Patent Publication Number: US-2018036619-A1

Title: Bicycle exercise apparatus

Description:
TECHNICAL FIELD 
     The present invention relates to a bicycle exercise apparatus, and more particularly, to a bicycle exercise apparatus capable of allowing a bicycle to be seated on the bicycle exercise apparatus and implementing the same effect as when the bicycle travels on an inclined road section such as an actual road. 
     BACKGROUND ART 
     In general, a user just uses a bicycle to travel a road, a park, a mountain road (forest road), and the like, but the bicycle cannot be used as an indoor exercise machine. 
     However, in a case in which it is difficult for the user to use actual bicycle for exercise, an indoor-only bicycle exercise apparatus is required for the user to inevitably use for exercising indoors, but most of the indoor-only bicycle exercise apparatuses just allow the user to sit on a chair and rotate a pedal. 
     However, because the user cannot have sufficiently do desired exercise with the aforementioned exercise apparatus, a bicycle exercise apparatus, which allows an actual bicycle to be installed indoors and allows the user to do traveling exercise, has been developed in addition to a bicycle-type exercise machine having a simple shape. 
     Specifically, a separate auxiliary device is provided on a general bicycle which is used on a road, such that the bicycle may be utilized as an indoor health bicycle, and an exercise machine, which allows the bicycle to be mounted on the exercise machine in the form of a running machine and allows the user to ride the bicycle, has been developed. 
     However, the aforementioned exercise machines just allow the user to ride the bicycle on a flat floor, but the exercise machines are insufficient to implement an environment like an actual road and allow the user to enjoy, even indoors, an exercise effect that can be obtained when the user rides the bicycle outdoors. 
     DISCLOSURE 
     Technical Problem 
     The present invention has been made in an effort to solve the problem in the related art, and an object of the present invention is as follows. 
     First, an object of the present invention is to provide a treadmill capable of traveling at a high speed. 
     Second, another object of the present invention is to provide a bicycle exercise apparatus capable of allowing a bicycle to be seated on the bicycle exercise apparatus and allowing a user to ride the bicycle while having the same effect as when the user rides the bicycle on a road, such as an actual traveling road, having an inclination. 
     Third, still another object of the present invention is to provide a bicycle exercise apparatus capable of allowing a user to enjoy acceleration and deceleration effects by implementing an inclined road. 
     Fourth, yet another object of the present invention is to provide a bicycle exercise apparatus capable of preventing a rollover of a bicycle and stably supporting the bicycle. 
     Technical problems of the present invention are not limited to the aforementioned technical problems, and other technical problems, which are not mentioned above, may be clearly understood by those skilled in the art from the following descriptions. 
     Technical Solution 
     To achieve the aforementioned objects, a bicycle exercise apparatus of the present invention includes a main frame, a front support unit, a rear support unit, and a rotation unit. 
     The main frame is elongated and has a predetermined width, and a bicycle is positioned on the main frame. 
     The front support unit is provided at one side in a longitudinal direction of the main frame, and a front wheel of the bicycle is rotatably seated on the front support unit. 
     The rear support unit includes a rotation support unit that has a predetermined length and a central portion in the longitudinal direction rotatably coupled to the other side in the longitudinal direction of the main frame such that the rotation support unit maintains a horizontal state while rotating together with the main frame in accordance with a rotation angle of the main frame, and one or more rear rollers that are provided on the rotation support unit, disposed in parallel with a front roller, and rotated together with a rear wheel when the bicycle travels. 
     The rotation unit supports the main frame such that the main frame is positioned at a predetermined height from a floor, and is rotatably coupled to a central portion of the main frame in the longitudinal direction so as to adjust an inclination angle of the main frame. 
     The front support unit may be a treadmill including: a pair of frames which has a length in a traveling direction; a deck which is positioned between the pair of frames and supports a load applied from above; a pair of rollers which is disposed at front and rear sides of the deck, is installed between the pair of frames so as to be rotatable in the same direction, and has anti-slip grooves formed at predetermined intervals in a circumferential direction on outer circumferential surfaces of the pair of rollers; and a belt which is installed to surround the pair of rollers and the deck from the outside, moves in accordance with the rotation of a driving roller, and has anti-slip protrusions formed corresponding to the anti-slip grooves on a surface that abuts against the pair of rollers. 
     Further, a friction reducing member for reducing friction by minimizing a contact area with the belt may be provided on an upper surface of the deck. 
     The friction reducing member may include: a ring-shaped support portion which is formed with a hollow portion; and a spherical rotating portion which is positioned in the hollow portion of the support portion and rotated in conjunction with the movement of the belt in a state in which the spherical rotating portion is in contact with the belt. 
     The treadmill may be mechanically connected to any one of the pair of rollers and may adjust tension of the belt by adjusting a distance between the pair of rollers. 
     In addition, the treadmill may include: a tension block to which a rotating shaft of any one of the pair of rollers is coupled and which is coupled to be movable in a front and rear direction with respect to the frame; and a tension adjusting member which fastens the frame and the tension block and moves the tension block in the front and rear direction while rotating. 
     Further, the treadmill may further include a drive motor which provides driving power to any one of the pair of rollers. 
     Meanwhile, the rear rollers may include a first rear roller and a second rear roller which are disposed at both ends in the longitudinal direction of the rotation support unit so as to be spaced apart from each other. 
     When an inclination angle of the main frame is changed such that the rear wheel is positioned at a position lower than the front wheel, at least one of the first rear roller and the second rear roller may provide a load to the rotation of the rear wheel corresponding to the inclination angle of the main frame. 
     Here, the second rear roller may include: a fixed shaft which is elongated in a width direction of the rotation support unit; a cylindrical second rotary drum which has an outer surface with which the rear wheel is in contact, and is coupled to be rotatable about the fixed shaft; and a load generating means which is provided in the second rotary drum, and selectively generates a load in accordance with the rotation of the second rotary drum corresponding to the inclination angle of the main frame. 
     The load generating means may have a disc shape, may be fixedly coupled to the second rotary drum, and may have a central portion rotatably coupled to the fixed shaft. 
     When the main frame has an upward inclination and the inclination angle thereof is increased, the load generating means may increase a load to be applied to the rotation of the second rotary drum. 
     When the main frame is rotated to be inclined forward and downward, the first rear roller may rotate the rear wheel regardless of external force by a user. 
     The first rear roller may include: a cylindrical first rotary drum which has an outer surface with which the rear wheel is in contact, and is rotatably coupled to the rotation support unit; a drive motor which is fixed to the rotation support unit in the first rotary drum and rotated; and a gear means which is rotated by a first drive motor to rotate the first rotary drum, and allows the first rotary drum to rotate in one direction relative to the drive motor. 
     Meanwhile, the front support unit may include the front roller which abuts against the front wheel and rotates together with the front wheel. 
     The plurality of front rollers may be provided to be disposed to be spaced apart from one another in the longitudinal direction of the main frame. 
     Further, the main frame may further include a power transmission unit which is connected to the front roller and the rear roller and transmits rotational force of the rear roller to the front roller to allow the front roller to rotate together with the rear roller when the rear wheel is operated by external force applied by the user. 
     The power transmission unit may include: a rear shaft which is provided on a rotation axis of the rotation support unit and the main frame, and has one side connected to any one of the first rear roller and the second rear roller by a separate transmission means such that the rear shaft is rotated together with the rear wheel when the rear wheel is rotated; a front shaft which is provided on a rotation axis of the main frame and the front roller, and rotated together with the front roller; and a circulation belt which is elongated, and has one side connected to the front shaft and the other side connected to the rear shaft, such that the circulation belt rotates the front shaft while circulating by the rotation of the rear shaft. 
     In addition, the rotation unit may include: a casing which is rotatably coupled to the central portion of the main frame in the longitudinal direction while having a main rotating shaft; a drive motor which is provided in the casing and selectively rotates; an arc portion which has an arc shape on the main frame, protrudes downward so that the main rotating shaft is positioned at a center of an arc, and has a rack gear that is formed on an inner surface of the arc so as to protrude in a direction toward the main rotating shaft; and one or more gear units which are connected to the drive motor, and engaged with the rack gear to rotate the arc portion. 
     Here, the arc portions may be provided at both sides in a width direction of the main frame, respectively. 
     The main frame may include a plurality of unit links so that a part of the main frame in the longitudinal direction is selectively tilted. 
     Meanwhile, the bicycle exercise apparatus of the present invention may include a guide unit which includes: a front frame which is positioned at a front side of the front wheel at one side in the longitudinal direction of the main frame and protrudes upward; a rear frame which is positioned at a rear side of the rear wheel at the other side in the longitudinal direction of the main frame and is elongated upward; and connecting wires which are elongated, are provided on the front frame and the rear frame, respectively, and each have one side detachably connected to a central portion of the bicycle in a width direction so as to support the bicycle so that the bicycle does not roll over. 
     The connecting wires may be spaced apart from the floor at a predetermined height, and provided, at the same height, on the front frame and the rear frame, respectively. 
     Further, the connecting wires may be detachably and selectively coupled to the bicycle through separate coupling means provided at one side in the longitudinal direction. 
     In addition, the connecting wire may include a material having elasticity. 
     The guide unit may further include a safety frame which is elongated, has both ends coupled to the front frame and the rear frame, respectively, at a predetermined height, and is disposed to be eccentric toward one side in the width direction of the main frame. 
     Advantageous Effects 
     The effects of the present invention configured as described above will be described below. 
     First, according to the treadmill according to the exemplary embodiment of the present invention, the anti-slip grooves are formed at predetermined intervals on the outer circumferential surfaces of a driving roller and a driven roller, and the anti-slip protrusions, which correspond to the anti-slip grooves, are formed on the belt, such that the belt is moved while the anti-slip grooves and the anti-slip protrusions are engaged with one another in accordance with the rotation of the driving roller and the driven roller, and the friction reducing members for minimizing friction with the belt are provided on the upper portion of the deck, and as a result, it is possible to prevent a slip of the belt caused by high-speed traveling and prevent the user from rolling over caused by the slip of belt. 
     Second, according to the bicycle exercise apparatus according to the exemplary embodiment of the present invention, the bicycle is seated on the main frame having the front support unit and the rear support unit at both ends thereof, and an inclination angle of the main frame is selectively adjusted, such that when the user rides the bicycle, the user may have the same effect as when the user rides the bicycle on an inclined road. 
     Third, according to the bicycle exercise apparatus according to the exemplary embodiment of the present invention, the second rear roller provides a load in accordance with the rotation of the rear wheel by being selectively operated in accordance with an inclination direction of the main frame, and the first rear roller accelerates the rear wheel to a predetermined speed regardless of external force applied by the user by being selectively operated in accordance with an inclination direction of the main frame, such that the user may enjoy the same effect as when the user rides the bicycle on an uphill road and a downhill road. 
     Fourth, the bicycle exercise apparatus according to the exemplary embodiment of the present invention includes the guide unit which is provided on the main frame at a predetermined height or higher and selectively coupled at the front and rear sides of the bicycle, and the guide unit with elasticity is connected to the front and rear sides of the bicycle and supports the bicycle, such that it is possible to prevent a rollover of the bicycle when the user rides the bicycle and to enable the dancing motion in the left and right direction, thereby implementing the same effect as when the user rides the bicycle on an actual road. 
     The effects of the present invention are not limited to the aforementioned effects, and other effects, which are not mentioned above, will be clearly understood by those skilled in the art from the claims. 
    
    
     
       DESCRIPTION OF DRAWINGS 
       A detailed description of the exemplary embodiment of the present application to be described below as well as the summary explained above will be understood well when reading the detailed description and the summary with reference to the accompanying drawings. The exemplary embodiments are illustrated in the drawings for the purpose of exemplifying the present invention. However, it should be understood that the present application is not limited to the illustrated exact arrangement and means. 
         FIG. 1  is a view schematically illustrating a configuration of a bicycle exercise apparatus according to an exemplary embodiment of the present invention. 
         FIG. 2  is a view illustrating a side of the bicycle exercise apparatus in  FIG. 1 . 
         FIG. 3  is a view illustrating a top side of the bicycle exercise apparatus in  FIG. 1 . 
         FIG. 4  is a view illustrating a state in which a separate safety bar and a bicycle are seated on the bicycle exercise apparatus in  FIG. 1  and the bicycle travels. 
         FIG. 5  is a view illustrating a state in which an inclination of a main frame of the bicycle exercise apparatus in  FIG. 4  is adjusted. 
         FIG. 6  is a view schematically illustrating a configuration of a rotation unit of the bicycle exercise apparatus in  FIG. 1 . 
         FIG. 7  is a view illustrating detailed configurations an arc portion and a gear unit of the rotation unit in  FIG. 6 . 
         FIG. 8  is a view illustrating an internal configuration of a second rear roller of the bicycle exercise apparatus in  FIG. 1 . 
         FIG. 9  is a view illustrating an internal configuration of a first rear roller of the bicycle exercise apparatus in  FIG. 1 . 
         FIG. 10  is a view illustrating a state in which the main frame of the bicycle exercise apparatus in  FIG. 4  is inclined forward and upward. 
         FIG. 11  is a view illustrating a state in which the main frame of the bicycle exercise apparatus in  FIG. 4  is inclined forward and downward. 
         FIGS. 12A and 12B  show views illustrating a state in which a first rotary drum and a drive motor are relatively rotated in accordance with a rotational speed of the first rotary drum in the first rear roller of the bicycle exercise apparatus in  FIG. 11 . 
         FIG. 13  is a view illustrating a top side of the bicycle exercise apparatus in  FIG. 1 . 
         FIG. 14  is a view illustrating a state in which the bicycle is moved while dancing by a user in the bicycle exercise apparatus in  FIG. 1 . 
         FIG. 15  is a view illustrating a state in which a connecting wire is coupled to the bicycle in the bicycle exercise apparatus in  FIG. 1 . 
         FIG. 16  is a perspective view illustrating a bicycle exercise apparatus according to another exemplary embodiment of the present invention. 
         FIG. 17  is a perspective view illustrating a state in which a bicycle is installed on the bicycle exercise apparatus according to another exemplary embodiment of the present invention. 
         FIG. 18  is a view illustrating an external appearance of a front support unit according to another exemplary embodiment of the present invention. 
         FIG. 19  is a view illustrating an interior of the front support unit according to another exemplary embodiment of the present invention. 
         FIG. 20  is an enlarged view of part A in  FIG. 19 . 
         FIG. 21  is an enlarged view of part B in  FIG. 19 . 
         FIG. 22  is an enlarged view of part C in  FIG. 19 . 
     
    
    
     BEST MODE 
     Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, it will be easily understood by those skilled in the art that the accompanying drawings are provided only to more easily disclose the contents of the present invention and the scope of the present invention is not limited to the scope of the accompanying drawings. 
     Further, it is noted that in the description of the exemplary embodiments of the present invention, like terms and like reference numerals are used for constituent elements having the same function, but the constituent elements are not substantially and completely identical to the constituent elements in the related art. 
     In addition, terms used in the present application are used only to describe specific exemplary embodiments, and are not intended to limit the present invention. Singular expressions used herein include plurals expressions unless they have definitely opposite meanings in the context. In the present application, it should be appreciated that terms “including” and “having” are intended to designate the existence of characteristics, numbers, steps, operations, constituent elements, and components described in the specification or a combination thereof, and do not exclude a possibility of the existence or addition of one or more other characteristics, numbers, steps, operations, constituent elements, and components, or a combination thereof in advance. 
     Hereinafter, a bicycle exercise apparatus according to an exemplary embodiment of the present invention will be described with reference to the drawings. 
       FIG. 1  is a view schematically illustrating a configuration of a bicycle exercise apparatus according to an exemplary embodiment of the present invention,  FIG. 2  is a view illustrating a side of the bicycle exercise apparatus in  FIG. 1 , and  FIG. 3  is a view illustrating a top side of the bicycle exercise apparatus in  FIG. 1 . Further,  FIG. 4  is a view illustrating a state in which a separate safety bar and a bicycle are seated on the bicycle exercise apparatus in  FIG. 1  and the bicycle travels. 
     As illustrated in  FIGS. 1 to 4 , the bicycle exercise apparatus according to the present invention broadly includes a main frame  100 , a front support unit  200 , a rear support unit  300 , and a rotation unit  400 . 
     The main frame  100  is configured to substantially support a bicycle  10  and adjust an inclination, the main frame  100  is elongated and has a predetermined width, and the bicycle  10  is positioned on the main frame  100 . 
     Specifically, the shape of the main frame  100  is formed by connecting a plurality of structures and is similar to a shape of a ladder. 
     As illustrated, in the present exemplary embodiment, the main frame  100  is elongated and has a predetermined width, and a central portion of the main frame  100  in a longitudinal direction is configured to be rotatable together with the rotation unit  400  to be described below. 
     In this case, a width of the main frame  100  is set to be sufficient for a user to seat himself/herself on the typical bicycle  10  in a state in which the bicycle  10  is positioned on the main frame  10 , and the front and rear support units  200  and  300  to be described below are provided at both ends in the longitudinal direction. 
     Further, the main frame  100  according to the present invention may be configured by continuously connecting a plurality of unit links  102  in the longitudinal direction, and the main frame  100  may be configured to be selectively tilted. 
     In the present exemplary embodiment, the longitudinal direction of the main frame  100  is a direction A that indicates a direction in which the bicycle  10  is disposed in a front and rear direction, and a width direction of the main frame  100  is a direction B that indicates a left and right direction of the bicycle  10 . 
     Specifically, as illustrated, the main frame  100  includes three or more unit links  102  in the longitudinal direction, the main frame  100  is configured to be tilted for convenience for the user, and therefore, a volume of the bicycle exercise apparatus is reduced such that the bicycle exercise apparatus is easily accommodated. 
     Otherwise, the main frame  100  may of course be integrally configured in the longitudinal direction. 
     Meanwhile, the front support unit  200  is provided at one side of the main frame  100  in the longitudinal direction, and a front wheel  12  of the bicycle  10  is rotatably seated on the front support unit  200 . 
     Specifically, the front support unit  200  has a front roller  202  which is provided at one side of the main frame  100  and supports the front wheel  12  of the bicycle  10 , and the front roller  202  is rotatably provided on the main frame  100 . 
     Further, the front roller  202  is in contact with the front wheel  12  and supports the front wheel  12 , and the front roller  202  is coupled to one side of the main frame  100  so as to be rotatable together with the front wheel  12 . 
     That is, the front support unit  200  includes one or more front rollers  202 , and the front roller  202  is formed in the form of a cylindrical roller, such that the front roller  202  is rotatably coupled to one side of the main frame  100  in the longitudinal direction. 
     Further, the front roller  202 , which is provided as described above, has an outer surface that supports the front wheel  12  of the bicycle  10  and has frictional force at a predetermined level or larger so that the front wheel  12  of the bicycle  10  may be rotated together with the front roller  202  when the front roller  202  is rotated by external force. 
     In the present exemplary embodiment, the front support unit  200  includes the single front roller  202 , as illustrated, but otherwise, a plurality of front rollers  202  may be provided to be disposed to be spaced apart from one another in the longitudinal direction of the main frame  100 . 
     In this case, in the case in which the plurality of front rollers  202  is provided, the plurality of front rollers  202  is disposed in parallel with a rotation axis of the front wheel  12  so as to be spaced apart from one another in the longitudinal direction of the main frame  100 . 
     Meanwhile, the rear support unit  300  is provided at the other side of the main frame  100  and supports a rear wheel  14  of the bicycle  10  so that the rear wheel  14  is rotatable, and the rear support unit  300  broadly includes a rotation support unit  310  and rear rollers  320 . 
     The rotation support unit  310  has a predetermined length and a width corresponding to the width of the main frame  100 , and a central portion of the rotation support unit  310  in the longitudinal direction is rotatably coupled to the other side of the main frame  100  in the longitudinal direction. 
     Specifically, the rotation support unit  310  is elongated in the form of a frame and rotatably coupled to the main frame  100 , and the rear rollers  320  to be described below are rotatably coupled to the rotation support unit  310  separately from the main frame  100 . 
     In the present exemplary embodiment, as illustrated, the rotation support unit  310  has a width relatively smaller than the width of the main frame  100  and is rotatably coupled to the other side of the main frame  100 . 
     In this case, the rotation support unit  310  is also formed in the form of a frame and has a predetermined width, and the rear rollers  320  are rotatably coupled to the rotation support unit  310 . 
     Further, the rotation support unit  310 , which is configured as described above, is maintained in a horizontal state, and when an inclination of the main frame  100  is changed, the rotation support unit  310  is relatively rotated at the other side of the main frame  100  corresponding to the change in the inclination of the main frame  100 , thereby maintaining the horizontal state. 
     Meanwhile, one or more rear rollers  320  are provided on the rotation support unit  310 , and disposed perpendicular to a traveling direction of the bicycle  10 . 
     Further, the rear roller  320  supports the rear wheel  14  of the bicycle  10  and rotates together with the rear wheel  14  of the bicycle  10  when the rear wheel  14  of the bicycle  10  is rotated by the user&#39;s operation. 
     Specifically, one or more rear rollers  320  are provided, the rear roller  320  has a rotation axis perpendicular to the traveling direction of the bicycle  10 , and the rear roller  320  is rotatably coupled to the rotation support unit  310 . 
     In the present exemplary embodiment, the rear rollers  320  include a pair of first and second rear rollers  322  and  324 , and the first and second rear rollers  322  and  324  are disposed at both ends in the longitudinal direction of the rotation support unit  310  so as to be spaced apart from each other. 
     Further, the rear wheel  14  of the bicycle  10  is supported by the first rear roller  322  and the second rear roller  324 . 
     Here, the first rear roller  322  and the second rear roller  324  have rotation axes parallel to each other on the rotation support unit  310 , and the first rear roller  322  and the second rear roller  324  are disposed to be spaced apart from each other in the longitudinal direction of the rotation support unit  310  and configured to be rotated together with the rear wheel  14  of the bicycle  10  when the rear wheel  14  of the bicycle  10  is rotated by the user. 
     That is, the first rear roller  322  and the second rear roller  324  are provided at both ends of the rotation support unit  310  in the longitudinal direction, and the central portion of the rotation support unit  310  in the longitudinal direction is provided at the other side of the main frame  100 . 
     As described above, the rear support unit  300  has the separate rotation support unit  310 , such that the rear rollers  320  are rotatably coupled to the rotation support unit  310  instead of being coupled directly to the main frame  100 . 
     Further, the rotation support unit  310  maintains the horizontal state by a load of the bicycle  10  of which the rear wheel  14  is seated on the rear rollers  320 . 
     Therefore, even though the main frame  100  is not maintained in the horizontal state but rotated to have an inclination, the rotation support unit  310  may be maintained in the horizontal state because a load of the bicycle  10  is applied to the rotation support unit  310 . 
     In addition, since the rotation support unit  310  is configured as described above, the rotation support unit  310  maintains the horizontal state while relatively rotating on the main frame  100  corresponding to a rotation angle of the main frame  100 , and the bicycle  10  seated on the main frame  100  is supported by the first rear roller  322  and the second rear roller  324  so that the bicycle  10  is not moved downward even though the main frame  100  has an inclination. 
     Meanwhile, the rotation unit  400  supports the main frame  100  so that the main frame  100  is positioned at a predetermined height from a floor, and the rotation unit  400  is rotatably coupled to the central portion of the main frame  100  in the longitudinal direction while having a main rotating shaft  402 , and adjusts the inclination angle of the main frame  100 . 
     Further, the rotation unit  400  has therein a separate drive motor (not illustrated) to rotate the main frame  100 , thereby adjusting the inclination angle of the main frame  100 . 
     In the present exemplary embodiment, the single rotation unit  400  is provided and configured to support the main frame  100  and selectively adjust the inclination angle of the main frame  100 . 
     Meanwhile, the bicycle exercise apparatus according to the present invention may further include a control unit (not illustrated) which selectively adjusts the inclination angle of the main frame  100  by using the rotation unit  400 . 
     The control unit may be provided in the main frame  100  or the rotation unit  400 , and may adjust the inclination angle of the main frame  100  based on information about a traveling road which is provided from the outside or inputted to the control unit. 
     Specifically, the control unit may control the rotation unit  400  to adjust the inclination angle of the main frame  100  in order to implement an inclination identical to an inclination of an actual traveling road in accordance with a traveling distance when the bicycle  10  travels based on separate information about the traveling road. 
     In this case, a rotational speed of the rear roller  320  or a rotational speed of a driving roller  232  or a driven roller  234  of a treadmill  200  is measured to measure the traveling distance of the bicycle  10 , and the inclination angle of the main frame  100  is adjusted by comparing the traveling distance of the bicycle  10  with the information about an actual traveling road. 
     As described above, the bicycle exercise apparatus according to the present invention includes the main frame  100 , the front support unit  200 , the rear support unit  300 , the rotation unit  400 , and the control unit, and the user may exercise while riding the bicycle  10  in a state in which the front wheel  12  and the rear wheel  14  of the bicycle  10  are seated on the front support unit  200  and the rear support unit  300 , respectively. 
     In addition, the inclination angle of the main frame  100  is adjusted by the rotation unit  400 , and as a result, the user may enjoy the same effect as when the user rides the bicycle on an actual inclined road. 
     Detailed configuration and operation of the rotation unit  400  will be described below. 
     Meanwhile, the main frame  100  according to the present invention may further include a separate power transmission unit  110 . 
     The power transmission unit  110  is connected to the front roller  202  and the rear roller  320  and transmits rotational force of the rear roller  320  to the front roller  202  when the rear wheel  14  is operated by external force applied by the user, thereby allowing the front roller  202  to be rotated together with the rear roller  320 . 
     Specifically, the power transmission unit  110  includes a rear shaft  112  which is rotated together with the rear roller  320  in accordance with the rotation of the rear roller  320 , a front shaft  114  which is rotated together with the front roller  202  in accordance with the rotation of the front roller  202 , and a circulation belt  116  which is connected to the front shaft  114  and the rear shaft  112  and transmits the rotational force. 
     The rear shaft  112  is provided on the rotation axis of the rotation support unit  310  and the main frame  100 , and the rear shaft  112  is connected to any one of the first rear roller  322  and the second rear roller  324  by a separate transmission means  112   d  and rotated in conjunction with the rotation of the rear wheel  14 . 
     In the present exemplary embodiment, the rear shaft  112  is elongated on the rotation axis of the rotation support unit  310  and the main frame  100 , one side of the rear shaft  112  protrudes outward from the main frame  100 , and a rear pulley  112   a  is provided at one side of the rear shaft  112 . 
     Further, the other side of the rear shaft  112  is connected to the first rear roller  322  by the belt-shaped transmission means  112   d , such that the rear shaft  112  is configured to be rotated together with the first rear roller  322  when the first rear roller  322  is rotated. 
     Here, a second pulley  112   b  may be provided at the other side of the rear shaft  112 , a first pulley  112   c , which is connected to the first rear roller  322  and rotated, may be provided on a rotation axis on which the first rear roller  322  and the rotation support unit  310  are coupled to each other, and the transmission means  112   d  is connected to the first pulley  112   c  and the second pulley  112   b  and configured to transmit the rotational force of the first rear roller  322  to the rear shaft  112  while circulating. 
     Otherwise, the transmission means  112   d  and the first pulley  112   c  may of course be provided on the second rear roller  324  and connected to the second rear roller  324 . 
     As described above, the rear shaft  112  is provided on the rotation axis on which the rear support unit and the main frame  100  are coupled to each other, and the rear shaft  112  is configured to be rotated by receiving the rotational force of the rear roller  320 . 
     Meanwhile, the front shaft  114  is formed similar to the rear shaft  112 , provided on the rotation axis of the main frame  100  and the front roller  202 , and rotated together with the front roller  202 . 
     Specifically, the front shaft  114  is elongated on the rotation axis of the front roller  202 , one side of the front shaft  114  protrudes outward from the main frame  100 , and a front pulley  114   a  is provided at one side of the front shaft  114 . Further, the other side of the front shaft  114  is connected to the front roller  202  and configured to be rotated together with the front roller  202 . 
     In the present exemplary embodiment, the front shaft  114  is formed to protrude toward one side in the width direction of the main frame  100 , as illustrated, but otherwise, the front shaft  114  may protrude toward both sides and the front pulleys  114   a  may be provided at both sides of the front shaft  114 . 
     As described above, the front shaft  114  is provided on the rotation axis of the front roller  202  and the main frame  100  and configured to be rotatable together with the front roller  202 . 
     Meanwhile, the circulation belt  116  is elongated, one side of the circulation belt  116  is connected to the front shaft  114 , the other side of the circulation belt  116  is connected to the rear shaft  112 , and the circulation belt  116  rotates the front shaft  114  while circulating by the rotation of the rear shaft  112 . 
     Specifically, the circulation belt  116  is connected to the front pulley  114   a  and the rear pulley  112   a , and rotates the front pulley  114   a  together with the rear pulley  112   a  while circulating when the rear pulley  112   a  is rotated. 
     In the present exemplary embodiment, the circulation belt  116  is formed in the form of a belt having elasticity, connected to the front pulley  114   a  and the rear pulley  112   a , and configured to transmit the rotational force while circulating, but otherwise, the circulation belt  116  may be formed in the form of a chain or a track. 
     The power transmission unit  110  according to the present invention is configured as described above, and the rotational force by which the rear roller  320  is rotated by the rear wheel  14  is transmitted to the front roller  202  through the power transmission unit  110 , such that the front wheel  12  may be rotated together with the rear wheel  14 . 
     If the front wheel  12  is not rotated when the user on the bicycle  10  rotates the rear wheel  14  to ride the bicycle  10 , the bicycle  10  will fall down laterally without maintaining an upright state. 
     Therefore, the power transmission unit  110  is provided to transmit the rotational force of the rear roller  320 , which is rotated together with the rear wheel  14 , to the front roller  202 , thereby rotating the front wheel  12  together with the rear wheel  14 . 
     That is, the power transmission unit  110  transmits the rotational force of the rear wheel  14  to the front roller  202  in order to rotate the front roller  202 , and as a result, the front wheel  12  may also be rotated together with the rear wheel  14 . 
     Therefore, since the front wheel  12  and the rear wheel  14  of the bicycle  10  are rotated together, the user may ride the bicycle  10  seated on the main frame  100  without a separate safety device, and the user may enjoy left and right dancing motions when riding the bicycle  10  in a similar way as the user actually rides the bicycle  10 . 
     The bicycle exercise apparatus according to the present invention is configured as described above and additionally includes a separate safety bar  500  and a separate connecting wire  510 , and the safety bar  500  and the connecting wire  510  may be used as safety devices for preventing excessive motion and withdrawal of the bicycle  10  when the bicycle  10  is seated on the main frame  100 . 
     Next, a state in which the inclination angle of the main frame  100  of the bicycle exercise apparatus according to the present invention is adjusted and the rear support unit  300  is operated will be described below. 
       FIG. 5  is a view illustrating a state in which the inclination of the main frame of the bicycle exercise apparatus in  FIG. 4  is adjusted. 
     Referring to the illustrated drawing, the rotation unit  400  rotates the main frame  100  clockwise so that the main frame  100  has an upward inclination in order to implement a state in which the bicycle  10  seated on the main frame  100  of the bicycle exercise apparatus according to the present invention travels an uphill road. 
     In this case, the rotation support unit  310  is rotated relative to the other side of the main frame  100  by a weight of the rear wheel  14  seated on the rear roller  320 , thereby maintaining the horizontal state. Here, the rotation support unit  310  is rotated counterclockwise, that is, in a direction opposite to the direction of the main frame  100 . 
     Since the rotation support unit  310  maintains the horizontal state regardless of the inclination of the main frame  100  as described above, the rear support unit, which includes the pair of rollers, supports the rear wheel  14  of the bicycle  10 , thereby preventing the bicycle  10  from falling down in the direction toward the other side of the main frame  100 . 
     Next, a specific configuration of the rotation unit  400  according to the present invention will be described below with reference to  FIGS. 6 and 7 . 
       FIG. 6  is a view schematically illustrating a configuration of the rotation unit of the bicycle exercise apparatus in  FIG. 1 , and  FIG. 7  is a view illustrating detailed configurations an arc portion and a gear unit of the rotation unit in  FIG. 6 . 
     The rotation unit  400  according to the present invention is configured to support the main frame  100  at the lower side of the main frame  100  and to adjust the inclination angle of the main frame  100  by the control unit, and the rotation unit  400  broadly includes a casing  410 , a drive motor  420 , an arc portion  430 , and a gear unit  440 . 
     The casing  410  supports the main frame  100  at a predetermined height or higher from the floor and accommodates therein the drive motor  420  and the gear unit  440 . 
     Specifically, as illustrated, an upper portion of the casing  410  is rotatably coupled to the central portion of the main frame  100  in the longitudinal direction while having the main rotating shaft  402 , and a lower portion of the casing  410  is positioned on the floor. 
     The drive motor  420  is provided in the casing  410  and configured to rotate the main frame  100  about the main rotating shaft  402  by being operated by the control unit. 
     Specifically, one or more drive motors  420  may be provided, and the driver motor  420  is connected to the main rotating shaft  402  to rotate the main frame  100  to a predetermined angle. 
     In this case, the drive motor  420  may be coupled directly to the main rotating shaft  402  while having the same rotation axis as the main frame  100 , but otherwise, as illustrated, the drive motor  420  may be coupled to the main rotating shaft  402  through the gear unit  440 . 
     Meanwhile, the arc portion  430  is formed to protrude downward from the main frame  100  and configured to rotate the main frame  100  by receiving rotational force of the drive motor  420 , and the arc portion  430  has an arc shape on the main frame  100  and protrudes downward so that the main rotating shaft  402  is positioned at a center of an arc. 
     Specifically, as illustrated, a pair of arc portions  430  is provided to be symmetrically disposed at left and right sides of the main frame  100  and fixedly coupled to the main frame  100  so that the center of the arc is positioned on the main rotating shaft  402 . 
     Further, the arc portion  430  has a rack gear  432  which is formed on an inner surface of the arc so as to protrude in a rotation axis direction, and the arc portion  430  is rotated about the main rotating shaft  402  by receiving rotational force of the drive motor  420 . 
     In this case, since the arc portion  430  is fixedly coupled to the main frame  100 , the main frame  100  is rotated together with the arc portion  430 . 
     That is, the arc portion  430  is rotated about the main rotating shaft  402  as the rack gear  432  slides along the arc by receiving rotational force by the drive motor  420  and the gear unit  440  to be described below which are accommodated in the casing  410 . 
     In the present exemplary embodiment, the arc portion  430  receives the rotational force of the drive motor  420  as the rack gear  432 , which is formed on the inner surface of the arc so as to protrude in the direction toward the main rotating shaft  402 , meshes with the gear unit  440  to be described below. 
     Meanwhile, one or more gear units  440  are provided and connected to the drive motor  420 , and the gear unit  440  is engaged with the rack gear  432  formed on the arc portion  430 , thereby rotating the arc portion  430 . 
     Specifically, the gear unit  440  is connected to a rotating shaft of the drive motor  420  and rotated, and the gear unit  440  meshes with the rack gear  432  formed on the arc portion  430 , thereby allowing the arc portion  430  to be rotated about the main rotating shaft  402 . 
     In the present exemplary embodiment, the gear unit  440  is configured such that a plurality of gears meshes one another, but otherwise, the gear unit  440  may include a single gear that is connected directly to the drive motor  420  and meshes with the rack gear  432 . 
     As described above, the rotation unit  400  according to the present invention adjusts the inclination angle of the main frame  100  as the drive motor  420  configured in the rotation unit  400  is selectively operated by the control unit. 
     Here, the rotation unit  400  is configured to selectively provide a load to at least one of the first rear roller  322  and the second rear roller  324 , and provides a load in accordance with the rotation of the rear wheel  14  by the control unit corresponding to the inclination angle of the main frame  100 . 
     In particular, the rear roller  320  generates a load in accordance with the rotation when the main frame  100  has an inclination by the rotation unit  400  to be described below and the rear wheel  14  is changed to a position lower than the front wheel  12 . 
     Further, as the load is generated on the rear roller  320  as described above, a larger effort is required for the user to rotate the rear wheel  14  of the bicycle. 
     That is, when the inclination angle of the main frame  100  is adjusted and the main frame  100  is disposed in a similar way as the bicycle travels an inclined road, a load is generated on the rear roller  320 , and as a result, a larger effort is required to operate the rear wheel  14  like when the user rides the bicycle on an uphill road. 
     In the present exemplary embodiment, an example in which a load generating means is provided on the second rear roller will be described. 
       FIG. 8  is a view illustrating an internal configuration of the second rear roller of the bicycle exercise apparatus in  FIG. 1 , and  FIG. 9  is a view illustrating an internal configuration of the first rear roller of the bicycle exercise apparatus in  FIG. 1 . 
     First, a configuration of the second rear roller  324  will be described with reference to  FIGS. 8 and 9 , the second rear roller  324  is configured in the rotation support unit  310  so as to be rotatable while having a rotation axis, and the rear wheel  14  is in contact with an outer surface of the second rear roller  324 , such that the second rear roller  324  is rotated together with the rear wheel  14  when the rear wheel  14  is rotated. 
     Here, the second rear roller  324  is provided at a rear side in the longitudinal direction of the rotation support unit  310 , and the first rear roller  322  is provided at a front side in the longitudinal direction of the rotation support unit  310 . 
     The second rear roller  324  according to the present invention broadly includes a fixed shaft  324   c , a second rotary drum  324   a , and a load generating means  324   b.    
     The fixed shaft  324   c  is a rotating shaft of the second rear roller  324 , the fixed shaft  324   c  is elongated in the width direction of the rotation support unit  310 , and both ends of the fixed shaft  324   c  are fixedly coupled to the rotation support unit  310 . 
     Further, the second rotary drum  324   a  has an outer surface that is in contact with the rear wheel  14 , and the second rotary drum  324   a  is configured to be rotatable about the fixed shaft  324   c.    
     Specifically, the outer surface of the second rotary drum  324   a  is in contact with the rear wheel  14 , and the second rotary drum  324   a  is formed in a cylindrical shape and coupled to be rotatable about the fixed shaft  324   c.    
     Further, when the rear wheel  14  is rotated by the user, the second rotary drum  324   a  is rotated together with the rear wheel  14  about the fixed shaft  324   c.    
     The load generating means  324   b  is provided in the second rotary drum  324   a , and selectively generates a load in accordance with the rotation of the second rotary drum  324   a  corresponding to the inclination angle of the main frame  100 . 
     Specifically, the load generating means  324   b  is configured to be rotatable about the fixed shaft  324   c  in the second rotary drum  324   a , and at least a part of the load generating means  324   b  is fixedly coupled to the second rotary drum  324   a.    
     Further, the load generating means  324   b  is rotated about the fixed shaft  324   c  together with the second rotary drum  324   a  when the second rotary drum  324   a  is rotated by the rear wheel  14 . 
     Here, the load generating means  324   b  is selectively operated by the control unit, and in the present exemplary embodiment, the load generating means  324   b  is formed in the form of a disc and fixedly coupled to an inner surface of the second rotary drum  324   a.    
     Further, a central portion of the load generating means  324   b  is rotatably coupled to the fixed shaft  324   c  by a separate bearing. 
     Therefore, when the rear wheel  14  is rotated by external force applied by the user, the second rotary drum  324   a  is also rotated together with the rear wheel  14 , and the load generating means  324   b  is selectively operated corresponding to the inclination angle of the main frame  100 , thereby providing a load in accordance with the rotation of the second rotary drum  324   a.    
     In this case, the load generating means  324   b  is configured to generate a load in accordance with the rotation relative to the fixed shaft  324   c  by providing electric power to a generally used disc. 
     Meanwhile, a configuration of the first rear roller  322  will be described, and the first rear roller  322  has therein a drive motor  322   b  to rotate the first rear roller  322  when the main frame  100  is disposed to have a downward inclination, thereby artificially rotating the rear wheel  14 . 
     In the present invention, the first rear roller  322  broadly includes a first rotary drum  322   a , the drive motor  322   b , and gear means  322   c  and  322   d.    
     Similar to the second rotary drum  324   a , the first rotary drum  322   a  has a cylindrical shape, the first rotary drum  322   a  is disposed in an elongated manner in the width direction of the rotation support unit  310 , and the rear wheel  14  is in contact with an outer surface of the first rotary drum  322   a . Therefore, the first rotary drum  322   a  is rotated together with the rear wheel  14  when the rear wheel  14  is rotated. 
     Further, the drive motor  322   b  is provided in the first rotary drum  322   a  and connected to the first rotary drum  322   a  through the gear means  322   c  and  322   d , thereby rotating the first rotary drum  322   a.    
     Specifically, when the main frame  100  is disposed to be inclined forward and downward as described above, the drive motor  322   b  is operated by the control unit, and a rotational speed of the drive motor  322   b  is adjusted corresponding to the inclination angle of the main frame  100 . 
     Meanwhile, the gear means  322   c  and  322   d  are provided in the drive motor  322   b  and the first rotary drum  322   a  and transmit rotational force of the drive motor  322   b  to the first rotary drum  322   a , thereby rotating the first rotary drum  322   a.    
     Here, as illustrated, the gear means  322   c  and  322   d  include a ratchet  322   c  which is provided on a rotating shaft of the drive motor  322   b , and a catching member  322   d  which protrudes from a surface of the first rotary drum  322   a  and is selectively caught by the ratchet  322   c.    
     Further, the ratchet  322   c , which is rotated by the drive motor  322   b , and the first rotary drum  322   a  are relatively rotated in one direction. 
     That is, when the drive motor  322   b  is rotated, the first rotary drum  322   a  is rotated as the catching member  322   d  is caught by a gear formed on the ratchet  322   c.    
     However, when a rotational speed of the first rotary drum  322   a  is higher than a rotational speed of the ratchet  322   c  rotated by the drive motor  322   b  when the first rotary drum  322   a  is rotated by the rotation of the rear wheel  14 , the catching member  322   d  is not caught by the ratchet  322   c , and as a result, the first rotary drum  322   a  is independently rotated regardless of whether the drive motor  322   b  is rotated. 
     Therefore, a load is not generated on the drive motor  322   b , and damage may be prevented when the drive motor  322   b  is not operated or the drive motor  322   b  is operated at a speed relatively lower than the rotational speed of the first rotary drum  322   a  even though the driver motor  322   b  is operated. 
     That is, the gear means  322   c  and  322   d  are means for protecting the drive motor  322   b  when the first rotary drum  322   a  and the drive motor  322   b  are rotated, and the gear means  322   c  and  322   d  are configured such that the rotating shaft of the drive motor  322   b  and the first rotary drum  322   a  may be relatively rotated in one direction. 
     Since the first rear roller  322  and the second rear roller  324  according to the present invention are configured as described above, it is possible to implement likeness of traveling on the inclined road by tilting the main frame  100  when the user rides the bicycle, and to implement acceleration and deceleration of the bicycle in accordance with an uphill road and a downhill road. 
       FIG. 10  is a view illustrating a state in which the main frame of the bicycle exercise apparatus in  FIG. 4  is inclined forward and upward,  FIG. 11  is a view illustrating a state in which the main frame of the bicycle exercise apparatus in  FIG. 4  is inclined forward and downward, and  FIGS. 12A and 12B  show views illustrating a state in which the first rotary drum and the drive motor are relatively rotated corresponding to a rotational speed of the first rotary drum of the first rear roller of the bicycle exercise apparatus in  FIG. 11 . 
     First,  FIG. 10  illustrates a state in which the bicycle exercise apparatus implements an uphill road, that is, the main frame  100  is tilted clockwise to a predetermined angle by the rotation unit  400 . 
     In this case, the rotation support unit  310  maintains the horizontal state by the relative rotation between the main frame  100  and the rotation support unit  310 , and the first rear roller  322  and the second rear roller  324  are rotated clockwise by the rotation of the rear wheel  14 . 
     Here, the control unit detects an inclination direction and an inclination angle of the main frame  100  and operates the load generating means  324   b  corresponding to the inclination direction and the inclination angle of the main frame  100 , such that a load is generated in accordance with the rotation of the second rear roller  324 , thereby providing a load in accordance with the rotation of the rear wheel  14 . 
     In this state, the drive motor  322   b  provided in the first rear roller  322  is not operated, and only the first rotary drum  322   a  is independently rotated by the gear means  322   c  and  322   d  in accordance with the rotation of the rear wheel  14 . 
     As described above, the bicycle exercise apparatus according to the present invention implements a state in which the user rides the bicycle on an uphill road as the main frame  100  is tilted to be inclined forward and upward and a load is generated only by the second rear roller  324 . 
     On the contrary, when the main frame  100  is tilted counterclockwise by the rotation unit  400  to implement a downhill road as illustrated in  FIG. 11 , the main frame  100  is disposed to be inclined forward and downward, and the rotation support unit  310  maintains the horizontal state while rotating relative to the main frame  100 . 
     Further, the control unit detects the inclination direction and the inclination angle of the main frame  100 , and rotates the first rear roller  322 . 
     Specifically, the control unit operates the drive motor  322   b  provided in the first rear roller  322 , and the first rotary drum  322   a  is rotated by the rotation of the drive motor  322   b , thereby rotating the rear wheel  14 . 
     In this case, because the load generating means  324   b  is not operated, the second rear roller  324  freely rotates together with the rear wheel  14 . 
     In general, the bicycle is accelerated by gravity when the user rides the bicycle on a downhill road, and similarly, acceleration is implemented at a predetermined level as the first rear roller  322  is rotated by the drive motor  322   b  regardless of external force applied by the user. 
     Of course, the user may rotate the rear wheel  14  regardless of a rotational speed of the drive motor  322   b  in a state in which the first rotary drum  322   a  is rotated by the drive motor  322   b.    
     Specifically, in the drawing illustrating the first rotary drum  322   a  and the gear means  322   c  and  322   d , when a rotational speed R 1  of the drive motor  322   b  is higher than a rotational speed R 2  of the first rotary drum  322   a , the ratchet  322   c  meshes with the catching member  322   d , such that the first rotary drum  322   a  is rotated. 
     However, on the contrary, when the user rotates the rear wheel  14  at a high speed in a state in which the drive motor  322   b  is rotated, the rotational speed R 2  of the first rotary drum  322   a  becomes relatively higher than the rotational speed R 1  of the drive motor  322   b.    
     Further, in this case, the gear formed on the ratchet  322   c  is not caught by the catching member  322   d , such that the first rotary drum  322   a  is independently rotated. 
     Therefore, when the main frame  100  is tilted to be inclined forward and downward, the rear wheel  14  is rotated at a predetermined speed by the drive motor  322   b , and the user may rotate the rear wheel  14  at a speed higher than the rotational speed of the drive motor  322   b  in accordance with the user&#39;s selection. 
     As described above, the bicycle exercise apparatus according to the present invention may more precisely implement likeness of traveling on the inclined road by the first rear roller  322  and the second rear roller  324 , and as a result, the user may enjoy the exercise similar to actually traveling on the road. 
     Meanwhile, the bicycle exercise apparatus according to the exemplary embodiment of the present invention includes a guide unit. The guide unit  500  is provided on the main frame  100  and configured to prevent a rollover of the bicycle  10  when the user rides the bicycle  10  by restricting a part of the motion of the bicycle  10  in a state in which the bicycle  10  is seated on the main frame  100 . 
       FIG. 13  is a view illustrating a top side of the bicycle exercise apparatus in  FIG. 1 , and  FIG. 14  is a view illustrating a state in which the bicycle is moved while dancing by the user in the bicycle exercise apparatus in  FIG. 1 . 
     As illustrated in  FIG. 13 , the guide unit  500  according to the present invention broadly includes a front frame  510 , a rear frame  520 , and connecting wires  530 . 
     The front frame  510  is positioned at a front side of the front wheel  12  at one side in the longitudinal direction of the main frame  100 , and the front frame  510  protrudes upward in an elongated manner. 
     Further, similar to the front frame  510 , the rear frame  520  is positioned at a rear side of the rear wheel  14  at the other side in the longitudinal direction of the main frame  100 , and the rear frame  520  protrudes upward in an elongated manner. 
     In this case, the front frame  510  and the rear frame  520  are detachably coupled to the main frame  100 , but otherwise, the front frame  510  and the rear frame  520  may be configured integrally with the main frame  100 . 
     The connecting wires  530  are provided on the front frame  510  and the rear frame  520 , respectively, and one side of each of the connecting wires  530  is connected to a central portion of the bicycle  10  in the width direction, thereby supporting the bicycle  10  so that the bicycle  10  does not roll over. 
     Specifically, the connecting wires  530  are provided at positions spaced apart from the floor at a predetermined height in a direction toward upper portions of the front frame  510  and the rear frame  520 , and the connecting wires  530  are provided at the same height. 
     In this case, the other sides of the connecting wire  530  are fixedly coupled to the front frame  510  and the rear frame  520 , and a separate coupling means  532  is provided at one side of each of the connecting wires  530 . 
     Further, the connecting wires  530  are coupled to a frame of the bicycle  10  through the coupling means  532  when the bicycle  10  is seated on the main frame  100 . Here, one or more coupling means  532  are provided and detachably coupled to the bicycle  10 . 
     In the present exemplary embodiment, as illustrated, the connecting wire  530  may be elongated in the form of a wire and made of a material having elasticity at a predetermined level, and the connecting wire  530  supports the bicycle  10  so that the bicycle  10  does not roll over and allows the bicycle  10  to dance in a left and right direction, as illustrated in  FIG. 14 , when the bicycle  10  travels by external force applied by the user. 
     Here, as illustrated, the other sides of the connecting wires  530  may be positioned on the front frame  510  and the rear frame  520  at a central portion of the main frame  100  in the width direction, and as a result, the bicycle  10  may be stably supported on the main frame  100 . 
     Meanwhile, the coupling means  532  is formed in various shapes and configured such that the connecting wires  530  are selectively and fixedly coupled to the bicycle  10 . 
       FIG. 15  is a view illustrating a state in which the connecting wires are coupled to the bicycle in the bicycle exercise apparatus in  FIG. 1 . 
     As illustrated in  FIG. 15 , in the present exemplary embodiment, the coupling means  532  is formed in the form of a bracket  532   a , and the connecting wire  530  may be fixed to the bicycle  10  through a separate fixing pin  532   b . Otherwise, the coupling means  532  may of course be formed in various shapes in addition to the bracket  532   a , and any other shape may be applied to the coupling means  532  as long as the coupling means  532  may be selectively fixed to the frame of the bicycle  10 . 
     Since the coupling means  532  are selectively coupled to the bicycle  10  as described above, the bicycle  10  is fixed by the connecting wires  530  so as not to roll over, and the bicycle  10  is supported to perform left and right dancing motions to a certain degree by external force applied by the user. 
     Here, the connecting wire  530  is made of metal or synthetic resin which is a material having elasticity at a predetermined level, and a degree to which the left and right dancing motions of the bicycle  10  are restricted may be adjusted in accordance with a material of the connecting wire  530 . 
     As described above, the guide unit  500  according to the present invention is configured to prevent the user&#39;s safety accident caused by a rollover of the bicycle  10  when the bicycle  10  seated on the main frame  100  travels, and to allow a motion in the width direction to a predetermined level or higher, thereby implementing the same effect as when the user rides the bicycle on an actual road. 
     Meanwhile, the guide unit  500  according to the present invention may further include a safety frame  540  in addition to the front frame  510 , the rear frame  520 , and the connecting wire  530 . 
     The safety frame  540  is elongated, both ends of the safety frame  540  are coupled to the front frame  510  and the rear frame  520  at a predetermined height, and the safety frame  540  is disposed to be eccentric toward one side in the width direction of the main frame  100 . 
     Specifically, as illustrated, the safety frame  540  is formed in a bar shape, and both ends of the safety frame  540  are connected to the front frame  510  and the rear frame  520 , respectively. In this case, the safety frame  540  is disposed to be eccentric toward one side so that the user or the bicycle  10  does not interfere with the safety frame  540  when the bicycle  10  is seated on the main frame  100 . 
     Therefore, when the bicycle  10  positioned on the main frame  100  is about to roll over, the safety frame  540  supports the bicycle  10  to prevent a rollover of the bicycle  10 , or the user grasps the safety frame  540 , and as a result, it is possible to prevent a safety accident. 
     That is, the safety frame  540 , together with the connecting wire  530 , is used as an auxiliary safety means for preventing a falling accident by allowing the user to stably keep his/her balance on the bicycle  10  or allowing the user to directly grasp the safety frame  540  when the bicycle is about to roll over. 
     Since the guide unit  500  is provided in the bicycle exercise apparatus as described above, it is possible to prevent an inadvertent rollover of the bicycle  10  when the user exercises by using the bicycle  10 , and to implement the left and right dancing motions of the bicycle  10  by external force applied by the user. 
     As described above, the bicycle exercise apparatus according to the exemplary embodiment of the present invention has been described. 
     Hereinafter, a bicycle exercise apparatus according to another exemplary embodiment of the present invention will be described with reference to the drawings. 
       FIG. 16  is a perspective view illustrating a bicycle exercise apparatus according to another exemplary embodiment of the present invention, and  FIG. 17  is a perspective view illustrating a state in which a bicycle is installed on the bicycle exercise apparatus according to another exemplary embodiment of the present invention. 
     As illustrated in  FIGS. 16 to 17 , the bicycle exercise apparatus according to another exemplary embodiment of the present invention broadly includes the main frame  100 , the front support unit  200 , the rear support unit  300 , the rotation unit  400 , and the guide unit  500 . 
     Here, because the main frame  100 , the rear support unit  300 , the rotation unit  400 , and the guide unit  500  are identical to those in the exemplary embodiment of the present invention, descriptions of the identical configurations and operations will be omitted. 
     However, the front support unit  200  in the present exemplary embodiment is a treadmill  200 , and the front support unit  200  is provided at one side of the main frame  100  and supports the front wheel  12  of the bicycle  10 . 
       FIG. 18  is a view illustrating an external appearance of the front support unit according to another exemplary embodiment of the present invention, and  FIG. 19  is a view illustrating an interior of the front support unit according to another exemplary embodiment of the present invention. 
     As illustrated in  FIGS. 18 and 19 , the treadmill  200 , which is the front support unit  200  of the present exemplary embodiment, includes a pair of frames  210 , a deck  220 , a pair of rollers, a belt  240 , and a drive motor  250 . 
     The pair of frames  210  has a length in the traveling direction, and is disposed to be spaced apart from each other while facing each other. 
     Further, the deck  220  is positioned between the pair of frames  210  and abuts against the front wheel  12 , thereby supporting a load of the bicycle  10  applied from above. 
     The pair of rollers includes the driving roller  232  which is connected to the drive motor  250  for providing driving power, and the driven roller  234  which is rotated together with the driving roller  232  in accordance with the rotation of the driving roller  232 . 
     The driving roller  232  and the driven roller  234  may be rotated by the drive motor  250 , but the driving roller  232  and the driven roller  234  may be rotated by the rotation of the front wheel  12  of the bicycle  10  even in a state in which the drive motor  250  is not operated. 
       FIG. 20  is an enlarged view of part A in  FIG. 19 . 
     As illustrated in  FIG. 19 , the driving roller  232  and the driven roller  234  are disposed at front and rear sides of the deck  220 , respectively, and installed between the pair of frames  210  so as to be rotatable in the same direction, and as illustrated in  FIG. 20 , anti-slip grooves  232   a  and  234   a  are formed at predetermined intervals in a circumferential direction on outer circumferential surfaces of the driving roller  232  and the driven roller  234 . 
     The belt  240  is installed to surround the driving roller  232 , the driven roller  234 , and the deck  220  from the outside, and moved in conjunction with the rotation of the driving roller  232 . Further, as illustrated in  FIG. 20 , anti-slip protrusions  240   a , which correspond to the anti-slip grooves  232   a  and  234   a , are formed on a surface of the belt  240  which abuts against the driving roller  232  and the driven roller  234 . 
     The bicycle  10  travels at a higher speed than a person running, and a larger load is applied when a person rides the bicycle  10  on the treadmill  200  than when a person runs on the treadmill  200 , and as a result, the belt may slip on the roller when the belt is operated at a high speed. This phenomenon often occurs on the typical treadmill  200 . 
     However, the anti-slip grooves  232   a  and  234   a  and the anti-slip protrusions  240   a  are formed on the driving roller  232 , the driven roller  234 , and the belt  240  of the treadmill  200  in the present exemplary embodiment and engaged with one another, and as a result, it is possible to prevent a slip of the belt  240 . 
     Meanwhile, friction reducing members  222  may be provided on an upper surface of the deck  220  in order to reduce friction by minimizing a contact area with the belt  240 . 
       FIG. 21  is an enlarged view of part B in  FIG. 19 . 
     As illustrated in  FIG. 21 , in the present exemplary embodiment, the friction reducing member  222  may include a ring-shaped support portion  222   a  which has a hollow portion, and a spherical rotating portion  222   b  which is positioned in the hollow portion of the support portion  222   a  and in contact with the belt  240  so as to be rotated in conjunction with the movement of the belt  240 . 
     Further, although not illustrated in the drawing, a ball is embedded in the ring-shaped support portion  222   a  in order to allow the rotating portion  222   b  to smoothly rotate, and the rotating portion  222   b  is rotated in a state in which the ball and the rotating portion  222   b  are in point-to-point contact with each other. 
     Since friction between the deck  220  and the belt  240  is reduced as described above, the treadmill  200  according to the present exemplary embodiment is more suitable for a high-speed operation in comparison with the typical treadmill  200 . 
     Here, the rotating portion  222   b  is not limited to the aforementioned configuration, and any configuration may be applied as long as the configuration may reduce friction between the deck  220  and the belt  240 . 
     Meanwhile, the treadmill  200  according to the present exemplary embodiment is mechanically connected to the driven roller  234  and may be configured to adjust tension of the belt  240  by adjusting a distance between the driving roller  232  and the driven roller  234 . 
       FIG. 22  is an enlarged view of part C in  FIG. 19 . 
     To implement this configuration, as illustrated in  FIG. 22 , a tension block  236 , to which a rotating shaft  234   b  of the driven roller  234  is coupled and which is coupled to be movable in the front and rear direction with respect to the frame  210 , may be provided, and a tension adjusting member  238 , which fastens the frame  210  and the tension block  236  and moves the tension block  236  in the front and rear direction while rotating, may be provided. 
     However, the configuration for adjusting tension of the belt  240  by using the tension block  236  and the tension adjusting member  238  is just one exemplary embodiment, and various configurations may be applied as long as tension of the belt  240  may be adjusted. 
     Since the front wheel  12  of the bicycle  10  is supported by the treadmill  200  as described above, the front wheel  12  and the treadmill  200  are in surface-to-surface contact with each other, such that the user may feel the same likeness as when the user rides the bicycle on an actual road. 
     While the exemplary embodiments according to the present invention have been described above, it is obvious to those skilled in the art that the present invention may be specified in other particular forms in addition to the aforementioned exemplary embodiments without departing from the spirit or the scope of the present invention. Accordingly, it should be understood that the aforementioned exemplary embodiments are not restrictive but illustrative, and thus the present invention is not limited to the aforementioned description, and may be modified within the scope of the appended claims and the equivalent range thereto.