JPS59106392A - Breather device for gear case in motorcycle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a breather device for a gear case of a shaft drive type power transmission mechanism in a motorcycle.

Generally, in a shaft drive type power transmission device for a motorcycle, a drive bevel gear that is integrally provided at the rear end of a propeller shaft that is linked to the engine meshes with a driven bevel gear that is mounted on the rear fork and is linked to the rear wheel. It is configured to transmit the rotation of the engine to the rear wheels.1. The driving and driven bevel gears are housed in a sealed gear chamber in a gear box provided on one side of the rear fork, and are lubricated by lubricating oil sealed in the chamber. In order to reduce air resistance during rotation, particularly at high rotation, the gearbox must be provided with a breather device for the gear chamber.

SUMMARY OF THE INVENTION Therefore, the main object of the present invention is to provide a breather device for a gear case in a motorcycle, which has a simple structure and which promotes the breathing action of the gear chamber. The bevel gear meshes with a driven bevel gear rotatably mounted on the fork and interlocked with the rear wheel, and the driving and driven bevel gears are housed in a gear chamber of a gear case provided on the rear fork, and the wall surface of the gear case is A main pleather passage that communicates the gear chamber with the outside air, and an auxiliary breather passage that communicates the gear chamber with the main pleather passage are formed, and a narrow passage is formed in the middle of the auxiliary breather passage with a shim plate for positioning the driven bevel gear. We are trying to form a

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS.

In FIG. 1, a V-type engine E is mounted horizontally on a body frame F of a motorcycle (its crankshaft 1 is perpendicular to the longitudinal direction of the body frame F). A propeller shaft 2 connected to the engine E runs longitudinally within a rear fork 3 that is pivotally supported by the vehicle body frame F so as to be able to swing up and down, and extends in the front-rear direction of the vehicle body frame F.

As shown in FIG. 2, the rear end of the propeller shaft 2 is rotatably supported by a rear fork 3 via a pawl bearing 4, and a drive bevel gear 11 is integrally provided at the rear end.

On the other hand, a ball bearing 6 is mounted on the axle 5 horizontally mounted on the rear fork 3.
, 7, a rear wheel W is rotatably supported. The rear wheel W is connected to a hollow power transmission shaft 10 rotatably supported by the rear fork 3 via ball bearings 8 and 9. The hollow transmission shaft 10 passes through the axle 5 and is arranged concentrically with the axle 5, and has a driven bevel gear 12 on its outer periphery.
are connected by splines. The driven bevel gear 12
is the drive bevel gear 11 integrated with the propeller shaft 2;
It is meshed with. Therefore, when the propeller shaft 2 is rotated by the operation of the engine E, this rotation is transmitted to the hollow power transmission shaft 10 via the drive bevel gear 11 and the driven bevel gear 12, and drives the rear wheel W connected to the shaft 10. Can be done.

The driving and driven bevel gears 11,12 are housed in a gear case 13 provided on one side of the fork 3 and integrally therewith. Gear chamber C' in the gear case 13
is formed to be oil-tight, and the opening on the rear wheel W side and the opening on the propeller shaft 2 side of the gear chamber C are both oil seals 14,
15, and an appropriate amount of lubricating oil is sealed inside.

A breather device B for causing the gear chamber C to breathe is provided on the wall surface of the gear case 13. Next, the structure of this device H will be explained. The gear case 13 wall has a main pleather passage 16 that communicates the gear chamber C with the outside air, and an auxiliary breather passage 17 that communicates the main pleather passage 16 with the gear chamber C. is formed. The main pleaser passage 16 is bored approximately vertically into the wall surface of the gear case 13,
Its lower end is opened between the driven bevel gear 12 and the ball bearing 8 in the gear chamber C. In addition, its upper end is open to the outside air,
A pleaser cap 19 is screwed there. The breather cap 19 prevents rainwater, dust, etc. from entering the main breather passage 16.

The auxiliary breather passage 17 is bent from the earth wall to the inner wall of the gear case 13, and its lower end communicates with the gear chamber C through the gap between the inner race 9i and the outer race 900 of the pole bearing 9, and its upper end , are connected approximately perpendicularly to the middle of the main pleather passage 16. Fourth
As shown in the figure, between the inner race 9t of the ball bearing 9 and the back surface of the driven bevel gear 12, the driven bevel gear 12
An annular shim plate 20 for positioning is interposed, this shim plate 20 is formed to have a larger diameter than the outer diameter of the inner race 9i, and its outer periphery is connected to the inner race 9i and the outer race 90.
It stands out in between. Since the gap between the inner race 9i and the outer race 90 is a part of the auxiliary breather passage 17, the shim plate 20 and the outer race 90 form a narrow passage 17α of the auxiliary breather passage 17. There is. Therefore, the gap ΔX between the narrow passages 1γα
is preferably set to approximately + the gap X between the inner race 9i and the outer race 900 (for example, X = 6 g, ΔX = 2 g).

Further, the narrowing path 171Z of the auxiliary breather passage 1γ
On the downstream side, there is a first. Second expansion chamber〃l.

D2 is formed. That is, the ball bearing 9 is removed, and the auxiliary breather passage 1 is connected downstream of the chamber D1.
A second expansion chamber D2 is formed in the middle of the expansion chamber D2, and the air mixed with lubricating oil that has passed through the narrow passage 17α is expanded in stages in the first expansion chamber I)1 and further in the second expansion chamber D2. Lubricating oil is efficiently separated.

Next, the operation of the first embodiment of the present invention will be explained. When the engine E is driven to run the motorcycle, the propeller shaft 2 is rotated, and this rotation is caused by the drive bevel gear 11.
, is transmitted to the rear wheels W via the driven bevel gear 12 and the hollow transmission shaft 10.

In the gear chamber C, a breathing action is performed through the main pleather passage 16 and the auxiliary breather passage 17 as will be described later due to pressure fluctuations due to the rotation of the driving and driven bevel gears 11° and 120 degrees. In this case, the air flowing through the auxiliary breather passage 17 is , the narrowed passage 17 formed in the middle thereof. After passing through z and being narrowed down, the first. It flows into the second expansion chamber D2 and is expanded in stages, at which time lubricating oil mixed in the air flowing through the auxiliary breather passage 17 is efficiently separated, and only the air flows into the main pleather passage 16. This prevents the passage 16 from being blocked by a lubricating oil film, improves the flow of air within the passage 16, and makes the gear chamber C more efficient.

FIG. 5 shows a second embodiment of the invention. In this embodiment, the outer race 90 of the ball bearing 9 and the gear case 13
An annular shim plate 20 for positioning the driven bevel gear 12 between
', and the inner diameter of the shim plate 21 is connected to the outer race 90.
0") i' is made smaller in diameter than the inner diameter, and its inner circumference protrudes between the inner race 9i and the outer race 90 to form a narrow passage 17'a in the auxiliary breather passage 11. The configuration is the same as that of the first embodiment.

FIG. 6 shows a third embodiment of the invention. In this third embodiment, an annular first shim plate 22 for positioning the gear 12 is sandwiched between the back surface of the driven bevel gear 12 and the inner race 9i of the ball bearing 9.
There is a second annular ring between the outer race 90 and the gear case 13.
The outer periphery of the shim plate 23 is clamped. This second shim plate 23
is an inclined surface 2 that is inclined downward toward the oil seal 15.
3α, the inner peripheral part of which enters into the oil seal 15, and the inner peripheral edge of the lip piece 1 of the oil seal 15.
5. Polymerize with 2. The outer diameter of the first arm plate 22 is equal to or smaller than the outer diameter of the inner race 9i of the ball bearing 9;
The inner peripheral edge of No. 3 cooperates with the lip piece 15α of the oil seal 15 to form a narrow passage 17 (Z) of the auxiliary breather passage 17.

Further, in this third embodiment, the inclined surface 23a of the second shim plate 23
This prevents the lubricating oil in the gear chamber C from scattering outward in the radial direction due to centrifugal force, thereby preventing lubricating oil droplets from entering the auxiliary breather passage 17.

As is clear from the above embodiments, according to the present invention, a main breather passage that communicates the gear chamber in the case with the outside air and a gear chamber are provided on the wall surface of the gear case housing the driving and driven bevel gears that mesh with each other. An auxiliary breather passage communicating with the main breather passage is formed in the middle of the breather passage, and a narrow passage is formed in the middle of the breather passage by a shim plate for positioning the driven bevel gear, and an expansion chamber is formed on the downstream side thereof. After the air is narrowed in the narrow passage, it flows into the expansion chamber, and at that time, the lubricating oil mixed in the air is efficiently separated, and only the air flows into the main breather passage, thereby controlling the flow of air in the passage. The breathing action of the gear chamber can be promoted efficiently, and the rotational resistance of the driving and driven bevel gears due to the air enclosed in the gear chamber can be reduced.

[Brief explanation of drawings]

1 to 4 show a first embodiment of the present invention, FIG. 1 is a side view of a motorcycle equipped with the device of the present invention, and FIG.
Figure 1 is an enlarged cross-sectional view along the line ■-■, Figure 3 is Figure 1 1
1.1-m line, FIG. 4 is a partially enlarged view of FIG. 3, FIG. 5 is a partial sectional view showing a second embodiment of the present invention, and FIG. FIG. 3 is a partial cross-sectional view showing a third embodiment. C"... Gear chamber, D,, D2... 1st and 2nd expansion chamber, L... Engine, tV... Rear wheel 2... Propeller shaft, 3... Rear fork, 11 .1
2... Drive, driven bevel gear, 13... Gear case,
16.17...Main, auxiliary breather passage, 17α...
Narrowed path, 21...Shim plate, 22, 23...First.
Second shim plate patent applicant Honda Motor Co., Ltd. Figure 4 Figure 3 Figure 9

Claims (1)

[Claims] The drive bevel gear integrated with the propeller shaft connected to the engine meshes with the driven bevel gear rotatably mounted on the fork and linked to the rear wheels, and the driving and driven bevel gears are stored in the gear chamber of the gear case provided on the rear fork. A main breather passage that communicates the gear chamber with outside air and an auxiliary breather passage that communicates the gear chamber with the main breather passage are formed on the wall surface of the gear case, and the driven breather passage is formed in the middle of the auxiliary breather passage. A breather device for a gear case in a motorcycle, characterized in that a narrow passage is formed using a shim plate for positioning a bevel gear, and an expansion chamber is formed on the downstream side of the narrow passage.