WO2007015609A1

WO2007015609A1 - A gear transmission for a bicycle

Info

Publication number: WO2007015609A1
Application number: PCT/KR2006/002952
Authority: WO
Inventors: Ji Hyun Ma
Original assignee: Ji Hyun Ma
Priority date: 2005-08-03
Filing date: 2006-07-27
Publication date: 2007-02-08
Also published as: KR20050083054A; KR100688611B1

Abstract

The present invention relates to a gear transmission for a bicycle, in that a driven assembly for a gear transmission is coupled to a driving assembly having a plurality of driving bevel gears arranged in the form of a concentric circle with different tooth profiles mutually, whereby it can minimize a power loss source and the number of components in the course of the power transmission. The gear transmission for a bicycle comprising: a driving assembly comprising a housing and a plurality of driving bevel gears different tooth profiles mutually arranged in the form of a concentric circle into the housing, the driving assembly being assembled to a pedal through a crank; a driven assembly partially inserted into the housing and having a driven shaft axially coupled to a plurality of driven bevel gears driven selectively by engaging with each of the driving bevel gears of the driving assembly; a bearing axially coupled to a rear of the driven bevel gears in such a manner that the driven shaft can be supported on the housing to be rotated; a pinion assembly comprising a pinion body axially coupled to the driven shaft, a plurality of pinion gears rotably formed along a circumference of the pinion body, and a transfer screw rotably fixed to the pinion gear; a rack assembly having a rack engaged with the pinion gear along an inner circumference thereof in order that the rack assembly is rotated together with the transfer screw of the pinion assembly; a moving plate axially coupled to the driven shaft and coupled to the transfer screw of the pinion assembly in order to reciprocate according to the rotation of the transfer screw; and a pin for transmitting a power having latching projections at both ends thereof, one projection formed at one side thereof being inserted into a latching groove formed at an inner circumference of the moving plate in order to move according to the reciprocating motion of the moving plate and another projection formed at the other side thereof being coupled to any one of the driven bevel gears.

Description

A MANUAL TRANSMISSION FOR A BICYCLE

Technical Field

[1] The present invention relates to a gear transmission for a bicycle, and more particularly to a gear transmission for a bicycle, in that a driven assembly for a gear transmission is coupled to a driving assembly having a plurality of driving bevel gears arranged in the form of a concentric circle with different tooth profiles mutually, whereby it can minimize a power loss source and the number of components in the course of the power transmission. Background Art

[2] Generally, a bicycle for sports or transportation is moved by means of a driving force transmitted through a pedal. Here, the driving force of the pedal is transmitted through a chain in a rear- wheel drive manner.

[3] However, in the conventional bicycle, since the relaxation state of the chain is repeatedly maintained in the course of the power transmission, the efficiency of the power transmission is lowered, thereby the chain can be separated.

[4] In order to solve the problem, a driving device of a bicycle for transmitting a power to an engaged gear has been proposed in Korean paten application No. 10-2002-0058350 filed by the present applicant. In the patent application, the gear transmission is performed through each bevel gear of a driving assembly arranged in the form of a concentric circle.

[5] However, in the present invention, a driving assembly provides only the power and the gear transmission can be performed through the driven assembly coupled to the driving assembly, dissimilarly with the patent application.

[6]

Disclosure of Invention Technical Problem

[7] Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and a first object of the present invention is to provide a gear transmission for a bicycle in that a driven assembly for a gear transmission is coupled to a driving assembly having a plurality of driving bevel gears arranged in the form of a concentric circle with different tooth profiles mutually, so that it can minimize a power loss source and the number of components in the course of the power transmission.

[8] A second object of the present invention is to provide a gear transmission for a bicycle in that the driving assembly provides only the power and the gear transmission can be performed through the driven assembly coupled to the driving assembly. [9]

Technical Solution

[10] To accomplish the objects, the present invention provides a gear transmission for a bicycle comprising: a driving assembly comprising a housing and a plurality of driving bevel gears different tooth profiles mutually arranged in the form of a concentric circle into the housing, the driving assembly being assembled to a pedal through a crank; a driven assembly partially inserted into the housing and having a driven shaft axially coupled to a plurality of driven bevel gears driven selectively by engaging with each of the driving bevel gears of the driving assembly; a bearing axially coupled to a rear of the driven bevel gears in such a manner that the driven shaft can be supported on the housing to be rotated; a pinion assembly comprising a pinion body axially coupled to the driven shaft, a plurality of pinion gears rotably formed along a circumference of the pinion body, and a transfer screw rotably fixed to the pinion gear; a rack assembly having a rack engaged with the pinion gear along an inner circumference thereof in order that the rack assembly is rotated together with the transfer screw of the pinion assembly; a moving plate axially coupled to the driven shaft and coupled to the transfer screw of the pinion assembly in order to reciprocate according to the rotation of the transfer screw; and a pin for transmitting a power having latching projections at both ends thereof, one projection formed at one side thereof being inserted into a latching groove formed at an inner circumference of the moving plate in order to move according to the reciprocating motion of the moving plate and another projection formed at the other side thereof being coupled to any one of the driven bevel gears.

[H]

[12] Preferably, the driven shaft has a plurality of pin grooves for inserting the pin therein extending to each of the driven bevel gears axially coupled to the driven shaft.

[13] Preferably, each of the driving bevel gears is rotated together with each other.

[14] Preferably, each of the driven bevel gears of the driven assembly can be rotated individually and has a plurality of splines capable of inserting the latching projection of the pin in an inner circumference thereof.

[15] Preferably, each of the driven bevel gears comprises a gear neutral portion extending to a front thereof and comprising a groove portion having the same depth as the spline formed at an inner circumference thereof in order that the power is not transmitted to the driven shaft so as to escape an interference with the latching projections inserted into the spline.

[16] Preferably, the pinion assembly further comprises a coupling member screwed on the housing along an outer circumference thereof and a pinion body screwed on an inside of the coupling member.

[17] Preferably, the pinion body has a stepped portion for adhering to the rack assembly.

[18] Preferably, a gear transmission wire is coupled to an outer circumference of the rack assembly in such a manner that the rack assembly is forcibly rotated to be transmitted the power through any one of the driven bevel gears.

[19] Preferably, an elastic means is interposed between the rack assembly and the pinion assembly in such a manner that the rack assembly rotated through the gear transmission wire is elastically returned in order to move the pin backward and forward.

[20]

Advantageous Effects

[21] As can be seen from the foregoing, the gear transmission for the bicycle, the driven assembly for the gear transmission is coupled to the driving assembly, thereby it can minimize a power loss source and the number of components in the course of the power transmission.

Brief Description of the Drawings [22] The above as well as the other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: [23] FIG. 1 is a sectional view illustrating a gear transmission for a bicycle according to the present invention; [24] FIG. 2 is an exploded perspective view illustrating the gear transmission for the bicycle exclusive a driving assembly according to the present invention; [25] FIG. 3 is a perspective view illustrating a driven bevel gear of FIG. 2;

[26] FIG. 4 through FIG. 6 are a sectional view illustrating an operation of the gear transmission for the bicycle according to the present invention; and [27] FIG. 7 is a sectional view illustrating the use state of the gear transmission for the bicycle according to the present invention. [28]

Best Mode for Carrying Out the Invention [29] A preferred embodiment of the invention will be described in detail below with reference to the accompanying drawings. [30] FIG. 1 is a sectional view illustrating a gear transmission for a bicycle according to the present invention, FIG. 2 is an exploded perspective view illustrating the gear transmission for the bicycle exclusive a driving assembly according to the present invention, and FIG. 3 is a perspective view illustrating a driven bevel gear of FIG. 2. [31] As shown in FIG. 1 through FIG. 3, the gear transmission for the bicycle according to the present invention includes a driving assembly 10 having a plurality of driving bevel gears 12, 13, 14, 15 and 16 arranged in the form of a concentric circle with different tooth profiles mutually and a driven assembly 20 for the gear transmission coupled to the driving assembly 10, thereby it can minimize a power loss source and the number of components in the course of the power transmission.

[32] The gear transmission for the bicycle according to the present invention includes the driving assembly 10, the driven assembly 20 coupled to the driving assembly 10 in order to receive the power, and a pinion assembly 40 axially mounted to the driven assembly 20, a rack assembly 60 for inserting the pinion assembly 40 therein, a moving plate 70 transferred through a transfer screw 43 coupled to a pinion gear of the pinion assembly 40, and a pin 80 for transmitting the power to a driven shaft 21 coupled to any one of driven bevel gears 22, 23, 24, 25 and 26 by means of a latching projection 81 formed at both ends thereof.

[33] Firstly, the driving assembly 10 includes a housing 11 and the plurality of driving bevel gears 12, 13, 14, 15 and 16 having different tooth profiles mutually arranged in the form of a concentric circle into the housing 11. Also, the driving assembly 10 is assembled to a pedal 220 through a crank 210.

[34] Here, the housing 11 of a circular plate includes a coupling portion 11a extending to one side thereof and coupled to the coupling means 90.

[35] Also, the plurality of driving bevel gears 12, 13, 14, 15 and 16 is formed in the form of a concentric circle into the housing 11. That is, the driving bevel gears 12, 13, 14, 15 and 16 for a five-speed bicycle become larger gradually toward the periphery from the center thereof while being arranged in the form of a concentric circle.

[36] Here, each of the driving bevel gears 12, 13, 14, 15 and 16 has a tooth structure arranged at the same interval. Also, the number of the tooth thereof is increased in proportion to the size of the diameter of the concentric circle.

[37] It is preferred that each of the driving bevel gears 12, 13, 14, 15 and 16 is rotated together with each other.

[38] The driven assembly 20 is partially inserted through the coupling portion 1 Ia of the housing 11 and includes a driven shaft 21 axially coupled to the driven bevel gears 22, 23, 24, 25 and 26 driven selectively by engaging with the driving bevel gears 12, 13, 14, 15 and 16 of the driving assembly 10.

[39] Also, the driven shaft 21 includes four pin grooves 21a for inserting the pins 80 therein arranged along the outer circumference at the same interval. Each pin groove 21a extends to each of the driven bevel gears 22, 23, 24, 25 and 26. Here, a bearing 30 is axially coupled to the coupling portion 1 Ia of the housing 11 in such a manner that the driven shaft 21 can be supported and rotated through the coupling portion 1 Ia of the driving assembly 10. [40] The first driven bevel gear 22 engaged with the first driving bevel gear 12, the second driven bevel gear 23 engaged with the second driving bevel gear 13, the third driven bevel gear 24 engaged with the third driving bevel gear 14, the fourth driven bevel gear 25 engaged with the fourth driving bevel gear 15, and the fifth driven bevel gear 26 engaged with the fifth driving bevel gear 16 are axially the driven shaft 21 in order.

[41] Here, each of the driven bevel gears 22, 23, 24, 25 and 26 can be rotated individually and includes eight splines 27 capable of inserting the latching projections 81 of each pin 80 in the inner circumference thereof.

[42] In the meantime, each of the driven bevel gears 22, 23, 24, 25 and 26 further includes a gear neutral portion 28 extending to the front thereof. The gear neutral portion 28 includes a groove portion 28a having the same depth as the spline 27 formed at the inner circumference thereof in order that the power is not transmitted to the driven shaft 21 so as to escape the interference with the latching projections 81 inserted into the splines 27.

[43] Accordingly, the gear transmission of one stage - neutral stage - two stage - neutral stage - three stage - neutral stage - four stage - neutral stage - five stage can be performed according to the selective position of the splines of each of the driven bevel gears 22, 23, 24, 25 and 26 and the groove portion 28a of the gear neutral portion 28.

[44] The pinion assembly 40 includes a coupling member 90 screwed on the coupling portion 1 Ia of the housing 11 and a pinion body 41 screwed on the inside of the coupling member 90 and axially coupled to the driven shaft 21.

[45] Here, four pinion gears 42 are formed along the circumference of the pinion body

41 and two transfer screws 43 are coupled to two pinion gears 42 among the pinion gears 42. Also, it is preferred that the pinion body 41 includes a stepped portion 41a for adhering to the rack assembly 60.

[46] The rack assembly 60 is adhered to the stepped portion 41a of the pinion body 41 interposed between the coupling member 90 and the rack assembly 60.

[47] The rack assembly 60 includes a rack 61 engaged with the pinion gear 42 in order that the rack assembly 60 for inserting the pinion assembly 40 therein is rotated together with the transfer screw 43.

[48] In the meantime, a gear transmission wire 62 is coupled to the outer circumference of the rack assembly 60.

[49] Where the gear transmission wire 62 is drawn, the rack assembly can be forcibly rotated for the gear transmission thereof.

[50] The moving plate 70 is axially coupled to the driven shaft 21 and is coupled to the transfer screw 43 of the pinion gear 42 in order to reciprocate according to the rotation of the transfer screw 43. That is, the transfer screw 43 of the pinion gear 42 is rotated according to the rotating direction of the rack assembly 60, so that the transfer screw

43 can be moved back and forward. Accordingly, the moving plate 70 can be moved along the driven shaft 21 while the pinion assembly 40 is coupled and fixed to the coupling member 90. [51] The pin 80 of a bar shape includes the latching projections 81 protruded from both sides thereof. At least two pins 80 are slid on and inserted into the pin grooves 21a of the driven shaft 21 and one latching projection 81 of each pin 80 is inserted into a latching groove 71 of the moving plate 70. [52] Accordingly, each pin 80 can be reciprocated along the pin grooves 21a of the driven shaft 21. [53] Also, since one side of each pin 80 can be moved along the pin grooves 21a extending toward each of the driven bevel gears 22, 23, 24, 25 and 26, one side of each pin 80 can be coupled to the spline 27 of any one of the driven bevel gears 22, 23, 24,

25 and 26 for the transmission of the power. [54] More concretely, the latching projections 81 of each pin 80 are coupled to the spline

27 of any one of the driven bevel gears 22, 23, 24, 25 and 26 for the transmission of the power. [55] In the meantime, preferably, an elastic means 50 is interposed between the rack assembly 60 and the pinion assembly 40 in such a manner that the rack assembly 60 rotated through the gear transmission wire 62 is elastically returned in order to move the pin 80 backward and forward.

[56] The elastic means 50 may be a mechanical spring or a coil spring.

[57] The coupling structure of the gear transmission for a bicycle according to the present invention will be described in detail below. [58] Each of the driven bevel gears 22, 23, 24, 25 and 26 of the driven assembly 20 is engaged with the driving bevel gears 12, 13, 14, 15 and 16 of the driving assembly 10 and the driven shaft 21 axially coupled to each of the driven bevel gears 22, 23, 24, 25 and 26 is partially inserted into the housing 11. [59] The bearing 30 is axially coupled to the driven shaft 21 and the coupling portion

1 Ia of the housing 11 in such a manner that the driven shaft 21 can be smoothly rotated. [60] The coupling member 90 is screwed on the coupling portion 1 Ia of the housing 11 in order to prevent the separation of the bearing 30. [61] The pinion body 41 of the pinion assembly 40 is screwed on and fixed to the inner circumference of the coupling member 90. [62] In a state that the gear transmission wire 62 is coupled to the outer circumference of the rack assembly 60, the rack assembly 60 is formed at the outside of the pinion body and adhered to the stepped portion 41a of the body and interposed between the pinion body 41 and the coupling member 90.

[63] Also, the moving plate 70 is axially coupled to the driven shaft 21 and is coupled to the transfer screw 43 of the pinion gear 42 in order to reciprocate along the driven shaft 21.

[64] Latching projection 81 formed at one side of each pin 80 is inserted into a latching groove 71 formed at the inner circumference of the moving plate 70 in order to move according to the reciprocating motion of the moving plate 70. Here, latching projection 81 formed at another side of each pin 80 is coupled to the spline 27 of any one of the driven bevel gears 22, 23, 24, 25 and 26.

[65] The operation of the gear transmission for a bicycle according to the present invention will be briefly described below with reference to the accompanying drawings.

[66] FIG. 4 through FIG. 6 are a sectional view illustrating an operation of the gear transmission for the bicycle according to the present invention and FIG. 7 is a sectional view illustrating the use state of the gear transmission for the bicycle according to the present invention.

[67] Firstly, as shown in the bicycle 200 of FIG. 4, latching projection 81 formed at one side of each pin 80 is located at the first driven bevel gear 22. Here, another latching projection 81 of each pin 80 is inserted into the latching groove 71 formed at the inner circumference of the moving plate 70.

[68] Continuously, as shown in FIG. 5, where the gear transmission wire 62 is drawn, the rack assembly 60 is forcibly rotated and the pinion gear 42 of the pinion assembly 40 is rotated together with the rack assembly in order to rotate the transfer screw 43.

[69] Thereafter, the moving plate 70 is moved backward in accordance with the number of the rotation of the transfer screw 43 and the pin 80 inserted into the moving plate 70 is moved backward, so that the latching projection 81 of each pin 80 is located at the second driven bevel gear 23.

[70] In this case, the driving assembly 10 is forcibly driven through the pedal 220, the power is transmitted to only the second driven bevel gear 23, the bicycle 200 can be traveled in two-stage.

[71]

[72] In the meantime, as shown in FIG. 6, where the gear transmission wire 62 is drawn in the opposite direction for neutral-stage, the rack assembly 60 is rotated in the opposite direction by means of the elastic strength of stability of the elastic means 50 interposed between the rack assembly 60 and the pinion assembly 40. At the same time, the moving plate 70 is moved forward and the latching projection 81 of each pin 80 is located at the groove portion 28a of the gear neutral portion 28 of the second driven bevel gear 23, thereby it becomes the neutral-stage. [73] Accordingly, the gear transmission of the five-stage can be performed through the above structure. Also, it can be selectively changed to the gear neutral stage per each stage.

[74] While this invention has been described in connection with what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments and the drawings, but, on the contrary, it is intended to cover various modifications and variations within the spirit and scope of the appended claims.

[75]

Industrial Applicability

[76] The present invention relates to a gear transmission for a bicycle, in that a driven assembly for a gear transmission is coupled to a driving assembly having a plurality of driving bevel gears arranged in the form of a concentric circle with different tooth profiles mutually, whereby it can minimize a power loss source and the number of components in the course of the power transmission.

[77]

[78]

Claims

[1] A gear transmission for a bicycle comprising: a driving assembly comprising a housing and a plurality of driving bevel gears different tooth profiles mutually arranged in the form of a concentric circle into the housing, the driving assembly being assembled to a pedal through a crank; a driven assembly partially inserted into the housing and having a driven shaft axially coupled to a plurality of driven bevel gears driven selectively by engaging with each of the driving bevel gears of the driving assembly; a bearing axially coupled to a rear of the driven bevel gears in such a manner that the driven shaft can be supported on the housing to be rotated; a pinion assembly comprising a pinion body axially coupled to the driven shaft, a plurality of pinion gears rotably formed along a circumference of the pinion body, and a transfer screw rotably fixed to the pinion gear; a rack assembly having a rack engaged with the pinion gear along an inner circumference thereof in order that the rack assembly is rotated together with the transfer screw of the pinion assembly; a moving plate axially coupled to the driven shaft and coupled to the transfer screw of the pinion assembly in order to reciprocate according to the rotation of the transfer screw; and a pin for transmitting a power having latching projections at both ends thereof, one projection formed at one side thereof being inserted into a latching groove formed at an inner circumference of the moving plate in order to move according to the reciprocating motion of the moving plate and another projection formed at the other side thereof being coupled to any one of the driven bevel gears.

[2] A gear transmission for a bicycle as claimed in claim 1, wherein the driven shaft has a plurality of pin grooves for inserting the pin therein extending to each of the driven bevel gears axially coupled to the driven shaft.

[3] A gear transmission for a bicycle as claimed in claim 1, wherein each of the driving bevel gears is rotated together with each other.

[4] A gear transmission for a bicycle as claimed in claim 1, wherein each of the driven bevel gears of the driven assembly can be rotated individually and has a plurality of splines capable of inserting the latching projection of the pin in an inner circumference thereof.

[5] A gear transmission for a bicycle as claimed in claims 1 or 4, wherein each of the driven bevel gears comprises a gear neutral portion extending to a front thereof and comprising a groove portion having the same depth as the spline formed at an inner circumference thereof in order that the power is not transmitted to the driven shaft so as to escape an interference with the latching projections inserted into the spline.

[6] A gear transmission for a bicycle as claimed in claim 1, wherein the pinion assembly further comprises a coupling member screwed on the housing along an outer circumference thereof and a pinion body screwed on an inside of the coupling member.

[7] A gear transmission for a bicycle as claimed in claims 1 or 6, wherein the pinion body has a stepped portion for adhering to the rack assembly.

[8] A gear transmission for a bicycle as claimed in claim 1, wherein a gear transmission wire is coupled to an outer circumference of the rack assembly in such a manner that the rack assembly is forcibly rotated to be transmitted the power through any one of the driven bevel gears.

[9] A gear transmission for a bicycle as claimed in claim 1, wherein an elastic means is interposed between the rack assembly and the pinion assembly in such a ma nner that the rack assembly rotated through the gear transmission wire is elastically returned in order to move the pin backward and forward.