Electronic device and projector

Abstract

Provided is an electronic device comprising: a main body to which a first wheel and a second wheel are rotatably coupled, the first wheel being rotatable about a first rotation axis; and a second wheel device, wherein the second wheel device comprises: a wheel cover rotatably connected to the main body and provided to rotate about a second rotation axis extending in a direction intersecting the direction corresponding to the first rotation axis; a wheel shaft coupled to the wheel cover and extending in a direction intersecting the direction in which the second rotation axis extends; and the second wheel rotatably coupled to the wheel shaft, the second wheel includes an outer circumferential surface including a first portion and a second portion, and the outer diameter of at least a portion of the first portion is longer than the outer diameter of the whole portion of the second portion.

Description

Electronic devices and projectors

[0001] The present disclosure relates to an electronic device and a projector having an improved structure.

[0002] The electronic device may include a main body and a plurality of wheels provided to move the main body. Through the above configuration, the electronic device may be able to move more easily within a space.

[0003] A plurality of wheels may include a main wheel configured to rotate by a driving device including a motor, and an auxiliary wheel configured to movably support the main body together with the main wheel and rotate as the main body moves.

[0004] The electronic device having the above-described configuration may include a projector movably arranged to project an image onto an arbitrary area, and a robot vacuum cleaner movably arranged to perform a cleaning function at an arbitrary location.

[0005] An electronic device including an auxiliary wheel with relatively fast responsiveness is provided.

[0006] An electronic device is provided to prevent foreign matter from entering the inner side of the auxiliary wheel.

[0007] An electronic device is provided that allows foreign matter introduced into the inner side of the auxiliary wheel to be easily removed.

[0008] The technical problems to be solved in this document are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art to which this invention belongs from the description below.

[0009] According to one aspect of the present disclosure, an electronic device comprises a main body, a first wheel device configured to move the main body, the first wheel device having a first wheel rotatable about a first rotation axis, and a second wheel device that movably supports the main body. The second wheel device comprises a wheel cover rotatable about the main body about a second rotation axis extending in a direction intersecting the first rotation axis, a wheel shaft connected to the wheel cover and extending in one direction intersecting the second rotation axis, and a second wheel rotatable about a center axis of the wheel shaft, the second wheel having a first portion and a second portion separated by a virtual line extending radially in the wheel shaft and aligned with the center of the second wheel along the one direction. The outer diameter of at least a portion of the first portion is longer than the outer diameter of all portions of the second portion.

[0010] According to one aspect of the present disclosure, an electronic device comprises a main body, a first wheel rotatably coupled to the main body, the first wheel being rotatable about a first rotation axis, and a second wheel device rotatably coupled to the main body, wherein the second wheel device comprises a wheel cover rotatably connected to the main body and arranged to rotate about a second rotation axis extending in a direction intersecting with a direction corresponding to the first rotation axis, a wheel shaft coupled to the wheel cover and extending in a direction intersecting with the direction in which the second rotation axis extends, and a second wheel rotatably coupled to the wheel shaft, wherein the second wheel comprises an outer surface including a first portion and a second portion, and the outer diameter of at least a portion of the first portion is longer than the outer diameter of all portions of the second portion.

[0011] The above and other aspects and features of specific embodiments of the present disclosure will become more apparent from the following description provided together with reference to the accompanying drawings.

[0012] FIG. 1 is a perspective view of a projector according to one or more embodiments.

[0013] FIG. 2 is a rear perspective view of a projector according to one or more embodiments.

[0014] FIG. 3 is a schematic diagram illustrating a main body, a first wheel device, and a second wheel device according to one embodiment.

[0015] FIG. 4 is an upper perspective view illustrating a second wheel device according to one embodiment.

[0016] FIG. 5 is a bottom perspective view illustrating a second wheel device according to one embodiment.

[0017] Figure 6 is a cross-sectional view along the line AA' of Figure 4.

[0018] FIG. 7 is an exploded view of a second wheel device according to one embodiment.

[0019] FIG. 8 is an exploded view of a second wheel device according to one embodiment.

[0020] FIG. 9 is a side view illustrating a projector driving according to one embodiment.

[0021] Figure 10 is an enlarged view of area D of Figure 6.

[0022] Figure 11 is a cross-sectional view along the BB' line of Figure 4.

[0023] Figure 12 is an enlarged view of area E of Figure 11.

[0024] FIG. 13 is a bottom view of a projector according to one embodiment.

[0025] Figure 14 illustrates the projector of Figure 13 changing its driving direction.

[0026] FIG. 15 illustrates the second wheel cover and the second wheel of the second wheel device of FIG. 14 rotated to correspond to the driving direction of the projector.

[0027] Figure 16 is an enlarged view of area D of Figure 6.

[0028] Figure 17 is an enlarged view of area E of Figure 11.

[0029] Figure 18 is an enlarged view of area F of Figure 16.

[0030] Figure 19 is an enlarged view of area G of Figure 16.

[0031] FIG. 20 is a cross-sectional view along the CC' line of FIG. 3.

[0032] FIG. 21 is a cross-sectional view showing an enlarged view of a second wheel and surrounding configuration according to one embodiment.

[0033] FIG. 22 is a perspective view of a robot vacuum cleaner according to one embodiment.

[0034] FIG. 23 is a bottom perspective view of the robot vacuum cleaner shown in FIG. 22.

[0035] The various embodiments of the present disclosure described in this specification and the terms used therein are not intended to limit the technical features described in the present disclosure to specific embodiments, and should be understood to include various modifications, equivalents, or substitutions of said embodiments.

[0036] In relation to the description of the drawings, similar reference numerals may be used for similar or related components.

[0037] The singular form of the noun corresponding to the item may include one or multiple items, unless the relevant context clearly indicates otherwise.

[0038] In this document, each of the 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 include any one of the items listed together in the corresponding phrase, or all possible combinations thereof.

[0039] The term “and / or” includes a combination of multiple related described components or any of the multiple related described components.

[0040] Terms such as "first," "second," or "first" or "second" may be used simply to distinguish a component from another component and do not limit the components in other aspects (e.g., importance or order).

[0041] 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.

[0042] Terms such as “include” or “have” are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in this document, and do not preclude the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0043] When it is said that a component is "connected," "combined," "supported," or "in contact" with another component, this includes not only cases where the components are directly connected, combined, supported, or in contact, but also cases where they are indirectly connected, combined, supported, or in contact through a third component.

[0044] When it is said that a component is located "on" another component, this includes not only cases where one component is in contact with the other, but also cases where another component exists between the two components.

[0045] The terms "part," "module," and "component" may be implemented in hardware or software. Depending on the embodiments, a plurality of "parts," "modules," and "components" may be implemented as a single component, or a single "part," "module," or "component" may include a plurality of components.

[0046] Terms such as "~part," "~unit," "~block," "~part," and "~module" may refer to a unit that processes at least one function or operation. For example, the above terms may refer to at least one piece of hardware such as an FPGA (field-programmable gate array) or ASIC (application specific integrated circuit), at least one piece of software stored in memory, or at least one process processed by a processor.

[0047] The symbols attached to each step are used to identify each step and do not indicate the order of the steps relative to one another; the steps may be performed differently from the specified order unless a specific order is clearly indicated in the context.

[0048] Terms such as "front," "rear," "left," "right," "top," and "bottom" used in the following description are defined based on the drawings; however, the shape and position of each component are not limited by these terms. For example, the front side may be defined as the +X side and the rear side as the -X side. For example, based on the drawings, the left side may be defined as the +Y side and the right side as the -Y side. For example, based on the drawings, the top side may be defined as the +Z side and the bottom side as the -Z side.

[0049] Hereinafter, embodiments according to the present invention will be described in detail with reference to the attached drawings.

[0050] The present disclosure relates to an electronic device (1). The electronic device (1) according to the present disclosure may include a projector, a robot vacuum cleaner, etc. In FIGS. 1 to 21, an example (1a) of a projector may be described. In FIGS. 22 and 23, an example (1b) of a robot vacuum cleaner may be described. However, it is not limited thereto. For example, any electronic device having a main body and a wheel device configured to move the main body on a floor may be included in the electronic device (1) according to the present disclosure.

[0051] FIG. 1 is a perspective view of a projector according to one embodiment. FIG. 2 is a rear perspective view of a projector according to one embodiment.

[0052] The projector (1a) may be a device configured to project an image. The image may include a photograph, video, text, etc.

[0053] Referring to FIGS. 1 and FIGS. 2, the projector (1a) may include a main body (10). The main body (10) may form the exterior of the projector (1a).

[0054] The main body (10) may include a light source configured to emit light, and a lens that receives light from the light source and forms an image. The configuration of the light source and the lens may be provided inside the main body (10).

[0055] The main body (10) may include a housing (11). The housing (11) may form the exterior of the main body (10). In other words, the housing (11) may form the exterior of the projector (1a). A receiving space may be formed inside the housing (11) to accommodate various components such as a light source or a lens. There are no specific restrictions on the shape of the housing (11).

[0056] The housing (11) may include a housing opening (11a). The housing opening (11a) may be provided to irradiate light emitted from a light source inside the main body (10) to the outside of the main body (10). That is, light emitted from a light source inside the main body (10) may pass through the housing opening (11a). An image formed by a lens inside the main body (10) may be projected onto any area outside the main body (10).

[0057] For example, the housing opening (11a) may be formed on the front surface of the housing (11). However, there is no particular restriction on the location where the housing opening (11a) is formed.

[0058] The projector (1a) may include a first wheel device (20). The first wheel device (20) may be provided to move the main body (10). The first wheel device (20) may be provided to support the main body (10). That is, the first wheel device (20) may support the main body (10) movably. The projector (1a) may be provided to be movable on a floor (S) on which the projector (1a) is placed. The first wheel device (20) may also be referred to as the main wheel device (20).

[0059] The first wheel device (20) may be provided at the bottom of the main body (10). In other words, the first wheel device (20) may be provided at the bottom of the housing (11).

[0060] The first wheel device (20) may be provided in multiple numbers. For example, the first wheel device (20) may be provided in two numbers. One of the two first wheel devices (20) may be provided on the lower side of one side of the main body (10), and the other may be provided on the lower side of the other side of the main body (10). Specifically, one of the two first wheel devices (20) may be provided on the lower left (+Y) side of the main body (10), and the other may be provided on the lower right (-Y) side of the main body (10).

[0061] The first wheel device (20) may include a first wheel (21). The first wheel (21) may be rotatable. Specifically, the first wheel (21) may be rotatable relative to the main body (10). The first wheel (21) may also be referred to as the main wheel (21).

[0062] As the first wheel (21) rotates, the main body (10) can move or change its direction of travel. In other words, as the first wheel (21) rotates, the projector (1a) can move or change its direction of travel.

[0063] The first wheel (21) may be provided at the bottom of the main body (10). In other words, the first wheel (21) may be provided at the bottom of the housing (11).

[0064] As described above, since the first wheel device (20) can be provided in multiple numbers, the first wheel (21) can also be provided in multiple numbers. For example, the first wheel (21) can be provided in two numbers. One of the two first wheels (21) can be provided on the lower side of one side of the main body (10), and the other can be provided on the lower side of the other side of the main body (10). Specifically, one of the two first wheels (21) can be provided on the lower left (+Y) side of the main body (10), and the other can be provided on the lower right (-Y) side of the main body (10).

[0065] The projector (1a) may include a second wheel device (100). The second wheel device (100) may be provided to move the main body (10). The second wheel device (100) may be provided to support the main body (10). That is, the second wheel device (100) may support the main body (10) movably. Specifically, the second wheel device (100) may support the main body (10) movably together with the first wheel device (20). The projector (1a) may be provided to be movable on the floor (S). The second wheel device (100) may also be referred to as an auxiliary wheel device (20).

[0066] The second wheel device (100) may be provided at the lower part of the main body (10). In other words, the second wheel device (100) may be provided at the lower part of the housing (11). The second wheel device (100) may be provided at the rear of the first wheel device (20).

[0067] In the drawing, the second wheel device (100) is shown as one, but there is no special limitation on the number of second wheel devices (100). For example, the second wheel device (100) may be provided in two or more.

[0068] FIG. 3 is a schematic diagram illustrating a main body, a first wheel device, and a second wheel device according to one embodiment.

[0069] Referring to FIG. 3, the first wheel device (20) may include a first wheel shaft (22). The first wheel (21) may be rotatable about the center axis of the first wheel shaft (22). The first wheel shaft (22) may also be referred to as the main wheel shaft (22).

[0070] The first wheel shaft (22) can be rotatably coupled with the first wheel (21). That is, the first wheel (21) can be rotated relative to the first wheel shaft (22). However, according to the embodiment, the first wheel shaft (22) and the first wheel (21) may be coupled so as not to rotate relative to each other, and may be able to rotate simultaneously relative to the main body (10).

[0071] The first wheel shaft (22) can be extended in a first direction (D1). For example, the first wheel shaft (22) can be extended in a left-right direction (Y-axis direction).

[0072] The central axis of the first wheel shaft (22) can form a first rotation axis (R1) that extends in a first direction (D1). The first rotation axis (R1) may be the rotation center of the first wheel (21). That is, the first wheel (21) may be able to rotate about the first rotation axis (R1).

[0073] In FIG. 3, only one first wheel shaft (22) is shown, but the number of first wheel shafts (22) is not limited thereto. For example, the first wheel device (20) may include two first wheel shafts (22) that are coupled to each of two first wheels (21).

[0074] Additionally, the first wheel shaft (22) may be omitted. For example, the first wheel (21) may rotate by being coupled with a gear. However, even in this case, the first wheel (21) may rotate around the first rotation axis (R1). At this time, the first rotation axis (R1) may be formed as an imaginary line.

[0075] The main body (10) may include a driving device (12). The driving device (12) may include a power source for transmitting power to other components. For example, the driving device (12) may include a motor.

[0076] The drive unit (12) can be coupled to the first wheel shaft (22). The drive unit (12) can transmit power to the first wheel shaft (22) to rotate the first wheel shaft (22). As the first wheel shaft (22) rotates, the first wheel (21) can also rotate. That is, the first wheel (21) can be arranged to rotate by the drive unit (12).

[0077] Although only one driving device (12) is shown in FIG. 3, the number of driving devices (12) is not limited thereto. For example, when two first wheel shafts (22) are provided, the main body (10) may include two driving devices (12) coupled to each of the two first wheel shafts (22).

[0078] As described above, the first wheel shaft (22) may be omitted, and the first wheel (21) may be coupled with a gear, etc. In this case, the driving device (12) may be coupled with the gear to transmit power to the gear.

[0079] The second wheel device (100) may include a second wheel (110). The second wheel (110) may be rotatable.

[0080] The second wheel (110) may be configured to rotate as the main body (10) moves. In other words, the second wheel (110) may rotate without a separate drive device directly coupled thereto. That is, the driving direction or driving speed of the main body (10) is determined by the first wheel (21) which rotates by the drive device (12), and the second wheel (110) may perform the function of assisting the first wheel (21) to enable the main body (10) to move smoothly. Therefore, the second wheel (110) may be referred to as an auxiliary wheel (110).

[0081] The second wheel device (100) may include a wheel cover (130). The wheel cover (130) may be provided to cover at least a portion of the second wheel (110).

[0082] The wheel cover (130) may be rotatable. Specifically, the wheel cover (130) may be rotatable relative to the main body (10).

[0083] The wheel cover (130) may be rotatable with respect to a second rotation axis (R2) that extends in a second direction (D2) that intersects the first rotation axis (R1). In other words, the wheel cover (130) may be rotatable with respect to a second rotation axis (R2) that extends in a second direction (D2) that intersects the first direction (D1). For example, the second direction (D2) may intersect perpendicularly with the first rotation axis (R1). For example, the second direction (D2) may intersect perpendicularly with the first direction (D1). The second rotation axis (R2) may be formed by the center axis of the connecting shaft (140) to be described later.

[0084] The second wheel (110) may be rotatable with respect to the wheel cover (130). That is, the wheel cover (130) may be rotatable with respect to the main body (10), and the second wheel (110) may be rotatable with respect to the wheel cover (130). Further details regarding the rotation direction of the second wheel (110) will be described later.

[0085] FIG. 4 is a drawing illustrating a second wheel device according to one embodiment. FIG. 5 is a drawing illustrating a second wheel device according to one embodiment. FIG. 6 is a cross-sectional view along the line AA' indicated in FIG. 4. FIG. 7 is an exploded view of a second wheel device according to one embodiment. FIG. 8 is an exploded view of a second wheel device according to one embodiment. FIG. 9 is a side view illustrating a projector driving according to one embodiment.

[0086] Referring to FIGS. 4 through 9, the second wheel device (100) may include a second wheel (110). The second wheel (110) may include an inner ring (111) and an outer ring (112).

[0087] The outer ring (112) may be positioned on the outer side (e.g., outer surface) of the inner ring (111). The outer ring (112) may be coupled to the outer side of the inner ring (111).

[0088] The inner ring (111) can be rotatably coupled to the second wheel shaft (120) to be described later. The outer ring (112) can be rotated relative to the second wheel shaft (120) by being coupled to the inner ring (111).

[0089] At least a portion of the outer ring (112) may be arranged to contact the floor (S) on which the projector (1a) is placed. For example, the outer ring (112) may be made of rubber material.

[0090] The second wheel device (100) may include a second wheel shaft (120). The second wheel (110) may be rotatable about the center axis of the second wheel shaft (120). The second wheel shaft (120) may also be referred to as an auxiliary wheel shaft (120).

[0091] The second wheel shaft (120) can be rotatably coupled to the second wheel (110). Specifically, the second wheel shaft (120) can be rotatably coupled to the inner ring (111) of the second wheel (110). That is, the second wheel (110) can be rotated with respect to the second wheel shaft (120). In other words, the inner ring (111) and the outer ring (112) of the second wheel (110) can be rotated with respect to the second wheel shaft (120). However, according to the embodiment, the second wheel shaft (120) and the second wheel (110) may be coupled so as not to rotate with respect to each other, and may be simultaneously rotatable with respect to the wheel cover (130).

[0092] The second wheel shaft (120) may be extended in a third direction (D3). Specifically, the second wheel shaft (120) may be extended in a third direction (D3) that intersects the second rotation axis (R2). In other words, the second wheel shaft (120) may be extended in a third direction (D3) that intersects the second direction (D2). For example, the third direction (D3) may intersect perpendicularly with the second rotation axis (R2). For example, the third direction (D3) may intersect perpendicularly with the second direction (D2).

[0093] The second wheel shaft (120) may be provided in a roughly cylindrical shape. The central axis of the second wheel shaft (120) may form a third rotation axis (R3) extending in a third direction (D3).

[0094] The third rotation axis (R3) may be the rotation center of the second wheel (110). That is, the second wheel (110) may be able to rotate around the third rotation axis (R3).

[0095] The second wheel device (100) may include a wheel cover (130). The wheel cover (130) may be provided to cover at least a portion of the second wheel (110). Specifically, the wheel cover (130) may cover the upper portion of the second wheel (110).

[0096] The wheel cover (130) can be combined with the second wheel shaft (120). In other words, the wheel cover (130) can support the second wheel shaft (120).

[0097] Specifically, the wheel cover (130) can be coupled to both ends of the second wheel shaft (120) along the third direction (D3). In other words, the wheel cover (130) can support both ends of the second wheel shaft (120) along the third direction (D3).

[0098] The wheel cover (130) may be rotatable about the second rotation axis (R2). Additionally, since the wheel cover (130) is coupled to the second wheel shaft (120) and the second wheel shaft (120) is rotatably coupled to the second wheel (110), the second wheel shaft (120) and the second wheel (110) may be rotatable about the second rotation axis (R2) together with the wheel cover (130). Further details regarding this will be described later.

[0099] The wheel cover (130) may include an upper cover (131) and a lower cover (132). The upper cover (131) and the lower cover (132) may be joined together. Details regarding the method of joining the upper cover (131) and the lower cover (132) will be described later.

[0100] The upper cover (131) may be positioned on the upper side of the second wheel (110). The upper cover (131) may cover the upper part of the second wheel (110). The upper cover (131) may form a receiving space for receiving the upper part of the second wheel (110).

[0101] The lower cover (132) may be positioned on the lower side of the upper cover (131). The lower cover (132) may be coupled to the lower side of the upper cover (131). The lower cover (132) may cover the lower part of the upper cover (131).

[0102] The lower cover (132) can be coupled with the second wheel shaft (120). In other words, the lower cover (132) can support the second wheel shaft (120).

[0103] Specifically, the lower cover (132) can be coupled to both ends of the second wheel shaft (120) along the third direction (D3). In other words, the lower cover (132) can support both ends of the second wheel shaft (120) along the third direction (D3).

[0104] The lower cover (132) may include a first lower cover (1321) and a second lower cover (1322). The first lower cover (1321) and the second lower cover (1322) may be provided on both sides of the second wheel (110) in a third direction (D3).

[0105] The first lower cover (1321) can be coupled to one end of the second wheel shaft (120) in the third direction (D3), and the second lower cover (1322) can be coupled to the other end of the second wheel shaft (120) in the third direction (D3). In other words, the first lower cover (1321) can support one end of the second wheel shaft (120) in the third direction (D3), and the second lower cover (1322) can support the other end of the second wheel shaft (120) in the third direction (D3).

[0106] The second wheel device (100) may include a coupling bracket (150). The coupling bracket (150) may be provided to be coupled to the main body (10). By coupling the coupling bracket (150) to the main body (10), the second wheel device (100) may be fixed to the main body (10).

[0107] The coupling bracket (150) can be connected to the wheel cover (130). By the coupling bracket (150) being coupled to the main body (10) and connected to the wheel cover (130), the second wheel device (100) can be connected to the main body (10).

[0108] The coupling bracket (150) may be positioned on the upper side of the wheel cover (130). Specifically, the coupling bracket (150) may be positioned on the upper side of the upper cover (131) of the wheel cover (130).

[0109] The coupling bracket (150) may include a first bracket (151) and a second bracket (152). The first bracket (151) may be coupled to the upper side of the second bracket (152). For example, the first bracket (151) may be coupled to the upper side of the second bracket (152) by inserting at least a portion of the lower part of the first bracket (151) into a bracket groove (152a) formed in the second bracket (152). However, the method of coupling the first bracket (151) and the second bracket (152) is not limited thereto.

[0110] The first bracket (151) may be provided to be coupled with the main body (10). For example, a main body coupling portion (151a) may be provided on the upper part of the first bracket (151) to be coupled with at least a part of the main body (10). The first bracket (151) may be fixed to the main body (10) by being coupled with the main body (10).

[0111] The second bracket (152) may be provided to be connected to the wheel cover (130). By connecting the second bracket (152) to the wheel cover (130) and the first bracket (151) to the main body (10), the second wheel device (100) may be connected to the main body (10). Specific details regarding the method of connecting the second bracket (152) to the wheel cover (130) will be described later.

[0112] The second bracket (152) may be provided in a roughly plate shape. However, there are no special restrictions on the shape of the second bracket (152).

[0113] The second wheel device (100) may include a connecting shaft (140). The connecting shaft (140) may be provided to connect the coupling bracket (150) and the wheel cover (130). In other words, the connecting shaft (140) may be provided to connect the second bracket (152) and the wheel cover (130).

[0114] The connecting shaft (140) can be extended in a second direction (D2). Specifically, the connecting shaft (140) can be extended in a second direction (D2) that intersects the first rotation axis (R1) (see FIG. 3). In other words, the connecting shaft (140) can be extended in a second direction (D2) that intersects the first direction (D1) (see FIG. 3). Additionally, the connecting shaft (140) can be extended in a second direction (D2) that intersects the third rotation axis (R3). In other words, the connecting shaft (140) can be extended in a second direction (D2) that intersects the third direction (D3). For example, the connecting shaft (140) can be extended in an up-and-down direction.

[0115] The connecting shaft (140) may be provided in a roughly cylindrical shape. The central axis of the connecting shaft (140) may form a second rotation axis (R2) extending in a second direction (D2). For example, the central axis of the connecting shaft (140) may form a second rotation axis (R2) extending in an up-and-down direction. Accordingly, the wheel cover (130) may rotate about the second rotation axis (R2) formed by the connecting shaft (140). In other words, the wheel cover (130) may rotate about the connecting shaft (140).

[0116] A first through hole (152b) may be provided in the coupling bracket (150), and a second through hole (131a) may be provided in the wheel cover (130). Specifically, a first through hole (152b) may be provided in the second bracket (152), and a second through hole (131a) may be provided in the upper cover (131). A connecting shaft (140) can connect the coupling bracket (150) and the wheel cover (130) by passing through the first through hole (152b) and the second through hole (131a).

[0117] The connecting shaft (140) may include a first through-hole insertion part (141). The first through-hole insertion part (141) may be inserted into a first through-hole (152b). The first through-hole insertion part (141) may be inserted into the first through-hole (152b) and fixed to the coupling bracket (150). Specifically, the first through-hole insertion part (141) may be inserted into the first through-hole (152b) and fixed to the second bracket (152). For example, the first through-hole insertion part (141) may be provided with screw threads, and the first through-hole insertion part (141) may be fixed by being inserted into the first through-hole (152b) and fastened. Through this configuration, the rotation of the coupling bracket (150) with respect to the connecting shaft (140) may be restricted.

[0118] The connecting shaft (140) may include a second through-hole insertion part (142). The second through-hole insertion part (142) may be inserted into the second through-hole (131a). By inserting the second through-hole insertion part (142) into the second through-hole (131a), the wheel cover (130) may be rotatable with respect to the second through-hole insertion part (142). That is, the wheel cover (130) may be rotatable with respect to the connecting shaft (140). Additionally, the first through-hole insertion part (141) of the connecting shaft (140) may be fixed to the coupling bracket (150), and since the coupling bracket (150) may be fixed to the main body (10), the wheel cover (130) may be rotatable with respect to the main body (10).

[0119] The second wheel shaft (120) may be provided at an eccentric position from the center axis of the connecting shaft (140) (see FIG. 9). In other words, the second wheel shaft (120) may be provided spaced apart from or offset from the center axis of the connecting shaft (140). When the wheel cover (130) rotates about the connecting shaft (140), the second wheel (110) may also rotate about the connecting shaft (140). In other words, when the wheel cover (130) rotates about the connecting shaft (140), the second wheel (110) may rotate about the second rotation axis (R2).

[0120] That is, the second wheel (110) may rotate about the connecting shaft (140) separately from rotating about the second wheel shaft (120). In other words, the second wheel (110) may rotate about the second rotation axis (R2) separately from rotating about the third rotation axis (R3).

[0121] The second wheel device (100) may include a bushing (160). The bushing (160) may be coupled to the inside of the second through hole (131a) of the upper cover (131). For example, the bushing (160) may be press-fitted into the inside of the second through hole (131a).

[0122] A bushing hole (161) may be formed on the inner side of the bushing (160). The bushing hole (161) may be formed at a position corresponding to the second through hole (131a).

[0123] A connecting shaft (140) can be inserted into the bushing hole (161). In other words, a second through-hole insertion part (142) can be inserted into the bushing hole (161). That is, by inserting the second through-hole insertion part (142) into the bushing hole (161), the second through-hole insertion part (142) can be inserted into the second through-hole (131a).

[0124] The inner surface of the bushing hole (161) can be provided relatively smoothly. Additionally, the outer surface of the second through-hole insertion part (142) can be provided relatively smoothly. When the second through-hole insertion part (142) is inserted into the bushing hole (161), the wheel cover (130) can rotate smoothly relative to the second through-hole insertion part (142). In other words, the wheel cover (130) can rotate smoothly relative to the connecting shaft (140).

[0125] However, the bushing (160) may be replaced with another component that performs the same function. For example, the bushing (160) may be replaced with a bearing.

[0126] The second wheel device (100) may include a connecting shaft fixing part (170). The connecting shaft fixing part (170) may fix the lower end of the connecting shaft (140). The connecting shaft fixing part (170) may fix the connecting shaft (140) at the lower side of the upper cover (131). In other words, the connecting shaft fixing part (170) may fix the connecting shaft (140) at the lower side of the bushing (160). For example, the connecting shaft fixing part (170) may be provided as an E-ring. The connecting shaft fixing part (170) may prevent the connecting shaft (140) from being separated from the second through-hole insertion part (142) or the bushing hole (161).

[0127] The second wheel device (100) may include a wheel cap (180). The wheel cap (180) may be positioned on the upper side of the wheel cover (130). The wheel cap (180) may cover the upper part of the wheel cover (130). This configuration may allow the components of the wheel device (100) to be less exposed to the user.

[0128] The wheel cap (180) may be provided in a hollow hemispherical shape. In other words, the wheel cap (180) may be provided in a dome shape. However, there are no special restrictions on the shape of the wheel cap (180).

[0129] The wheel cap (180) can be coupled with the coupling bracket (150). Specifically, the wheel cap (180) may include a cap groove (181) into which the first bracket (151) is inserted. Additionally, the wheel cap (180) may include a fastening member insertion groove (182), and the second bracket (152) may include a fastening member insertion hole (152c), and a separate fastening member may be inserted into the fastening member insertion hole (152c) of the second bracket (152) and the fastening member insertion groove (182) of the wheel cap (180) to be fastened. As a result of this configuration, the wheel cap (180) can be coupled with the coupling bracket (150).

[0130] At least a portion of a connecting bracket (150) may be disposed between the wheel cap (180) and the wheel cover (130). Specifically, a second bracket (152) may be disposed between the wheel cap (180) and the wheel cover (130).

[0131] Below, with reference to FIG. 9, we will examine the position of the second wheel (110) when the projector (1a) travels in one direction.

[0132] Referring to FIG. 9, when the projector (1a) travels in one direction, the second wheel (110) may be positioned in a direction (X2) opposite to the travel direction (X1) of the projector (1a) from the connecting shaft (140). For example, when the projector (1a) travels in the +X direction, the second wheel (110) may be positioned in the -X direction from the connecting shaft (140). As a result, the first rotation axis (R1), which is the center of rotation of the first wheel (21), and the third rotation axis (R3), which is the center of rotation of the second wheel (110), may be arranged parallel to each other, and the projector (1a) may travel stably.

[0133] If the projector (1a) changes its driving direction (X1), the second wheel (110) may not be positioned in a direction opposite to the changed driving direction of the projector (1a) from the connecting shaft (140). In this case, the first rotation axis (R1), which is the center of rotation of the first wheel (21), and the third rotation axis (R3), which is the center of rotation of the second wheel (110), are not arranged parallel to each other, so the projector (1a) may drive unstably, such as by shaking. Therefore, the second wheel (110) needs to rotate rapidly relative to the connecting shaft (140) so that when the projector (1a) changes its driving direction (X1), it is positioned in a direction (X2) opposite to the driving direction (X1) of the projector (1a).

[0134] At this time, as the projector (1a) changes its driving direction (X1), the rotation of the second wheel (110) relative to the connecting shaft (140) can be referred to as the responsiveness of the second wheel (110). The faster the responsiveness of the second wheel (110), the better the driving stability of the projector (1a) can be.

[0135] Below, we will explain the structure of the second wheel (110) in more detail and examine a method to improve the responsiveness of the second wheel (110).

[0136] FIG. 10 is an enlarged view of area D of FIG. 6. FIG. 11 is a cross-sectional view along line BB' of FIG. 4. FIG. 12 is an enlarged view of area E of FIG. 11.

[0137] Referring to FIGS. 10 to 12, the projector (1a) may be movably positioned on the floor (S). As the projector (1a) moves on the floor (S), the second wheel (110) may rotate about the second wheel shaft (120).

[0138] The second wheel (110) may have an outer surface and an inner surface. The outer surface of the second wheel (110) may refer to the outer surface of the second wheel (110) along the radial direction of the second wheel shaft (120), and the inner surface of the second wheel (110) may refer to the inner surface of the second wheel (110) along the radial direction of the second wheel shaft (120). Additionally, the outer surface of the second wheel (110) may refer to the outer surface of the outer ring (112), and the inner surface of the second wheel (110) may refer to the inner surface of the inner ring (111). At this time, the radial direction of the second wheel shaft (120) may be a direction from the center axis of the second wheel shaft (120) toward the outer surface of the second wheel shaft (120).

[0139] At least a portion of the outer surface of the second wheel (110) may be able to come into contact with the floor (S) as the second wheel (110) rotates. In other words, at least a portion of the outer surface of the outer ring (112) may come into contact with the floor (S).

[0140] The inner surface of the second wheel (110) may be arranged to face the outer surface of the second wheel shaft (120). In other words, the inner surface of the inner ring (111) may be arranged to face the outer surface of the second wheel shaft (120).

[0141] The second wheel (110) may have a first part (110a) and a second part (110b) separated based on the center of the second wheel (110) according to the third direction (D3). Specifically, the first part (110a) and the second part (110b) may be separated based on an imaginary line (L1) extending radially from the center of the second wheel (110) according to the third direction (D3) to the second wheel shaft (120). Accordingly, one end of the second wheel (110) according to the third direction (D3) may be provided in the first part (110a), and the other end of the second wheel (110) according to the third direction (D3) may be provided in the second part (110b).

[0142] At least a portion of the outer diameter of the first part (110a) may be longer than the outer diameter of the second part (110b). Specifically, at least a portion of the outer diameter of the first part (110a) may be longer than the outer diameter (W2) that is longest in the second part (110b). In other words, the distance at least a portion of the outer surface of the first part (110a) is spaced radially from the second wheel shaft (120) may be longer than the distance at which the outer surface of the second part (110b) is spaced radially from the second wheel shaft (120).

[0143] The first part (110a) may include a contact portion (110c) with the floor (S) as the second wheel (110) rotates. The contact portion (110c) may be provided on the outer surface of the second wheel (110).

[0144] The outer diameter (W1) measured at the part where the contact portion (110c) is provided may be longer than the outer diameter of the second part (110b). Specifically, the outer diameter (W1) measured at the part where the contact portion (110c) is provided may be longer than the outer diameter (W2) that is longest at the second part (110b). The outer diameter (W1) measured at the part where the contact portion (110c) is provided may be longer than the outer diameter of all parts of the second part (110b). In other words, the distance at which the contact portion (110c) is separated from the second wheel shaft (120) in the radial direction of the second wheel shaft (120) may be longer than the distance at which the outer surface of the second part (110b) is separated from the second wheel shaft (120) in the radial direction of the second wheel shaft (120).

[0145] Additionally, the outer diameter (W1) of the second wheel (110) measured at the part where the contact portion (110c) is provided may be longer than the outer diameter measured at any other part of the second wheel (110) excluding the contact portion (110c). In other words, the distance at which the contact portion (110c) is spaced radially from the second wheel shaft (120) may be longer than the distance at which any other part of the second wheel (110) excluding the contact portion (110c) is spaced radially from the second wheel shaft (120). That is to say, the part of the second wheel (110) that contacts the floor (S) may be provided offset to one side with respect to the third direction (D3).

[0146] The contact portion (110c) may be provided at one end of the second wheel (110) according to the third direction (D3). Specifically, the contact portion (110c) may be provided on the outer surface of one end (e.g., the first end) of the second wheel (110) according to the third direction (D3). However, the location where the contact portion (110c) is formed is not limited thereto. For example, the contact portion (110c) may be provided between one end of the second wheel (110) according to the third direction (D3) and the center of the second wheel (110) according to the third direction (D3).

[0147] The contact portion (110c) may be formed along the circumferential direction of the second wheel (110). That is, the contact portion (110c) may be the outer surface of the part having the longest diameter of the second wheel (110).

[0148] The contact portion (110c) may be provided as a small area. However, the present disclosure is not limited thereto, and the contact portion (110c) may be provided extending in a third direction (D3). Specific details regarding this will be described later.

[0149] An inclined portion (110d) may be provided on at least a portion of the outer surface of the second wheel (110). The inclined portion (110d) may extend from the contact portion (110c) toward the second portion (110b). In other words, the contact portion (110c) may be formed on one side of the inclined portion (110d).

[0150] The inclined portion (110d) may extend in an inclined direction relative to the second wheel shaft (120). Specifically, the inclined portion (110d) may be inclined in a direction opposite to the radial direction of the second wheel shaft (120). In other words, the inclined portion (110d) may be inclined in a direction approaching the second wheel shaft (120) from the contact portion (110c).

[0151] The inclined portion (110d) may extend to the other end of the second wheel (110) according to the third direction (D3). Since the contact portion (110c) may be provided at one end of the second wheel (110) according to the third direction (D3) and the inclined portion (110d) may extend from the contact portion (110c), the inclined portion (110d) may extend from one end of the second wheel (110) according to the third direction (D3) to the other end of the second wheel (110).

[0152] Accordingly, the outer surface of the second part (110b) may be provided as an inclined portion (110d). Since the inclined portion (110d) is inclined in a direction approaching the second wheel shaft (120) from the contact portion (110c), the longest outer diameter (W2) provided in the second part (110b) may be the outer diameter (W2) at the part closest to the center of the second wheel (110) according to the third direction (D3).

[0153] As described above, at least a portion of the outer diameter of the first part (110a) may be longer than the outer diameter (W2) that is longest in the second part (110b). Specifically, the outer diameter (W1) measured at the portion where the contact portion (110c) is provided may be longer than the outer diameter (W2) of the portion closest to the center of the second wheel (110) in the third direction (D3) in the second part (110b). In other words, the distance at which the outer surface of one end of the second wheel (110) in the third direction (D3) is spaced radially from the second wheel shaft (120) may be longer than the distance at which the portion closest to the center of the second wheel (110) in the third direction (D3) in the second part (110b) is spaced radially from the second wheel shaft (120).

[0154] Additionally, the outer diameter (W1) of one end of the second wheel (110) according to the third direction (D3) may be longer than the outer diameter (W3) of the other end of the second wheel (110) according to the third direction (D3). In other words, the distance at which the outer surface of one end of the second wheel (110) according to the third direction (D3) is separated from the second wheel shaft (120) in the radial direction of the second wheel shaft (120) may be longer than the distance at which the outer surface of the other end of the second wheel (110) according to the third direction (D3) is separated from the second wheel shaft (120) in the radial direction of the second wheel shaft (120).

[0155] The inclined portion (110d) can be formed along the circumferential direction of the second wheel (110). Due to this configuration, the exterior of the second wheel (110) can be formed in a roughly truncated cone shape.

[0156] According to the concept of the present disclosure, the contact portion (110c), which is the part of the second wheel (110) that contacts the floor (S), may be arranged to be offset to one side with respect to the third direction (D3). Additionally, the inclined portion (110d) may be provided on one side of the contact portion (110c) and may be provided spaced apart from the floor (S).

[0157] The center of gravity (C) of the second wheel (110) may be located off the imaginary region extending vertically from the part where the second wheel (110) contacts the floor (S). Additionally, considering that the second wheel shaft (120) is provided approximately parallel to the floor (S), the contact portion (110c) may not be provided radially from the center of gravity (C) of the second wheel (110) to the second wheel shaft (120), and the inclined portion (110d) may be provided radially from the center of gravity (C) of the second wheel (110) to the second wheel shaft (120). In other words, the imaginary line (L2) extending radially from the center of gravity (C) of the second wheel (110) to the second wheel shaft (120) may intersect the inclined portion (110d) rather than the contact portion (110c).

[0158] Since the inclined portion (110d) can be provided spaced apart from the floor (S) and can be provided radially from the center of gravity (C) of the second wheel (110) to the second wheel shaft (120), the second wheel (110) can be slightly tilted toward the inclined portion (110d). As the second wheel (110) tilts toward the inclined portion (110d), the second wheel (110) can press the wheel cover (130) in one direction. For example, the third direction (D3) can be a direction from the first part (110a) toward the second part (110b), and the second wheel (110) can press the wheel cover (130) in the third direction (D3).

[0159] At this time, since the wheel cover (130) can rotate around the connecting shaft (140) as an axis, torque can be applied to the wheel cover (130) by the force with which the second wheel (110) presses against the wheel cover (130). That is, due to the above-described structure of the second wheel (110), the tendency of the wheel cover (130) to rotate around the connecting shaft (140) as an axis can be made stronger. Accordingly, when the projector (1a) changes its driving direction, the wheel cover (130) and the second wheel (110) can rotate more quickly to be positioned in a direction opposite to the driving direction of the projector (1a). That is, the responsiveness of the second wheel (110) can be made relatively faster.

[0160] Additionally, since the second wheel (110) is tilted in only one direction, the rotational direction of the wheel cover (130) and the second wheel (110) can be limited to the direction from the first part (110a) toward the second part (110b) with respect to the second rotation axis (R2).

[0161] However, the above-mentioned effect is not realized only when the second wheel (110) includes the aforementioned inclined portion (110d). Specifically, if at least a portion of the outer diameter of the first portion (110a) is formed to be longer than the outer diameter of the second portion (110b), the second wheel (110) is provided to be inclined to one side, thereby realizing the above-mentioned effect. For example, the above-mentioned effect can also be realized when the second wheel (110) is provided on one side of the contact portion (110c) and has a stepped portion formed with a step difference from the contact portion (110c).

[0162] Additionally, according to the concept of the present disclosure, the second wheel (110) may be provided asymmetrically with respect to an imaginary line (L1) extending radially from the center of the second wheel (110) in the third direction (D3) to the second wheel shaft (120). Accordingly, the center of gravity (C) of the second wheel (110) may be provided at an eccentric (or offset) position from the center of the second wheel shaft (120) in the third direction (D3). Specifically, the center of gravity (C) of the second wheel (110) may be eccentrically positioned toward the first part (110a) as the first part (110a) has a relatively larger volume compared to the second part (110b). Considering this configuration, when the projector (1a) travels on the floor (S), the first rotation axis (R1), which is the rotation center of the first wheel (21), and the second rotation axis (R2), which is the rotation center of the second wheel (110), are not arranged to be completely parallel to each other, but may be arranged to be slightly inclined relative to each other. Further details regarding this will be described later.

[0163] Hereinafter, with reference to FIGS. 13 to 15, an example is described in which the second wheel (110) and the wheel cover (130) rotate when the projector (1a) changes its driving direction.

[0164] FIG. 13 is a bottom view of a projector according to one embodiment. FIG. 14 illustrates the projector of FIG. 13 changing its driving direction. FIG. 15 illustrates the second wheel cover and the second wheel of the second wheel device of FIG. 14 rotating in correspondence with the driving direction of the projector.

[0165] Referring to FIGS. 13 to 15, the projector (1a) can be driven with the first rotation axis (R1), which is the rotation center of the first wheel (21), and the third rotation axis (R3), which is the rotation center of the second wheel (110), not parallel to each other and slightly inclined relative to each other. This is because the center of gravity (C) of the second wheel (110) is eccentric (or offset) toward the first part (110a) (see FIG. 10). Accordingly, when the projector (1a) is driven, the second wheel (110) and the wheel cover (130) can be maintained in a slightly rotated state from the first part (110a) toward the second part (110b) around the second rotation axis (R2, see FIG. 3).

[0166] Referring to FIG. 13, the projector (1a) can travel in a first driving direction (X3). At this time, the second wheel (110) can be positioned in a direction (X4) opposite to the first driving direction (X3) from the connecting shaft (140).

[0167] Referring to FIG. 14, the projector (1a) can change its driving direction by means of the first wheel (21). Specifically, the projector (1a) can drive in a second driving direction (X5), which is a direction rotated 90 degrees clockwise with respect to FIG. 14. At this time, the second wheel (110) may not be located in a direction (X6) opposite to the second driving direction (X5) from the connecting shaft (140). For example, the second wheel (110) may be located in a direction intersecting the second driving direction (X5) from the connecting shaft (140).

[0168] Referring to FIG. 15, when the projector (1a) travels in the second driving direction (X5), the wheel cover (130) and the second wheel (110) can rotate rapidly in one direction due to the tilted structure of the second wheel (110). Specifically, the wheel cover (130) and the second wheel (110) can rotate in a direction from the first part (110a) toward the second part (110b) around the second rotation axis (R2, see FIG. 3).

[0169] When the second wheel (110) is positioned in a direction (X6) opposite to the second driving direction (X5) relative to the connecting shaft (140), the second wheel (110) may no longer rotate relative to the connecting shaft (140). This is because when the second wheel (110) deviates slightly from the above position, a frictional force acts on the second wheel (110) in a direction (X6) opposite to the driving direction (X5) of the projector (1a).

[0170] FIG. 16 is an enlarged view of area D of FIG. 6. FIG. 17 is an enlarged view of area E of FIG. 11. FIG. 18 is an enlarged view of area F of FIG. 16. FIG. 19 is an enlarged view of area G of FIG. 16.

[0171] Referring to FIGS. 16 through 19, the second wheel (110) may have a first side (110e) and a second side (110f). The first side (110e) and the second side (110f) of the second wheel (110) may each be formed between the inner surface and the outer surface of the second wheel (110). The first side (110e) of the second wheel (110) may be provided on the opposite side of the second side (110f) of the second wheel (110).

[0172] The first side (110e) may include one side of the inner ring (111) and one side of the outer ring (112). The second side (110f) may include another side opposite to one side of the inner ring (111) and another side opposite to one side of the outer ring (112). The first side (110e) may face the first lower cover (1321). The second side (110f) may face the second lower cover (1322).

[0173] The second wheel (110) may include a first groove (110g). The first groove (110g) may be provided on a first side (110e) of the second wheel (110). The first groove (110g) may be recessed on the first side (110e) of the second wheel (110). Specifically, the first groove (110g) may be recessed on one side of the inner ring (111).

[0174] The first groove (110g) may extend along the circumferential direction of the second wheel (110). In other words, the first groove (110g) may be provided along the circumferential direction of the second wheel (110). In other words, the first groove (110g) may extend along the circumferential direction of the second wheel shaft (120). In other words, the first groove (110g) may be provided along the circumferential direction of the second wheel shaft (120).

[0175] The first groove (110g) may be formed spaced apart from the second wheel shaft (120). That is, the first groove (110g) may extend along the circumferential direction of the second wheel (110) while spaced apart from the second wheel shaft (120).

[0176] The first groove (110g) can form a receiving space. The receiving space formed by the first groove (110g) may extend along the circumferential direction of the second wheel (110). The receiving space formed by the first groove (110g) may be provided along the circumferential direction of the second wheel (110). For example, the receiving space formed by the first groove (110g) may have a roughly torus shape.

[0177] The second wheel (110) may include a second groove (110h). The second groove (110h) may be provided on the second side (110f) of the second wheel (110). The second groove (110h) may be recessed on the second side (110f) of the second wheel (110). That is, the second groove (110h) may be provided on the opposite side of the first groove (110h). Specifically, the second groove (110h) may be recessed on the other side of the inner ring (111).

[0178] The second groove (110h) may extend along the circumferential direction of the second wheel (110). In other words, the second groove (110h) may be provided along the circumferential direction of the second wheel (110). In other words, the second groove (110h) may extend along the circumferential direction of the second wheel shaft (120). In other words, the second groove (110h) may be provided along the circumferential direction of the second wheel shaft (120).

[0179] The second groove (110h) may be formed spaced apart from the second wheel shaft (120). That is, the second groove (110h) may extend along the circumferential direction of the second wheel (110) while spaced apart from the second wheel shaft (120). The distance at which the second groove (110h) is spaced apart from the second wheel shaft (120) may be the same as the distance at which the first groove (110g) is spaced apart from the second wheel shaft (120). That is, the second groove (110h) may be formed at a position corresponding to the first groove (110g).

[0180] The second groove (110h) can form a receiving space. The receiving space formed by the second groove (110h) may extend along the circumferential direction of the second wheel (110). The receiving space formed by the second groove (110h) may be provided along the circumferential direction of the second wheel (110). For example, the receiving space formed by the second groove (110h) may be approximately ring-shaped.

[0181] The first lower cover (1321) may include a first lower cover body (1321a). The first lower cover body (1321a) may form the overall appearance of the first lower cover (1321).

[0182] One side (1321aa) of the first lower cover body (1321a) can cover the second wheel (110). Specifically, one side (1321aa) of the first lower cover body (1321a) can cover at least a portion of the first side (110e) of the second wheel (110). Specifically, one side (1321aa) of the first lower cover body (1321a) can cover one side of the inner ring (111) of the second wheel (110).

[0183] One side (1321aa) of the first lower cover body (1321a) and the first side (110e) of the second wheel (110) may be spaced apart from each other by a predetermined distance. Through this configuration, the second wheel (110) can rotate smoothly without causing interference with the first lower cover body (1321a).

[0184] The first lower cover (1321) may include a first protrusion (1321b). The first protrusion (1321b) may protrude from the first lower cover body (1321a). Specifically, the first protrusion (1321b) may protrude from the first lower cover body (1321a) toward the first groove (110g). Specifically, the first protrusion (1321b) may protrude from one side (1321aa) of the first lower cover body (1321a).

[0185] The first protrusion (1321b) may extend along the circumferential direction of the second wheel shaft (120). In other words, the first protrusion (1321b) may be provided along the circumferential direction of the second wheel shaft (120). In other words, the first protrusion (1321b) may extend along the circumferential direction of the second wheel (110). In other words, the first protrusion (1321b) may be provided along the circumferential direction of the second wheel (110).

[0186] The first protrusion (1321b) may be spaced apart from the second wheel shaft (120). That is, the second protrusion (1322b) may extend along the circumferential direction of the second wheel (110) while spaced apart from the second wheel shaft (120).

[0187] The first protrusion (1321b) can be received inside the first groove (110g). In other words, the first protrusion (1321b) can be received in the receiving space formed by the first groove (110g). In other words, the first protrusion (1321b) can be inserted into the first groove (110g).

[0188] The first protrusion (1321b) may be provided in a shape corresponding to the receiving space formed by the first groove (110g). For example, the first protrusion (1321b) may be provided in a roughly ring shape.

[0189] The first protrusion (1321b) may be spaced apart from the first groove (110g) by a predetermined distance. With this configuration, the second wheel (110) can rotate smoothly without causing interference with the first lower cover body (1321a).

[0190] The first protrusion (1321b) may have an outer surface (1321ba) and an inner surface (1321bb). The outer surface (1321ba) of the first protrusion (1321b) may be provided on the opposite side of the inner surface (1321bb) of the first protrusion (1321b). Specifically, the outer surface (1321ba) of the first protrusion (1321b) may be provided on the outer side along the radial direction of the second wheel shaft (120), and the inner surface (1321bb) of the first protrusion (1321b) may be provided on the inner side along the radial direction of the second wheel shaft (120). In other words, the inner surface (1321bb) of the first protrusion (1321b) may be provided closer to the second wheel shaft (120) than the outer surface (1321ba) of the first protrusion (1321b). The outer surface (1321ba) and the inner surface (1321bb) of the first protrusion (1321b) may each extend in the direction in which the first protrusion (1321b) protrudes.

[0191] The first protrusion (1321b) may include a first end (1321bc). The first end (1321bc) may be provided at one end of the protrusion (1321ba) according to the direction in which the first protrusion (1321b) protrudes. At this time, the first end (1321bc) may be the part furthest apart from one side (1321aa) of the first lower cover body (1321a) with respect to the direction in which the first protrusion (1321b) protrudes.

[0192] The first end (1321bc) may be formed on the outer surface (1321ba) of the first protrusion (1321b). That is, the first end (1321bc) may be formed on one end of the outer surface (1321ba) of the first protrusion (1321b) with respect to the direction in which the first protrusion (1321b) protrudes.

[0193] The first protrusion (1321b) may include a second end (1321bd). The second end (1321bd) may be provided at the other end of the protrusion (1321ba) according to the direction in which the first protrusion (1321b) protrudes. At this time, the other end of the protrusion (1321ba) may be provided on the opposite side of the first end of the protrusion (1321ba) with respect to the direction in which the first protrusion (1321b) protrudes. That is, the other end of the protrusion (1321ba) may be a part provided adjacent to one side (1321aa) of the first lower cover body (1321a).

[0194] The second end (1321bd) may be formed on the outer surface (1321ba) of the first protrusion (1321b). That is, the second end (1321bd) may be the part where the outer surface (1321ba) of the first protrusion (1321b) and one side (1322aa) of the second lower cover body (1322a) come into contact. The second end (1321bd) may be provided on the opposite side of the first end (1321bc) with respect to the direction in which the first protrusion (1321b) protrudes.

[0195] The outer surface (1321ba) of the first protrusion (1321b) may extend from the second end (1321bd) toward the first end (1321bc). In other words, the outer surface (1321ba) of the first protrusion (1321b) may extend from the second end (1321bd) to the first end (1321bc).

[0196] The distance at least a portion of the first protrusion (1321b) provided between the first end (1321bc) and the second end (1321bd) is spaced radially from the second wheel shaft (120) may be longer than the distance (L5) at which the second end (1321bd) is spaced radially from the second wheel shaft (120). Specifically, the distance (L4) at which the first end (1321bc) is spaced radially from the second wheel shaft (120) may be longer than the distance (L5) at which the second end (1321bd) is spaced radially from the second wheel shaft (120). In other words, based on the radial direction of the second wheel shaft (120), the first end (1321bc) may be provided outside the second end (1321bd).

[0197] The outer surface (1321ba) of the first protrusion (1321b) may be inclined with respect to the extension direction of the second wheel shaft (120). In other words, the outer surface (1321ba) of the first protrusion (1321b) may be inclined with respect to the third direction (D3). Specifically, the outer surface of the first protrusion (1321b) may extend obliquely from the first end (1321bc) toward the radial direction of the second wheel shaft (120).

[0198] The first lower cover (1321) may include a first wheel shaft receiving portion (1321c). The first wheel shaft receiving portion (1321c) may be recessed from one side (1321aa) of the first lower cover body (1321a). The first wheel shaft receiving portion (1321c) may form a receiving space for receiving one end of the second wheel shaft (120). By receiving one end of the second wheel shaft (120) in the first wheel shaft receiving portion (1321c), the first lower cover (1321) can support one end of the second wheel shaft (120).

[0199] The first wheel shaft receiving portion (1321c) may be provided on the inner side of the first protrusion (1321b). In other words, the first protrusion (1321b) may be provided on the outer side of the first wheel shaft receiving portion (1321c).

[0200] The second lower cover (1322) may include a second lower cover body (1322a). The second lower cover body (1322a) may form the overall appearance of the second lower cover (1322).

[0201] One side (1322aa) of the second lower cover body (1322a) can cover the second wheel (110). Specifically, one side (1322aa) of the second lower cover body (1322a) can cover at least a portion of the second side (110f) of the second wheel (110). Specifically, one side (1322aa) of the second lower cover body (1322a) can cover one side of the inner ring (111) of the second wheel (110).

[0202] One side (1322aa) of the second lower cover body (1322a) and the second side (110f) of the second wheel (110) may be spaced apart from each other by a predetermined distance. Through this configuration, the second wheel (110) can rotate smoothly without causing interference with the second lower cover body (1322a).

[0203] The second lower cover (1322) may include a second protrusion (1322b). The second protrusion (1322b) may protrude from the second lower cover body (1322a). Specifically, the second protrusion (1322b) may protrude from the second lower cover body (1322a) toward the second groove (110h). Specifically, the second protrusion (1322b) may protrude from one side (1322aa) of the second lower cover body (1322a).

[0204] The second protrusion (1322b) may extend along the circumferential direction of the second wheel shaft (120). In other words, the second protrusion (1322b) may be provided along the circumferential direction of the second wheel shaft (120). In other words, the second protrusion (1322b) may extend along the circumferential direction of the second wheel (110). In other words, the second protrusion (1322b) may be provided along the circumferential direction of the second wheel (110).

[0205] The second protrusion (1322b) may be spaced apart from the second wheel shaft (120). That is, the second protrusion (1322b) may be extended along the circumferential direction of the second wheel (110) while spaced apart from the second wheel shaft (120). The distance at which the second protrusion (1322b) is spaced apart from the second wheel shaft (120) may be the same as the distance at which the first protrusion (1321b) is spaced apart from the second wheel shaft (120). That is, the second protrusion (1322b) may be formed at a position corresponding to the first protrusion (1321b).

[0206] The second protrusion (1322b) can be received inside the second groove (110h). In other words, the second protrusion (1322b) can be received in the receiving space formed by the second groove (110h). In other words, the second protrusion (1322b) can be inserted into the second groove (110h).

[0207] The second protrusion (1322b) may be provided in a shape corresponding to the receiving space formed by the second groove (110h). For example, the second protrusion (1322b) may be provided in a roughly torus shape.

[0208] The second protrusion (1322b) may be spaced apart from the second groove (110h) by a predetermined distance. With this configuration, the second wheel (110) can rotate smoothly without causing interference with the second lower cover body (1322a).

[0209] The second protrusion (1322b) may have an outer surface (1322ba) and an inner surface (1322bb). The outer surface (1322ba) of the second protrusion (1322b) may be provided on the opposite side of the inner surface (1322bb) of the second protrusion (1322b). Specifically, the outer surface (1322ba) of the second protrusion (1322b) may be provided on the outer side along the radial direction of the second wheel shaft (120), and the inner surface (1322bb) of the second protrusion (1322b) may be provided on the inner side along the radial direction of the second wheel shaft (120). In other words, the inner surface (1322bb) of the second protrusion (1322b) may be provided closer to the second wheel shaft (120) than the outer surface (1322ba) of the second protrusion (1322b). The outer surface (1322ba) and the inner surface (1322bb) of the second protrusion (1322b) may each extend in the direction in which the second protrusion (1322b) protrudes.

[0210] The second protrusion (1322b) may include a third end (1322bc). The third end (1322bc) may be provided at one end of the protrusion (1322ba) according to the direction in which the second protrusion (1322b) protrudes. In this case, the third end (1322bc) may be the part furthest apart from one side (1322aa) of the second lower cover body (1322a) with respect to the direction in which the second protrusion (1322b) protrudes.

[0211] A third end (1322bc) may be formed on the outer surface (1322ba) of the second protrusion (1322b). That is, the third end (1322bc) may be formed on one end of the outer surface (1322ba) of the second protrusion (1322b) with respect to the direction in which the second protrusion (1322b) protrudes.

[0212] The second protrusion (1322b) may include a fourth end (1322bd). The fourth end (1322bd) may be provided at the other end of the protrusion (1322ba) according to the direction in which the second protrusion (1322b) protrudes. At this time, the other end of the protrusion (1322ba) may be provided on the opposite side of the first end of the protrusion (1322ba) based on the direction in which the second protrusion (1322b) protrudes. That is, the other end of the protrusion (1322ba) may be a part provided adjacent to one side (1322aa) of the second lower cover body (1322a).

[0213] The fourth end (1322bd) may be formed on the outer surface (1322ba) of the second protrusion (1322b). That is, the fourth end (1322bd) may be the part where the outer surface (1322ba) of the second protrusion (1322b) and one side (1322aa) of the second lower cover body (1322a) come into contact. The fourth end (1322bd) may be provided on the opposite side of the third end (1322bc) based on the direction in which the second protrusion (1322b) protrudes.

[0214] The outer surface (1322ba) of the second protrusion (1322b) may extend from the fourth end (1322bd) toward the third end (1322bc). In other words, the outer surface (1322ba) of the second protrusion (1322b) may extend from the fourth end (1322bd) to the third end (1322bc).

[0215] The distance at least a portion of the second protrusion (1322b) provided between the third end (1322bc) and the fourth end (1322bd) is spaced radially from the second wheel shaft (120) may be longer than the distance (L7) at which the fourth end (1322bd) is spaced radially from the second wheel shaft (120). Specifically, the distance (L6) at which the third end (1322bc) is spaced radially from the second wheel shaft (120) may be longer than the distance (L7) at which the fourth end (1322bd) is spaced radially from the second wheel shaft (120). In other words, based on the radial direction of the second wheel shaft (120), the third end (1322bc) may be provided outside the fourth end (1322bd).

[0216] The outer surface (1322ba) of the second protrusion (1322b) may be inclined with respect to the extension direction of the second wheel shaft (120). In other words, the outer surface (1322ba) of the second protrusion (1322b) may be inclined with respect to the third direction (D3). Specifically, the outer surface of the second protrusion (1322b) may extend obliquely from the fourth end (1322bd) toward the radial direction of the second wheel shaft (120).

[0217] The second lower cover (1322) may include a second wheel shaft receiving portion (1322c). The second wheel shaft receiving portion (1322c) may be recessed from one side (1322aa) of the second lower cover body (1322a). The second wheel shaft receiving portion (1322c) may form a receiving space for receiving the other end of the second wheel shaft (120). By receiving the other end of the second wheel shaft (120) in the second wheel shaft receiving portion (1322c), the second lower cover (1322) may support the other end of the second wheel shaft (120).

[0218] The second wheel shaft receiving portion (1322c) may be provided on the inner side of the second protrusion (1322b). In other words, the second protrusion (1322b) may be provided on the outer side of the second wheel shaft receiving portion (1322c).

[0219] As described above, one side (1321aa) of the first lower cover body (1321a) and the first side (110e) of the second wheel (110) may be spaced apart from each other by a predetermined distance, and the first protrusion (1321b) may be spaced apart from the first groove (110g) by a predetermined distance. Accordingly, a first spaced-away space (P1) may be formed between the first lower cover (1321) and the second wheel (110).

[0220] The first separation space (P1) may extend from the outside of the projector (1a) to the first wheel shaft receiving portion (1321c). Therefore, there is a possibility that foreign matter from outside the projector (1a) may enter the first wheel shaft receiving portion (1321c) through the first separation space (P1). That is, the first separation space (P1) may form an inflow path through which foreign matter from outside the projector (1a) enters the inside of the second wheel (110). The first separation space (P1) may also be referred to as the first inflow path (P1).

[0221] Additionally, one side (1322aa) of the second lower cover body (1322a) and the second side (110f) of the second wheel (110) may be spaced apart from each other by a predetermined distance, and the second protrusion (1322b) may be spaced apart from the second groove (110h) by a predetermined distance. Accordingly, a second spaced-away space (P2) may be formed between the second lower cover (1322) and the second wheel (110).

[0222] The second separation space (P2) may extend from the outside of the projector (1a) to the second wheel shaft receiving portion (1322c). Therefore, there is a possibility that foreign matter from outside the projector (1a) may enter the second wheel shaft receiving portion (1322c) through the second separation space (P2). That is, the second separation space (P2) may form an inflow path through which foreign matter from outside the projector (1a) enters the inside of the second wheel (110). The second separation space (P2) may also be referred to as the second inflow path (P2).

[0223] Foreign substances introduced into each inflow path (P1, P2) can rotate together with the second wheel (110). Accordingly, the foreign substances may move to the inflow path (P1, P2) on the upper side of the second wheel shaft (120). In this case, the foreign substances may move further downward due to their own weight, and the possibility of foreign substances entering the wheel shaft receiving portion (1321c, 1322c) may increase.

[0224] If foreign matter enters the wheel shaft receiving portion (1321c, 1322c), the rotation of the second wheel (110) relative to the second wheel shaft (120) may be restricted. That is, smooth rotation of the second wheel (110) may become difficult.

[0225] According to the concept of the present disclosure, the lower cover body (1321a, 1322a) includes a protrusion (1321b, 1322b) and the second wheel (110) includes a groove (110g, 110h), so that each inflow path (P1, P2) does not extend in one direction and may have a plurality of bending points. Due to this configuration, foreign matter from outside the projector (1a) can be primarily prevented from entering the wheel shaft receiving portion (1321c, 1322c) through the inflow path (P1, P2). In other words, foreign matter from outside the projector (1a) can be primarily prevented from entering the inside of the second wheel (110) through the inflow path (P1, P2).

[0226] In particular, based on the radial direction of the second wheel shaft (120), the first end (1321bc) may be provided further outward than the second end (1321bd), and the third end (1322bc) may be provided further outward than the fourth end (1322bd). Due to this configuration, even if foreign matter moves to the upper inflow path (P1, P2) of the second wheel shaft (120), further downward movement due to its own weight may be restricted. For example, even if foreign matter flows toward the second end (1321bd), since the first end (1321bc) is provided further outward from the second end (1321bd) according to the radial direction of the second wheel shaft (120), the foreign matter may be restricted from falling down past the first end (1321bc). Therefore, it is possible to secondarily prevent foreign matter from outside the projector (1a) from entering the wheel shaft receiving portion (1321c, 1322c) through the gap space. In other words, it is possible to secondarily prevent foreign matter from outside the projector (1a) from entering the inside of the second wheel (110) through the gap space.

[0227] FIG. 20 is a cross-sectional view along the CC' line of FIG. 3.

[0228] Referring to FIG. 20, the upper cover (131) may include an upper cover body (1311). The upper cover body (1311) may form the overall appearance of the upper cover (131).

[0229] The upper cover (131) may include a first hook (1312). The first hook (1312) may protrude downward from the upper cover body (1311). In other words, the first hook (1312) may protrude from the upper cover body (1311) toward the lower cover (132). Specifically, the first hook (1312) may protrude from the upper cover body (1311) toward the first lower cover (1321). More specifically, the first hook (1312) may protrude from the upper cover body (1311) toward the first cover opening (1321d) to be described later.

[0230] The first hook (1312) may include a first hook body (1312a). The first hook body (1312a) may extend downward from the upper cover body (1311). In other words, the first hook body (1312a) may protrude downward from the upper cover body (1311). The lower end of the first hook body (1312a) may pass through the first cover opening (1321d).

[0231] The first hook (1312) may include a first hook projection (1312b). The first hook projection (1312b) may protrude from the lower end of the first hook body (1312a). Specifically, the first hook projection (1312b) may protrude from the lower end of the first hook body (1312a) in a direction intersecting the direction in which the first hook body (1312a) extends. More specifically, the first hook projection (1312b) may protrude from the lower end of the first hook body (1312a) toward the inner side of the second wheel device (100). For example, the first hook projection (1312b) may protrude from the lower end of the first hook body (1312a) toward the second lower cover (1322).

[0232] The first hook projection (1312b) can be caught on at least a portion of the first lower cover (1321). Specifically, the first hook projection (1312b) can be caught on the lower surface of at least a portion of the first lower cover (1321). For example, the first hook projection (1312b) can be caught on the first catch (1321e) to be described later.

[0233] The first hook projection (1312b) may have a first inclined surface (1312c) that slopes upward from the lower portion of the first hook projection (1312b). In other words, the lower surface of the first hook projection (1312b) may be provided with a first inclined surface (1312c) that extends upwardly from the lower portion of the first hook body (1312a).

[0234] The upper cover (131) may include a second hook (1313). The second hook (1313) may protrude downward from the upper cover body (1311). In other words, the second hook (1313) may protrude from the upper cover body (1311) toward the lower cover (132). Specifically, the second hook (1313) may protrude from the upper cover body (1311) toward the second lower cover (1322). More specifically, the second hook (1313) may protrude from the upper cover body (1311) toward the second cover opening (1322d) to be described later.

[0235] The second hook (1313) may include a second hook body (1313a). The second hook body (1313a) may extend downward from the upper cover body (1311). In other words, the second hook body (1313a) may protrude downward from the upper cover body (1311). The lower end of the second hook body (1313a) may pass through the second cover opening (1322d).

[0236] The second hook (1313) may include a second hook projection (1313b). The second hook projection (1313b) may protrude from the lower end of the second hook body (1313a). Specifically, the second hook projection (1313b) may protrude from the lower end of the second hook body (1313a) in a direction intersecting with the direction in which the second hook body (1313a) extends. More specifically, the second hook projection (1313b) may protrude from the lower end of the second hook body (1313a) toward the inner side of the second wheel device (100). For example, the second hook projection (1313b) may protrude from the lower end of the second hook body (1313a) toward the first lower cover (1321).

[0237] The second hook projection (1313b) can be caught on at least a part of the second lower cover (1322). Specifically, the second hook projection (1313b) can be caught on the lower surface of at least a part of the second lower cover (1322). For example, the second hook projection (1313b) can be caught on the second catch (1322e) to be described later.

[0238] The second hook projection (1313b) may have a second inclined surface (1313c) that slopes upward from the lower portion of the second hook projection (1313b). In other words, the lower surface of the second hook projection (1313b) may be provided with a second inclined surface (1313c) that extends upwardly from the lower portion of the second hook body (1313a).

[0239] The first lower cover (1321) may include a first cover opening (1321d). The first cover opening (1321d) may be formed in the first lower cover body (1321a).

[0240] The first cover opening (1321d) may be provided so that at least a portion of the first hook (1312) is inserted. In other words, at least a portion of the first hook (1312) may pass through the first cover opening (1321d). For example, the first hook projection (1312b) may pass through the first cover opening (1321d).

[0241] The first lower cover (1321) may include a first catch (1321e). A first hook projection (1321b) may be engaged with the first catch (1321e). By engaging the first hook projection (1321b) with the first catch (1321e), the first lower cover (1321) may be coupled to the upper cover (131).

[0242] The first stopper (1321e) may be formed on one side of the first cover opening (1321d). The first stopper (1321e) may be formed at a position corresponding to the first hook projection (1321b).

[0243] The first stopper (1321e) may be formed with a step difference from the lower surface of the first lower cover (1321). In other words, the first stopper (1321e) may be formed with a step difference from the lower surface of the first lower cover body (1321a). Specifically, the first stopper (1321e) may be formed above the lower surface of the first lower cover body (1321a).

[0244] The second lower cover (1322) may include a second cover opening (1322d). The second cover opening (1322d) may be formed in the second lower cover body (1322a).

[0245] The second cover opening (1322d) may be provided so that at least a portion of the second hook (1313) is inserted. In other words, at least a portion of the second hook (1313) may pass through the second cover opening (1322d). For example, the second hook projection (1313b) may pass through the second cover opening (1322d).

[0246] The second lower cover (1322) may include a second catch (1322e). A second hook projection (1313b) may be engaged with the second catch (1322e). By engaging the second hook projection (1313b) with the second catch (1322e), the second lower cover (1322) may be coupled to the upper cover (131).

[0247] The second stopper (1322e) may be formed on one side of the second cover opening (1322d). The second stopper (1322e) may be formed at a position corresponding to the second hook projection (1313b).

[0248] The second stopper (1322e) may be formed with a step difference from the lower surface of the second lower cover (1322). In other words, the second stopper (1322e) may be formed with a step difference from the lower surface of the second lower cover body (1322a). Specifically, the second stopper (1322e) may be formed above the lower surface of the second lower cover body (1322a).

[0249] According to the concept of the present disclosure, the first lower cover (1321) can be coupled with the upper cover (131) by the first hook projection (1312b) engaging with the first catch (1321e), and the second lower cover (1322) can be coupled with the upper cover (131) by the second hook projection (1313b) engaging with the second catch (1322e). At this time, the first hook projection (1312b) can be separated from the first hook projection (1312b) by pressing the first inclined surface (1312c) of the first hook projection (1312b) upward, and the second hook projection (1313b) can be separated from the second hook projection (1322e) by pressing the second inclined surface (1313c) of the second hook projection (1313b) upward.

[0250] Due to this configuration, the lower cover (1321, 1322) can be separated more easily from the upper cover (131). Additionally, as the lower cover (1321, 1322) is separated from the upper cover (131), the second wheel shaft (120) coupled to the wheel cover (130) and the second wheel (110) coupled to the second wheel shaft (120) can both be separated. Accordingly, foreign substances that have entered between the lower cover (1321, 1322) and the upper cover (131), or foreign substances that have entered into the second wheel (110), can be easily removed.

[0251] FIG. 21 is a cross-sectional view showing an enlarged view of a second wheel and surrounding configuration according to one embodiment.

[0252] Hereinafter, with reference to FIG. 21, a second wheel device (100') according to one embodiment of the present disclosure will be described. In describing the second wheel device (100'), the same reference numerals are assigned to components that are substantially identical to the components of FIG. 1 to FIG. 20, and detailed descriptions may be omitted.

[0253] Referring to FIG. 21, the second wheel device (100') may include a second wheel (110'). The second wheel (110') may include an inner ring (111) and an outer ring (112').

[0254] The outer ring (112') can be positioned on the outside of the inner ring (111). The outer ring (112') can be coupled to the outside of the inner ring (111).

[0255] At least a portion of the outer ring (112') may be arranged to contact the floor (S) on which the projector (1a) is placed. For example, the outer ring (112') may be made of rubber.

[0256] The second wheel (110') may have an outer surface and an inner surface. The outer surface of the second wheel (110') may refer to the outer surface of the second wheel (110') along the radial direction of the second wheel shaft (120), and the inner surface of the second wheel (110') may refer to the inner surface of the second wheel (110') along the radial direction of the second wheel shaft (120'). Additionally, the outer surface of the second wheel (110') may refer to the outer surface of the outer ring (112'), and the inner surface of the second wheel (110') may refer to the inner surface of the inner ring (111).

[0257] The second wheel (110') may have a first part (110a') and a second part (110b') separated based on the center of the second wheel (110') according to the third direction (D3). Specifically, the first part (110a') and the second part (110b') may be separated based on an imaginary line (L1) extending radially from the center of the second wheel (110') according to the third direction (D3) to the second wheel shaft (120). Accordingly, one end of the second wheel (110') according to the third direction (D3) may be provided in the first part (110a'), and the other end of the second wheel (110') according to the third direction (D3) may be provided in the second part (110b').

[0258] At least a portion of the outer diameter of the first part (110a') may be longer than the outer diameter of the second part (110b'). Specifically, at least a portion of the outer diameter of the first part (110a') may be longer than the longest outer diameter (W2') provided in the second part (110b'). In other words, the distance at least a portion of the outer surface of the first part (110a') is spaced radially from the second wheel shaft (120) may be longer than the distance at which the outer surface of the second part (110b') is spaced radially from the second wheel shaft (120).

[0259] The first part (110a') may include a possible contact portion (110c') with the floor (S) as the second wheel (110') rotates. The contact portion (110c') may be provided on the outer surface of the second wheel (110').

[0260] The outer diameter (W1') measured at the part where the contact portion (110c') is provided may be longer than the outer diameter of the second part (110b'). Specifically, the outer diameter (W1') measured at the part where the contact portion (110c') is provided may be longer than the outer diameter (W2') that is longest at the second part (110b'). In other words, the distance at which the contact portion (110c') is separated from the second wheel shaft (120) in the radial direction of the second wheel shaft (120) may be longer than the distance at which the outer surface of the second part (110b') is separated from the second wheel shaft (120) in the radial direction of the second wheel shaft (120). Through this configuration, the part where the second wheel (110') contacts the floor (S) may be provided offset to one side with respect to the third direction (D3).

[0261] The contact portion (110c') may be formed along the circumferential direction of the second wheel (110). That is, the contact portion (110c') may be the outer surface of the part having the longest diameter of the second wheel (110).

[0262] The contact portion (110c') may be provided at one end of the second wheel (110') according to the third direction (D3). Specifically, the contact portion (110c') may be provided on the outer surface of one end of the second wheel (110') according to the third direction (D3).

[0263] An inclined portion (110d') may be provided on at least a portion of the outer surface of the second wheel (110'). The inclined portion (110d') may extend from the contact portion (110c') toward the second portion (110b'). In other words, the contact portion (110c') may be formed on one side of the inclined portion (110d').

[0264] The inclined portion (110d') may extend in an inclined direction relative to the second wheel shaft (120'). That is, the inclined portion (110d') may be inclined in a direction opposite to the radial direction of the second wheel shaft (120'). In other words, the inclined portion (110d') may be inclined in a direction approaching the second wheel shaft (120) from the contact portion (110c'). The inclined portion (110d') may extend to the other end of the second wheel (110') along the third direction (D3).

[0265] The contact portion (110c') may be provided by extending in the direction in which the second wheel shaft (120) extends. That is, the contact portion (110c') may be provided by extending in the third direction (D3).

[0266] Specifically, the contact portion (110c') may extend in a third direction (D3) until it reaches an imaginary line (L2') extending radially from the center of gravity (C') of the second wheel (110') to the second wheel shaft (120). In other words, the imaginary line (L2') extending radially from the center of gravity (C') of the second wheel (110') to the second wheel shaft (120) may intersect the inclined portion (110d') rather than the contact portion (110c').

[0267] Since the inclined portion (110d') can be provided spaced apart from the floor (S) and can be provided in the radial direction of the second wheel shaft (120) from the center of gravity (C') of the second wheel (110'), the second wheel (110') can be slightly tilted toward the inclined portion (110d').

[0268] FIG. 22 is a perspective view of a robot vacuum cleaner according to one embodiment. FIG. 23 is a bottom perspective view of the robot vacuum cleaner of FIG. 22.

[0269] Hereinafter, a robot vacuum cleaner (1b) according to one embodiment of the present disclosure will be described with reference to FIGS. 22 and 23. In describing the robot vacuum cleaner (1b), the same reference numerals are assigned to components that are substantially identical to those shown in FIGS. 1 to 20, and detailed descriptions may be omitted.

[0270] Referring to FIGS. 22 and 23, the robot vacuum cleaner (1b) may include a main body (10''). The main body (10'') may form the exterior of the robot vacuum cleaner (1b).

[0271] Components of the robot vacuum cleaner (1b) can be accommodated inside the main body (10''). For example, electrical components can be placed inside the main body (10'').

[0272] The main body (10'') may include a suction port (210). The suction port (210) may be provided at the bottom of the main body (10''). The suction port (210) may be formed to face the surface to be cleaned. The suction port (210) may be open toward the surface to be cleaned. Dirt on the surface to be cleaned may be sucked into the interior of the main body (10'') through the suction port (210) along with air.

[0273] The main body (10'') may include a brush (220). The brush (220) may be provided at the bottom of the main body (10''). The brush (220) may be formed on the front side of the suction port (210). The brush (220) may strike the surface to be cleaned to scatter dirt. The dirt scattered by the brush (220) may be introduced into the suction port (210) along with air.

[0274] The main body (10'') may include a dust collection container. Dirt and / or air sucked in through the suction port (210) may move to the dust collection container. Dirt sucked in through the suction port (210) may be collected in the dust collection container.

[0275] The robot vacuum cleaner (1b) may include a first wheel device (20''). The first wheel device (20'') may be provided to move the main body (10''). The first wheel device (20'') may be provided to support the main body (10''). That is, the first wheel device (20'') may support the main body (10'') in a movable manner. Through this configuration, the robot vacuum cleaner (1b) may be provided to be movable on the surface to be cleaned. The first wheel device (20'') may be provided at the bottom of the main body (10''). The first wheel device (20'') may also be referred to as the main wheel device (20'').

[0276] The first wheel device (20'') may be provided in multiple numbers. For example, the first wheel device (20'') may be provided in two numbers. One of the two first wheel devices (20'') may be provided on the lower side of one side of the main body (10''), and the other may be provided on the lower side of the other side of the main body (10''). Specifically, one of the two first wheel devices (20'') may be provided on the lower left (+Y) side of the main body (10''), and the other may be provided on the lower right (-Y) side of the main body (10'').

[0277] The first wheel device (20') may include a first wheel (21''). The first wheel (21'') may be rotatable. Specifically, the first wheel (21'') may be rotatable about a first axis of rotation extending in a first direction. Specifically, the first wheel (21'') may be rotatable about the main body (10''). The first wheel (21'') may be provided at the bottom of the main body (10''). The first wheel (21'') may also be referred to as the main wheel (21'').

[0278] As the first wheel (21'') rotates, the main body (10'') can move or change its driving direction. In other words, as the first wheel (21'') rotates, the robot vacuum cleaner (1b) can move or change its driving direction.

[0279] As described above, since the first wheel device (20'') can be provided in multiple numbers, the first wheel (21'') can also be provided in multiple numbers. For example, the first wheel (21'') can be provided in two numbers. One of the two first wheels (21'') can be provided on the lower side of one side of the main body (10''), and the other can be provided on the lower side of the other side of the main body (10''). Specifically, one of the two first wheels (21'') can be provided on the lower left (+Y) side of the main body (10''), and the other can be provided on the lower right (-Y) side of the main body (10'').

[0280] The main body (10'') may include a driving device. The driving device may include a power source for transmitting power to other components. For example, the driving device (not shown) may include a motor. The first wheel (21'') may be arranged to rotate by the driving device.

[0281] The robot vacuum cleaner (1b) may include a second wheel device (100''). The second wheel device (100'') may be provided to move the main body (10''). The second wheel device (100'') may be provided to support the main body (10''). That is, the second wheel device (100'') may movably support the main body (10''). Specifically, the second wheel device (100'') may movably support the main body (10'') together with the first wheel device (20''). Through this configuration, the robot vacuum cleaner (1b) may be provided to be movable on the surface to be cleaned. The second wheel device (100'') may also be referred to as an auxiliary wheel device (20'').

[0282] The second wheel device (100'') may be provided at the lower part of the main body (10''). The second wheel device (100'') may be provided in front of the first wheel device (20'').

[0283] In the drawing, the second wheel device (100'') is shown as one, but there is no special limitation on the number of second wheel devices (100''). For example, the second wheel device (100'') may be provided in two or more.

[0284] The second wheel device (100'') may include a second wheel (110''). The second wheel (110'') may be rotatable.

[0285] The second wheel (110'') may be configured to rotate as the main body (10'') moves. In other words, the second wheel (110'') may rotate without a separate drive device directly coupled thereto. That is, the driving direction or driving speed of the main body (10'') is determined by the first wheel (21'') which rotates by the drive device, and the second wheel (110'') may perform the function of assisting the first wheel (21'') to enable the main body (10'') to move smoothly. Therefore, the second wheel (110') may be referred to as an auxiliary wheel (110'').

[0286] The second wheel device (100'') may include a wheel cover (130''). The wheel cover (130'') may be provided to cover at least a portion of the second wheel (110'').

[0287] The wheel cover (130'') may be rotatable. Specifically, the wheel cover (130'') may be rotatable relative to the main body (10'').

[0288] The wheel cover (130'') may be rotatable with respect to a second rotation axis extending in a second direction that intersects the first rotation axis, which is the rotation center of the first wheel (21''). In other words, the wheel cover (130'') may be rotatable with respect to a second rotation axis extending in a second direction that intersects the first direction.

[0289] The second wheel (110'') may be rotatable with respect to the wheel cover (130''). The second wheel (110'') may be rotatable with respect to a third rotation axis extending in a third direction that intersects the second rotation axis, which is the rotation center of the wheel cover (130''). In other words, the second wheel (110'') may be rotatable with respect to a third rotation axis extending in a third direction that intersects the second direction.

[0290] That is, the wheel cover (130'') can rotate relative to the main body (10''), and the second wheel (110') can rotate relative to the wheel cover (130'').

[0291] The detailed configuration of the second wheel device (100'') and the structure of the second wheel (110) are substantially the same as the configuration of the second wheel device (100) and the structure of the second wheel (110) shown in FIGS. 1 to 20. Therefore, details regarding this are omitted.

[0292] An electronic device (1) according to one embodiment comprises a main body (10), a first wheel device (20) provided to move the main body (10), the first wheel device (20) having a first wheel (21) rotatable about a first rotation axis (R1), and a second wheel device (100) that supports the main body (10) so as to be movable. The second wheel device (100) comprises a wheel cover (130) rotatable with respect to the main body (10) with respect to a second rotation axis (R2) extending in a direction intersecting the first rotation axis (R1), a wheel shaft (120) connected to the wheel cover (130) and extending in one direction (D3) intersecting the second rotation axis (R2), and a second wheel (110) rotatable with respect to the center axis of the wheel shaft (120), the second wheel (110) having a first part (110a) and a second part (110b) that extends radially along the wheel shaft (120) and is divided by a virtual line (L1) that is aligned with the center of the second wheel (110) along the one direction (D3). At least a portion of the outer diameter of the first part (110a) is longer than the outer diameter of all portions of the second part (110b).

[0293] The electronic device (1) may be movably provided on the floor (S). At least a portion of the outer surface of the second wheel (110) may be able to come into contact with the floor (S) as the second wheel (110) rotates.

[0294] The first part (110a) may include a contact portion (110c) that can contact the floor (S) as the second wheel (110) rotates. The distance at which the contact portion (110c) is separated from the wheel shaft (120) may be longer than the distance at which the outer surface of the second part (110b) is separated from the wheel shaft (120).

[0295] On the outer surface of the second wheel (110), an inclined portion (110d) may be provided that extends from the contact portion (110c) toward the second portion (110b) and is inclined with respect to the wheel shaft (120).

[0296] The first stage of the second wheel (110) according to the above one direction (D3) may be provided in the first part (110a). The second stage of the second wheel (110) according to the above one direction (D3) may be provided in the second part (110b). The inclined portion (110d) may extend to the second stage of the second wheel (110) according to the above one direction (D3).

[0297] The above contact portion (110c) may be provided at the first end of the second wheel (110).

[0298] The above-mentioned inclined portion (110d) can be aligned with the center of gravity (C) of the second wheel (110) along the radial direction of the wheel shaft (120).

[0299] The second wheel device (100) may further include a coupling bracket (150) provided on the upper side of the wheel cover (130) and configured to be coupled to the main body (10), and a connecting shaft (140) that passes through a first through hole (152b) of the coupling bracket (150) and a second through hole (131a) of the wheel cover (130) to connect the coupling bracket (150) and the wheel cover (130). The central axis of the connecting shaft (140) may form the second rotation axis (R2).

[0300] The above coupling bracket (150) may be restricted from rotating with respect to the connecting shaft (140). The above wheel cover (130) may be rotatable with respect to the connecting shaft (140).

[0301] The wheel shaft (120) may be offset from the center axis of the connecting shaft (140).

[0302] The wheel cover (130) may include an upper cover (131) covering the upper part of the second wheel (110), and a lower cover (132) that is coupled to the lower side of the upper cover (131) and supports the wheel shaft (120).

[0303] The lower cover (132) may include a first lower cover (1321) that supports a first end of the wheel shaft (120) and a second lower cover (1322) that supports a second end of the wheel shaft (120).

[0304] The upper cover (131) may include an upper cover body (1311) and a hook (1312) protruding downward from the upper cover body (1311). The lower cover (132) may include a cover opening (1321d, 1322d) into which the hook is inserted.

[0305] The above hook may include a hook body (1312a) extending downward from the upper cover body (1311), and a hook projection (1312b) protruding from the lower end of the hook body (1312a) in a direction intersecting with the direction in which the hook body (1312a) extends. The hook projection (1312b) may have an upwardly inclined surface (1312c) extending from the lower end of the hook projection (1312b).

[0306] The electronic device (1) may further include a driving device (12) including a motor. The driving device (12) may be configured to rotate the first wheel (21). The second wheel (110) may be configured to rotate as the main body (10) moves.

[0307] An electronic device (1) according to one embodiment comprises a main body (10), a first wheel (21) rotatably coupled to the main body (10) and rotatably coupled to the main body (10), a first wheel (21) rotatably coupled to the main body (10) and a second wheel device (100) rotatably coupled to the main body (10), wherein the second wheel device (100) comprises a wheel cover (130) rotatably connected to the main body (10) and arranged to rotate about a second rotation axis (R2) extending in a direction intersecting with the direction corresponding to the first rotation axis (R1), a wheel shaft (120) coupled to the wheel cover (130) and extending in a direction intersecting with the direction in which the second rotation axis (R2) extends, and a second wheel (110) rotatably coupled to the wheel shaft (120), wherein the second wheel (110) comprises an outer surface including a first part (110a) and a second part (110b), and the first At least a portion of the outer diameter of part (110a) is longer than the outer diameter of all portions of the second part (110b).

[0308] The first portion (110a) may include a contact portion (110c) arranged to contact the floor (S) as the second wheel (110) rotates. The contact portion (110c) may be positioned further from the wheel shaft (120) than the second portion (110b).

[0309] At least one part of the above outer surface may be inclined with respect to the direction corresponding to the second rotation axis (R2).

[0310] The second wheel (110) may include a truncated cone shape.

[0311] The outer surface may include an inclined portion (110d) extending from the contact portion (110c) toward the second portion (110b).

[0312] According to the concept of the present disclosure, an inclined portion is provided on the outer surface of the auxiliary wheel so that the auxiliary wheel can be tilted in one direction. Accordingly, the responsiveness of the auxiliary wheel to a change in the driving direction of the main wheel can be relatively faster.

[0313] According to the concept of the present disclosure, with respect to the radial direction of the second wheel shaft, a first end may be provided further outward than the second end, and a third end may be provided further outward than the fourth end. Accordingly, foreign matter may be prevented from entering the inner side of the auxiliary wheel.

[0314] According to the concept of the present disclosure, the upper cover and the lower cover of the auxiliary wheel cover can be joined through a hook, and an inclined surface can be provided at the lower end of the hook projection. Through this configuration, it becomes easier to separate the lower cover from the upper cover, and it also becomes easier to separate the auxiliary wheel and the auxiliary wheel shaft from the auxiliary wheel cover. Accordingly, the user can more easily remove foreign matter that has entered the inside of the protective wheel.

[0315] Specific embodiments have been illustrated and described above. However, the invention is not limited to the embodiments described above, and those skilled in the art may make various modifications without departing from the essence of the technical concept of the invention as described in the following claims.

Claims

1. Main body; A first wheel device configured to move the above-mentioned main body, comprising a first wheel device having a first wheel rotatable about a first rotation axis; and It includes a second wheel device that movably supports the main body, and The above second wheel device is, A wheel cover rotatable with respect to the main body based on a second rotation axis extending in a direction intersecting the first rotation axis; A wheel shaft connected to the wheel cover and extending in one direction intersecting the second rotation axis; and A second wheel rotatable about the central axis of the wheel shaft, comprising a second wheel that extends radially in the direction of the wheel shaft and has a first portion and a second portion separated by a virtual line aligned with the center of the second wheel along the one direction. An electronic device in which the outer diameter of at least a portion of the first part is longer than the outer diameter of all portions of the second part.

2. In Paragraph 1, The above electronic device is configured to be movable on the floor, and An electronic device in which at least a portion of the outer surface of the second wheel is capable of contacting the floor as the second wheel rotates.

3. In Paragraph 2, The first part above includes a contact portion capable of contacting the floor as the second wheel rotates, and An electronic device in which the distance at which the contact portion is spaced from the wheel shaft is longer than the distance at which the outer surface of the second portion is spaced from the wheel shaft.

4. In Paragraph 3, An electronic device having an inclined portion on the outer surface of the second wheel that extends from the contact portion toward the second portion and is inclined with respect to the wheel shaft.

5. In Paragraph 4, The first stage of the second wheel according to the above one direction is provided in the first part, and The second stage of the second wheel according to the above one direction is provided in the second part, and The above-mentioned inclined portion is an electronic device that extends to the second stage of the second wheel according to the above-mentioned direction.

6. In Paragraph 5, The above contact portion is an electronic device provided at the first stage of the second wheel.

7. In Paragraph 4, The above-mentioned inclined portion is an electronic device aligned with the center of gravity of the second wheel along the radial direction of the wheel shaft.

8. In Paragraph 1, The above second wheel device is, A coupling bracket provided on the upper side of the wheel cover and coupled to the main body; and It further includes a connecting shaft that passes through a first through hole of the coupling bracket and a second through hole of the wheel cover to connect the coupling bracket and the wheel cover, The central axis of the above connecting shaft is an electronic device that forms the second rotation axis.

9. In Paragraph 8, The above coupling bracket is restricted from rotation with respect to the above connecting shaft, and The above wheel cover is an electronic device capable of rotating with respect to the above connecting shaft.

10. In Paragraph 9, The above wheel shaft is an electronic device offset from the center axis of the above connecting shaft.

11. In Paragraph 1, The above wheel cover is, An upper cover covering the upper part of the second wheel; and An electronic device comprising a lower cover that is coupled to the lower side of the upper cover and supports the wheel shaft.

12. In Paragraph 11, The lower cover mentioned above is, A first lower cover supporting the first end of the wheel shaft; and An electronic device comprising a second lower cover that supports the second end of the wheel shaft.

13. In Paragraph 11, The upper cover mentioned above is, Upper cover body; and It includes a hook protruding downward from the upper cover body, and The above lower cover is an electronic device comprising a cover opening into which the hook is inserted.

14. In Paragraph 13, The above hook is, A hook body extending downward from the upper cover body; and It includes a hook projection protruding from the lower part of the hook body in a direction intersecting with the direction in which the hook body extends, and The above hook projection is an electronic device having an upwardly inclined surface from the lower part of the above hook projection.

15. In Paragraph 1, It further includes a driving device including a motor, The above driving device is configured to rotate the first wheel, and The above second wheel is an electronic device configured to rotate as the main body moves.

Images