JPH026291Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a camshaft in which a shaft end member is coupled to the shaft end of a hollow shaft in which parts such as a cam lobe, a journal, and a gear are assembled. More specifically, the present invention relates to a camshaft in which a through hole penetrating the inside of a hollow shaft is formed at the axis of the shaft end member.

[Prior art]

Conventionally, in this type of camshaft, a shaft end member for attaching a belt pulley or the like for rotating the shaft is coupled to the shaft end of a hollow shaft. Since this shaft end member is required to have strong bonding strength with the shaft, bonding means such as welding and brazing are usually used. However, with these coupling methods, the coaxiality between the shaft and the shaft end member may deviate after coupling, so if the shaft end member requires an axial hole, this drilling process is generally performed on the shaft end. This is done by drilling after the parts are joined.

When penetrating the shaft center hole with a drill to the hollow part in the shaft, the chips generated by the drill will enter the hollow part in the shaft, and since this through hole is smaller than the hollow hole, the chips must be removed. It has become extremely difficult to do so, and the shaft is used with chips remaining inside it.

Therefore, while the camshaft is in use, the chips inside the shaft leak out from inside the shaft through the oil holes in the cam lobes, etc., along with lubricating oil, and act as a wear agent for the cam lobes. There was a problem that caused abnormal wear of the camshaft, resulting in a fatal defect in the camshaft.

[Purpose of invention]

The present invention solves the above-mentioned problems and provides a camshaft in which chips that have entered the hollow shaft can be easily removed and which does not cause abnormal wear on assembled parts such as cam lobes, journals, gears, etc. The purpose is to

[Structure of the invention] The camshaft according to the invention includes a shaft end member coupled to the shaft end of a hollow shaft, and a through hole penetrating into the hollow shaft in at least one of the shaft end members. A recess that widens toward the inside of the hollow shaft is formed on the inside of the hollow shaft of the member, and the through hole is configured to communicate with this recess, allowing chips to be easily removed from the through hole when the through hole is drilled. It is characterized by being able to be discharged.

Note that it is preferable to form the opening diameter of the recess to be approximately equal to the inner diameter of the hollow shaft, since the chips produced when drilling the through hole can be smoothly removed without being blocked by the inner end surface of the shaft end member. .

This camshaft is suitable when the shaft end member is connected to the hollow shaft by welding or brazing.

〔Example〕

Next, an embodiment of the present invention will be described in detail with reference to the drawings, using a camshaft for opening and closing intake and exhaust valves of an internal combustion engine as an example.

As shown in FIG. 1, a shaft end member 11 is inserted into the shaft end of the hollow shaft 10 and coupled by brazing.
A truncated conical recess 12 is previously bored inside the hollow shaft 10 of the shaft end member 11 . The recess 12 is formed to widen toward the inside of the hollow shaft 10 (toward the left side in the figure), and its opening diameter is approximately equal to the inner diameter of the hollow shaft 10. 13 is Kamlob.

Next, as shown in FIG. 2, a through hole 15 is drilled in a portion of the shaft end member 11 connected to the hollow shaft 10 corresponding to the axis of the hollow shaft 10 using a drill (not shown). 16 is chips generated by the drill.

A camshaft with such a configuration has a through hole 15
After the threads are cut, the belt pulley 17 is fitted into the shaft end member 11 as shown in FIG. Next, the bolt 18 is screwed into the through hole 15 to fix the belt pulley 17. Even if chips get inside the hollow shaft 10 at this time, if the hollow shaft 10 is lightly vibrated or tapped with the shaft end member 11 facing down before the belt pulley 17 is fixed, the inside of the hollow shaft 10 can be removed. The chips remaining in the shaft end member 11 are not blocked by the inner end surface of the shaft end member 11, are collected by their own weight at the center of the recess 12 along the truncated conical slope, and are easily discharged from the through hole 15.

FIG. 4 shows an example of application of the camshaft according to the embodiment, and in this example, another shaft end member 20 is connected to the shaft end opposite to the shaft end to which the shaft end member 11 shown in the embodiment is connected. Joined by brazing. A stepped through hole 21 is bored in the center of this shaft end member 20 .

In a camshaft having such a structure, if chips enter the inside of the hollow shaft 10, air or cleaning liquid is forced into the stepped through hole 21 to clean the through hole 15 while keeping the camshaft horizontal.
Chips can be easily discharged from.

In the above example, the recess 12 has a truncated cone shape, but the recess 12 is not limited to a cone, but may have other shapes such as a pyramid shape as long as it widens toward the inside of the hollow shaft 10.

Furthermore, the method of joining the shaft end members 11 is not limited to brazing, but may also be used with welding or other joining methods.

[Effect of idea]

As described above, according to the present invention, even if chips from the drill when drilling a through hole enter the inside of the hollow shaft, it can be easily removed by the weight of the chips or by pressurizing the cleaning fluid from another hole in the camshaft. chips can be removed.

In particular, if the opening diameter of the recess is made approximately equal to the inner diameter of the hollow shaft, the chips will not be blocked by the inner end surface of the shaft end member and will be smoothly and reliably discharged from the inside of the hollow shaft, leaving no chips remaining. Therefore, an excellent camshaft that does not cause abnormal wear on parts such as cam lobes during use can be obtained.

[Brief explanation of drawings]

1 is a cross-sectional view of the main parts of the camshaft according to the embodiment of the present invention showing the state in which the shaft end members are connected; FIG. 2 is a cross-sectional view of the main parts showing the state in which the shaft end members of FIG. 3 is a sectional view of a main part showing a state in which a belt pulley is fixed to the shaft end member of FIG. 2, and FIG. 4 is a sectional view of a main part of another embodiment of the camshaft. 10...Hollow shaft, 11...Shaft end member, 12...
Recess, 13...cam lobe, 15...through hole.

Claims (1)

[Scope of utility model registration request] A camshaft in which a shaft end member is coupled to a shaft end of a hollow shaft on which a component including a cam lobe is assembled, and a through hole penetrating into the hollow shaft is bored in at least one of the shaft end members, In the camshaft, a recess is formed on the inner side of the hollow shaft of the shaft end member, and the through hole is configured to communicate with the recess, and the through hole is in communication with the recess.
A camshaft characterized in that an opening diameter of the recess is approximately equal to an inner diameter of the hollow shaft.