Bicycle crank speed change device

Abstract

The invention discloses a bicycle crank speed change device. A bicycle crank transmission according to one embodiment of the present invention comprises: a ring gear unit having a direct connection ratchet disposed on the outside thereof and having gear teeth formed on the inner peripheral surface thereof; a crank cover having an inner peripheral surface on which direct-connection ratchet teeth selectively meshing with the direct-connection ratchet are formed, and a coupling shaft is formed; a sun gear attached to the coupling shaft; a reduction gear unit including: an eccentric guide on which an eccentric hole is formed; and an eccentric gear coupled to the eccentric guide and having one region engaged with the ring gear unit and the other region engaged with the sun gear; a link housing that rotates together with the ring gear unit, has the direct connection ratchet disposed on one surface thereof, and has a link coupling unit formed on the outer peripheral surface thereof; the direct connection ratchet wheel is selectively meshed with the direct connection ratchet wheel sawteeth through the electromagnet; the power supply unit is controlled by the control module and provides current for the electromagnet; and an operation module connected to the control module through radio communication and selectively turning on / off the power supply unit.

Description

Technical Field

[0001] The present invention relates to a bicycle crank speed change device, and more particularly, to a bicycle crank speed change device having a speed changer built therein. Background Art

[0002] Generally, the gear speed changer of a bicycle is set to be able to pedal out a certain force and speed according to the driving state. The speed change of a bicycle is divided into front gear speed change and rear gear speed change. The front gear speed change is achieved by overlapping chainrings with different numbers of teeth, and the rear gear speed change is achieved by overlapping sprockets with different numbers of teeth. The gear ratio determined by the number of teeth of the chainring of the front gear and the sprocket of the rear gear shows a difference in the driving speed of the bicycle under the same pedaling conditions.

[0003] However, due to the speed change mechanism of the shift method that forcibly moves the position of the chain in the front gear speed change of the existing bicycle, there is a problem that the chain frequently disengages from the chainring during the speed change process. Moreover, it is not easy to reinstall the derailed chain onto the chainring, and the hands or clothing of the user will be contaminated by the lubricating oil coated on the chain during the chain installation process.

[0004] Furthermore, if the front gear speed change of a bicycle is achieved by stacking multiple chainrings and moving the position of the chain, there are limitations in the miniaturization and weight reduction of the device.

[0005] The applicant applied for a patent for a "bicycle crank speed change device" to solve the above problems and has been authorized. The patent number is 10-1701289. It is recorded in this patent that the driving protrusion of the direct-connected ratchet will be received in the receiving unit of the direct-connected ratchet clutch or will be supported on the support ball during the speed change process, and thus the elastically supported driving protrusion expands or contracts. The operation of the driving protrusion being received in the receiving unit or supported on the support ball will be repeated, resulting in problems such as a decrease in durability.

[0006] To solve the problems of this patent, the applicant applied for a patent for a "crank assembly with an internal speed changer" and has been authorized. The patent number is 10-2186944. However, for this patent, reverse rotation is required during speed change, and there are defects in reverse rotation of the pedal during driving. Summary of the Invention

[0007] Technical Problem

[0008] An object of the bicycle crank speed change device according to an embodiment of the present invention is to provide a bicycle crank speed change device that can achieve speed change by having an internal speed changer and using a single chainring.

[0009] In addition, an object of a bicycle crank speed change device according to an embodiment of the present invention is to provide a bicycle crank speed change device that can easily perform speed change by selectively applying power to an electromagnet through wireless communication.

[0010] In addition, an object of a bicycle crank speed change device according to an embodiment of the present invention is to provide a bicycle crank speed change device that can achieve a simple structure and light weight.

[0011] The technical problems of the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned herein can also be clearly understood by those skilled in the art through the following description.

[0012] Means for solving the problem

[0013] A bicycle crank speed change device according to an embodiment of the present invention includes: an annular gear unit having a direct-connect ratchet disposed on an outer side thereof and gear teeth formed on an inner circumferential surface; a crank cover having direct-connect ratchet teeth selectively meshing with the direct-connect ratchet formed on an inner circumferential surface thereof and a coupling shaft formed thereon; a sun gear unit mounted on the coupling shaft; a reduction gear unit including: an eccentric guide member having an eccentric hole formed thereon; and an eccentric gear coupled to the eccentric guide member and meshing with the annular gear unit in one region and the sun gear unit in another region; a chain ring housing rotating together with the annular gear unit, having the direct-connect ratchet disposed on one surface thereof and a chain ring coupling unit formed on an outer circumferential surface; an electromagnet selectively engaging the direct-connect ratchet with the direct-connect ratchet teeth; a power supply unit controlled by a control module and supplying current to the electromagnet; and an operation module connected to the control module through radio communication and selectively turning on / off the power supply unit.

[0014] Wherein, the direct-connect ratchet can be elastically supported outward along a radial direction of the annular gear unit and mesh with the direct-connect ratchet teeth, and move reversely and disengage from the direct-connect ratchet teeth when power is supplied to the electromagnet.

[0015] Wherein, the chain ring housing may include: a bottom plate on which the annular gear unit is disposed, having the chain ring coupling unit formed on an outer circumferential surface thereof and spaced apart circumferentially and coupled to a chain ring, the direct-connect ratchet disposed on one surface of the bottom plate, a recessed unit formed in the chain ring coupling unit, and the power supply unit and the control module disposed in the recessed unit.

[0016] Wherein, a rotation unit may further be included, disposed on another surface of the bottom plate and connected to the direct-connect ratchet, and rotating about an axis when power is applied to the electromagnet.

[0017] Wherein, a first side wall formed in a protruding manner may be formed at an edge of one side of the bottom plate, and a second side wall formed in a protruding manner may be formed at an edge of the other side of the bottom plate, and the electromagnet is disposed on the other side of the bottom plate.

[0018] Wherein, the electromagnet may be disposed on the other side of the bottom plate, and a pin may also be included, which is connected to the electromagnet, penetrates through the bottom plate and is spaced apart from one end of the direct-connection ratchet, and the direct-connection ratchet contacts the pin when current is introduced into the electromagnet.

[0019] Advantages of the Invention

[0020] According to an embodiment of the present invention, there are at least the following advantages.

[0021] According to the bicycle crank speed change device of the present invention, speed change can be achieved by using a single chain link.

[0022] In addition, power is selectively applied to the electromagnet through wireless communication, so that speed change can be easily performed.

[0023] In addition, by selectively applying power to the electromagnet and performing speed change, speed change can be easily performed during driving.

[0024] In addition, the overall structure of the crank can be simplified and lightened.

[0025] The advantages of the present invention are not limited to the above-described content, and more advantages are included in this specification. Brief Description of the Drawings

[0026] Figure 1 is a perspective view of a bicycle crank speed change device according to a first embodiment of the present invention.

[0027] Figure 2 is a bottom perspective view of a bicycle crank speed change device according to a first embodiment of the present invention.

[0028] Figure 3 is a perspective view of a crank cover of a bicycle crank speed change device according to a first embodiment of the present invention.

[0029] Figure 4 is a perspective view of a sun gear of a bicycle crank speed change device according to a first embodiment of the present invention.

[0030] Figure 5 is a schematic diagram of a crank cover and a sun gear unit of a bicycle crank speed change device according to a first embodiment of the present invention.

[0031] Figure 6 is a front view of an annular gear unit of a bicycle crank speed change device according to a first embodiment of the present invention.

[0032] Figure 7 is a perspective view of a reduction gear unit of a bicycle crank speed change device according to a first embodiment of the present invention.

[0033] Figure 8 is a schematic diagram of the relationship between gears of a bicycle crank speed change device according to a first embodiment of the present invention.

[0034] Figure 9 and Figure 10 is a perspective view of a chain housing of a bicycle crank speed change device according to a first embodiment of the present invention.

[0035] Figure 11 is a front view of a chain housing of a bicycle crank speed change device according to a first embodiment of the present invention.

[0036] Figure 12 is a schematic diagram of a bicycle crank speed change device according to a second embodiment of the present invention.

[0037] Figure 13 is a schematic diagram of a bicycle crank speed change device according to an embodiment of the present invention when traveling at a high speed.

[0038] Figure 14 is a schematic diagram of a bicycle crank speed change device according to an embodiment of the present invention when traveling at a low speed. Detailed Description

[0039] The present invention can be variously modified and can have multiple embodiments. Specific embodiments are illustrated in the drawings and described in detail herein. The effects, features, and methods of the present invention will become clearer with reference to the drawings and the following embodiments. It should be understood that the present invention is not limited to the embodiments disclosed below and can be implemented in various forms, including all modifications, equivalents, and alternatives within the concept and technical scope of the present invention.

[0040] Before the description, the terms described in the specific description are described. In the following embodiments, terms such as first and second do not have a limiting meaning and are used to distinguish one component from other components. Therefore, the first component described below can also be the second component within the technical idea of the present invention. Also, unless otherwise defined in the specification, singular expressions include plural expressions. In addition, terms such as "including" or "having" indicate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and do not preclude the possibility of including at least one other feature or component in advance.

[0041] In addition, for ease of explanation, the sizes of the components in the drawings may be enlarged or reduced. For example, for ease of explanation, the sizes and thicknesses of the components shown in the drawings are artificially defined, and the present invention is not necessarily limited thereto.

[0042] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. When describing with reference to the accompanying drawings, the same or corresponding components are denoted by the same reference numerals, and repeated descriptions thereof are omitted here.

[0043] The bicycle crank speed change device according to an embodiment of the present invention relates to a bicycle crank speed change device that incorporates a speed changer and can perform speed change by rotating a crank based on a single chain ring, and can selectively apply power to an electromagnet through wireless communication, thereby enabling easy speed change.

[0044] Figure 1 is a perspective view of a bicycle crank speed change device according to a first embodiment of the present invention, Figure 2 is a bottom perspective view of a bicycle crank speed change device according to a first embodiment of the present invention, Figure 3 is a perspective view of a crank cover of a bicycle crank speed change device according to a first embodiment of the present invention.

[0045] The bicycle crank speed change device according to a first embodiment of the present invention includes: a crank cover (100), a sun gear unit (200), an annular gear unit (300), a reduction gear unit (400), a chain ring housing (500), an electromagnet (600), a power supply unit (700), a control module (800), and an operation module (900).

[0046] The crank cover (100) is a member that is coupled to a pedal shaft (not shown) and rotates together with the pedal shaft (not shown) based on the user's pedaling. Driving force is transmitted to the wheels based on the rotation of the crank cover (100), thereby causing the bicycle to travel.

[0047] A coupling shaft (110) for coupling to a main shaft (not shown) of a base bracket (not shown) is formed at the center of the inner surface of the crank cover (100). The coupling shaft (110) allows an axial member (not shown) to be inserted.

[0048] Direct connection ratchet teeth (120) are formed on the inner side wall of the crank cover (100). The direct connection ratchet teeth (120) are members for meshing with a direct connection ratchet (330) when the direct connection ratchet (330) unfolds from the annular gear unit (300). That is, the direct connection ratchet teeth (120) are members that mesh with the direct connection ratchet (330), and the direct connection ratchet (330) is elastically supported (elastically unfolded) by an elastic member.

[0049] Figure 4 is a perspective view of a sun gear of a bicycle crank speed change device according to a first embodiment of the present invention. Figure 5 is a schematic view of a crank cover and a sun gear unit of a bicycle crank speed change device according to a first embodiment of the present invention.

[0050] The sun gear unit (200) is a component for transmitting driving force when the crank cover (100) rotates. The sun gear unit (200) includes a sun gear (210) and a reverse rotation prevention unit (220).

[0051] The sun gear (210) is arranged such that sun gear teeth (211) are formed on the outer peripheral surface to mesh with an eccentric gear (420) in a region. When the bicycle is running, the sun gear (210) rotates. Specifically, it rotates idly in high gear and rotates together with the crank cover (100) in low gear. The rotation of the sun gear unit (200) will be described in detail in the operation part described later.

[0052] Sun gear ratchet teeth (212) are formed on the inner peripheral surface of the sun gear (210). The sun gear ratchet teeth (212) are arranged to rotate around the coupling shaft (110) when the crank cover (100) rotates in the positive direction. At this time, the sun gear ratchet teeth (212) are arranged to rotate only in one direction based on the reverse rotation prevention unit (220). In this embodiment, it is arranged to rotate only in the positive direction (counterclockwise direction, refer to Figure 5 ) for rotation.

[0053] The reverse rotation prevention unit (220) is installed on the outer peripheral surface of the coupling shaft (110) and on the crank cover (100). The reverse rotation prevention unit (220) includes a sun gear ratchet (230) and a sun gear ratchet fixing unit (240) coupled to the sun gear ratchet (230). The sun gear ratchet (230) is formed to mesh with the sun gear ratchet teeth (212) formed on the inner peripheral surface of the sun gear unit (200). Based on the meshing of the sun gear ratchet teeth (212) and the sun gear ratchet (230), the sun gear unit (200) is only allowed to rotate in the counterclockwise direction in the drawing. The sun gear ratchet (230) can be arranged to be elastically supported in a direction away from the center of the coupling shaft (110), that is, toward the axis of the sun gear ratchet teeth (212). In addition, the reverse rotation prevention unit (220) may further include a cover portion (not shown) to prevent the sun gear ratchet (230) from detaching.

[0054] Figure 6 It is a front view of an annular gear unit of a bicycle crank speed change device according to a first embodiment of the present invention.

[0055] The ring gear unit (300) is a component that determines whether the bicycle runs in a high gear or a low gear. The ring gear unit (300) is arranged on one side of the bottom plate (510). The inner circumferential surface of the ring gear unit (300) is formed with ring gear teeth (310), and a part of the ring gear teeth (310) is arranged to mesh with the eccentric gear (420). The outer circumferential surface of the ring gear unit (300) may be formed with a direct-connect ratchet arrangement unit (320) for arranging the direct-connect ratchet (330). The direct-connect ratchet arrangement units (320) are formed at intervals, and positioning protrusions (513) formed on the other side of the bottom plate (510) may be arranged between the direct-connect ratchet arrangement units (320). The position of the direct-connect ratchet (330) may be determined by the position of the direct-connect ratchet arrangement unit (320).

[0056] The direct-connect ratchet (330) is a component that selectively meshes with the direct-connect ratchet teeth (120). Based on whether the direct-connect ratchet (330) meshes or not, it is determined whether it is in a high gear or a low gear. The direct-connect ratchet (330) is arranged to be elastically supported outward along the radial direction of the ring gear unit (300). As an example, an elastic member is arranged, the direct-connect ratchet (330) is combined with the elastic member, and is elastically supported in a direction away from the virtual center of the ring gear unit (300). Specifically, a leaf spring may be used as the elastic member and is arranged on the direct-connect ratchet arrangement unit (320). At this time, the leaf spring may be fixed to the direct-connect ratchet arrangement unit (320) and the direct-connect ratchet (300). The elastic member is clamped between the direct-connect ratchet (330) and the direct-connect ratchet arrangement unit (320) and elastically supports the direct-connect ratchet (330) outward (that is, in a direction away from the virtual center of the ring gear unit (300)), and the elastically supported direct-connect ratchet (330) meshes with the direct-connect ratchet teeth (120).

[0057] A plurality of direct-connect ratchets (330) are arranged at intervals. In this embodiment, there are four direct-connect ratchets (330), and thus four direct-connect ratchet arrangement units (320) are also provided. However, the number of direct-connect ratchets (330) is not limited to this.

[0058] Figure 7 It is a perspective view of the reduction gear unit of the bicycle crank speed change device according to the first embodiment of the present invention. Figure 8 It is a schematic diagram of the relationship between gears of the bicycle crank speed change device according to the first embodiment of the present invention.

[0059] The reduction gear unit (400) is a component that reduces the speed of the ring gear unit (300) in the low gear. Specifically, the reduction gear unit (400) is a component that receives the rotational force of the crankcase (100) transmitted from the sun gear unit (200) in the low gear and rotates the ring gear unit (300) at a reduced rotational speed. The reduction gear unit (400) includes an eccentric guide (410) and an eccentric gear (420). An eccentric hole (411) is formed in the eccentric guide (410). The eccentric guide (410) is fixedly disposed on one side surface of the coupling shaft (110), and the eccentric hole (411) is aligned with the hollow center of the coupling shaft (110). In addition, the eccentric guide (410) is disposed inside the ring gear unit (300), and is disposed such that the center of the eccentric hole (411) is aligned with the center of the ring gear unit (300). A bearing (412) may be provided in the eccentric hole (411).

[0060] The eccentric gear (420) is disposed to be rotatable along the outer circumferential surface of the eccentric guide (410). Depending on the position of the eccentric guide (410), a region of the teeth of the eccentric gear (420) can be engaged with the ring gear unit (300), and another region can be engaged with the sun gear unit (200). The eccentric gear (420) rotates in the same direction as the sun gear unit (200) and transmits the reduced rotational force to the ring gear unit (300), so the wear or breakage of the eccentric gear (420) can be significantly lower than that of the planetary gear.

[0061] Figure 9 and Figure 10 is a perspective view of the chain case of the bicycle crank speed change device according to the first embodiment of the present invention. Figure 11 is a front view of the chain case of the bicycle crank speed change device according to the first embodiment of the present invention.

[0062] The chain case (500) includes a bottom plate (510) and a chain coupling unit (520). The bottom plate (510) is for fixedly disposing the ring gear unit (300), and the chain coupling unit (520) is formed at intervals in the circumferential direction on the outside of the bottom plate (510), and its outer circumferential surface is coupled to the chain.

[0063] In this embodiment, the chain case (500) is configured to be separable from the chain (not shown) so that the user can alternately use it according to preference, but it is not necessarily limited thereto. The chain case (500) and the chain (not shown) may also be integrally formed.

[0064] At this time, the chain coupling unit (520) is formed with a plurality of arm units (521) for coupling to the chain. Each of the plurality of arm units (521) is formed with a recess unit (530). The formation of the recess unit (530) can make the crank lighter.

[0065] The electromagnet (600), which is a magnet magnetized by the power supply provided by the power supply unit (700), is a component that drives the directly-connected ratchet wheel (330) elastically supported to rotate when power is provided. That is, when no power is provided to the electromagnet (600), the directly-connected ratchet wheel (330) is elastically supported outward in the radial direction of the annular gear unit (300) by an elastic member and meshes with the directly-connected ratchet teeth (120). When power is provided to the electromagnet (600), it rotates in the reverse direction, i.e., inward, and disengages from the directly-connected ratchet teeth (120).

[0066] In addition, a first side wall (511) formed in a protruding shape is formed at one edge of the bottom plate (510), and a second side wall (512) formed in a protruding shape is formed at the other edge of the bottom plate (510).

[0067] The annular gear unit (300) as described above is arranged on one side of the bottom plate (510), and the electromagnet (600) and the rotating unit (610) are arranged on the other side of the bottom plate (510).

[0068] In this embodiment, the electromagnet (600) can be arranged on the second side wall (512) and / or the other side of the bottom plate (510). In addition, the rotating unit (610) is a component that rotates when current is applied to the electromagnet (600) and drives the directly-connected ratchet wheel (330) to rotate.

[0069] In this embodiment, the rotating unit (610) is arranged to rotate around an axis, and the rotating unit (610) and the directly-connected ratchet wheel (330) are connected to each other through the axis. At this time, the axis penetrates one side and the other side of the bottom plate (510). In addition, in this embodiment, the rotating unit (610) can be a magnetic material. This is because when the electromagnet (600) generates magnetism, the rotating unit (610) needs to rotate toward the electromagnet (600).

[0070] When the directly-connected ratchet wheel (330) is elastically supported, that is, when it meshes with the directly-connected ratchet teeth (120), the rotating unit (610) is in a state separated from the electromagnet (600). When power is applied to the electromagnet (600), the rotating unit (610) is driven by magnetism to rotate toward the electromagnet (600) and contacts the electromagnet (600). At this time, the directly-connected ratchet wheel (330) rotates inward, compresses the elastic member, and disengages from the directly-connected ratchet teeth (120).

[0071] The power supply unit (700) is controlled by the control module (800). That is, power can be selectively supplied to the electromagnet (600) via the control module (800). A battery / dry battery, a rechargeable battery / dry battery, etc. can be used as the power supply unit (700). When installed on an electric bicycle, it can receive power from the electric bicycle and supply the power to each component.

[0072] The power supply unit (700) and the control module (800) are arranged in the recessed unit (530). By arranging them in the recessed unit (530), even if the power supply unit (700) and the control module (800) are set on the crank, the volume increase can be prevented. Therefore, miniaturization and weight reduction are not restricted.

[0073] The operation module (900) is a component that is connected to the control module (800) through radio communication and is used to selectively turn on / off the power supply unit (700). The operation module (900) is arranged on the handlebar frame of the bicycle. When the user operates the operation module (900), a signal is transmitted to the control module (800) through wireless communication, and thus power (current) can be selectively supplied to the electromagnet (600) through the power supply unit (700).

[0074] That is, when the user wants to shift gears, the operation module (900) is operated (for example, pressing a button or operating a control lever), and the corresponding signal is transmitted to the control module (800) through wireless communication (Bluetooth). The control module (800) drives the power supply unit (700) and supplies power to the electromagnet (600) or cuts off the power supply.

[0075] Next, the bicycle crank speed change device according to the second embodiment of the present invention will be described.

[0076] Figure 12 It is a schematic diagram of the bicycle crank speed change device according to the second embodiment of the present invention.

[0077] The bicycle crank speed change device according to the second embodiment of the present invention includes: a crank cover (100), a sun gear unit (200), an annular gear unit (300), a reduction gear unit (400), a chain link housing (500), an electromagnet (600), a power supply unit (700), a control module (800), and an operation module (900). In this embodiment, the components other than the rotation unit (610) are the same as those in the first embodiment, so the repeated description of the same components will be omitted.

[0078] The chain link housing (500) includes a bottom plate (510) and a chain link coupling unit (520). The bottom plate (510) is used to fixedly arrange the annular gear unit (300). The chain link coupling unit (520) is formed at intervals along the circumferential direction on the outer surface of the bottom plate (510), and the outer peripheral surface is coupled to the chain link.

[0079] In this embodiment, the link housing (500) is configured to be separable from the link (not shown) so that the user can use them alternately according to their preference. However, it is not necessarily limited to this, and the link housing (500) and the link (not shown) can also be integrally formed.

[0080] At this time, the link coupling unit (520) is formed with a plurality of arm units (521) for coupling with the link. Each of the plurality of arm units (521) is formed with a recessed unit (530). The formation of the recessed unit (530) can make the crank lighter.

[0081] The electromagnet (600), as a magnet magnetized by the power supplied by the power supply unit (700), is a component that drives the directly connected ratchet (330) supported elastically to rotate when power is supplied. That is, when no power is supplied to the electromagnet (600), the directly connected ratchet (330) is elastically supported by the elastic member and meshes with the directly connected ratchet teeth (120). When power is supplied to the electromagnet (600), it rotates in the reverse direction, i.e., inward, and disengages from the directly connected ratchet teeth (120).

[0082] In addition, a first side wall (511) formed in a protruding shape is formed at one edge of the bottom plate (510), and a second side wall (512) formed in a protruding shape is formed at the other edge of the bottom plate (510).

[0083] The annular gear unit (300) as described above is arranged on one side of the bottom plate (510), and the electromagnet (600) is arranged on the other side of the bottom plate (510).

[0084] In this embodiment, the electromagnet (600) can be arranged on the second side wall (512) and / or the other side of the bottom plate (510).

[0085] In addition, this embodiment is different from the first embodiment and may include a pin (630) to replace the rotating unit (610).

[0086] The pin (630) is arranged through the bottom plate (510) and one end is in contact with the electromagnet (600). In addition, the other end of the pin (630) can pass through the bottom plate (510) and be arranged on the directly connected ratchet arrangement unit (320). Specifically, it can be arranged between the outer peripheral surface of the annular gear unit (300) and the directly connected ratchet (330).

[0087] When a power source is applied to the electromagnet (600), the pin (630) also generates magnetism, and thus the directly connected ratchet (330) that is elastically supported rotates toward the pin (630), i.e., the inner side, and contacts the pin (630). At this time, the directly connected ratchet (330) rotates inward and compresses the elastic member, and disengages from the directly connected ratchet teeth (120). The pin (630) can be made of an electromagnet, can be integrally formed with the electromagnet (600), or can be separately formed and maintained in a contact state. In addition, in this embodiment, the directly connected ratchet (330) can be a magnetic material. This is because when the pin (630) generates magnetism, the directly connected ratchet (330) needs to rotate toward the pin (630).

[0088] When the directly connected ratchet (330) is elastically supported, i.e., engaged with the directly connected ratchet teeth (120), the pin (630) is in a state separated from the electromagnet (600). When a power source is applied to the electromagnet (600), the pin (630) also generates magnetism, and based on the magnetism, the directly connected ratchet (630) is driven to rotate toward the pin (630) and contact the electromagnet (600). At this time, the directly connected ratchet (330) rotates inward and compresses the elastic member, and disengages from the directly connected ratchet teeth (120).

[0089] Next, the operation of the crank assembly with a transmission according to an embodiment of the present invention will be described.

[0090] For the operation of the crank assembly with a transmission according to this embodiment, for the sake of convenience of description, it will be described in the order of high gear - shifting - low gear.

[0091] 1. High gear

[0092] Figure 13 It is a schematic diagram of the bicycle crank speed change device according to an embodiment of the present invention when traveling in high gear.

[0093] In high gear, the power supply unit (700) does not supply current to the electromagnet (600). That is, the directly connected ratchet (330) is expanded by the elasticity of the elastic member and engaged with the directly connected ratchet teeth (120) of the crank cover (100).

[0094] Therefore, when the user pedals the pedal to rotate the crank cover (100), the crank cover (100) drives the annular gear unit (300) to perform direct connection rotation at the same rotation speed. The rotation of the annular gear unit (300) drives the reduction gear unit (400) to rotate, and the sun gear unit (200) reversely receives the rotational force of the annular gear unit (300) transmitted through the reduction gear unit (400) and performs idle rotation at a rotation speed greater than that of the crank cover (100).

[0095] 2. Shifting 1

[0096] When the bicycle is set to the high gear state, if the user wants to shift gears, the operation module (900) is operated. That is, the button or the control lever is pressed. The corresponding signal is transmitted to the control module (800) through wireless communication, and the control module (800) controls the power supply unit (700) and supplies power to the electromagnet (600).

[0097] When power is supplied to the electromagnet (600), it becomes magnetic, and thus the directly connected ratchet (330) rotates inward (i.e., toward the virtual center side of the ring gear unit (300)), and disengages from the teeth of the directly connected ratchet (120).

[0098] 3. Low gear

[0099] Figure 14 It is a schematic diagram of the bicycle crank speed change device according to an embodiment of the present invention when driving in the low gear.

[0100] In the low gear, the power supply unit (700) supplies current to the electromagnet (600). That is, the directly connected ratchet (330) rotates toward the electromagnet (600) side and disengages from the teeth of the directly connected ratchet (120).

[0101] Therefore, if the crank cover (100) rotates, there is no engagement between the ring gear unit (300) and the crank cover (100), so direct connection rotation does not occur. Instead, the sun gear unit (200) is driven to rotate clockwise around the coupling shaft (110) of the crank cover (100). The rotation of the sun gear unit (200) drives the engaged reduction gear unit (400) to rotate, and the ring gear unit (300) is driven to rotate at a reduced speed through the reduction gear unit (400).

[0102] 4. Speed change 2

[0103] When the bicycle is set to the low gear state, if the user wants to shift gears, the operation module (900) is operated. That is, the button or the control lever is pressed. The corresponding signal is transmitted to the control module (800) through wireless communication, and the control module (800) controls the power supply unit (700) and cuts off the power supply to the electromagnet (600).

[0104] If the power supply to the electromagnet (600) is cut off, it loses magnetism, and thus the directly connected ratchet (330) is elastically expanded by the elastic member, that is, elastically supported, and engages with the teeth of the directly connected ratchet (120).

[0105] As described above, the present invention provides a bicycle crank speed change device, which is built-in with a speed changer and can shift gears by rotating the crank based on a single chain ring, and can shift gears by selectively applying power to the electromagnet through wireless communication.

[0106] Industrial applicability

[0107] Provided is a bicycle crank speed change device that has a speed changer incorporated therein and can perform speed change by rotating a crank based on a single chainring, and can perform speed change by selectively applying power to an electromagnet through wireless communication.

Claims

1. A bicycle crank speed change device, comprising: An annular gear unit, on the outer side of which a direct-connected ratchet is arranged, and gear teeth are formed on the inner circumferential surface; A crank cover, on the inner circumferential surface of which direct-connected ratchet teeth are formed to selectively engage with the direct-connected ratchet, and a coupling shaft is formed; A sun gear unit, which is mounted on the coupling shaft; A reduction gear unit, which includes: an eccentric guide member, on which an eccentric hole is formed; and an eccentric gear, which is combined with the eccentric guide member and one area meshes with the annular gear unit while the other area meshes with the sun gear unit; A chain ring housing, which rotates together with the annular gear unit, and on one side a direct-connected ratchet is arranged, and a chain ring coupling unit is formed on the outer circumferential surface; An electromagnet, which selectively engages the direct-connected ratchet with the direct-connected ratchet teeth; A power supply unit, which is controlled by a control module and supplies current to the electromagnet; and An operation module, which is connected to the control module through radio communication and selectively turns on / off the power supply unit.

2. The bicycle crank speed change device according to claim 1, wherein The direct-connected ratchet is elastically supported outward along the radial direction of the annular gear unit and engages with the direct-connected ratchet teeth, and moves reversely and disengages from the direct-connected ratchet teeth when power is supplied to the electromagnet.

3. The bicycle crank speed change device according to claim 2, wherein The chain ring housing includes: A bottom plate, on which the annular gear unit is arranged, and a chain ring coupling unit that is formed at intervals along the circumferential direction and is coupled with the chain ring is formed on the outer circumferential surface, On one side of the bottom plate, the direct-connected ratchet is arranged, The chain ring coupling unit is formed with a recessed unit, The power supply unit and the control module are arranged in the recessed unit.

4. The bicycle crank speed change device according to claim 3, wherein A rotating unit is further included, which is arranged on the other side of the bottom plate and is connected to the direct-connected ratchet, and rotates around the axis when power is applied to the electromagnet.

5. The bicycle crank speed change device according to claim 4, wherein On one side edge of the bottom plate, a first side wall is formed to protrude, on the other side edge of the bottom plate, a second side wall is formed to protrude, and the electromagnet is arranged on the other side of the bottom plate.

6. The bicycle crank speed change device according to claim 3, wherein The electromagnet is arranged on the other side of the bottom plate, A pin is further included, which is connected to the electromagnet, penetrates through the bottom plate and one end is arranged at a distance from the direct-connected ratchet, and the direct-connected ratchet contacts the pin when current is applied to the electromagnet.

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