JPS61201955A - Transmission gear mechanism - Google Patents

Abstract

PURPOSE:To prevent the occurrence of hit sounds in back-lash by preventing the meshing tooth surfaces of a drive gear and a driven gear from separating from each other. CONSTITUTION:An one-way clutch 21 is provided in the inner periphery with a spline 21a fitted on a crank shaft 20 and formed on the outer periphery with three clutch portions 21b. On the clutch portion 21b are disposed a needle roller 23 and a damper spring 24 to be inserted in the inner periphery of a drive gear 20 and secured fixedly to the crankshaft 20. Thus, when the rotation of a driven gear 19 is faster than that of the drive gear 22, the tooth surface of the driven gear 19 slips before hitted by the reverse tooth surface of the drive gear 22 so that the meshing tooth surfaces of the drive 22 and driven gears 19 are not separated from each other to prevent the occurrence of hit sounds in back-lash.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a gear transmission mechanism.

[Conventional technology]

For example, in a gear transmission mechanism that transmits power between a driving gear of a power source such as an internal combustion engine and a driven gear that meshes with the driving gear, backlash is created as a gap between the meshing teeth of the gears to supply oil for lubrication. be.

[Problem that the invention attempts to solve]

However, in an internal combustion engine, there are fluctuations in the rotation of the crankshaft, and due to the influence of these rotational fluctuations, there is
Generates backlash hitting sound.

For example, in the case of a two-stroke single-cylinder engine, due to the explosive force during the explosion stroke, the driving gear on the crankshaft becomes faster than the driven gear and transmits rotational force, but when it enters the compression stroke, the bumping caused by compression occurs. For gross,
The rotation speed of the drive gear of the crankshaft is slower than the explosion stroke.

However, at this time, the driven gear attempts to rotate at the same speed as before due to inertia, and the driven gear hits the opposite tooth surface of the driving gear within the range of backlash.

In the gear in this state, the driving gear rotates faster than the driven gear in the next explosion stroke, so the driven gear is knocked back from the opposite tooth surface to the original south side, and this repetition causes backlash sound. Occur.

Therefore, the object of the present invention is to reduce this balaclatural hitting sound.

[Means for solving problems]

In order to achieve the above object, the present invention has a drive shaft that reaches a drive source that causes rotational fluctuations, and a driven shaft driven by the drive shaft, and a pair of gear wheels 11 provided on both shafts. In a gear transmission mechanism that transmits power, one of the pair of gears is fixed to either the drive shaft or the driven wheel, and the other of the pair of gears is a one-sided clutch that transmits power only in the drive direction. It is characterized in that it is rotatably supported by either the driven wheel or the drive shaft via the drive shaft.

[Function] As a result, the rotation of the gear via the one-way clutch and the rotation of the other gear become smooth, and the meshing tooth surfaces do not separate.

〔Example〕

An embodiment of the present invention will be described based on FIGS. 1 to 4.

The exhaust system 2 for the engine 1 is provided with a subchamber 4 in communication with the exhaust passage 3 in the middle of the exhaust passage 3, and opens a valve 5 provided in the subchamber 4 according to the rotation speed of the engine 1. The output performance of the engine 1 is improved, and the open valve 5 is provided in the communication section between the exhaust passage 3 and the subchamber 4 so that the communication section can be opened and closed by rotation of the rotation shaft 6. There is. The rotation shaft 6 is provided parallel to the exhaust passage 3, and a pinion 7 is provided at one end thereof, and a rack 8 disposed orthogonally to the rotation shaft 6 is meshed with the pinion 7.

A second rack 9 is formed at the other end of the rack 8 and is perpendicular to the rack 8, and meshes with a second pinion 12 provided at one end of a pinion shaft 11 protruding from the crankcase 10.

A third pinion 13 is installed at the other end of the pinion shaft 11 that protrudes into the crankcase 10.
It meshes with a sector gear 15 provided at one end of a swing lever 14 disposed inside the shaft.

The other end of the swing lever 14 is connected to a centrifugal governor device 18 provided on a pump shaft 17 of a water pump 16 adjacent to the crankcase 10, and the centrifugal governor device 18 moves the swing lever in response to rotation of the pump shaft 17. 14 to pump shaft 17
swings in the axial direction.

A driven gear 19 that rotates the water pump 16 is provided on the pump shaft 17 that is a driven shaft, and is provided via a one-sided clutch 21 that transmits power only in the driving direction to a crankshaft 20 that is the drive shaft of the engine 1. The drive gear 22 meshes with the drive gear 22.

The one-way clutch 21, as shown in FIGS. 2 to 4,
A spline 21a that fits into the crankshaft 20 is provided on the inner periphery, and three clutch portions 21b each having an inclined surface that deepens in the driving direction are formed on the outer periphery. A spring 24 is arranged and inserted into the inner periphery of the drive gear 22, and two thrust washers t? 25.25 is supported from both sides and fixed to the crankshaft 20, and when locked, as shown in FIG. Drive gear 22 is moved to a shallow position on the inclined surface of 21b.
is locked and the rotation is transmitted to the drive gear 22 to rotate the drive gear 22 in the direction of arrow A. If the rotation of the drive gear 22 is faster than the one-way latch 21, as shown in FIG. The needle roller 23 is the clutch part 21b
The drive gear 22 is moved to a deep position on the slope of the drive gear 22 to be in a free state.

With this configuration, even if the rotation of the crankshaft 20 fluctuates, the rotation of the driven gear 19 will be faster than that of the drive gear 22 because the drive gear 22 is attached to the crankshaft 20 via the one-sided clutch 21. When the speed increases, the tooth surface of driven gear 19 slips before being hit by the opposite tooth surface of drive gear 22, and drive gear 2
The meshing tooth surfaces of the driven gear 2 and the driven gear 19 do not separate, thereby preventing the occurrence of a rattling sound.

Furthermore, when the engine 1 is running at a low speed, the exhaust system 2 opens the on-off valve 5 to introduce exhaust gas into the subchamber 4 to increase the volume of the exhaust passage 3, and as the engine 1 speeds up, the exhaust system 2 is equipped with a centrifugal governor device. 18 swings the swing lever 14, and this swing causes the third pinion 13, pinion shaft 11,
The rotating shaft 6 that engages with the rack 8 via the second pinion 12 and the second rack 9 is rotated to close the on-off valve 5, and when the rotation is high, the communication between the exhaust passage 3 and the sub-chamber 4 is cut off, and when the rotation is low. This system generates exhaust pulsations suitable for both engine speed and high speed, thereby improving the output performance of the engine 1.
When the rotation speed of the engine 1 is increased or decreased in the vicinity of the rotation range where the on-off valve 5 switches between opening and opening, a hysteresis effect can be provided on the driven gear 19 side, and changes in the output of the engine 1 can be prevented. can.

FIG. 5 shows an embodiment in which the present invention is applied to a kick starter device d for an engine. The kick idle gear 33 is engaged with the starter pinion, and the kick idle gear 33 is connected to the main shirt which becomes the driven shaft.
A kick starter gear 36, which is pivotally supported via a one-way latch 35, is engaged with the kick starter gear 36.

With this configuration, the one-way clutch 35 is provided to transmit power only in the direction to start the engine, so when the engine starts, the one-way clutch 35 slips and the kick idle gear 33 , the kickstarter tabbinion 32 no longer rotates, and the sound of the balaclava hammer disappears.

〔Effect of the invention〕

As described above, the present invention has a drive EJJ shaft that reaches a drive source that causes rotational fluctuations, and a driven wheel driven by the drive shaft, and power is transmitted by a pair of gear trains provided on both shafts. In the gear transmission mechanism, one of the pair of gears is fixed to either the drive shaft or the driven shaft, and the other of the pair of gears is connected to the drive shaft through a one-sided clutch that transmits power only in the drive direction. Since it is rotatably supported on either the driven shaft or the driving shaft,
Covered with drive gear! Since the meshing tooth surfaces of the 71 gears do not separate, it is possible to prevent backlash sound from occurring.

[Brief explanation of drawings]

FIG. 1 is a partially sectional front view showing one embodiment of the present invention, and FIG.
The figure shows an inclined surface showing an example of a one-sided clutch, Fig. 3 is a front view showing the one-sided clutch in the cocked state, Fig. 4 is a dimensional front view showing the free state of the one-sided clutch, and Fig. 5 is a different one-sided clutch. It is a sectional view showing an example. 1...Engine 17...Pump shaft 19...
・Driven gear 20...Crankshaft 21...
・One-way clutch 22...Drive gear 31
...Kick starter spindle 32...Kick starter pinion 33...Kick idle gear 3
4... Main shaft 35... One-way clutch 36... Kick starter gear

Claims (1)

[Claims] 1. A gear transmission mechanism that has a drive shaft that reaches a drive source that causes rotational fluctuations and a driven shaft that is driven by the drive shaft, and that transmits power by a pair of gear trains provided on both shafts. One of the gears is fixed to either the drive shaft or the driven shaft, and the other of the pair of gears is connected to either the driven shaft or the drive shaft via a one-way clutch that transmits power only in the drive direction. A gear transmission mechanism characterized by being rotatably supported on one or the other.