JPH0633759B2 - Ignition distributor for internal combustion engine and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to an ignition distributor for an internal combustion engine and a manufacturing method thereof.

[Conventional technology]

In the conventional one, a ring-shaped O-ring groove is formed on the outer periphery of the small diameter part of the housing fitted in the fitting hole of the internal combustion engine,
An O-ring is inserted in this O-ring groove (for example,
Japanese Utility Model Publication No. 53-1462).

[Problems to be solved by the invention]

By the way, the above-mentioned housing is generally formed by die-casting aluminum, and if the O-ring groove is formed by cutting in the post-processing, the thick portion of the small diameter portion of the housing is deeply cut. However, cavities appeared at the cutting portion, and even if the O-ring was inserted into the O-ring groove, a sufficient sealing effect was not obtained. Therefore, in the conventional case, it is general that the O-ring groove is also molded by a die casting type, but it is necessary to divide the die casting type in four directions.
There is a problem that the structure of the mold is complicated and the accuracy of the housing is deteriorated.

Therefore, the present invention has a simple mold structure and improves accuracy without impairing the sealing effect.

[Means for solving problems]

Therefore, according to the present invention, a housing having a small diameter portion fitted into a fitting hole on the internal combustion engine side, an O-ring groove formed in a ring shape on the outer periphery of the small diameter portion of the housing, and an O-ring groove inserted into the O-ring groove. From the ring and the tip of the small diameter portion,
An ignition distributor for an internal combustion engine including a plurality of axial grooves formed in the axial direction up to the ring groove and a plurality of ribs formed alternately adjacent to the respective axial grooves and a fitting on the internal combustion engine side. A small-diameter portion fitted in the dowel, a plurality of axial grooves extending in the axial direction from the tip of the small-diameter portion for a predetermined length, and a plurality of ribs alternately adjacent to the respective axial grooves in the circumferential direction. The housing having the same is molded by die casting which is divided into only two directions, and the outer periphery of the upper end position of the rib in the axial direction is cut to form an O slightly deeper than the axial groove.
Provided is a method for manufacturing an ignition distributor for an internal combustion engine, which comprises forming a ring groove into a ring shape and then inserting an O ring into the O ring groove.

[Work]

As a result, it is possible to use a die-casting mold in which the O-ring groove is not post-processed even after the O-ring groove is post-processed by cutting the rib portion that is thin and has few cavities. Moreover, the same strength as that of the conventional housing is obtained by the plurality of ribs.

〔Example〕

The present invention will be described below with reference to embodiments shown in the drawings. In FIG. 1, 1 is a housing made of aluminum, 2 is a cap that covers the open end of the housing 1, and 3 is an O-ring. Then, the housing 1 is formed with a small diameter portion 1a which is fitted into a fitting hole on the internal combustion engine side.
A ring-shaped O-ring groove 1b is formed on the outer periphery of the. Further, twelve axial grooves 1c are formed at equal intervals in the axial direction from the tip of the small diameter portion 1a to the O-ring groove 1b, whereby twelve ribs 1d are circumferentially adjacent to each groove 1c. It is formed at equal intervals with a pitch of °.

2 and 3 show the housing 1 before cutting the O-ring groove 1b, and each axial groove 1c and each rib are provided on the outer periphery of the small diameter portion 1a by a predetermined length from the tip of the small diameter portion 1a. 1d is extended. The rib 1d has a height of about 2.5 mm and a width of about 3 mm.

Next, a method of manufacturing the housing 1 having the above structure will be described. As shown in FIG. 2, a housing 1 having a small diameter portion 1a and axial grooves 1c and ribs 1d axially extending a predetermined length from the tip of the small diameter portion 1a.
Is molded by die casting in which the mold is split only in the two upper and lower directions (axial direction). After that, the outer periphery of the upper end position of each rib 1d in the axial direction is cut to a position slightly (about 0.3 mm) deeper than the axial groove 1c to form an O-ring groove 1b slightly deeper than the axial groove 1c in a ring shape. At this time, the portion of the small diameter portion 1a facing the upper end of the axial groove 1c is slightly cut (about 0.3 mm). At this time, the portion to be cut is only a small portion of each thin rib 1d having a narrow width and the small diameter portion 1c in the periphery thereof, and since the thin portion is unlikely to have a nest inside in die casting, Even if the O-ring groove 1b is post-processed, no cavities appear there.

Further, since the small diameter portion 1a is an important portion that fits into the fitting hole on the internal combustion engine side, the number of ribs 1d is 12 so that there is no difference in strength from the conventional one.

The height, width, and number of ribs 1d are not limited to those in the above-described embodiment, and it goes without saying that the ribs 1d are arbitrarily set according to various types of power distributors.

〔The invention's effect〕

As described above, according to the present invention, by cutting the rib portion which is thin and is less likely to have cavities inside, even if the O-ring groove is post-processed, no cavities are generated and the mold is divided only in two directions. It is possible to use a die-casting die that has a simple structure, so that the accuracy of the housing can be improved without impairing the sealing effect, and sufficient strength can be secured with multiple ribs. There is.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional front view showing an embodiment of a distributor of the present invention, FIG. 2 is a front view showing a housing before O-ring groove processing in the distributor, and FIG. 3 is a small diameter in the housing shown in FIG. It is a bottom view of a part. 1 ... Housing, 1a ... Small diameter part, 1b ... O-ring groove, 1c ... Axial groove, 1d ... Rib, 3 ... O-ring.

Claims (2)

[Claims] 1. A housing having a small diameter portion to be fitted into a fitting hole on the internal combustion engine side, an O-ring groove formed in a ring shape on the outer periphery of the small diameter portion of the housing, and an O-ring groove inserted in the O-ring groove. Internal combustion engine including a ring, a plurality of axial grooves formed in the axial direction from the tip of the small diameter portion to the O-ring groove, and a plurality of ribs formed alternately adjacent to the axial grooves in the circumferential direction. Ignition distributor. 2. A small diameter portion fitted in a fitting hole on the internal combustion engine side, a plurality of axial grooves extending in the axial direction by a predetermined length from the tip of the small diameter portion, and these axial grooves and the circumferential direction. A housing having a plurality of ribs that are alternately adjacent to each other is formed by die casting that is die-divided only in two directions, and the outer periphery of the upper end of the rib in the axial direction is cut to form an O-ring groove slightly deeper than the axial groove. A method for manufacturing an ignition distributor for an internal combustion engine, which is formed in a ring shape, and then an O-ring is inserted in the ring groove.