Belt type continuous reduction gear mechanism

Claim 2

A belt type continuous reduction gear mechanism comprising: a drive V-pulley; a driven V-pulley; and a V-belt made to run under tension between said two V-pulleys, wherein said drive V-pulley is arranged coaxially with a start clutch, which is arranged coaxially with the crankshaft of an engine and is constructed of a hydraulic multi-disc clutch, and has its external diameter reduced to substantially the same as that of said start clutch thereby to set the reduction ratio range at a relatively small value, and wherein said driven V-pulley is connected to an auxiliary reduction gear mechanism of plural-step type for compensating the shortage of said reduction ratio range.

Claim 3

A belt type continuous reduction gear mechanism as set forth in claim 1, wherein said drive and driven V-pulleys and said V-belt are accommodated in an auxiliary case which abuts against the outer side of a main case bearing the crankcase of said engine and accommodating said auxiliary reduction gear mechanism, and wherein a coaction mechanism for effecting the coaction between said drive and driven V-pulleys is accommodated in a cover which closes the outer side of said auxiliary case.

Claim 4

A belt type continuous reduction gear mechanism, wherein, in a casing accommodating an engine and a start clutch connected to the crankshaft of said engine outside of said engine, there are accommodated both drive and driven V-pulleys, which are positioned outside of said start clutch and each of which is equipped with such a movable pulley half as can move back and forth relative to a fixed pulley half thereby to adjust an effective radius, and a V-belt which is made to run under tension between said two pulleys, wherein, on a drive pulley shaft which is arranged coaxially with said crankshaft, there are mounted both the fixed pulley half of said drive V-pulley at the inner side and such a movable pulley half at the outer side as carries an actuator for adjusting the effective radius, wherein said fixed pulley half is connected to said start clutch, and wherein, on a driven pulley shaft which is arranged in parallel with said drive pulley shaft, there are mounted both the fixed pulley half of said driven V-pulley at the outer side and such a movable pulley half at the inner side as carries an actuator for adjusting the effective radius.

Claim 5

A belt type continuous reduction gear mechanism, wherein, in a casing accommodating an engine and a start clutch connected to the crankshaft of said engine outside of said engine, there are accommodated both drive and driven V-pulleys, which are positioned outside of said start clutch and each of which is equipped with such a movable pulley half as can move back and forth relative to a fixed pulley half thereby to adjust an effective radius, and a V-belt which is made to run under tension between said two pulleys, wherein, on a drive pulley shaft which is arranged coaxially with said crankshaft, there are mounted both the fixed pulley half of said drive V-pulley at the inner side and such a movable pulley half at the outer side as carries an actuator for adjusting the effective radius, wherein said fixed pulley half is connected to said start clutch, and wherein, on a driven pulley shaft which is arranged in parallel with said drive pulley shaft, there are mounted both the fixed pulley half of said driven V-pulley at the outer side and such a movable pulley half at the inner side as carries an actuator for adjusting the effective radius.

Claim 6

A belt type continuous reduction gear mechanism as set forth in claim 3, the respective actuators for adjusting the effective radii of said drive and driven V-pulleys are constructed of pistons and hydraulic cylinders accommodating the former, and wherein the hydraulic cylinder of said drive V-pulley is made to have a larger diameter than that of said driven V-pulley.

Claim 7

A belt type continuous reduction gear mechanism as set forth in claim 3, wherein said start clutch is constructed of hydraulic type, wherein an oil pump is connected through a control line to said start clutch, and wherein there is disposed in said control line a clutch valve for controlling the discharge pressure of said oil pump so that the connection oil pressure of said start clutch is varied proportionately of the squeezed extent of a clutch lever.

Claim 8

A belt type continuous reduction gear mechanism as set forth in claim 5, wherein said start clutch comprises: a rotary shaft; an outer clutch member so mounted on said rotary shaft as to rotate together with the same; an inner clutch member rotatably mounted on said rotary shaft; a plurality of drive and driven friction discs alternately interposed in a coextensive manner between said outer clutch member and said inner clutch member and slidably coupled to said outer and inner clutch members, respectively; a hydraulic actuator mechanism disposed in said outer clutch member for thrusting said drive and driven friction discs; a working oil passage formed in said rotary shaft for supplying the working oil to said hydraulic actuator mechanism; a cooling oil passage branched from said working oil passage for supplying the working oil as cooling oil to said drive and driven friction discs; a flow regulating valve slidably fitted in said working oil passage and made operative in response to the oil pressure of said oil passage to reduce the flow rate of said cooling oil passage to a zero or low level when the clutch is blocked or connected, or to increase the flow rate of said cooling oil passage to a high level when the clutch is partially applied.

Claim 9

A belt type continuous reduction gear mechanism as set forth in claim 6, wherein said rotary shaft is made hollow and is borne in a casing having an oil supply passage, wherein said hydraulic actuator mechanism is arranged on the outer circumference of said rotary shaft, and wherein a communication conduit for supplying the working oil to said hydraulic actuator mechanism has its one end supported in a floating manner through an elastic seal member in the oil port of said oil supply passage, which is formed in the inner wall of said casing and which has its center line aligned with the axis of said rotary shaft, and its other end fitted in said rotary shaft.