JPH0540329Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applied to the end of a rotating shaft such as a crankshaft or camshaft in an internal combustion engine, in order to transmit power from the rotating shaft to another shaft, etc. This invention relates to a device for attaching a power transmission body such as a gear or a pulley.

[Conventional technology]

When attaching a power transmission body such as a gear or a pulley to one end of a rotating shaft such as a crankshaft in an internal combustion engine, conventionally, a power transmission body such as a gear or a pulley is attached to one end of a rotating shaft such as a crankshaft. , rotation axis 2
0 is formed into a stepped small diameter part 20a, and a power transmission body 21 such as a gear is non-rotatably fitted into this small diameter part 20a, and the small diameter part 20a is provided with a tap hole extending along its axis. 22 is bored, and the power transmission body 21 is fixed by being tightened in the axial direction with a bolt 23 screwed into the tap hole 22.

[Problem that the invention attempts to solve]

However, in this way, the small diameter portion 20 of the rotating shaft 20
A bolt 23 for tightening and fixing the power transmission body 21 fitted in the small diameter portion 20 in the axial direction
When the bolt 2 is screwed into the tap hole 22 drilled in the hole 20a, the bolt 2 is inserted into the base of the small diameter portion 20a.
In addition to the tightening force No. 3 acting as an axial tensile force on the small diameter portion 20a, a torsion force generated due to power transmission from the rotating shaft 20 to another shaft, etc. acts at the same time. The tightening force of the bolt 23 acts as a compressive force in the axial direction on the stepped surface from the large diameter portion to the large diameter portion.

That is, in the vicinity of the root of the small diameter portion 20a, there is a tensile stress of the tensile force applied to the root of the small diameter portion 20a, a torsional stress of the torsional force accompanying power transmission, and a compressive stress of the compressive force to the stepped surface. When these three factors act as a combined stress, the allowable stress in the part is significantly lowered, causing breakage and deformation in this part.

In contrast, conventionally, the strength of the small diameter portion 20a is increased by increasing the diameter of the small diameter portion 20a, but in this case, the diameter of the entire rotating shaft 20 is Therefore, the rotary shaft 20 becomes large and its weight increases.

The present invention makes it possible to reduce the weight of the rotating shaft without reducing its strength by adjusting the screwing position of the bolt with respect to the rotating shaft.

[Means for solving problems]

In order to achieve this object, the present invention integrally forms a small diameter part at the tip of the large diameter part of the rotating shaft, fits a power transmission body such as a gear or a pulley into the small diameter part, and connects the power transmission body. , an attachment device for a power transmission body to a rotating shaft of an internal combustion engine, which is configured to tighten in the axial direction with a bolt inserted in the axial direction from one end surface of the rotating shaft; Drilling a hole for bolt insertion so that the hole extends beyond the small diameter portion of the rotating shaft to the large diameter portion,
A tap hole into which the threaded portion of the bolt is screwed is formed in each large diameter portion of the rotating shaft.

[Functions and effects of the idea]

With this configuration, the bolt for tightening and fixing the power transmission body fitted into the small diameter portion of the rotating shaft is simply inserted through the small diameter portion of the rotating shaft, and is not inserted into the large diameter portion of the rotating shaft. When the bolt is screwed in, the power transmission body fitted into the small diameter part is pressed against the stepped surface between the small diameter part and the large diameter part, and the power transmission body is fitted into the small diameter part. Since no tensile force is applied to the base of the bolt due to screwing in the bolt, only the torsional force for power transmission is applied to the small diameter part. Since only the necessary simple shearing stress is applied, the strength at the small diameter portion is significantly improved compared to the above-mentioned conventional structure.

Therefore, according to the present invention, even if the diameter of the small-diameter portion of the rotating shaft into which the power transmission body is fitted is reduced overall, the same torsional strength as before can be maintained. This has the effect of making the rotating shaft smaller and lighter.

〔Example〕

Hereinafter, embodiments of the present invention will be explained based on drawings (Figs. 1 and 2) in which gears or pulleys are attached to the crankshaft of an internal combustion engine. (not shown)
The crankshaft 1 has a small diameter portion 1 at the tip of the large diameter portion 1a.
A timing pulley 2 for transmitting power to camshafts (not shown) for intake valves and exhaust valves is integrally formed on the inner peripheral surface of this timing pulley 2. A protruding key 2a is fitted into a key groove 7 in the small diameter portion 1b.

Reference numeral 3 indicates a bolt for tightening and fixing the timing pulley 2 in the axial direction, and the small diameter portion 1b of the crankshaft 1 has a blank hole 5 through which the bolt 3 is inserted. Appropriate dimension l beyond the small diameter part 1b to the large diameter part 1a.
The large diameter portion 1a of the crankshaft 1 is provided with a tapped hole 6 into which the threaded portion 3a of the bolt 3 is screwed.

In addition, on the outer peripheral surface of the timing pulley 2,
A belt pulley 8 for transmitting power to an auxiliary device such as an alternator is fastened with a plurality of bolts 9. By making the outer diameter of the washer 4 inserted between the belt pulley 8 and the timing pulley 2 smaller, the belt pulley 8 can be attached and detached while the timing pulley 2 is still attached to the crankshaft 1. Further, the washer 4 is attached to the bolt 3.
It may be configured integrally with

In this way, the small diameter portion 1b of the crankshaft 1
, a hole 5 for inserting the bolt 3 is bored so that the hole 5 extends beyond the small diameter portion 1b to the large diameter portion 1a, and the threaded portion 3a of the bolt 3 is screwed into the hole 5. By forming a tap hole 6 in the large diameter portion 1a of the crankshaft 1, by screwing the bolt 3, the tamming pulley 2, which is a power transmission body, can be inserted into the small diameter portion 1b where the timing pulley 2 is fitted. This allows it to be tightened and fixed to the crankshaft 1 without generating any tensile force.

Note that the present invention is not limited to the embodiments shown in FIGS. 1 and 2, but as shown in FIG. 3, the timing pulley 2 and belt pulley 8 are simultaneously tightened and fixed to the crankshaft 1. Or,
As shown in FIG. 4, the small diameter part 1b is formed in two stages, and the timing gear case 11 is formed in the first small diameter part 1b'.
The timing gear 12 in the second small diameter portion 1
It can also be applied to the case where the belt pulleys 8 located outside the timing gear case 11 are fitted onto the belt pulleys 8 located outside the timing gear case 11, respectively, and these are simultaneously tightened and fixed with the bolts 3. The present invention can be similarly applied to the case where a power transmission body such as a timing gear or a pulley is attached to the camshaft of an engine.

[Brief explanation of the drawing]

1 to 4 show embodiments of the present invention, FIG. 1 is a sectional view showing the first embodiment, and FIG. 2 is a cross-sectional view of the first embodiment.
3 is a sectional view showing the second embodiment, FIG. 4 is a sectional view showing the third embodiment, and FIG. 5 is a diagram showing the prior art. 1...Crankshaft as an example of a rotating shaft, 1a
... Large diameter part, 1b ... Small diameter part, 2 ... Timing pulley as an example of a power transmission body, 3 ... Bolt, 5 ... Hole for bolt insertion, 6 ... Tap hole, 8 ... Power A belt pulley is an example of a transmission body.

Claims (1)

[Scope of utility model registration request] A small diameter part is integrally formed at the tip of the large diameter part of the rotating shaft, a power transmitting body such as a gear or a pulley is fitted into the small diameter part, and the power transmitting body is attached to one end surface of the rotating shaft. In a device for attaching a power transmission body to a rotating shaft of an internal combustion engine, which is tightened in the axial direction with a bolt inserted in the axial direction from the shaft, a hole for inserting the bolt is provided in a small diameter portion of the rotating shaft. The hole is drilled so as to extend beyond the small diameter portion of the rotating shaft to the large diameter portion, and a tap hole into which the threaded portion of the bolt is screwed is drilled in the large diameter portion of the rotating shaft. A device for attaching a power transmission body to a rotating shaft of an internal combustion engine.