A Crank Set for Bicycle

Abstract

The present invention comprises a base ring portion; a crank arm portion fixed to the front of the base ring portion; a chain ring portion fixed to the rear surface of the base ring portion; and a pedal portion connected to the other end of the crank arm portion to apply force to the crank arm portion, wherein the crank arm portion comprises: a crank arm; a first coupling portion located at one end of the crank arm and fixed to a certain area of ​​the base ring portion; and a second coupling portion located at the other end of the crank arm and to which the pedal portion is coupled, wherein the base ring portion comprises: a circular base ring; a first-1 straight support member extending from the inner circumference of a first area of ​​the base ring to the inner circumference of a second area of ​​the base ring; a first-2 straight support member arranged to intersect the first-1 straight support member and extending from the inner circumference of a third area of ​​the base ring to the inner circumference of a fourth area of ​​the base ring; and a crank arm first fixing portion located in the area where the first-1 straight support member and the first-2 straight support member intersect, to which one end of the crank arm is fixed. The invention relates to a bicycle crank set comprising a second crank arm fixing part disposed in a certain area of ​​the circular base ring, wherein the center area of ​​the crank arm is fixed, and wherein, when rotating the chain ring, the forward speed of the bicycle can be varied while the force applied by the user to the pedal remains the same.

Description

Technology Field

[0001] The present invention relates to a crank set for a bicycle, and more specifically, to a crank set for a bicycle that allows the force applied by the user to the pedals to remain the same while changing the forward speed of the bicycle. Background Technology

[0002] Currently, bicycles are becoming increasingly popular not only as a means of transportation but also for recreational purposes. Furthermore, competitive cycling is becoming a highly popular sport, regardless of whether the participants are professional or amateur.

[0003] In other words, bicycles are used for various purposes, such as transportation, recreation, and operation in sports.

[0004] Figure 1 is a schematic diagram illustrating a crankset of a bicycle with a general structure.

[0005] A typical bicycle is composed of a handle, a front wheel, a rear wheel, a seat, and a crank set for driving the rear wheel, and with reference to FIG. 1, the crank set (1) includes a chain ring (2), a crank arm (3) for applying rotational force to the chain ring (2), and a pedal (4) for applying force to the crank arm (3).

[0006] At this time, a chain (5) is connected to the chainring (2) of the crank set (1), and the rotational force of the chainring (2) is transmitted to the rear gear sprocket (6) included in the rear wheel through the chain (5), thereby causing the bicycle to move forward.

[0007] Meanwhile, due to the diversity of bicycle applications, the bicycle industry is constantly improving various components.

[0008] Among these areas of improvement, one component that has undergone significant improvement is the crankset part located in the center of the bicycle mentioned above.

[0009] Generally, a bicycle crankset includes one to three chainrings for threading the bicycle chain.

[0010] That is, after attaching a chain to one of the chainrings included in the crank set, when the driver applies force to the pedal included in the crank set as described above, the chainring rotates due to the force applied from the pedal, and the rotational force of the chainring is transmitted through the chain to the rear gear sprocket and the rear wheel of the bicycle, causing the bicycle to move forward.

[0011] At this time, the driver applies force to the pedal to rotate the chainring. Depending on the driver's needs, the chainring may be configured to have 1 to 3 stages so that the driver can rotate the chainring more easily, that is, to reduce the force applied to the pedal.

[0012] That is, based on the gear selection, the driver can select a rotation ring so that less force can be applied to the pedal by fitting the chain to any one of the 1st to 3rd chain rings.

[0013] The distinction between the first and third chainrings can be made by the radius of the chainrings, for example, by making the radius (r1) of the first chainring smaller than the radius (r2) of the second chainring (r1 < r2), and making the radius (r2) of the second chainring smaller than the radius (r3) of the third chainring (r2 < r3), thereby configuring the first and third chainrings.

[0014] At this time, assuming that each chainring makes the same one rotation, a larger force must be applied to the chainring with a larger radius and a smaller force can be applied to the chainring with a smaller radius, so, for example, the force that must be applied to the first chainring is smaller than the force that must be applied to the second chainring.

[0015] However, in this case, although the force applied to the first chainring is smaller than the force applied to the second chainring, the rotational force transmitted to the rear gear sprocket through the chain as the chainring rotates is smaller for the first chainring compared to the second chainring.

[0016] The rotational force transmitted to these rear gear sprockets can be determined by the circumference (2πr) of each of the chainrings, for example, since the radius of the second chainring is larger than the radius of the first chainring, the rotational force 2πr2 that the second chainring can transmit to the rear gear sprocket by the same rotation is greater than the rotational force 2πr1 that the first chainring can transmit to the rear gear sprocket.

[0017] That is, since the second chainring can rotate the chain more than the first chainring by an amount of 2πr2 - 2πr1, the rotational force transmitted to the rear gear sprocket, which rotates according to the rotation of the chain, is smaller for the first chainring compared to the second chainring.

[0018] The rotational force transmitted to this rear gear sprocket is ultimately related to the forward speed of the bicycle, and consequently, when changing the gear from the 2nd chainring to the 1st chainring in order to reduce the force applied by the user to the pedals, although the force applied by the user to the pedals is reduced, the forward speed of the bicycle is reduced by that amount.

[0019] In other words, in the case of conventional bicycle cranksets, if the force applied by the user to the pedals decreases, the forward speed of the bicycle decreases accordingly, and conversely, if the forward speed of the bicycle increases, the force applied by the user to the pedals increases accordingly. Prior art literature

[0020] Registered Patent 10-1957122 The problem to be solved

[0021] The objective of the present invention is to provide a bicycle crank set that allows the force applied by the user to the pedals to remain the same while changing the forward speed of the bicycle when rotating the chainring.

[0022] The objectives of the present invention are not limited to those mentioned above, and other unmentioned objectives will be clearly understood by those skilled in the art from the description below. means of solving the problem

[0023] To solve the aforementioned problems, the present invention comprises: a base ring portion; a crank arm portion fixed to the front of the base ring portion; a chain ring portion fixed to the rear surface of the base ring portion; and a pedal portion connected to the other end of the crank arm portion to apply force to the crank arm portion, wherein the crank arm portion comprises: a crank arm; a first coupling portion located at one end of the crank arm and fixed to a certain area of ​​the base ring portion; and a second coupling portion located at the other end of the crank arm to which the pedal portion is connected, wherein the base ring portion comprises: a circular base ring; a first-1 straight support member extending from the inner circumference of a first area of ​​the base ring to the inner circumference of a second area of ​​the base ring; and a first-2 straight support member arranged to intersect the first-1 straight support member and extending from the inner circumference of a third area of ​​the base ring to the inner circumference of a fourth area of ​​the base ring. A bicycle crank set is provided, comprising: a first crank arm fixing part located in an area where the first-1 straight support and the first-2 straight support intersect, wherein one end of the crank arm is fixed; and a second crank arm fixing part disposed in a certain area of ​​the circular base ring, wherein the center area of ​​the crank arm is fixed.

[0024] In addition, the present invention provides a bicycle crank set characterized in that one end of the crank arm is fixed to the first fixing part of the crank arm, and the center area of ​​the crank arm is fixed to the second fixing part of the crank arm.

[0025] In addition, the present invention comprises a chain ring portion that is disposed adjacent to the base ring portion and is located in the rear direction of the base ring portion, and includes a first chain ring portion of a first diameter, wherein the first chain ring portion comprises: a circular first chain ring; a first tooth portion located on the outer circumference of the first chain ring; a second-1 straight support member disposed in an area corresponding to the first-1 straight support member and extending from the inner circumference direction of the first area of ​​the first chain ring to the inner circumference direction of the second area of ​​the first chain ring; and a second-2 straight support member disposed in an area corresponding to the first-2 straight support member, disposed intersecting with the second-1 straight support member and extending from the inner circumference direction of the third area of ​​the first chain ring to the inner circumference direction of the fourth area of ​​the first chain ring. The present invention provides a bicycle crank set comprising a second through hole located in an area where the second-1 straight support and the second-2 straight support intersect, wherein the first chain ring portion includes a plurality of first fixing members for fixing the circular base ring of the base ring portion and the circular first chain ring, wherein the plurality of first fixing members comprises a first-1 fixing member located in a first area of ​​the first chain ring; a first-2 fixing member located in a second area of ​​the first chain ring; a first-3 fixing member located in a third area of ​​the first chain ring; and a first-4 fixing member located in a fourth area of ​​the first chain ring.

[0026] In addition, the present invention comprises a chain ring portion that is positioned adjacent to the first chain ring portion and is located in the rear direction of the base ring portion, and includes a second chain ring portion of a second diameter, wherein the second chain ring portion comprises: a circular second chain ring; a second tooth portion located on the outer circumference of the second chain ring; a third-1 straight support member positioned in an area corresponding to the first-1 straight support member, extending from the inner circumference direction of the first area of ​​the second chain ring to the inner circumference direction of the second area of ​​the second chain ring; and a third-2 straight support member positioned in an area corresponding to the first-2 straight support member, intersecting with the third-1 straight support member, and extending from the inner circumference direction of the third area of ​​the second chain ring to the inner circumference direction of the fourth area of ​​the second chain ring. The present invention provides a bicycle crank set comprising a third through hole located in an area where the second-1 straight support and the second-2 straight support intersect, wherein the second chain ring portion includes a plurality of second fixing members for fixing the first-1 straight support of the base ring portion, the first-2 straight support of the base ring portion, and the circular second chain ring, respectively, wherein the plurality of second fixing members include a second-1 fixing member located in a first area of ​​the second chain ring; a second-2 fixing member located in a second area of ​​the second chain ring; a second-3 fixing member located in a third area of ​​the second chain ring; and a second-4 fixing member located in a fourth area of ​​the second chain ring. Effects of the invention

[0027] According to the present invention as described above, a bicycle crank set can be provided in which the force applied by the user to the pedals can be the same while changing the forward speed of the bicycle when rotating the chainring.

[0028] In addition, as described above, in the present invention, a pedal coupling portion located at the other end of the crank arm can be a point of force, a center area of ​​the crank arm fixed to the second fixing portion (115) of the crank arm can be a first point of support, and one end of the crank arm fixed to the first fixing portion (114) of the crank arm can be a second point of support, and the tooth portion of each chainring portion, that is, the first tooth portion to the third tooth portion, can be a point of application. Therefore, in the present invention, there exists a first rotational force generated between the point of force, the first point of support, and the point of application, and a second rotational force generated between the point of force, the second point of support, and the point of application. Accordingly, by the force applied by the driver to the point of force, a first rotational force and a second rotational force are generated at any one of the first tooth portion to the third tooth portion, which is the point of application, respectively, so that two rotational forces can be generated by a single force. Brief explanation of the drawing

[0029] Figure 1 is a schematic diagram illustrating a crankset of a bicycle with a general structure. FIG. 2 is a front view illustrating a bicycle crank set according to the present invention, FIG. 3 is a rear view illustrating a bicycle crank set according to the present invention, and FIG. 4 is a side view illustrating a bicycle crank set according to the present invention. Figure 5 is a schematic diagram illustrating the principle of a lever in a general crankset. Specific details for implementing the invention

[0030] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims.

[0031] Specific details for implementing the present invention will be described in detail with reference to the drawings attached below. Regardless of the drawings, identical reference numerals refer to identical components, and "and / or" includes each of the mentioned items and all combinations of one or more.

[0032] Although terms such as "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another. Therefore, it goes without saying that the first component mentioned below may also be the second component within the technical scope of the present invention.

[0033] The terms used herein are for describing the embodiments and are not intended to limit the invention. In this specification, the singular form includes the plural form unless specifically stated otherwise in the text. As used herein, "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components in addition to the components mentioned.

[0034] Unless otherwise defined, all terms used in this specification (including technical and scientific terms) may be used in a meaning that is commonly understood by those skilled in the art to which the present invention pertains. Additionally, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0035] Spatially relative terms such as "below," "beneath," "lower," "above," and "upper" may be used to facilitate the description of the relationship between one component and other components as illustrated in the drawings. Spatially relative terms should be understood as encompassing different orientations of components during use or operation, in addition to the orientations depicted in the drawings. For example, if a component depicted in a drawing is inverted, a component described as "below" or "beneath" of another component may be placed "above" of that component. Therefore, the exemplary term "below" may encompass both the lower and upper directions. Components may also be oriented in other directions, and accordingly, spatially relative terms may be interpreted according to the orientation.

[0036] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0037] FIG. 2 is a front view illustrating a bicycle crank set according to the present invention, FIG. 3 is a rear view illustrating a bicycle crank set according to the present invention, and FIG. 4 is a side view illustrating a bicycle crank set according to the present invention.

[0038] Referring to FIGS. 2 to 4, a bicycle crank set (100) according to the present invention comprises: a base ring portion (110); a crank arm portion (120) fixed to a first surface, for example, the front surface, of the base ring portion (110); a chain ring portion (200) fixed to a second surface, for example, the back surface, of the base ring portion (110); and a pedal portion (not shown) fastened to the other end of the crank arm portion to apply force to the crank arm portion.

[0039] As illustrated in FIG. 1 above, a crank set of a bicycle with a general structure includes a chain ring (2), a crank arm (3) for applying rotational force to the chain ring (2), and a pedal (4) for applying force to the crank arm (3). A chain (5) is connected to the chain ring (2) of the crank set (1), and through the chain (5), the rotational force of the chain ring (2) is transmitted to a rear gear sprocket (6) included in the rear wheel, thereby causing the bicycle to move forward.

[0040] That is, in a crank set of a bicycle with a general structure, the crank arm is directly connected to the chain ring, and when a rider applies force to the pedal included in the crank set, the chain ring rotates due to the force applied from the pedal, and the rotational force of the chain ring is transmitted through the chain to the rear gear sprocket and the rear wheel of the bicycle, causing the bicycle to move forward.

[0041] However, the bicycle crank set (100) according to the present invention includes a base ring portion (110), and after fixing the crank arm portion to the front of the base ring portion (110) and fixing the chain ring portion to the back of the base ring portion, when a driver applies force to the pedal included in the crank set, the base ring portion rotates by the force applied from the pedal, and the chain ring portion rotates by the rotational force of the base ring portion, and the rotational force of the chain ring portion is transmitted to the rear gear sprocket and rear wheel of the bicycle through the chain, so that the bicycle moves forward.

[0042] More specifically, first, the crank arm portion (120) comprises: a crank arm (121); a first coupling portion (122) located at one end of the crank arm (121) and fixed to a certain area of ​​the base ring portion; and a second coupling portion (123) located at the other end of the crank arm (121) to which the pedal portion is coupled.

[0043] In addition, the first coupling portion of the crank arm includes a first through hole (122a), and a crank shaft of a bicycle is inserted into the first through hole, so that the crank set can be fastened to the bicycle through the first through hole.

[0044] Next, the base ring portion (110) comprises: a circular base ring (111); a first-1 straight support member (112) extending from the inner circumference of a first region of the base ring to the inner circumference of a second region of the base ring; a first-2 straight support member (113) arranged to intersect the first-1 straight support member (112) and extending from the inner circumference of a third region of the base ring to the inner circumference of a fourth region of the base ring; and a crank arm first fixing portion (114) located in the region where the first-1 straight support member (112) and the first-2 straight support member (113) intersect, wherein one end of the crank arm is fixed.

[0045] At this time, in the present invention, it is preferable that the spacing between the first region and the third region, the spacing between the second region and the fourth region, the spacing between the first region and the fourth region, and the spacing between the second region and the third region are the same. Accordingly, in the present invention, the first straight support (112) and the second straight support (113) can be defined as intersecting at an angle of 90°. The same applies to the chain ring section below.

[0046] Additionally, the base ring portion (110) includes a crank arm second fixing portion (115) that is positioned in a certain area of ​​the circular base ring (111), for example, between the second area and the fourth area, and in which the center area of ​​the crank arm is fixed.

[0047] That is, in the present invention, the crank arm portion is understood to include the crank arm, wherein one end of the crank arm is fixed to the first fixing portion (114) of the crank arm and the center area of ​​the crank arm is fixed to the second fixing portion (115) of the crank arm.

[0048] Continuing with reference to FIGS. 2 to 4, the chain ring portion (200) is fixed to a second surface, for example, the back surface of the base ring portion, and the chain ring portion (200) comprises: a first chain ring portion (210) having a first diameter, which is positioned adjacent to the base ring portion and is located in the back direction of the base ring portion; a second chain ring portion (220) having a second diameter, which is positioned adjacent to the first chain ring portion (210) and is located in the back direction of the base ring portion; and a third chain ring portion (230) having a third diameter, which is positioned adjacent to the second chain ring portion (220) and is located in the back direction of the base ring portion.

[0049] At this time, the drawing shows that there are three chain ring portions, but in the present invention, it is preferable that there are at least two chain ring portions, and therefore, the number of chain ring portions is not limited in the present invention.

[0050] In addition, by making the first diameter larger than the second diameter and the second diameter larger than the third diameter, the chain ring portion can be configured in 1 to 3 stages, and since this is obvious in the art, a detailed explanation below will be omitted.

[0051] Furthermore, the first chain ring portion (210) comprises: a circular first chain ring (211); a first tooth portion (211a) located on the outer circumference of the first chain ring; a second-1 straight support (not shown in the drawing) positioned in an area corresponding to the first-1 straight support (112), extending from the inner circumference direction of the first area of ​​the first chain ring (211) to the inner circumference direction of the second area of ​​the first chain ring (211); and a second-2 straight support (not shown in the drawing) positioned in an area corresponding to the first-2 straight support (113), positioned intersecting the second-1 straight support, and extending from the inner circumference direction of the third area of ​​the first chain ring (211) to the inner circumference direction of the fourth area of ​​the first chain ring (211). and includes a second through hole (not shown in the drawing) located in the area where the second-1 straight support and the second-2 straight support intersect, wherein a crank shaft of a bicycle is inserted into the second through hole, and the crank set can be fastened to the bicycle through the second through hole.

[0052] At this time, the second through hole is continuously penetrated through the first through hole.

[0053] Additionally, the first chain ring portion (210) includes a plurality of first fixing members (212) for fixing the circular base ring (111) of the base ring portion (110) and the circular first chain ring (211), and the plurality of first fixing members (212) include a first-1 fixing member (212a) located in a first area of ​​the first chain ring (211); a first-2 fixing member (212b) located in a second area of ​​the first chain ring (211); a first-3 fixing member (212c) located in a third area of ​​the first chain ring (211); and a first-4 fixing member (212d) located in a fourth area of ​​the first chain ring (211).

[0054] That is, in the present invention, the first chain ring of the first chain ring part is fixed to the base ring of the base ring part, so that when a driver applies force to the pedal included in the crank set, the base ring part rotates by the force applied from the pedal, and the chain ring part rotates by the rotational force of the base ring part, and the rotational force of the chain ring part is transmitted to the rear gear sprocket and rear wheel of the bicycle through the chain, so that the bicycle moves forward.

[0055] Furthermore, the second chain ring section (220) comprises: a circular second chain ring (221); a second gear section (221a) located on the outer circumference of the second chain ring; a third-1 straight support (222) positioned in an area corresponding to the first-1 straight support (112) and extending from the inner circumference direction of the first area of ​​the second chain ring (221) to the inner circumference direction of the second area of ​​the second chain ring (221); and a third-2 straight support (223) positioned in an area corresponding to the first-2 straight support (113), positioned intersecting the third-1 straight support, and extending from the inner circumference direction of the third area of ​​the second chain ring (221) to the inner circumference direction of the fourth area of ​​the second chain ring (221). and includes a third through hole (not shown in the drawing) located in the area where the second-1 straight support and the second-2 straight support intersect, wherein a crank shaft of a bicycle is inserted into the third through hole, and the crank set can be fastened to the bicycle through the third through hole.

[0056] At this time, the third through hole is continuously penetrated through the first through hole.

[0057] Additionally, the second chain ring portion (220) includes a plurality of second fixing members (225) for fixing the first-1 straight support of the base ring portion (110), the first-2 straight support of the base ring portion (110), and the circular second chain ring (221), respectively, and the plurality of second fixing members (225) include a second-1 fixing member (225a) located in a first area of ​​the second chain ring (221); a second-2 fixing member (225b) located in a second area of ​​the second chain ring (221); a second-3 fixing member (225c) located in a third area of ​​the second chain ring (221); and a second-4 fixing member (225d) located in a fourth area of ​​the second chain ring (221).

[0058] That is, in the present invention, the second chain ring of the second chain ring part is fixed to the first-1 straight support of the base ring part (110) and the first-2 straight support of the base ring part (110), respectively, so that when a driver applies force to the pedal included in the crank set, the base ring part rotates by the force applied from the pedal, and the second chain ring part rotates by the rotational force of the base ring part, and the rotational force of the second chain ring part is transmitted to the rear gear sprocket and rear wheel of the bicycle through the chain, so that the bicycle moves forward.

[0059] Furthermore, the third chain ring section (230) comprises: a circular third chain ring (231); a second gear section (231a) located on the outer circumference of the third chain ring; a fourth-1 straight support (not shown in the drawing) positioned in an area corresponding to the first-1 straight support (112), extending from the inner circumference direction of the first area of ​​the third chain ring (231) to the inner circumference direction of the second area of ​​the third chain ring (231); and a fourth-2 straight support (not shown in the drawing) positioned in an area corresponding to the first-2 straight support (113), positioned intersecting the fourth-1 straight support, and extending from the inner circumference direction of the third area of ​​the third chain ring (231) to the inner circumference direction of the fourth area of ​​the third chain ring (231). and includes a fourth through hole (not shown in the drawing) located in the area where the fourth-1 straight support and the fourth-2 straight support intersect, wherein a crank shaft of a bicycle is inserted into the fourth through hole, and the crank set can be fastened to the bicycle through the fourth through hole.

[0060] At this time, the fourth through hole is continuously penetrated through the first through hole.

[0061] Additionally, the third chain ring section (230) includes a plurality of third fixing members (235) for fixing the third-1 straight support of the second chain ring section (220), the third-2 straight support of the second chain ring section (220), and the circular third chain ring (231), respectively, and the plurality of third fixing members (235) include a third-1 fixing member (235a) located in a first area of ​​the third chain ring (231); a third-2 fixing member (235b) located in a second area of ​​the third chain ring (231); a third-3 fixing member (235c) located in a third area of ​​the third chain ring (231); and a third-4 fixing member (235d) located in a fourth area of ​​the third chain ring (231).

[0062] That is, in the present invention, the third chain ring of the third chain ring part is fixed to the third-1 straight support of the second chain ring part (220) and the third-2 straight support of the second chain ring part (220), respectively, so that when a driver applies force to the pedal included in the crank set, the base ring part rotates by the force applied from the pedal, and the second chain ring part rotates by the rotational force of the base ring part, and the rotational force of the second chain ring part is transmitted to the third chain ring part, and the rotational force of the third chain ring part is transmitted to the rear gear sprocket and rear wheel of the bicycle through the chain, so that the bicycle moves forward.

[0063] Meanwhile, although not shown in the drawing, the third chain ring of the third chain ring section may be fixed to the first-1 straight support of the base ring section (110) and the first-2 straight support of the base ring section (110), respectively. In this case, the third chain ring of the third chain ring section may be fixed to the first-1 straight support of the base ring section (110) and the first-2 straight support of the base ring section (110), respectively, as the plurality of third fixing members (235) are each fixed to the third-1 straight support of the second chain ring section (220) and the third-2 straight support of the second chain ring section (220).

[0064] As described above, the bicycle crank set (100) according to the present invention includes a base ring portion (110), and after fixing the crank arm portion to the front of the base ring portion (110) and fixing the chain ring portion to the back of the base ring portion, when a driver applies force to the pedal included in the crank set, the base ring portion rotates by the force applied from the pedal, and the chain ring portion rotates by the rotational force of the base ring portion, and the rotational force of the chain ring portion is transmitted to the rear gear sprocket and rear wheel of the bicycle through the chain, so that the bicycle moves forward.

[0065] Meanwhile, in the present invention, the crank arm portion may be understood to include the crank arm, wherein one end of the crank arm is fixed to the first fixing portion (114) of the crank arm and the center area of ​​the crank arm is fixed to the second fixing portion (115) of the crank arm.

[0066] Figure 5 is a schematic diagram illustrating the principle of a lever in a general crankset.

[0067] Referring to FIG. 5, a lever generally includes a point where force is applied, a point where the applied force acts, and a fulcrum located between the point where force is applied and the point where the force acts.

[0068] At this time, in the crank set of the bicycle, the pedal coupling located at the other end of the crank arm (3) can be the point of force, the crank shaft coupling located at the other end of the crank arm (3) can be the point of fulcrum, and the gear located on the outer diameter of the chain ring (2) can be the point of application, and through this lever principle, the crank arm (3) can rotate the chain ring (2).

[0069] In addition, as shown in Fig. 5, when a force is applied in the F direction, a rotational force is generated in the T direction.

[0070] When this is applied to the present invention, in the present invention, the pedal coupling part located at the other end of the crank arm can be the point of force, the center area of ​​the crank arm fixed to the second fixing part (115) of the crank arm can be the first support point, the one end of the crank arm fixed to the first fixing part (114) of the crank arm can be the second support point, and the toothed part of each chainring part, that is, the first toothed part to the third toothed part, can be the point of application.

[0071] That is, in the present invention, there exists a first rotational force generated between the force point, the first fulcrum, and the point of application, and a second rotational force generated between the force point, the second fulcrum, and the point of application. Accordingly, by the force applied by the driver to the force point, a first rotational force and a second rotational force are generated at any one of the first to third toothed parts, which are the points of application.

[0072] In addition, in the present invention, the first chain ring of the first chain ring portion, the second chain ring of the second chain ring portion, and the third chain ring of the third chain ring portion are each fixed to the first-1 straight support of the base ring portion (110) and the first-2 straight support of the base ring portion (110), respectively.

[0073] At this time, because the positions of the first to third gears are different due to the different diameters of the first to third chain rings, the first to third chain rings each have different points of action.

[0074] Accordingly, in the present invention, in the first to third chain ring portions, the respective force point and point of application are the same, but the respective points of application are different from each other.

[0075] This means that, in the first to third chainring sections, the force point and the point of application are identical, so the magnitude of the force applied by the user to the first to third chainring sections is the same; furthermore, since the points of application of the first to third chainring sections are different, the forward speed of the bicycle changes.

[0076] Accordingly, the present invention provides a bicycle crank set in which the force applied by the user to the pedals can remain the same while changing the forward speed of the bicycle when rotating the chainring.

[0077] In addition, as described above, in the present invention, a pedal coupling portion located at the other end of the crank arm can be a point of force, a center area of ​​the crank arm fixed to the second fixing portion (115) of the crank arm can be a first point of support, and one end of the crank arm fixed to the first fixing portion (114) of the crank arm can be a second point of support, and the tooth portion of each chainring portion, that is, the first tooth portion to the third tooth portion, can be a point of application. Therefore, in the present invention, there exists a first rotational force generated between the point of force, the first point of support, and the point of application, and a second rotational force generated between the point of force, the second point of support, and the point of application. Accordingly, by the force applied by the driver to the point of force, a first rotational force and a second rotational force are generated at any one of the first tooth portion to the third tooth portion, which is the point of application, respectively, so that two rotational forces can be generated by a single force.

[0078] Although embodiments of the present invention have been described above with reference to the attached drawings, those skilled in the art will understand that the present invention may be implemented in other specific forms without changing its technical concept or essential features. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

Claims

Claim 1 A base ring portion; a crank arm portion fixed to the front of the base ring portion; a chain ring portion fixed to the rear surface of the base ring portion; and a pedal portion attached to the other end of the crank arm portion to apply force to the crank arm portion, wherein the crank arm portion comprises: a crank arm; a first coupling portion located at one end of the crank arm and fixed to a certain area of ​​the base ring portion; and a second coupling portion located at the other end of the crank arm to which the pedal portion is coupled, wherein the base ring portion comprises: a circular base ring; a first-1 straight support member extending from the inner circumference of a first area of ​​the base ring to the inner circumference of a second area of ​​the base ring; a first-2 straight support member arranged to intersect the first-1 straight support member and extending from the inner circumference of a third area of ​​the base ring to the inner circumference of a fourth area of ​​the base ring; and a crank arm first fixing portion located in the area where the first-1 straight support member and the first-2 straight support member intersect, to which one end of the crank arm is fixed. A bicycle crank set comprising a second crank arm fixing part disposed in a certain area of ​​the circular base ring, wherein the center area of ​​the crank arm is fixed. Claim 2 A bicycle crank set according to claim 1, wherein one end of the crank arm is fixed to the first fixing part of the crank arm and the center area of ​​the crank arm is fixed to the second fixing part of the crank arm. Claim 3 In claim 1, the chain ring portion is disposed adjacent to the base ring portion and is located in the rear direction of the base ring portion and includes a first chain ring portion of a first diameter, wherein the first chain ring portion comprises: a circular first chain ring; a first tooth portion located on the outer circumference of the first chain ring; a second-1 straight support member disposed in an area corresponding to the first-1 straight support member and extending from the inner circumference direction of the first area of ​​the first chain ring to the inner circumference direction of the second area of ​​the first chain ring; and a second-2 straight support member disposed in an area corresponding to the first-2 straight support member, disposed intersecting with the second-1 straight support member and extending from the inner circumference direction of the third area of ​​the first chain ring to the inner circumference direction of the fourth area of ​​the first chain ring. A bicycle crank set comprising a second through hole located in an area where the second-1 straight support and the second-2 straight support intersect, and further comprising a plurality of first fixing members for fixing the circular base ring and the circular first chain ring of the base ring portion, wherein the plurality of first fixing members comprises a first-1 fixing member located in a first area of ​​the first chain ring; a first-2 fixing member located in a second area of ​​the first chain ring; a first-3 fixing member located in a third area of ​​the first chain ring; and a first-4 fixing member located in a fourth area of ​​the first chain ring. Claim 4 In claim 3, the chain ring portion comprises a second chain ring portion having a second diameter, which is disposed adjacent to the first chain ring portion and is located in the rear direction of the base ring portion, and the second chain ring portion comprises: a circular second chain ring; a second tooth portion located on the outer circumference of the second chain ring; a third-1 straight support member disposed in an area corresponding to the first-1 straight support member and extending from the inner circumference direction of the first area of ​​the second chain ring to the inner circumference direction of the second area of ​​the second chain ring; and a third-2 straight support member disposed in an area corresponding to the first-2 straight support member, which is disposed intersecting with the third-1 straight support member and extends from the inner circumference direction of the third area of ​​the second chain ring to the inner circumference direction of the fourth area of ​​the second chain ring. A bicycle crank set comprising a third through hole located in an area where the second-1 straight support and the second-2 straight support intersect, wherein the second chain ring portion includes a plurality of second fixing members for fixing the first-1 straight support of the base ring portion, the first-2 straight support of the base ring portion, and the circular second chain ring, respectively, wherein the plurality of second fixing members include a second-1 fixing member located in a first area of ​​the second chain ring; a second-2 fixing member located in a second area of ​​the second chain ring; a second-3 fixing member located in a third area of ​​the second chain ring; and a second-4 fixing member located in a fourth area of ​​the second chain ring.

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