Title of Invention	"GEAR DEVICE"
Abstract	A gear device having a first gear as a drive gear and second gear as a driven gear meshed with each other, characterized in that: either said first gear or said second gear is constituted by a main gear (30) and a sub-gear (31) which has the same diameter as said main gear (30) and is relatively rotatable; and only said sub-gear (31) is meshed with a third gear (22, 24) as a driven gear.

Full Text

FORM 2 THE PATENTS ACT 1970 [39 OF 1970] COMPLETE SPECIFICATION [See Section 10] "GEAR DEVICE" HONDA GIKEN KOGYO KABUSHIKI KAISHA, a corporation of Japan, having a place of business at 1-1, Minamiaoyama 2-chome, Minato-ku, Tokyo, Japan, The following specification particularly describes the nature of the invention and the manner in which it is to be performed:- [DETAILED DESCRIPTION OF THE INVENTION] This invention relates to a gear device having a canceling structure suitable for a power transmission system gear train of an engine. In the present invention, a mechanism in which a main gear and a sub-gear are superposed, and a canceling load is applied between both the gears to form a phase difference is called a canceling structure, and a gear having a main gear having such a canceling structure as described combined with a sub-gear is called a canceling gear. [RELATED ART] There is well known that for relieving meshing noises in a gear train, one gear in the gear train is constituted into a canceling gear comprising a main gear, a sub-gear which has the same diameter as the main gear and is superposed relatively rwatably, a spring (hereinafter called a canceling spring) which is interposed between the sub-gear and the main gear to bias both the gears to be rotated in a direction reverse to each other to form a phase difference (For example, Japanese Utility Model Application Laid-Open No. 1-169659, and Japanese Utility Model Publication No. 4-13468). Further, in the Japanese Utility Model Application Laid-Open No. 1-169659, there is shown that an idle gear provided between a drive gear and a driven gear constitutes a canceling gear. [PROBLEM TO BE SOLVED BY THE INVENTION] Incidentally, in any of the aforementioned conventional canceling gears, a canceling spring has to be provided between a main gear and a sub-gear, thus posing problems that a canceling spring has to be prepared; the number of parts increases; working or processing is necessary for mounting a canceling spring on the gear side; and the whole structure becomes large-scaled. It is therefore an object of the present invention to provide a gear device having a canceling structure capable of solving such problems as noted above. [MEANS FOR SOLVING THE PROBLEM] For solving the aforementioned problems, according to the present invention, there is provided a gear device having a first gear as a drive gear and a second gear as a driven gear meshed with each other, characterized in that either the first gear or the second gear is constituted by a main gear and a sub-gear which has the same diameter as the main gear and is relatively rotatable; and only the sub-gear is meshed with a third gear as a driven gear. [EFFECT OF THE INVENTION] Suppose that the first gear is constituted by the main gear and the sub-gear which has the same diameter as that of the main gear and is relatively rotatable, both the main gear and the sub-gear are meshed with the second gear, and only the sub-gear is meshed with the third gear as a driven gear for driving other parts. Then, in addition to a power transmission channel comprising the main gear and the second gear, and in connection with the sub-gear, a power transmission channel comprising the main gear, the second gear, and the third gear is formed. At this time, the third gear drives other parts to thereby receive a resistance, and this resistance is applied from the third gear to the main gear whereby the sub-gear forms a phase difference with respect to the main gear, functioning similarly to the conventional canceling gear. Accordingly, the resistance in the third gear generates a canceling load, and even if a canceling spring for the gear is not provided, the meshing noises can be reduced similarly to the conventional canceling construction. Therefore, it is possible to omit the canceling spring to reduce the number of parts, possible to require no mounting work of the canceling spring, and possible to achieve compactness of the whole device. Accordingly, the present invention relates to a gear device having a first gear as a drive gear and second gear as a driven gear meshed with each other, characterized in that: either said first gear or said second gear is constituted by a main gear and a sub-gear which has the same diameter as said main gear and is relatively rotatable; and only said sub-gear is meshed with a third gear as a driven gear. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS FIG. 1 is a side view of an engine according to an embodiment. FIG. 2 is a view schematically showing a power transmission channel over the side of the engine. FIG. 3 is a top view showing a part of the engine in a cutaway Form. FIG. 4 is an enlarged sectional view showing a canceling gear portion in the embodiment. FIG.5 is a sectionaly view taken on line 5-5 of FIG. 1. [ BODIMENTS OF THE INVENTION] One embodiment will be described hereinafter with reference to the drawings. FIG. 1 is a side view of a 4-cycle engine, FIG. 2 is a view schematically showing a power transmission channel on the side thereof, FIG. 3 is a top view of the engine showing it with a part cutaway, FIG. 4 is an enlarged sectional view showing a canceling gear portion, and FIG. 5 is a sectional view taken on line 5-5 of FIG. 1. In these drawings, an engine 1 has a cylinder 2, a cylinder head 3, and a head cover 4. Numeral 5 designates a carburetor; 6 a supply and exhaust valve; 7 a piston, and 8 a connecting rod. The connecting rod 8 is connected to a crank shaft 9 to rotate a primary gear 10 provided on the crank shaft 9. The primary gear 10 is meshed with a primary driven gear 12 provided on the clutch outer side of a clutch mechanism 11. The clutch inner side of the clutch mechanism 11 is connected to a main shaft 13, and a main gear train 14 provided thereon is always meshed with a counter gear train 16 provided on a counter shaft 15 parallel with the main shaft 13 to constitute a transmission (speed change gear). A power of the crank shaft 9 is transmitted to the primary gear 10, the primary driven gear 12, the clutch mechanism 11, the main shaft 13, the main gear train 14, the counter gear train 16, and the counter shaft 15, and is output in speed change from an output sprocket 17 on the same shaft as the counter shaft. Numeral 18 designates a kick shaft; 19 a kick gear; and a kick arm. The respective shafts in FIG. 2 show the respective center positions by a cross line. Further, the primary gear 10 is also meshed with a drive gear 22 of a water pump 21 provided thereabove and a drive gear 24 of an oil pump 23 to drive them. Numeral 25 in FIG. 2 designates a balancer gear, which is meshed with a drive gear on the crank shaft 9 (FIG. 3). Next, the canceling structure in the present embodiment will be described with reference to FIGS. 4 and 5. As shown in FIG. 4, the primary gear 10 comprises a main gear 30, and a sub-gear 31 which has the same diameter as that of the main gear 30, the main gear 30 is integrated with the crank shaft 9 by a key 32, and the sub-gear 31 is rotatably supported on a shoulder 33 of the main gear 30 and is relatively rotatable with the main gear 30. The main gear 30 is secured by a nut 35 through a washer 34 from the end of the crank shaft 9. Both the main gear 30 and the sub-gear 31 are meshed with the primary driven gear 12 of the clutch mechanism 11. As shown in FIG. 5, only the sub-gear 31 is further meshed with the drive gear 22 of the water pump 21 and the drive gear 24 of the oil pump 23 arranged vertically. So, when the crank shaft 9 is rotated, the main gear 30 of the primary gear 10 drives and rotates the primary driven gear 12, and drives and rotates the drive gear 22 of the water pump 21 and the drive gear 24 of the oil pump 23 through the sub-gear 31 from the primary driven gear 12. The primary gear 10, the primary driven gear 12 , the drive gear 22 of the water pump 21 and the drive gear 24 of the oil pump 23 in the present embodiment respectively correspond to the first gear, the second gear, and the third gear in the present invention. Next, the operation of the present embodiment will be described. By rotation of the crank shaft 9, power is transmitted from the main gear 30 of the primary gear 10 to the primary driven gear 12 of the clutch mechanism 11, and at this time, separately from the main gear 30, the sub-gear 31 rotates and drives the drive gears 22 and 24 simultaneously by the power transmission channel comprising the main gear 30, the primary driven gear 12, the sub-gear 31, the drive gear 22 of the water pump 21 and the drive gear 24 of the oil pump 23. Therefore, the resistances are applied to the sub-gear 31 from the water pump 21 and oil pump 23 sides, and a phase difference is formed between the sub-gear 31 and the main gear 30, and in a meshing portion with the primary driven gar 12, a meshing portion of the primary driven gear 12 is sandwiched between the meshing portions of the main gear 30 and the sub-gear 31 to enable reducing the meshing noises. Accordingly, the resistances applied to the sub-gear 31 from the drive gear 22 of the water pump 21 and the drive gear 24 of the oil pump 23 generate a canceling load, and only the main gear 30 and the sub-gear 31 function as a canceling gear similarly to the prior art. Therefore, a canceling spring need not be interposed between the main gear 30 and the sub-gear 31 as in prior art, and the reduction in the number of parts and abolition of working at the canceling spring mounting portion become enabled to enable making the whole canceling gear compact. In addition, the sub-gear 31 is merely meshed with other parts, that is, the drive gears 22, 24 with respect to the water pump 21 and the oil pump 23, and an exclusive-use part as a canceling gear is not particularly demanded, this capable of simplifying the construction. The present invention is not limited to the aforementioned embodiment but various modifications can be made within the principle of the present invention. For example, an object to be meshed with the sub-gear 31 may be a drive gear on either side of the water pump 21 or the oil pump 23, and further, a gear for driving other parts comprising accessories separately from the former may be employed. Furthermore, the canceling gear in the present invention may be provided not only on the primary gear 10 but on the primary driven gear 12, and in addition, may be provided on any gear train if it is a gear train for transmitting power which requires [DESCRIPTION OF REFERENCE NUMERALS] 1: engine, 9: crank shaft, 10 : primary gear, 11: clutch mechanism, 12 : primary driven gear, 21: water pump, 22: drive gear, 23: oil pump, 24: drive gear, 30: main gear, 31: sub-gear. We claim: 1. A gear device having a first gear as a drive gear and second gear as a driven gear meshed with each other, characterized in that: either said first gear or said second gear is constituted by a main gear (30) and a sub-gear (31) which has the same diameter as said main gear (30) and is relatively rotatable; and only said sub-gear (31) is meshed with a third gear (22, 24) as a driven gear. 2. A gear device substantially as herein described with reference to the accompanying drawings. Dated this 21st day of September, 2001. (RANJNA MEHTA-DUTT) OF REMFRY 8B SAGAR ATTORNEYS FOR THE APPLICANTS

Documents:

914-MUM-2001-ABSTRACT(21-9-2001).pdf

914-mum-2001-cancelled pages(17-01-2006).pdf

914-mum-2001-claims (granted) (17-01-2006).doc

914-mum-2001-claims (granted) (17-01-2006).pdf

914-MUM-2001-CLAIMS(21-9-2001).pdf

914-mum-2001-claims(granted)-(1-3-2007).pdf

914-mum-2001-correspondence(09-03-2006).pdf

914-MUM-2001-CORRESPONDENCE(18-12-2006).pdf

914-mum-2001-correspondence(ipo)(20-01-2006).pdf

914-MUM-2001-CORRESPONDENCE(IPO)-(23-4-2007).pdf

914-MUM-2001-DECLARATION(21-9-2001).pdf

914-MUM-2001-DESCRIPTION(COMPLETE)-(21-9-2001).pdf

914-mum-2001-description(granted)-(1-3-2007).pdf

914-mum-2001-drawing(21-09-2001).pdf

914-MUM-2001-DRAWING(21-9-2001).pdf

914-mum-2001-drawing(granted)-(1-3-2007).pdf

914-mum-2001-form 1(21-09-2001).pdf

914-mum-2001-form 18(02-09-2005).pdf

914-MUM-2001-FORM 2(COMPLETE)-(21-9-2001).pdf

914-mum-2001-form 2(granted) (17-01-2006).doc

914-mum-2001-form 2(granted) (17-01-2006).pdf

914-mum-2001-form 2(granted)-(1-3-2007).pdf

914-MUM-2001-FORM 2(TITLE PAGE)-(21-9-2001).pdf

914-mum-2001-form 2(title page)-(granted)-(1-3-2007).pdf

914-mum-2001-form 3(02-01-2002).pdf

914-mum-2001-form 3(17-01-2006).pdf

914-mum-2001-form 3(21-09-2001).pdf

914-mum-2001-form 5(02-09-2001).pdf

914-MUM-2001-FORM 5(21-9-2001).pdf

914-mum-2001-petition under rule-138(17-01-2006).pdf

914-mum-2001-power of attorney(17-01-2006).pdf

914-MUM-2001-POWER OF AUTHORITY(23-11-2001).pdf

914-MUM-2001-SPECIFICATION(AMENDED)-(17-1-2006).pdf