the first structural layer <NUM> of the display <NUM>; or the axle center C<NUM> of the fifth arc-shaped part <NUM> may be located in the fifth structural layer <NUM>, the fourth structural layer <NUM>, the third structural layer <NUM> or the second structural layer <NUM> of the display <NUM>, which is not specifically limited in this application.

In this implementation, a structure of the second swing arm <NUM> is roughly the same as that of the first swing arm <NUM>. The second rotating shaft portion <NUM> includes three arc-shaped parts distributed in a circumferential direction of the second rotating shaft portion <NUM>, and the three arc-shaped parts are sequentially connected. The three arc-shaped parts are a third arc-shaped part, a fourth arc-shaped part, and a sixth arc-shaped part (not shown in the figure). The third arc-shaped part is located at one end that is of the second rotating shaft portion <NUM> and that is away from the second swing portion <NUM>; the sixth arc-shaped part is located at one end that is of the second rotating shaft portion <NUM> and that is close to the second swing portion <NUM>, and is fixedly connected to the second swing portion <NUM>; and the fourth arc-shaped part is connected between the third arc-shaped part and the sixth arc-shaped part.

Specifically, an axle center of the third arc-shaped part is located at the first structural layer <NUM>, an axle center of the fourth arc-shaped part is located at the second structural layer <NUM>, the axle center located in the third arc-shaped part is away from one side of the first swing arm <NUM>, an axle center of the sixth arc-shaped part is located at the third structural layer <NUM>, and the axle center located in the fourth arc-shaped part is away from one side of the first swing arm <NUM>. It should be noted that a structure of the third arc-shaped part is roughly the same as that of the first arc-shaped part <NUM>, a structure of the fourth arc-shaped part is roughly the same as that of the second arc-shaped part <NUM>, and a structure of the sixth arc-shaped part is roughly the same as that of the fifth arc-shaped part <NUM>. Therefore, for specific structures of the third arc-shaped part, the fourth arc-shaped part and the sixth arc-shaped part, reference may be made to foregoing descriptions of the first arc-shaped part <NUM>, the second arc-shaped part <NUM> and the fifth arc-shaped part <NUM>, and details are not described herein again.

In this implementation, because the axle center C<NUM> of the first arc-shaped part <NUM> is located at the first structural layer <NUM>, the axle center C<NUM> of the second arc-shaped part <NUM> is located at the second structural layer <NUM>, the axle center C<NUM> located in the first arc-shaped part <NUM> is away from one side of the second swing arm <NUM>, the axle center C<NUM> of the fifth arc-shaped part <NUM> is located at the third structural layer <NUM>, and the axle center C<NUM> located in the second arc-shaped part <NUM> is away from one side of the second swing arm <NUM>, during folding of the foldable terminal <NUM>, a stretching deformation amount of the first structural layer <NUM> and a stretching deformation amount of the second structural layer <NUM> may be reduced to match a stretching deformation amount of the third structural layer <NUM>, so that a degree of matching among the first structural layer <NUM>, the second structural layer <NUM>, and the third structural layer <NUM> may be improved. Therefore, rotation processes of the first swing arm <NUM> and the second swing arm <NUM> with respect to the limit base <NUM> can match a bending process of the display <NUM>, so as to reduce stretching of the rotating mechanism <NUM> on the display <NUM>, and avoid the problem that the display <NUM> has wrinkles due to stretching, thereby ensuring use reliability of the foldable terminal <NUM>.

Referring to <FIG> and <FIG> is a schematic diagram of a partial structure of the foldable terminal <NUM> shown in <FIG> according to a second example not covered by the claims. <FIG> shows only the display <NUM>, the axle center C<NUM> of the first arc-shaped part <NUM>, the radius R<NUM>, the axle center C<NUM> of the second arc-shaped part <NUM>, the radius R<NUM>, the axle center C<NUM> of the fifth arc-shaped part <NUM>, and the radius R<NUM>.

The foldable terminal <NUM> according to this implementation differs from the foldable terminal <NUM> according to the first implementation in that the radius R<NUM> of the first arc-shaped part <NUM> is not equal to the radius R<NUM> of the second arc-shaped part <NUM>, and the radius R<NUM> of the second arc-shaped part <NUM> is not equal to the radius R<NUM> of the fifth arc-shaped part <NUM>. For example, the radius R<NUM> of the first arc-shaped part <NUM> is greater than the radius R<NUM> of the second arc-shaped part <NUM>, and the radius R<NUM> of the second arc-shaped part <NUM> is greater than the radius R<NUM> of the fifth arc-shaped part <NUM>.

A curvature of the first arc-shaped part <NUM> is designed to be tangent a curvature of the second arc-shaped part <NUM>, that is, a difference between the radius R<NUM> of the first arc-shaped part <NUM> and the radius R<NUM> of the second arc-shaped part <NUM> is <NUM>~<NUM>. A curvature of the second arc-shaped part <NUM> is designed to be tangent a curvature of the fifth arc-shaped part <NUM>, that is, a difference between the radius R<NUM> of the second arc-shaped part <NUM> and the radius R<NUM> of the fifth arc-shaped part <NUM> is <NUM>~<NUM>. The curvature of the second arc-shaped part <NUM> is designed to be tangent the curvature of the first arc-shaped part <NUM> and the curvature of the fifth arc-shaped part <NUM>. Therefore, when the first rotating shaft portion <NUM> rotates with respect to the limit base <NUM>, a amplitude of a curvature change can be reduced, and smoothness of rotation of the first rotating shaft portion <NUM> with respect to the limit base <NUM> can be ensured while avoiding stretching the display <NUM>.

In this implementation, because the axle center C1 of the first arc-shaped part <NUM> is located at the first structural layer <NUM>, the axle center C2 of the second arc-shaped part <NUM> is located at the second structural layer <NUM>, the axle center C1 located in the first arc-shaped part <NUM> is away from one side of the second swing arm <NUM>, the axle center C3 of the fifth arc-shaped part <NUM> is located at the third structural layer <NUM>, and the axle center C2 located in the second arc-shaped part <NUM> is away from one side of the second swing arm <NUM>, during folding of the foldable terminal <NUM>, a stretching deformation amount of the first structural layer <NUM> and a stretching deformation amount of the second structural layer <NUM> may be reduced to match a stretching deformation amount of the third structural layer <NUM>, so that a degree of matching among the first structural layer <NUM>, the second structural layer <NUM>, and the third structural layer <NUM> may be improved. Therefore, rotation processes of the first swing arm <NUM> and the second swing arm <NUM> with respect to the limit base <NUM> can match a bending process of the display <NUM>, so as to reduce stretching of the rotating mechanism <NUM> on the display <NUM>, and avoid the problem that the display <NUM> has wrinkles due to stretching, thereby ensuring use reliability of the foldable terminal <NUM>.

Referring to <FIG> and <FIG> is a schematic diagram of a partial structure of the foldable terminal <NUM> shown in <FIG> according to a third implementation. <FIG> shows only the display <NUM>, the axle center C<NUM> of the first arc-shaped part <NUM>, the axle center C<NUM> of the second arc-shaped part <NUM>, and the axle center C<NUM> of the fifth arc-shaped part <NUM>.

The foldable terminal <NUM> according to this implementation differs from the foldable terminal <NUM> according to the first implementation in that the axle center C<NUM> of the first arc-shaped part <NUM>, the axle center C<NUM> of the second arc-shaped part <NUM>, and the axle center C<NUM> of the fifth arc-shaped part <NUM> are located at the same layer of the display <NUM>.

In some other implementations, the axle center C<NUM> of the first arc-shaped part <NUM> and the axle center C<NUM> of the second arc-shaped part <NUM> may be located at the same layer of the display <NUM>, but located at different layers from the axle center C<NUM> of the fifth arc-shaped part <NUM>. Alternatively, the axle center C<NUM> of the first arc-shaped part <NUM> and the axle center C<NUM> of the fifth arc-shaped part <NUM> may be located at the same layer of the display <NUM>, but located at different layers from the axle center C<NUM> of the second arc-shaped part <NUM>. Alternatively, the axle center C<NUM> of the second arc-shaped part <NUM> and the axle center C<NUM> of the fifth arc-shaped part <NUM> are located at the same layer of the display <NUM>, but located at different layers from the axle center C<NUM> of the first arc-shaped part <NUM>, which is not specifically limited in this application.

Specifically, the axle center C<NUM> of the first arc-shaped part <NUM>, the axle center C<NUM> of the second arc-shaped part <NUM>, and the axle center C<NUM> of the fifth arc-shaped part <NUM> are located at the neutral layer 200a of the display <NUM>, and are spaced apart from each other. That is, the axle center C<NUM> of the first arc-shaped part <NUM>, the axle center C<NUM> of the second arc-shaped part <NUM>, and the axle center C<NUM> of the fifth arc-shaped part <NUM> are located at the third structural layer <NUM> of the display <NUM>. The axle center C<NUM> of the second arc-shaped part <NUM> is located between the axle center C<NUM> of the first arc-shaped part <NUM> and the axle center C<NUM> of the fifth arc-shaped part <NUM>. In some other implementations, the axle center C<NUM> of the first arc-shaped part <NUM>, the axle center C<NUM> of the second arc-shaped part <NUM>, and the axle center C<NUM> of the fifth arc-shaped part <NUM> may alternatively be located at the fifth structural layer <NUM>, the fourth structural layer <NUM>, the second structural layer <NUM>, or the first structural layer <NUM> of the display <NUM>.

In this implementation, because the axle center C<NUM> of the first arc-shaped part <NUM>, the axle center C<NUM> of the second arc-shaped part <NUM>, and the axle center C<NUM> of the fifth arc-shaped part <NUM> are located at the neutral layer 200a of the display <NUM>, and are spaced apart from each other, during folding of the foldable terminal <NUM>, a center of rotation of the first swing arm <NUM> is located at the neutral layer 200a when rotating with respect to the limit base <NUM>, so that rotation of the first swing arm <NUM> with respect to the limit base <NUM> can match a change in the neutral layer 200a. Therefore, rotation processes of the first swing arm <NUM> and the second swing arm <NUM> can match a bending process of the display <NUM>, so as to reduce stretching of the rotating mechanism <NUM> on the display <NUM>, and avoid the problem that the display <NUM> has wrinkles due to stretching, thereby ensuring use reliability of the foldable terminal <NUM>.

Referring to <FIG> and <FIG> is a schematic diagram of a partial structure of the foldable terminal <NUM> shown in <FIG> according to a fourth implementation. <FIG> shows only the display <NUM>, the axle center C<NUM> of the first arc-shaped part <NUM>, the radius R1, the axle center C<NUM> of the second arc-shaped part <NUM>, the radius R2, the axle center C<NUM> of the fifth arc-shaped part <NUM>, and the radius R3.

The foldable terminal <NUM> according to this implementation differs from the foldable terminal <NUM> according to the second implementation in that the axle center C<NUM> of the first arc-shaped part <NUM>, the axle center C<NUM> of the second arc-shaped part <NUM>, and the axle center C<NUM> of the fifth arc-shaped part <NUM> are located at the same layer of the display <NUM>, and coincide with each other.

In some other implementations, the axle center C<NUM> of the first arc-shaped part <NUM> may coincide with the axle center C<NUM> of the second arc-shaped part <NUM>, but does not coincide with the axle center C<NUM> of the fifth arc-shaped part <NUM>. Alternatively, the axle center C<NUM> of the first arc-shaped part <NUM> may coincide with the axle center C<NUM> of the fifth arc-shaped part <NUM>, but does not coincide with the axle center C<NUM> of the second arc-shaped part <NUM>. Alternatively, the axle center C<NUM> of the second arc-shaped part <NUM> and the axle center C<NUM> of the first arc-shaped part <NUM> may coincide with the axle center C<NUM> of the fifth arc-shaped part <NUM>, but does not coincide with the axle center C<NUM> of the first arc-shaped part <NUM>, which is not specifically limited in this application.

Specifically, the axle center C<NUM> of the first arc-shaped part <NUM>, the axle center C<NUM> of the second arc-shaped part <NUM>, and the axle center C<NUM> of the fifth arc-shaped part <NUM> are located at the neutral layer 200a of the display <NUM>, and coincide with each other. That is, the axle center C<NUM> of the first arc-shaped part <NUM>, the axle center C<NUM> of the second arc-shaped part <NUM>, and the axle center C<NUM> of the fifth arc-shaped part <NUM> are located at the third structural layer <NUM>. In some other implementations, the axle center C<NUM> of the first arc-shaped part <NUM>, the axle center C<NUM> of the second arc-shaped part <NUM>, and the axle center C<NUM> of the fifth arc-shaped part <NUM> may alternatively be located at the first structural layer <NUM>, the second structural layer <NUM>, the fourth structural layer <NUM> or the fifth structural layer <NUM> of the display <NUM>.

In this implementation, because the axle center C1 of the first arc-shaped part <NUM>, the axle center C2 of the second arc-shaped part <NUM>, and the axle center C3 of the fifth arc-shaped part <NUM> are located at the neutral layer 200a of the display <NUM>, and are spaced apart from each other, during folding of the foldable terminal <NUM>, a center of rotation of the first swing arm <NUM> is located at the neutral layer 200a when rotating with respect to the limit base <NUM>, so that rotation of the first swing arm <NUM> with respect to the limit base <NUM> can match a change in the neutral layer 200a. Therefore, rotation processes of the first swing arm <NUM> and the second swing arm <NUM> can match a bending process of the display <NUM>, so as to reduce stretching of the rotating mechanism <NUM> on the display <NUM>, and avoid the problem that the display <NUM> has wrinkles due to stretching, thereby ensuring use reliability of the foldable terminal <NUM>.

It should be noted that, in some other embodiments, the structure of the second swing arm <NUM> may alternatively be different from that of the first swing arm <NUM>. For example, the first swing arm <NUM> is of the structure of the first swing arm <NUM> according to the first implementation, while the second swing arm <NUM> is of the structure of the first swing arm <NUM> according to the second implementation, the third implementation, or the fourth implementation; or the second swing arm <NUM> is not of the structure of the first swing arm <NUM> according to any one of the implementations. During folding of the foldable terminal <NUM>, the rotating mechanism <NUM> can also reduce stretching on the display <NUM>, and avoid the problem that the display <NUM> has wrinkles due to stretching, thereby ensuring use reliability of the foldable terminal <NUM>.

Claim 1:
A rotating mechanism (<NUM>), used in a foldable terminal (<NUM>), wherein the foldable terminal (<NUM>) comprises a display (<NUM>), the display (<NUM>) comprises a neutral layer (200a), the rotating mechanism (<NUM>) comprises a limit base (<NUM>), a first swing arm (<NUM>), and a second swing arm (<NUM>), and the limit base (<NUM>) is provided with a first arc-shaped groove (<NUM>) and a second arc-shaped groove (<NUM>);
the first swing arm (<NUM>) comprises a first rotating shaft portion (<NUM>), the first rotating shaft portion (<NUM>) is slidably mounted in the first arc-shaped groove (<NUM>) and is configured to rotate with respect to the limit base (<NUM>), the second swing arm (<NUM>) comprises a second rotating shaft portion (<NUM>), the second rotating shaft portion (<NUM>) is slidably mounted in the second arc-shaped groove (<NUM>) and is configured to rotate with respect to the limit base (<NUM>), and the first rotating shaft portion (<NUM>) and the second rotating shaft portion (<NUM>) rotate in opposite directions with respect to the limit base (<NUM>); and
the first rotating shaft portion (<NUM>) comprises a first arc-shaped part (<NUM>) and a second arc-shaped part (<NUM>) that are distributed in a circumferential direction of the first rotating shaft portion (<NUM>), the first arc-shaped part (<NUM>) and the second arc-shaped part (<NUM>) are fixedly connected, an axle center (C<NUM>) of the first arc-shaped part (<NUM>) and an axle center (C<NUM>) of the second arc-shaped part (<NUM>) are both located at the neutral layer (200a), and a radius of the first arc-shaped part (<NUM>) is different from a radius of the second arc-shaped part (<NUM>),
wherein the second rotating shaft portion (<NUM>) comprises a third arc-shaped part and a fourth arc-shaped part that are distributed in a circumferential direction of the second rotating shaft portion (<NUM>), the third arc-shaped part and the fourth arc-shaped part are fixedly connected, an axle center of the third arc-shaped part and an axle center of the fourth arc-shaped part are both located at the neutral layer (200a) and coincide with each other, and a radius of the third arc-shaped part is different from a radius of the fourth arc-shaped part.