JPH0532608B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gear engagement noise reduction mechanism in a reduction gear device.

(Prior Art) Conventionally, meshing noise between a driving gear and a driven gear has been a problem in a primary reduction gear device of an internal combustion engine. The cause of this noise is the internal combustion engine, especially the
Due to the sudden fluctuations in rotational torque that tend to occur in cycle internal combustion engines, the drive gear and driven gear shift relative to each other in the circumferential direction due to the bumps that exist in their meshing parts, and this shift causes the tooth surfaces of each gear to collide. It is thought that this is to produce the so-called crunching sound.

(Problems to be Solved by the Invention) The purpose of the present invention is to effectively reduce the meshing noise of gears as described above, and to achieve this purpose, the relative circumferential deviation between the driving gear and the driven gear is braked. This means that there is a means to do so.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a circular driving-side elastic rotating body and a driven-side elastic rotating body disposed on one side of a driving gear and a driven gear that meshes with the driving gear. a rotating body, the sum of the radii of the driving side elastic rotating body and the driven side elastic rotating body is made larger than the sum of the meshing pitch circle radii of the driving gear and the driven gear, and the driving side elastic rotating body and the driven side The elastic rotating body is fixed so as to coaxially rotate integrally with the driving gear and the driven gear, respectively, and the outer circumferential surfaces of the driving-side elastic rotating body and the driven-side elastic rotating body are each provided with opposite tapers, and the outer circumferential surface They are brought into pressure frictional contact with each other.

(Embodiment) An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a primary reduction gear device for a two-stroke internal combustion engine. In the primary reduction gear device, a drive gear 1 is fixed to the end of a crankshaft 5, a driven gear 2 is fixed to a housing 7a of a clutch 7 provided at the end of a main shaft 6, and the driven gear 2 is engaged with the drive gear 1. It is a combination.

In such a gear device, as shown in FIGS. 2 to 4, one side of the driving gear 1 and the driven gear 2 is provided with, for example, a crankcase 3 and a driven side elastic rotating body 4. The drive-side elastic rotating body 3 is formed with an elastic member 10 fixed to the outer periphery of a disc to have a larger diameter than the drive gear 1, and rotates integrally with the crankshaft 5 by sharing a key 9 for fixing the drive gear 1. The elastic material 10 is made of a rubber material having oil resistance and heat resistance, and its outer peripheral surface is tapered toward the drive gear 1 side. The driven side elastic rotating body 4 is formed to have a smaller diameter than the driven gear 2 by fixing an elastic material 11 made of the same material as the elastic material 10 of the driving side elastic rotating body 3 and tapered in the opposite direction to the outer periphery of an annular member. and is screwed to the driven gear 2 to rotate integrally with the driven gear 2. When the driving side elastic rotating body 3 and the driven side elastic rotating body 4 are assembled, the elastic members 10 and ₁₁ are pressed against each other, and _the driven gear is Contact occurs at a position offset toward the rotation center side O ₂ of 2. That is, as shown in FIG. 4, the sum (r1+r2) of the radii of arbitrary points where the rotating bodies 3 and 4 come into contact with each other is the radius R of the meshing pitch circles P ₁ and P ₃ of the gears 1 and 2. ₁ , sum of R ₁ (R ₁ + R ₃ )
is set slightly larger than . the rotating body 3,
4 is assembled by the driven side elastic rotating body 4 and the driven gear 2.
Since the housing 7a of the clutch 7, which is integrated with the clutch 7, overlaps the outside of the drive gear 1 in the assembled state, the drive-side elastic rotor 3 is assembled first, and the driven-side elastic rotor 4 is assembled later. That is, by fitting and sliding the driven-side elastic rotor 4 onto the main shaft 6 together with the driven gear 2 and the housing 7a, the elastic material 11 of the rotor 4 is attached to the previously assembled drive-side elastic rotor 3. It comes into contact with the elastic member 10 while sliding through both tapered surfaces. In this way, the elastic material 10,1
The tapered shape of the outer periphery of the rotating body 1 facilitates the assembly of both the rotating bodies 3 and 4.

Next, the operation of the above embodiment will be explained. When the driving gear 1, the driven gear 2, the driving side elastic rotating body 3, and the driven side elastic rotating body 4 rotate together, the rotational speed ratio of each rotating body 3, 4 is different from the reduction ratio of each gear 1, 2. A constant relative slip occurs at the contact portion of the elastic members 10 and 11 of the rotating bodies 3 and 4, and each gear 1 and 2
Frictional torque is generated that brakes the rotation of the Therefore, when the gears 1 and 2 try to shift relative to each other in the circumferential direction due to fluctuations in rotational torque, the movement is braked by the friction torque of the rotating bodies 3 and 4, and the tooth surfaces of the gears 1 and 2 are Conflicts are reduced.

In the gear device described above, the elastic members 10, 1
1, the width of the contact portion between the gears 1 and 2 is wide due to the tapered shape of both gears, and the contact portion is deviated from the contact point of the meshing pitch circles P ₁ and P ₂ of each gear 1 and 2, and the elastic member 10 , 11, the friction torque for braking each gear 1, 2 is effectively obtained. Therefore, the width of the rotating bodies 3 and 4 can be narrowed to reduce the space they occupy, which is particularly effective in an engine with limited space, such as an internal combustion engine.

The present invention is not limited to the above-mentioned embodiments, and the following embodiments are also possible.

For example, the outer periphery of the elastic members 10, 11 of each rotating body 3, 4 may be tapered in the same direction or in the opposite direction to that of the embodiment described above, and the contact portion of the elastic members 10, 11 may be adjusted to the meshing pitch of each gear 3, 4. The contact point Q of circles P ₁ and P ₂ is located offset toward the rotation center O ₁ of the drive gear 1, or the midpoint of the contact portion is located on the same line as the contact point Q. . The latter does not cause relative slip because the rotational speed ratio matches the reduction ratio of gears 1 and 2 at the midpoint of the contact part, but since relative slip always occurs on both sides of the midpoint, friction torque is reduced. That's what you get.

(Effects of the Invention) As described above, the present invention includes a circular driving-side elastic rotating body and a driven-side elastic rotating body arranged on one side of a driving gear and a driven gear, and these driving-side elastic rotating bodies The sum of the radii of the driven-side elastic rotating body is made larger than the sum of the meshing pitch circles of the driving gear and the driven gear, and the driving-side elastic rotating body and the driven-side rotating body are coaxial with the driving gear and the driven gear, respectively. The drive-side elastic rotating body and the driven-side elastic rotating body are fixed on the top so that they rotate together, and the outer circumferential surfaces of the driving-side elastic rotating body and the driven-side elastic rotating body are each tapered in opposite directions, and the outer circumferential surfaces are brought into elastic frictional contact with each other. .

Therefore, when the driving gear and the driven gear try to shift relative to each other in the circumferential direction due to fluctuations in rotational torque, the movement is also braked by the friction torque caused by the relative slip occurring between the tapered surfaces on the outer periphery of each of the rotating bodies. , noise can be reduced by alleviating collisions between the tooth surfaces of each gear.

Furthermore, by providing opposite tapers on the outer circumferential surfaces of the driving side elastic rotating body and the driven side elastic rotating body, by appropriately setting the assembly direction and the taper direction of both rotating bodies, it is possible to The assembly work can be easily performed. Furthermore, even if the axial dimensions of the elastic bodies are small, a wide contact width between the elastic bodies is ensured, so a large friction torque can be ensured at the friction contact portion. In other words, the axial width dimension of the elastic material required to obtain a predetermined grinding torque can be suppressed, and the space occupied by the elastic material can be reduced.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway plan view showing a primary reduction gear device for a two-stroke internal combustion engine equipped with the mechanism of the present invention, Fig. 2 is an enlarged sectional view of the main parts, and Fig. 3 shows the relationship between the gear and the rotating body. The front view and FIG. 4 are exploded views of the gear and the rotating body. In addition, in the figure, 1... driving gear, 2... driven gear,
3... Drive-side elastic rotating body, 4... Drive-side elastic rotating body, r1... Radius of driving-side elastic rotating body, r2...
Radius of the driven side elastic rotating body, P ₁ , P ₃ ... meshing pitch circle, R ₁ , R ₃ ... radius of meshing pitch circle,
Q... Contact point of meshing pitch circles.

Claims (1)

[Claims] 1. A driving gear and a circular driving side elastic rotating body and a driven side elastic rotating body are respectively disposed on one side of a driving gear and a driven gear meshing with the driving gear, and the radius of the driving side elastic rotating body and the driven side elastic rotating body is is larger than the sum of the meshing pitch radiuses of the driving gear and the driven gear, and the driving side elastic rotating body and the driven side elastic rotating body are fixed so as to coaxially rotate integrally with the driving gear and the driven gear, respectively. A mechanism for reducing gear meshing noise in a reduction gear device in which the outer circumferential surfaces of the driving-side elastic rotating body and the driven-side elastic rotating body are respectively tapered in opposite directions, and the outer circumferential surfaces are brought into elastic frictional contact with each other. .