JPS6335176Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a holding structure for auxiliary equipment in a split type crankcase.

FIG. 1 is a sectional view of a main part of a conventional crankcase 1. As shown in FIG.

This crankcase 1 is a vertically split type crankcase, and is composed of a left side case part 2 and a right side case part 3.

Among the case parts 2 and 3 of the crankcase 1, a recess 2a is formed in the left case part 2, and an oil pump (auxiliary equipment) is installed in the recess 2a.
4 is accommodated. Further, a cylindrical boss portion 2b is formed integrally with this recess portion 2a toward the right case portion 3 side, and this boss portion 2b is integrally formed with this recess portion 2a.
A shaft portion 5a of a drive gear 5 that drives the oil pump 4 is fitted and supported in the hole b. In addition,
The tip surface 2c of the boss portion 2b is located on a mating surface 6 (hereinafter referred to as a cable mating surface) of the left case portion 2 with the right case portion 3. On the other hand, a boss portion 3a is formed integrally with the case portion 3 on the right side at a position facing the center of the drive gear 5, and this boss portion 3a is formed integrally with the case portion 3 on the right side.
The distal end surface 3b of the drive gear 5 is in contact with the center of one end surface 5b of the drive gear 5, and the gear 5 is positioned to prevent the gear 5 from falling out of the hole of the boss portion 2b.

On the other hand, one end surface 5b of the drive gear 5 is
Since it protrudes further into the right case part 3 from the case mating surface 6 of the left case part 2 and the right case part 3, the tip surface 3b of the boss part 3a that positions the drive gear 5 is located at the case mating surface 6 of the case part 2 and the right case part 3. It is formed at a position recessed from the surface 6 into the right case portion 3. In FIG. 1, numeral 7 is a crankcase cover, 8 is a clutch portion, 9 is a countershaft, 10 is a drive shaft, 11 is a drive sprocket fixed to the drive shaft 10, and 12 is a shaft. Also,
The driving force of the drive gear 5 that drives the oil pump 4 is transmitted from a crankshaft (not shown) via a gear 14 that meshes with the gear 5 and a gear 15 that meshes with the gear 14.

By the way, according to the above-mentioned holding structure for the auxiliary equipment (drive gear 5), the tip end surface 3b of the boss portion 3a formed protrudingly on the right case portion 3 is connected to the case mating surface 6.
Since it cannot be located on the same plane as
When machining the mating surface 6 of the right case portion 3, it is not possible to machine the tip surface 3b at the same time as the mating surface. Therefore, the tip end surface 3b of the boss portion 3a must be processed separately, which causes an increase in the number of processing steps for the crankcase.

The present invention was developed in view of the above-mentioned problems, and the auxiliary equipment (including its driving parts) housed in a split type crankcase is separated by bosses formed on one case part and the other case part. The end faces of these bosses can be machined at the same time as the respective case mating surfaces.The feature is that the bosses formed on each case part The tip surfaces of the boss portions are respectively formed to protrude so as to match the mating surfaces of the case, and the parts of the auxiliary machine that face the tip surfaces of these boss portions are retracted to the mating surface of the case.

Hereinafter, one embodiment of the auxiliary equipment holding structure in the split type crankcase according to the present invention will be described in detail.

FIG. 2 is a cutaway sectional view of the main parts of a motorcycle engine showing a crankcase 20 that employs the auxiliary equipment holding structure according to the present invention, and the same parts as in FIG. 1 are designated by the same reference numerals.

The crankcase 20 is a vertically split type crankcase, and is divided into a left side case part 21 and a right side case part 22, respectively.

Case parts 21 and 2 of this crankcase 20
2, the left case portion 21 is formed with a recess 21a and a cylindrical boss portion 21b integrally with the recess 21a, as in FIG. The boss portion 21b protrudes toward the right case portion 22, and its tip surface 21C is connected to the mating surface 24 of the case.
is located on the same plane. Further, the recess 21
An oil pump (auxiliary machine) 4 is housed in the interior a, and a shaft portion 23a of a drive gear 23 that drives the oil pump 4 is fitted and supported in a hole of the boss portion 21b. A cylindrical recess 23b is formed at the center of the drive gear 23 and at a position facing the right case portion 22. Further, the bottom surface 23c of the recess 23b allows the drive gear 23 to be placed in the hole of the boss 21b, and one end surface of the drive gear 23 is connected to the tip surface 23 of the boss 21b.
1c, it is formed so as to be located on the same plane as the mating surface 24 of the left case portion 21 and the right case portion 22. On the other hand, a boss portion 22a is formed integrally with the right side case portion 22 on the right side case portion 22 at a position facing the center of the drive gear 23, and the tip end surface 22b of this boss portion 22a is a mating surface of the case. It is formed protrudingly on the same plane as 24. Therefore, when the crankcase 20 is assembled by aligning the mating surfaces 24 of the left side case portion 21 and the right side case portion 22, the boss portion 22a will fit into the recess 23b formed in the drive gear 23 that drives the oil pump 4. is inserted,
The tip surface 22b is the bottom surface 23c of the recess 23b.
The drive gear 23 contacts the tip surface 21c of the boss portion 21b and the tip surface 2 of the boss portion 22a.
2b, and the left case portion 21
It does not escape from the hole of the boss portion 21b formed in the hole.

Incidentally, in the above embodiment, a vertically split type split type crankcase was described, but of course the present invention is not limited to the above embodiment, but can be applied to a horizontally split type split type crankcase that can be split vertically. Also good. Further, in the above embodiment, the recess 23b is provided only in the portion of the drive gear 23 that corresponds to the tip end surface 22b of the boss portion 22a of the right case portion 22, but the present invention is not limited to this. Left side case part 2
The recessed portion may be provided only in a portion corresponding to the tip end surface 21c of the first boss portion 21b, or may be provided in both locations.

As explained above, the present invention provides a concave part in the auxiliary machine housed in the split type crankcase, and positions the tip surfaces of the boss parts protruding from each case part on the same plane as the mating surface of the case. Therefore, it is possible to simultaneously machine the end face of the boss portion and the mating face of the case, thereby reducing the number of processing steps for the crankcase.

[Brief explanation of drawings]

Fig. 1 is a cutaway cross-sectional view of the main parts of a small engine showing a crankcase that uses a conventional auxiliary equipment holding structure, and Fig. 2 shows a crankcase of a small engine that uses an auxiliary equipment holding structure according to the present invention. It is a main part broken sectional view. 20... Crank case, 21, 22... Case part, 21b, 22a... Boss part, 21c, 2
2b... tip surface, 23... auxiliary machine, 23b... recess, 24... mating surface.

Claims (1)

[Scope of utility model registration request] Boss portions are provided on one case portion and the other case portion at positions shifted from each other, and when the one case portion and the other case portion are combined, there is a compensation between the tip surfaces of the boss portions. In a structure for holding an auxiliary machine in a split type crankcase for positioning a machine, a recess is provided in at least one of the parts of the auxiliary machine corresponding to the tip surface of each of the boss parts, and the one case part and the An auxiliary machinery holding structure in a split type crankcase, characterized in that the tip surface of each boss portion of the other case portion is located on a mating surface of the one case portion and the other case portion. .