Wheel unit with variable stiffness using tension control

Abstract

A wheel unit capable of varying stiffness through tension adjustment includes a hub unit, a rotating body, an outer surface, and a wire section. The hub unit rotates by receiving driving force from a wheel drive unit. The rotating body rotates independently of the hub unit at the center of the hub unit. The outer surface rotates according to the rotation of the hub unit at the outer side of the hub unit. The wire section extends from the outer surface, passes through the hub unit, and is fixed to the rotating body, and its tension varies according to the rotation of the rotating body.

Description

Technology Field

[0001] The present invention relates to a wheel unit capable of variable stiffness, and more specifically, to a wheel unit capable of variable stiffness through tension control that can overcome obstacles and achieve optimal driving in various driving environments by adjusting the tension of a wire or spoke using an independently rotatable body provided in a hub unit. Background Technology

[0002] Recently, numerous technologies regarding wheel units capable of freely passing through obstacles or stairs, or performing optimal operation in various driving environments, are being developed.

[0003] In particular, regarding conventional wheel unit-related technologies, as seen in Korean Patent No. 10-2174498, the focus of development has been on obstacle-overcoming wheels; a representative technology involves overcoming obstacles through shape deformation, such as the deformation or compression of parts of the wheel's structure upon contact with an obstacle.

[0004] Furthermore, as described in Korean Patent Publication No. 10-2024-0000882, a technology is being developed that makes it easier to overcome obstacles by designing the internal structure of the wheel unit to vary and change stiffness while the wire or spoke maintains a predetermined tension.

[0005] In particular, in the case of Korean registered patent No. 10-2567827, technology for a wheel unit with a variable stiffness structure that is more suitable for driving environments is also being developed by varying the stiffness of the wheel unit by variably controlling the tension of the wire or spoke that maintains tension.

[0006] However, in controlling the tension of the wire or spokes, the hub unit is designed with a structure in which the length or spacing along the axial direction is varied, which causes wire damage due to stress concentration and requires space for the movement of the hub unit, which limits the miniaturization of the wheel unit. Prior art literature

[0007] Republic of Korea Registered Patent No. 10-2174498 Republic of Korea Published Patent No. 10-2024-0000882 Republic of Korea Registered Patent No. 10-2567827 The problem to be solved

[0008] Accordingly, the technical problem of the present invention is conceived from this point, and the objective of the present invention is to provide a wheel unit capable of variable stiffness through tension adjustment, which minimizes wire damage and improves space utilization through miniaturization by adjusting the tension of a wire or spoke using an independently rotatable body provided in a hub unit, and enables overcoming obstacles and achieving optimal driving in various driving environments. means of solving the problem

[0009] A wheel unit according to one embodiment for realizing the purpose of the present invention described above comprises a hub unit, a rotating body, an outer surface portion, and a wire portion. The hub unit rotates by receiving driving force from a wheel drive unit. The rotating body rotates independently of the hub unit at the center of the hub unit. The outer surface portion rotates according to the rotation of the hub unit at the outer side of the hub unit. The wire portion extends from the outer surface portion, passes through the hub unit, and is fixed to the rotating body, and its tension varies according to the rotation of the rotating body.

[0010] In one embodiment, the outer surface portion forms the outer shape of the wheel unit, and the wire portion may be connected in multiple numbers at regular intervals on the outer surface portion and extended to the rotating body.

[0011] In one embodiment, between the hub unit and the outer surface portion, a variable structure may be further included, the shape of which is deformed and restored according to the movement of the wheel unit.

[0012] In one embodiment, the wire portion may extend straight from the outer surface portion through the hub unit to the rotating body, or the direction of extension may be changed in the section from the hub unit to the rotating body according to the rotation of the rotating body, thereby increasing the tension.

[0013] In one embodiment, the hub unit includes a hub frame having a plurality of pin portions formed along the circumferential direction, and the wire portion extending from the outer surface portion is supported by the pin portion and can extend to the rotating body.

[0014] In one embodiment, the wire portion may have its extension direction changed relative to the pin portion as the rotating body rotates.

[0015] In one embodiment, the rotating body includes a frame portion formed along the outer surface, and a plurality of through portions through which the wire portion passes may be formed in the frame portion.

[0016] In one embodiment, the pin portions and the through portions are aligned with each other in a direction toward the center of the rotating body, and as the rotating body rotates, the alignment of the pin portions and the through portions may be misaligned with each other.

[0017] In one embodiment, a rotating body driving unit that is controlled independently of the wheel driving unit and provides rotational driving force of the rotating body may be further included.

[0018] In one embodiment, the rotary body drive unit may include a first drive unit that generates rotational driving force at the rear end of the rotary body, a power line that provides power to the first drive unit, and a slip hub unit through which the power line passes and which blocks the driving force of the wheel drive unit from being transmitted to the power line and the first drive unit.

[0019] In one embodiment, the wheel drive unit may include a second drive unit that generates rotational driving force, a drive transmission unit that transmits the rotational driving force generated by the second drive unit, and a drive hub unit that transmits the rotational driving force of the drive transmission unit to the hub unit.

[0020] In one embodiment, when the outer surface overcomes an obstacle, the wire extends in a straight line from the outer surface to the rotating body, so that the rigidity of the wheel unit may be relatively reduced.

[0021] In one embodiment, when the outer surface travels on flat ground, the rotating body rotates, and the wire portion changes its extension direction in the section from the hub unit to the rotating body, thereby increasing tension and relatively increasing the rigidity of the wheel unit. Effects of the invention

[0022] According to embodiments of the present invention, compared to controlling the tension of a conventional wire by varying the length or spacing in the axial direction of the hub unit, it is possible to improve durability by minimizing damage to the wire regardless of repeated tension variation of the wire, and to improve space utilization through miniaturization.

[0023] That is, as the extension direction of the wire section is changed by the rotation of the rotating body and the tension of the wire section is increased, there is no variation in length or spacing in the axial direction, and since only the extension direction of the wire section varies within a certain range, damage to the wire section can be minimized.

[0024] In particular, since the rotation of the above-mentioned rotating body is driven independently of the hub unit that rotates the wheel unit, the tension of the wire section can be controlled at any point where switching is required, regardless of the driving state of the wheel unit, thereby enabling various wire section tension controls to suit diverse driving environments.

[0025] Of course, by controlling the amount of rotation of the rotating body that rotates the wire portion, the magnitude of the tension applied to the wire portion can be varied, thereby enabling tension maintenance suitable for a wider variety of driving environments and variable stiffness control accordingly.

[0026] At this time, a plurality of pin portions supporting individual wire portions are formed on the hub frame of the hub unit to enable the direction change of the wire portions, and the wire portions are fixed by penetrating the rotating body while being supported by the pin portions, thereby enabling stable and uniform tension control over the entire wire portion even with a relatively simple design.

[0027] Furthermore, as the rotary drive unit for driving the rotary body is configured to include a slip hub portion for blocking the driving force transmitted to the hub unit, independent rotational driving of the hub unit and the rotary body can be realized. Brief explanation of the drawing

[0028] FIG. 1 is a front view illustrating a wheel unit according to one embodiment of the present invention. FIG. 2 is a front view illustrating the hub frame of the hub unit of FIG. 1. Figure 3 is an enlarged view illustrating the state in which a wire portion penetrates the interior of the rotating body of Figure 1. FIG. 4 is a perspective view illustrating the state in which a wire portion is extended to the wheel unit of FIG. 1. FIG. 5a is an enlarged view illustrating the state in which the wire portion of FIG. 1 extends through the hub frame and the rotating body, and FIG. 5b is an enlarged view illustrating the state in which the tension of the wire portion varies according to the rotation of the rotating body in FIG. 5a. FIG. 6 is a perspective view showing a wheel drive unit and a rotary body drive unit simultaneously driving the wheel unit of FIG. 1. Fig. 7 is a side view illustrating the wheel unit of Fig. 6. FIGS. 8A and FIGS. 8B are front views illustrating a state in which the wheel unit of FIG. 1 varies the tension of the wire portion regardless of the driving state. FIGS. 9A and FIGS. 9B are front views illustrating the state in which the wheel unit of FIG. 1 varies the tension of the wire section in consideration of the driving state. Specific details for implementing the invention

[0029] The present invention is susceptible to various modifications and may take various forms, and embodiments are to be described in detail in the text. However, this is not intended to limit the invention to the specific disclosed forms, and it should be understood that the invention includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention. Similar reference numerals have been used for similar components in the description of each figure. Terms such as "first," "second," etc., may be used to describe various components, but said components should not be limited by said terms.

[0030] The above terms are used solely for the purpose of distinguishing one component from another. The terms used in this application are used merely to describe specific embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise.

[0031] In this application, terms such as "comprising" or "consisting of" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0032] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0033] Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the attached drawings.

[0034] FIG. 1 is a front view illustrating a wheel unit according to one embodiment of the present invention.

[0035] Referring to FIG. 1, the wheel unit (10) according to the present embodiment includes a rotating body (100), a hub unit (200), an outer surface portion (300), a fixed wire (400), a variable structure (500), and a wire portion (600).

[0036] First, the hub unit (200) is located at the center of the wheel unit (10) and rotates around a center point by receiving rotational driving force through the wheel driving unit (800, see FIG. 7) described later.

[0037] In this case, the hub unit (200) may have a cylindrical shape with an open center overall and is configured to have a width equal to the width of the wheel unit (10), thereby providing rotational driving force to the wheel unit (10) overall from the center of the wheel unit (10).

[0038] The above-mentioned rotating body (100) is located in the central part of the hub unit (200), and as illustrated, has a radius smaller than the radius of the hub unit (200) and is located in an opening (222, see FIG. 2) formed in the center of the hub unit (200).

[0039] The above-mentioned rotating body (100) rotates independently of the above-mentioned hub unit (200) and rotates around a center point by receiving rotational driving force through a rotating body driving unit (700, see FIG. 7) that provides separate rotational driving force.

[0040] The rotation of the above-mentioned rotating body (100) is independent of the driving of the above-mentioned wheel unit (10) and is intended to control the tension of the above-mentioned wire section (600), which will be described in detail later. Accordingly, the control of the rotation of the above-mentioned rotating body (100) is also performed independently of the rotation control of the above-mentioned wheel unit (10), and the control is performed in a driving state where tension control of the above-mentioned wire section (600) is required.

[0041] The above-described rotating body (100) has a circular plate structure, and a frame portion (110) is formed on the circumferential edge of the rotating body (100). The frame portion (110) protrudes beyond the plate surface of the rotating body (100) and has a shape that protrudes to have a predetermined width along the axial direction (i.e., the direction perpendicular to the drawing in FIG. 1) (see FIG. 3).

[0042] At this time, the width of the frame part (110) in the radial direction (i.e., the direction toward the center of the rotating body (100)) can be designed to vary in various ways.

[0043] The outer surface portion (300) forms the outermost part of the wheel unit (10) and is positioned on the outside of the hub unit (200) so as to be spaced apart from the hub unit (200) by a predetermined distance.

[0044] The outer surface portion (300) is a part that comes into direct contact with the ground or obstacles when the wheel unit (10) travels or overcomes obstacles, and although not illustrated in detail, it may have a structure in which a plurality of individual unit blocks are connected to each other. At this time, the individual unit blocks may be in close contact with each other or released from close contact when the wheel unit (10) overcomes obstacles, and thereby the overcoming of obstacles can be performed more easily.

[0045] At this time, the individual unit blocks constituting the outer surface portion (300) can be maintained in close contact with each other through the fixing wire (400). That is, the fixing wire (400) extends along the outer and inner surfaces of the individual unit blocks in a circular shape and may be an elastic body having a predetermined tension.

[0046] Thus, through the tension of the elastic body, the individual unit blocks are positioned to be in close contact with each other with a constant force, and accordingly, the wheel unit (10) can maintain a circular shape such as a wheel overall. Of course, the tension of the fixed wire (400) is limited and does not restrict the close contact of the individual unit blocks from being released and separated when the wheel unit (10) particularly overcomes an obstacle.

[0047] However, the outer surface portion (300) is not necessarily composed only of unit blocks that are separable from one another, and may be formed as a structure that is not separable from one another and deforms within a certain range. Furthermore, if the outer surface portion (300) is formed as a structure that is not separable from one another, the fixing wire (400) may be omitted.

[0048] The variable structure (500) is formed between the hub unit (200) and the outer surface portion (300), and forms the overall structure of the wheel unit (10). That is, a predetermined support force or fixing force between the hub unit (200) and the outer surface portion (300) can be provided through the variable structure (500).

[0049] At this time, the variable structure (500) may be a structure in which polygonal frame structures are intertwined and extended as illustrated, and the frame structure may have a deformable elastic structure. That is, the variable structure (500) may be deformed or compressed depending on the application of an external force, and may be restored to its original shape when the external force is removed. Through this, particularly when the wheel unit (10) overcomes an obstacle, it may be deformed or compressed by the external force applied from the obstacle, and may be restored to its original shape when the overcoming of the obstacle is completed.

[0050] In this case, the variable structure (500) may be a simple filler in addition to the illustrated frame structure, and may be designed with various structures in addition to a polygonal frame.

[0051] The above wire part (600) performs the role of a so-called spoke in the wheel unit (10) and may be a wire having a predetermined tension.

[0052] As illustrated, the wire section (600) extends from the outer surface section (300) through the hub unit (200) and is fixed onto the frame section (110) of the rotating body (100). At this time, a plurality of wire sections (600) are extended along the outer surface of the outer surface section (300) at regular intervals, and each wire section is extended to the frame section (110) and fixed.

[0053] Accordingly, the spacing of the wire sections (600) is greatest on the outer surface section (300), and the spacing is relatively reduced at the position where it is fixed to the frame section (110). This is obvious because the radius of the outer surface section (300) is larger than the radius of the frame section (110).

[0054] Meanwhile, although FIG. 1 illustrates that the other end of the wire portion (600) passes through the frame portion (110) and is fixed on the frame portion (110), it is not limited thereto, and the rotating body (100) may additionally be provided with a separate fixing frame having a smaller radius than the frame portion (110) as a separate structure for fixing the other end of the wire portion (600).

[0055] That is, it is sufficient for the wire portion (600) to extend through the hub unit (200) and the frame portion (110), and the fixed position of the other end is not limited. However, it is necessary to design the fixed position to prevent the other ends of the wire portions (600) from interfering with each other.

[0056] Below, the extended state of the wire section (600) is explained based on a more detailed drawing.

[0057] FIG. 2 is a front view illustrating the hub frame of the hub unit of FIG. 1. FIG. 3 is an enlarged view illustrating the state in which a wire portion penetrates the interior of the rotating body of FIG. 1. FIG. 4 is a perspective view illustrating the state in which a wire portion extends to the wheel unit of FIG. 1.

[0058] First, referring to FIG. 2, the hub unit (200) includes a first cover (210) and a hub frame (220), and the hub frame (220) corresponds to a frame located inside the first cover (210) in FIG. 1.

[0059] At this time, the coupling unit (201) secures the first cover (210) and the hub frame (220) and is coupled to the coupling portion (221) of the hub frame (220).

[0060] That is, the hub frame (220) has a circular ring shape with an opening (222) formed in the center, and the rotating body (100) is located in the opening (222) as previously described.

[0061] The hub frame (220) is a frame having a cylindrical ring structure, and a plurality of pin portions (230) are formed along the circumference of the hub frame (220) as shown in the illustration.

[0062] As illustrated, the pin portions (230) are formed in each of the multiple regions (I, II, ...) on the cylindrical frame, and in each region, multiple pin portions are formed at regular intervals.

[0063] At this time, the regions (I, II, ...) where the pin portions (230) are formed are arbitrarily set, and their number is not limited, and furthermore, the pin portions can be formed at regular intervals throughout without distinction between the regions.

[0064] That is, the pin portions (230) are arranged at regular intervals along the circumference, and each pin portion may have a structure such as a pin that protrudes a predetermined length from the surface of the hub frame (220).

[0065] Meanwhile, referring to FIG. 3, a plurality of through-holes (120) are formed on the inner side of the frame portion (110) of the rotating body (100). As previously described, the frame portion (110) is formed to protrude a predetermined length from the plate surface of the rotating body (100), and the through-holes (120) are formed at regular intervals in the protruding portion of the frame portion (110).

[0066] At this time, the arrangement positions of the through parts (120) are aligned with the arrangement positions of the pin parts (230). That is, along the radial direction from the center of the rotating body (100) toward the outer surface part (300), the respective positions of the through parts (120) and the respective positions of the pin parts (230) are aligned in a line with each other.

[0067] As shown in FIG. 2 above, if the pin portions (230) are divided into multiple regions (I, II, ...) and formed at equal intervals in each region, the penetration portions (120) can also be divided into multiple regions and formed to be aligned radially with the pin portions in each region.

[0068] In contrast, if the pin portions (230) are formed at equal intervals without partitioning the regions, the penetration portions (120) can also be formed to be aligned radially with the pin portions without partitioning the regions.

[0069] Thus, as illustrated in FIG. 4, the wire portion (600) extends from the outer surface portion (300) to the pin portion (230), is supported by the pin portion (230), and extends through the penetration portion (120). At this time, the other end of the wire portion (600) can be fixed to the inner outer edge of the frame portion (110) by penetrating the penetration portion (120) as in FIG. 1, or alternatively, it can be fixed through a separate fixing frame, as previously explained.

[0070] Meanwhile, although FIG. 3 illustrates a state in which a pair of wire sections (600) are connected by passing through a single penetration section (120), this is merely due to the structure of the unit blocks forming the outer surface section (300), and the pair of wire sections do not necessarily extend by passing through a single penetration section (120). That is, a wire section may be extended through a single penetration section (1200), and likewise, a wire section may be extended while being supported by a single pin section (230).

[0071] The individual extension states of the above-mentioned wire section (600) are illustrated in FIGS. 5a and FIGS. 5b below.

[0072] FIG. 5a is an enlarged view illustrating the state in which the wire portion of FIG. 1 extends through the hub frame and the rotating body, and FIG. 5b is an enlarged view illustrating the state in which the tension of the wire portion varies according to the rotation of the rotating body in FIG. 5a.

[0073] First, referring to FIG. 5a, the wire portion (600), which has one end fixed to the outer surface portion (300) and extends, is supported on one side by a pin portion (220) formed in the hub frame (220) and extends through the penetration portion (120) of the frame portion (110), and finally, the other end is fixed to the inside of the frame portion (110).

[0074] FIG. 5a illustrates a state in which the wire portion (600) extends in a straight line along the radial direction, that is, from the center of the rotating body (100) toward the outer surface portion (300). In this state, the wire portion (600) is maintained in a straight line without bending or changing its direction of travel.

[0075] At this time, regarding the wire portion (600), when the wire extending from the outer surface portion (300) to the pin portion (220) is divided into the first wire (610) and the wire extending from the pin portion (220) to the frame portion (110) is divided into the second wire (620), the extension direction of the first and second wires (610, 620) is maintained the same.

[0076] Additionally, as illustrated, a wire portion (600) is supported and extended on each of the plurality of pin portions (220), and accordingly, a wire portion (600) can also pass through each of the plurality of penetration portions (120).

[0077] In contrast, referring to FIG. 5b, when the rotating body (100) rotates clockwise (see arrow direction) and the frame part (110) also rotates clockwise, the extension direction of the wire part (600) is varied.

[0078] In the wire section (600), the first wire (610), which is a wire extended from the outer surface section (300) to the pin section (220), maintains its extension direction, but the second wire (620), which is a wire extended from the pin section (220) to the frame section (110), has a variable extension direction.

[0079] That is, the wire portion (600) is supported by the pin portion (220), and the extension direction of the second wire (620) is bent and changed relative to the extension direction of the first wire (610).

[0080] Meanwhile, as described above, as the second wire (620) is bent and changed in the direction of extension relative to the first wire (610), the length of the second wire (620) is substantially increased, and accordingly, tension is applied to the first wire (610) in the direction of the arrow, and the tension of the first wire (610) increases.

[0081] At this time, as the angle of rotation of the rotating body (100) in the clockwise direction increases, the tension of the first wire (610) increases further. That is, by controlling the amount of rotation of the rotating body (100), the tension applied to the wire part (600) can be controlled.

[0082] However, in FIG. 5a, the wire portion (600) is supported by contacting the left side of the pin portion (220), and the rotating body (100) is shown rotating clockwise in consideration of this support state of the pin portion (2220). Accordingly, if the wire portion (600) is supported by contacting the right side of the pin portion (220), the rotating body (100) can rotate counterclockwise to increase the tension of the wire portion (600).

[0083] In contrast, if the rotating body (100) is rotated counterclockwise to return to the state of FIG. 5a, the first and second wires (610, 620) are extended in the same direction without bending, and the tension of the wire section (600) is reduced and restored to the initial state.

[0084] The state in which the extension direction of the wire sections (600) of FIG. 5b is switched is as shown in FIG. 4, and in FIG. 4, only some wire sections are shown to explain the state in which the extension direction of the wire sections (600) is switched.

[0085] As described above, by driving the rotating body (100) so that it can rotate independently of the hub unit (200), the wire portion (600) extending from the outer surface portion (300) through the hub unit (200) to the rotating body (100) is supported by the hub unit (200) and its extension direction is bent, thereby increasing the tension.

[0086] In addition, due to the increase in tension of the wire portion (600) corresponding to the spoke of the wheel unit (10), the wheel unit (10) as a whole becomes more rigid.

[0087] Furthermore, when the above-mentioned rotating body (100) is rotated in the opposite direction to its original state, the wire portion (600) maintains its radial extension state without bending in the extension direction as in the initial state, so the increased rigidity of the wheel unit (10) returns to the initial state and the rigidity is relatively reduced.

[0088] As described above, in order to drive the above-mentioned rotating body (100) independently of the above-mentioned hub unit (200), an independent drive type drive structure must be applied, and this will be explained through the following drawings.

[0089] FIG. 6 is a perspective view showing a wheel drive unit and a rotary body drive unit simultaneously driving the wheel unit of FIG. 1. FIG. 7 is a side view showing the wheel unit of FIG. 6.

[0090] Referring to FIGS. 6 and 7, first, the hub unit (200) includes a first cover (210) that covers the outer surface of the hub frame (220) described above. At this time, in the wheel unit (10) described above, the wire portion (600) can be extended not only to the front of the wheel unit (10) (i.e., the front portion where the drawing of FIG. 1 is observed) but also to the rear of the wheel unit (10) (i.e., the rear portion where the drawing of FIG. 1 is not observed).

[0091] Accordingly, in the case of the hub unit (200), the hub frame (220) can be provided in the same manner on the rear side based on the cylindrical hub part (240) in which the variable structure (500) and the outer surface part (300) are formed.

[0092] Accordingly, the hub unit (200) may further include a second cover (250) that covers the outer surface of the hub frame (220) located on the rear side, in addition to the first cover (210) that covers the outer surface of the hub frame (220) located on the front side. At this time, the connection state of the wire portion through the hub frame located on the inner side of the second cover (250) is the same as previously described.

[0093] Likewise, this is applied equally to the above-mentioned rotating body (100), so that the rotating body (100) may be provided on the front as well as the rear of the hub unit (200), and the extension state of the wire portion to the rotating body provided on the rear of the hub unit (200) is the same as previously described.

[0094] As described above, a pair of wire sections (600) on both sides centered on the hub section (240) are in the same extended state and the extension state is varied, thereby enabling more stable variable stiffness control of the wheel unit (10).

[0095] Furthermore, as illustrated in FIGS. 7 and 8, the wheel unit (10) further includes a rotary drive unit (700), a wheel drive unit (800), and a frame unit (900).

[0096] The above-described rotating body drive unit (700) generates and transmits driving force for the rotation of the above-described rotating body (100), and includes a first drive unit (710), a power line (720), a slip hub unit (730), and a slip ring unit (740).

[0097] The wheel drive unit (800) generates and transmits driving force for rotation of the hub unit (200), and includes a second drive unit (810), first and second drive transmission units (820, 850), first and second drive gears (830, 840), and a drive hub unit (860).

[0098] Meanwhile, the frame unit (900) is a frame to which the rotary drive unit (700) and the wheel drive unit (800) are fixed, and includes a horizontal frame (910) extending in a first direction (X), a vertical frame (920) extending in a second direction (Y) perpendicular to the first direction (X), and a fixing block (930).

[0099] The first drive unit (710) is located inside the drive hub unit (860) and is located at the rear end of the rotor (100), and is directly connected to the rotation axis of the rotor (100) to transmit rotational driving force to the rotor (100). In this case, although not illustrated, the rotation axis of the rotor (100) extends through the hub unit (240) along the first direction (X), and the rotation axis of the rotor (100) may be connected to or integrally formed with the rotational driving axis of the first drive unit (710).

[0100] At this time, the power line (720) may extend from the first drive unit (710), pass through the drive hub unit (860), and extend through the rear slip hub unit (730) and the slip ring unit (740). Furthermore, although not illustrated, the power may be provided through a separate power supply unit to provide energy for the operation of the first drive unit (710).

[0101] In this case, the power line (720) and the first drive unit (710) must be provided independently so as not to be affected by the drive of the wheel drive unit (800). To this end, the drive hub unit (860) must be designed to have a hollow space inside, and likewise, the slip hub unit (730) and the slip ring unit (740) must also be designed to have a predetermined space inside.

[0102] That is, even though the drive hub part (860), as well as the slip hub part (730) and the slip ring part (740), are all rotated by the driving force transmitted from the wheel drive unit (800), only the outer case rotates, and the internal hollow space is designed to remain constant regardless of rotation, and accordingly, when the rotational driving force of the first drive part (710) is not provided, the rotating body (100) is not affected by the driving force transmitted through the wheel drive unit (800).

[0103] Meanwhile, the second drive unit (810) may be located in a position parallel to the direction in which the rotational center axis of the first drive unit (710) extends, and as illustrated in FIGS. 6 and 7, it may be located above the direction in which the rotational center axis of the first drive unit (710) extends. Accordingly, the rotational center axis of the second drive unit (810) also extends along the first direction (X), but does not overlap with the rotational center axis of the first drive unit (710).

[0104] The rotational driving force of the second driving unit (810) is transmitted through the first driving transmission unit (820), and is switched in direction by the first and second driving gears (830, 840) that are gear-coupled and meshed with each other to rotate, and is provided to the third driving transmission unit (850).

[0105] In this case, the rotational center axis of the third drive transmission unit (850) overlaps with the rotational center axis of the first drive unit (710) along the first direction (X), but the third drive transmission unit (850) is also structured so that the center is formed as an empty space, and the first drive unit (710) is not affected by the drive transmission of the third drive transmission unit (850).

[0106] In this way, the rotational driving force of the second drive unit (810) transmitted to the third drive transmission unit (850) is provided to the hub unit (200) through the drive hub unit (860). That is, the drive hub unit (860) has a cylinder shape with a hollow interior and is connected to the hub unit (240) through the second cover (250), so that when the drive hub unit (860) rotates, the hub unit (200) rotates as a whole in conjunction with it.

[0107] The rotation of the hub unit (200) ultimately induces the overall rotation of the wheel unit (10), and the rotational drive for the actual movement of the wheel unit (10) is provided by the rotation of the hub unit (200).

[0108] As described above, the rotational driving force of the second drive unit (810) ultimately induces rotation of the hub unit (200), and at this time, the rotation of the rotating body (100) is induced by the rotational driving force of the first drive unit (710) independently of the hub unit (200). Accordingly, regardless of the overall driving state of the wheel unit (10), tension control of the wire unit (600) is possible through the rotation of the rotating body (100) at any time when tension control is required, and overall rigidity control of the wheel unit (10) is possible through this.

[0109] FIGS. 8A and FIGS. 8B are front views illustrating a state in which the wheel unit of FIG. 1 varies the tension of the wire portion regardless of the driving state.

[0110] That is, as shown in FIG. 8a and FIG. 8b, even when the wheel unit (10) is not in contact with the ground (20) and no separate driving is performed, the rotating body (100) can be driven to rotate clockwise independently of the hub unit (200).

[0111] Accordingly, as the rotation of the above-mentioned rotating body (100) is driven, the wire portion (600) is bent and extended at the part corresponding to the second wire (620), thereby increasing the overall tension, and accordingly, the characteristics of the wheel unit (10) change so that the spoke has relatively high rigidity.

[0112] In contrast, when the rotating body (100) is driven to rotate counterclockwise, the wire section (600) has its overall tension reduced as the first and second wire sections (610, 620) are all extended in the same direction, and accordingly, the wheel unit (10) has its characteristics changed so that the spokes have relatively low rigidity.

[0113] By varying the stiffness of the wheel unit (10) as described above, the tension of the wire part (600) can be varied according to various driving conditions, thereby inducing optimal driving.

[0114] FIGS. 9A and FIGS. 9B are front views illustrating the state in which the wheel unit of FIG. 1 varies the tension of the wire section in consideration of the driving state.

[0115] That is, as shown in FIG. 9a, if the wheel unit (10) passes over a flat surface (20), it is necessary for the wheel unit (10) to maintain the shape of the wheel unit overall, that is, a circular shape, and for the variation of the shape to be minimized. In other words, if the wheel unit (10) maintains its shape consistently and deformation is minimized, it is advantageous to drive relatively quickly on flat surfaces.

[0116] Accordingly, the wheel unit (10) needs to have relatively high rigidity, and to this end, the rotating body (100) rotates, for example, counterclockwise so that the extension direction of the wire part (600) is changed independently of the rotation direction of the hub unit (200), that is, so that the second wire (620) is bent.

[0117] In contrast, as shown in FIG. 9b, if the wheel unit (10) passes through an obstacle (30), it is necessary for the shape or structure of the wheel unit (10) to be varied in order to effectively overcome the obstacle (30). That is, as illustrated, the wheel unit (10) undergoes a deformation in which it is indented inward around the contact portion (A) with the obstacle (30), and at this time, the wheel unit (10) rotates around the contact portion (A) by the rotational driving force of the entire wheel unit (10), thereby enabling it to overcome the obstacle (30).

[0118] In the process of overcoming the above obstacle (30), deformation of the wheel unit (10) must eventually be induced, and thus the rigidity of the wheel unit (10) must be maintained at a minimum. Accordingly, the rotating body (100) that rotated counterclockwise in FIG. 9a rotates clockwise again to return to its initial state, and accordingly, the tension of the wire part (600) is reduced and the rigidity of the wheel unit (10) is also reduced.

[0119] As described above, in order to vary the rigidity of the wheel unit (10) by considering various driving conditions of the wheel unit (10), the tension of the wire portion (600) corresponding to the spoke of the wheel unit (10) can be varied, and thereby, optimal driving in the corresponding driving condition can be achieved.

[0120] According to the embodiments of the present invention as described above, compared to conventional methods of controlling wire tension by varying the length or spacing in the axial direction of the hub unit, it is possible to improve durability by minimizing damage to the wire section regardless of repeated tension variation of the wire section, and to improve space utilization through miniaturization.

[0121] That is, as the extension direction of the wire section is changed by the rotation of the rotating body and the tension of the wire section is increased, there is no variation in length or spacing in the axial direction, and since only the extension direction of the wire section varies within a certain range, damage to the wire section can be minimized.

[0122] In particular, since the rotation of the above-mentioned rotating body is driven independently of the hub unit that rotates the wheel unit, the tension of the wire section can be controlled at any point where switching is required, regardless of the driving state of the wheel unit, thereby enabling various wire section tension controls to suit diverse driving environments.

[0123] Of course, by controlling the amount of rotation of the rotating body that rotates the wire portion, the magnitude of the tension applied to the wire portion can be varied, thereby enabling tension maintenance suitable for a wider variety of driving environments and variable stiffness control accordingly.

[0124] At this time, a plurality of pin portions supporting individual wire portions are formed on the hub frame of the hub unit to enable the direction change of the wire portions, and the wire portions are fixed by penetrating the rotating body while being supported by the pin portions, thereby enabling stable and uniform tension control over the entire wire portion even with a relatively simple design.

[0125] Furthermore, as the rotary drive unit for driving the rotary body is configured to include a slip hub portion for blocking the driving force transmitted to the hub unit, independent rotational driving of the hub unit and the rotary body can be realized.

[0126] Although the present invention has been described above with reference to preferred embodiments, those skilled in the art will understand that various modifications and changes can be made to the invention without departing from the spirit and scope of the invention as set forth in the following claims. Explanation of the symbols

[0127] 10 : Wheel unit 100 : Rotating body 110 : Frame part 120 : Penetration part 200 : Hub unit 210 : 1st cover 220 : Hub frame 230 : Pin part 240 : Hub section 250 : Second cover 300 : Outer surface 400 : Fixing wire 500 : Variable structure 600 : Wire section 700: Rotating body drive unit 710: First drive unit 730 : Slip hub section 740 : Slip ring section 800: Wheel drive unit 810: Second drive unit 860: Drive hub section 900: Frame unit

Claims

Claim 1 A wheel unit comprising: a hub unit that rotates by receiving driving force from a wheel drive unit; a rotating body that rotates independently of the hub unit at the center of the hub unit; an outer surface portion that rotates according to the rotation of the hub unit at the outer side of the hub unit; and a wire portion that extends from the outer surface portion through the hub unit to be fixed to the rotating body, and whose extension direction changes in the section from the hub unit to the rotating body and whose tension is variable according to the rotation of the rotating body. Claim 2 A wheel unit according to claim 1, wherein the outer surface portion forms the outer shape of the wheel unit, and the wire portion is connected in multiple numbers at regular intervals on the outer surface portion and extends to the rotating body. Claim 3 A wheel unit according to paragraph 2, further comprising a variable structure between the hub unit and the outer surface portion, the shape of which is deformed and restored according to the movement of the wheel unit. Claim 4 A wheel unit according to claim 1, wherein the wire portion extends in a straight line from the outer surface portion, through the hub unit, to the rotating body. Claim 5 A wheel unit according to claim 1, wherein the hub unit comprises a hub frame having a plurality of pin portions formed along the circumferential direction, and the wire portion extending from the outer surface portion is supported by the pin portion and extends to the rotating body. Claim 6 A wheel unit according to claim 5, wherein the wire portion is characterized in that its extension direction is changed relative to the pin portion as the rotating body rotates. Claim 7 A wheel unit according to claim 6, wherein the rotating body comprises a frame portion formed along the outer surface, and the frame portion is formed with a plurality of through portions through which the wire portion passes. Claim 8 A wheel unit according to claim 7, wherein the pin portions and the penetration portions are aligned with each other in a direction toward the center of the rotating body, and as the rotating body rotates, the alignment of the pin portions and the penetration portions becomes misaligned with each other. Claim 9 A wheel unit according to claim 1, further comprising a rotating body driving unit that is controlled independently of the wheel driving unit and provides rotational driving force of the rotating body. Claim 10 In claim 9, the wheel unit is characterized in that the rotary body drive unit comprises: a first drive part that generates rotational driving force at the rear end of the rotary body; a power line that provides power to the first drive part; and a slip hub part through which the power line passes and which blocks the driving force of the wheel drive unit from being transmitted to the power line and the first drive part. Claim 11 In claim 9, the wheel drive unit is characterized by comprising: a second drive unit that generates rotational driving force; a drive transmission unit that transmits the rotational driving force generated by the second drive unit; and a drive hub unit that transmits the rotational driving force of the drive transmission unit to the hub unit. Claim 12 A wheel unit according to claim 1, characterized in that when the outer surface overcomes an obstacle, the wire extends in a straight line from the outer surface to the rotating body, thereby relatively reducing the rigidity of the wheel unit. Claim 13 A wheel unit according to claim 1, characterized in that when the outer surface travels on flat ground, the rotating body rotates, and the wire portion changes its extension direction in the section from the hub unit to the rotating body, thereby increasing tension and relatively increasing the rigidity of the wheel unit.

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