JPS61197839A - Power transmission gear - Google Patents

Abstract

PURPOSE:To prevent the vibration generated in a larger reduction gear from being transmitted to a transmission case as well as said vibration being damped by friction, by utilizing a frictional force generated through pushing action of a conical spring material for shifting the larger gear in a reduction gear train in the direction of a thrust. CONSTITUTION:A driven shaft 17, an intermediate shaft 18 and a rear axle 20 are supported on the transmission case 12. The larger gear 35 in a reduction gear train is fixed on the intermediate shaft 18 and is in mesh with a smaller reduction gear 34 of the driven shaft 17. A conical spring member 38 is interposed between the end face of the larger reduction gear 35 and the wall face 16a of the transmission case 12 with the periphery of the spring member 38 pressed into contact with the rim 41 of the larger reduction gear 35. The larger reduction gear 35 is pushed in the direction of thrust by main of said spring member 38, thus a frictional force being generated on the pushed surface. Since the periphery of the spring member 38 is pressed in contact with the rim 41 of a large diameter, the pushing force in the thrust direction is enlarged to give a frictional force of a considerable magnitude on said periphery.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a power transmission device used, for example, in a scooter type motorcycle, and particularly to a noise prevention structure for a reduction gear train incorporated in a transmission case thereof.

[Prior Art] Generally, this type of power transmission device is
As shown in Japanese Patent No. 127956, a driven shaft, an intermediate shaft, and a rear axle bow, which are parallel to the crankshaft, are provided at the rear end of a transmission case that is integrated with the engine crankcase.
The crankshaft and the driven shaft are interlocked via a V-belt type continuously variable transmission and an automatic centrifugal clutch, and the driven shaft, intermediate shaft, and rear axle are connected to each other by a pair of reduction gears. It has a structure in which the combined reduction is linked through a chain of vehicles.

[Problem that the invention seeks to solve]

By the way, in the case of the power transmission device as described above, 1. Since there is an automatic centrifugal clutch that disconnects power transmission on the drive source side of the reduction gear train, engine vibrations can cause damage to the transmission case and the shaft inside this case, especially during idle link when the automatic centrifugal clutch is in the OFF state. This makes it easier for the signal to be transmitted to the reduction gear train through the neck.

Then, due to the above vibration, the reduction gear rotates around the axis. Normally, there is a certain amount of backlash between the tooth surfaces of the reduction gears that mesh with each other, so the tooth surfaces that mesh with each other collide with each other, resulting in deceleration. A problem occurs where the gear vibrates. When the reduction gear vibrates in this way, this vibration is transmitted to the transmission case through the shaft neck, so the vibration of the transmission case is amplified and resonance sound is generated, which is a major cause of noise.

[Means for solving problems]

Therefore, in the present invention, a conical spring material is coaxially disposed on the end face of the large-diameter reducing gear of a pair of gears meshing with each other, and the outer circumferential portion of this spring material is It is characterized in that it is brought into pressure contact with the rim part, and the reducing gear is pressed in the thrust direction by the outer peripheral part of this spring material.

[Effect]

According to this configuration, the outer diameter of the spring material increases, and the spring force that presses the reducing gear increases accordingly, so the reducing gear has a relatively large thrust force and accompanying pressure. Frictional force is applied.

Therefore, the vibration generated in the reduction gear is efficiently frictionally attenuated by the presence of the rrl friction force, and the vibration becomes less likely to be transmitted to the transmission case.

[Embodiments of the invention]

An embodiment of the present invention will be described below based on the drawings in which the present invention is applied to a scooter type motorcycle.

Reference numeral 1 in FIG. 4 indicates an underbone type frame, and this frame 1 is bent significantly downward between the front fork 2 and the seat 3, and the engine unit 4 is swingably mounted at the rear end of this bent portion 1a. connected. This engine unit 4 will be explained with reference to FIGS. 1 to 3. Reference numeral 5 is a forced air-cooled two-stroke engine, and inside the crankcase 6 is a cantilevered engine placed horizontally along the left and right direction. A crankshaft 1 of the formula is supported.

A carburetor 9 is housed in an air cleaner case 8 attached to the right end of the crankcase 6, and the carburetor 9 is connected to an intake hole 10 formed in the end face of the crankcase 6 via a reed valve 11. .

A transmission case 12 extending rearward is integrally formed at the left end of the crankcase 6 , and the rear end of the transmission case 12 is suspended from the frame 1 via a hydraulic shock absorber 13 . A case cover 1 is attached to the side opening of the transmission case 12.
4 are bolted together, and a transmission chamber 15 that is long in the front-rear direction is formed between the transmission case 12 and the transmission case 12. At the rear of the transmission case 12, there is a reduction gear chamber 1 separated from the inside of the transmission chamber 15.
6 is formed in the reducer chamber 16, and a driven shaft 17. The intermediate shaft 18 and the axle 20 of the rear wheel 19 are pivotally supported.

Each of these shafts 17.18° 20 is parallel to the crankshaft 7, and one end of the crankshaft 1 and the driven shaft 17 are led out into the transmission chamber 15. Inside this transmission chamber 15, a belt-type continuously variable transmission 2 is installed as a transmission path for transmitting the engine power taken out to the crankshaft 7 to the driven shaft 11.
1 is accommodated. ■The belt type continuously variable transmission 21 is constructed by passing a V-belt 24 between a primary sheave 22 on the crankshaft 1 and a secondary sheave 23 on the driven shaft 11. When the flyweight 25 of the primary sheave 22 moves in the outer radial direction due to centrifugal force as it rises, the groove width of the V-shaped groove 26 is reduced and the V-belt 24 is pushed out in the outer radial direction. and,
When the V-belt 24 is pushed out in this way, on the secondary sheep 23 side, the V-belt 24 is pulled in the inner diameter direction against the biasing force of the spring 27, and
Since the width of the groove 28 is widened, the rotation of the crankshaft 7 is transmitted to the secondary sheave 23 at an increased speed. This secondary sheave 23 is rotatably provided on the driven shaft 17 via a hollow cylindrical collar 29, and a flyweight 31 of an automatic centrifugal clutch 30 is attached to this collar 29.
is fixed. Flyway i-31 has driven shaft 17
When the rotational speed of the secondary sheave 23 exceeds a predetermined value, the flyweight 31 is pushed radially outward by centrifugal force and comes into contact with the clutch housing 32. death,
Due to this contact, the rotation of the secondary seam 723 is transmitted to the driven shaft 17.

By the way, in the reducer chamber 16 which is the driven side of the automatic centrifugal clutch 30, there is a driven shaft 17. A reduction gear train 33 that interlocks the intermediate shaft 18 and the axle 20 is housed. That is, the driven shaft 17 is integrally equipped with a reduction gear 34 on its outer peripheral surface facing the reduction gear chamber 16, and this reduction gear 34 meshes with a large diameter reduction gear 35 fixed on the intermediate shaft 18. There is. Further, the intermediate shaft 18 is integrally provided with another reducing gear 36 adjacent to the increasing reducing gear 35, and this reducing gear 36 meshes with another reducing gear 37 fixed to the axle 20. Therefore, the rotation of the driven shaft 17 is controlled by the gears 3 that mesh with each other.
4.35.36.37, the speed is reduced in multiple stages and transmitted to the axle 20.

In the case of this embodiment, helical gears are used for the reduction gear 34 and large reduction gear 35, and spur gears are used for the other reduction gear 36 and large reduction gear 37, respectively. , between the tooth surfaces of these gears 34, 35, 36, 37 that mesh with each other,
A certain backlash is provided.

In this embodiment, a disc spring 38 as a spring material is interposed between the reduction gear 35 on the intermediate shaft 18 and the wall surface 16a of the reduction gear chamber 16 adjacent to this end surface. Since the disk spring 38 is formed into a conical disk having a through hole 39 in the center, the through hole 39 is attached coaxially to the outer periphery of the intermediate shaft 18, and the opening peripheral edge of the through hole 39 is attached coaxially to the outer periphery of the intermediate shaft 18. is pressed against the wall surface 16a via a washer 40. Further, the outer diameter of the disc spring 38 is formed to be approximately the same diameter as the rim portion 41 connected to the tooth bottom of the reducing gear 35, and the outer peripheral portion thereof
is movably pressed against the end face of the Therefore, the disc spring 38 is interposed between the wall surface 16a and the rim portion 41 in a compressed state in the axial direction, and the pressure of the disc spring 38 causes the reduction gear 35 to move in the thrust direction away from the wall surface 16a. It is pressed, and a frictional force is applied to this pressing surface.

According to such a configuration, since the outer peripheral part of the disc spring 3& is brought into pressure contact with the rim part 41 of the large-diameter reducing gear 35, the diameter of the disc spring 38 increases and the thrust force in the thrust direction increases. A relatively large frictional force is applied to the pressure contact portion of the disc spring 38 on the reducing gear 35 . Therefore, during engine operation, the transmission case 14 and each shaft 17, 18 are connected to the reduction gear train 33.
．． Even when engine vibration is applied through the gear 20, since a large frictional force is applied to the reducing gear 35 as described above, the entrainment phenomenon as in the conventional case can be suppressed. Therefore, even though there is a butt crush between the tooth surfaces that mesh with each other, the collision between the tooth surfaces can be alleviated, and the occurrence of hammering noise can be suppressed accordingly.
5 is attenuated, and the vibration of the reducing gear 35 is less likely to be transmitted to the transmission case 12 side. Therefore, resonance of the transmission case 12 is suppressed, and noise can be reduced.

Further, although there is a certain amount of clearance between the end face of the reducing gear 35 and the wall surface 16a, in the case of this embodiment,
Since helical gears are used for the reducing gear 35 and the reducing gear 34 that mesh with each other, there is a risk that the reducing gear 35 may shift in the thrust direction on the intermediate shaft 18 during rotation and come into contact with the wall surface 16a. There is. However, according to the above configuration, since the reducing gear 35 is pressed in a direction away from the wall surface 16a by the disc spring 38 interposed between it and the wall surface 16a, the disc spring 38 absorbs the force that tends to shift. functions as a buffer against Therefore, the movement of the reducing gear 35 in the thrust direction can be alleviated, and there is also an advantage that generation of hammering noise due to contact with the wall surface IGa can be prevented.

In the above-mentioned embodiment, the disc spring was provided corresponding to the reduction gear on the intermediate shaft, but depending on the case, it may be provided corresponding to another reduction gear on the axle, or it may be provided in correspondence with the reduction gear on both shafts. It may also be provided corresponding to the large gear.

Further, the power transmission path is not limited to a V-belt type continuously variable transmission, and may be a combination of a chain or various gears, for example.

〔Effect of the invention〕

According to the present invention described in detail above, since the entrainment phenomenon of the decreasing gear due to vibration transmission is suppressed, collisions between the tooth surfaces can be alleviated even though backlash exists between the tooth surfaces. Therefore, not only the occurrence of hammering noise is suppressed to a minimum, but also the vibration of the reduction gear is frictionally damped. Therefore, since the vibration of the reduction gear train is less likely to be transmitted to the transmission case, resonance of the transmission case is suppressed to that extent, and noise caused by engine vibration can be efficiently reduced.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a cross-sectional view showing the area around the reduction gear room of the engine unit, FIG. 2 is a cross-sectional view of the whole, and FIG. 3 is a cross-sectional view of the part FIG. 4 is a side view of the scooter type motorcycle. 5...Engine, 6...Crankcase, 12...
・Transmission case, 17... Driven shaft, 21... Transmission path (V-belt type continuously variable transmission), 30... Automatic centrifugal clutch, 33... Reduction gear train, 34... Reduction Gear, 35... Decreasing gear, 38... Spring material (disc spring),
41... Rim part.

Claims (1)

[Claims] A driven shaft is supported in a transmission case that is integrated with the engine crankcase in parallel with the crankshaft, and an automatic centrifugal clutch is provided on the transmission path that transmits engine power to the driven shaft. A reduction gear train consisting of a pair of reducing gears and reducing gears is provided on the driven side of the transmission path than the driven shaft and the automatic centrifugal clutch, and this reduction gear train decelerates the rotation of the driven shaft. In the power transmission device, a conical spring material is disposed coaxially with the end face of the reducing gear, and the outer circumferential portion of the spring material is pressed into contact with the rim portion of the reducing gear. , a power transmission device characterized in that the reducing gear is pressed in the thrust direction by the outer periphery of the spring material.