JPH09310621A - Engine for model - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine for model which elongates life of bearings for rotatably supporting a clutch bell of a centrifugal clutch. SOLUTION: A shaft insertion hole 20 is formed on a crank shaft 15 which is rotated in one direction by a reciprocating piston 13. A pilot shaft 21 is inserted into the shaft insertion hole 20. Both ends of the pilot shaft 21 is rotatably supported by a pair of bearings 22, 24. A clutch bell 26 is fixed to an intermediate portion between bearings of the pilot shaft 21. Bending moment is applied to the clutch bell 26 by difference of pressurizing force of a plurality of clutch shoes 27 which pressurize an inner periphery of the clutch bell 26. In such a case, the bending moment is received by the intermediate portion of the pilot shaft 21 for preventing direct application to the bearings 22, 24 and elongating the life of the bearings 22, 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a model engine.

[0002]

2. Description of the Related Art As a model car engine, those shown in FIGS. 3 and 4 have been conventionally known. In each engine, a flywheel 3 is attached to the tip of a crankshaft 2 which is rotated in one direction by the reciprocating motion of a piston 1, and the flywheel 3 is rotated by a centrifugal clutch 4
Is transmitted to the drive gear 5 for transmitting torque via the.

The centrifugal clutch 4 is a clutch bell 6 rotatably supported on the crankshaft 2.
And a clutch shoe 7 swingably supported by the flywheel 3 and swinging outward by a centrifugal force generated by the rotation of the flywheel 3.
The rotation of the flywheel 3 is transmitted to the clutch bell 6 by the pressure contact of the clutch shoe 7 with the inner periphery of the clutch bell 6, and is transmitted to the drive gear 5 provided on the clutch bell 6.

In supporting the clutch bell 6 of the centrifugal clutch 4, in the engine shown in FIG. 3, an extension shaft 8a is integrally provided at the tip of the crankshaft 2, and the clutch is attached by a bearing 9 attached to the extension shaft 8a. The bell 6 is rotatably supported.

Further, in the engine shown in FIG. 4, an extension shaft 8b is connected to the tip of the crankshaft 2 by means of screw engagement, and a clutch 9 is supported by a bearing 9 supported by the extension shaft 8b. It is rotatably supported.

As bearings for supporting the clutch bell 6, slide bearings, needle bearings and ball bearings are used.

[0007]

Centrifugal clutch 4 is generally used.
In the above, due to variations in the sizes of the clutch bell 6 and the clutch shoe 7 and variations in the assembly accuracy of the centrifugal clutch 4, variations in the pressing force of the plurality of clutch shoes 7 that press the inner circumference of the clutch bell 6 occur. Cannot be made uniform.

For this reason, in the model engine in which the clutch bell 6 is directly supported by the bearing 9, a bending moment acts directly on the bearing 9 due to the variation in the pressing force of the plurality of clutch shoes 7, and the bending moment causes the bearing 9 to move. The bearing 9 is damaged, the life of the bearing 9 is short, and it has to be replaced frequently.

Further, the extension shafts 8a and 8b are provided on the free side end of the crankshaft 2, and the clutch bell 6 having the drive gear 5 is provided by the extension shafts 8a and 8b.
Since the drive gear 5 supports the
There is also the inconvenience that the power transmission efficiency is poor.

A technical object of the present invention is to improve the service life of a bearing for supporting a clutch bell and the power transmission efficiency.

[0011]

In order to solve the above problems, according to the present invention, a piston is slidably incorporated in a cylinder formed in a cylinder block, and the piston reciprocates in one direction. A flywheel is attached to the tip of the rotated crankshaft that penetrates the cylinder block and faces the outside, and a shaft insertion hole extending in the axial direction from the tip surface is formed in the crankshaft. Support both ends of the pilot shaft whose front end faces the outside by bearings, and install a clutch bell axially facing the flywheel between the bearings of the pilot shaft.
A plurality of clutch shoes swingably supported by the flywheel and swinging outward by centrifugal force are arranged in the clutch bell, and a drive wheel for torque transmission is provided on one of the clutch bell and the pilot shaft. The configuration adopted is

Here, the drive wheel may be a gear or a toothed pulley for a timing belt.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, a cylinder block 11 supported by a base 10 has a cylinder chamber 12, and a piston 13 is slidably incorporated in the cylinder chamber 12.

Further, the cylinder block 11 is provided with a shaft support cylinder 14, and a disc 16 is provided at a rear end portion of a crankshaft 15 inserted into the shaft support cylinder 14 and rotatably supported. . A pin 17 is attached to the outer peripheral portion of the circular plate 16, and the pin 17 and the piston 1
3 are connected by a connecting rod 18.

Therefore, when the piston 13 reciprocates,
The crankshaft 15 rotates in one direction.

Shaft support cylinder 1 of crankshaft 15
A flywheel 19 is attached to a front end portion of the No. 4 which is exposed to the outside. Further, the crankshaft 15 is formed with an axial shaft insertion hole 20 that opens at the tip end surface, and the rear end portion of the pilot shaft 21 that is inserted into the shaft insertion hole 20 and has its tip end exposed to the outside is a shaft insertion hole. Two
It is rotatably supported by a bearing 22 mounted inside the No. 0.

The tip end portion of the pilot shaft 21 penetrates a bearing housing 23 provided on the base 10, and the tip end portion is rotatably supported by a bearing 24 attached to the bearing housing 23.

A centrifugal clutch 25 is provided between the pilot shaft 21 and the flywheel 19 for transmitting and interrupting the rotation of the flywheel 19.

The centrifugal clutch 25 comprises a cylindrical clutch bell 26 and a plurality of clutch shoes 27. The clutch bell 26 is integrally provided with a drive gear 28 as a drive wheel for transmitting torque. The clutch bell 26 is a pair of bearings 22, 2 of the pilot shaft 21.
It is fixed to an intermediate portion between the four and is mounted so as to face the flywheel 19 in the axial direction. On the other hand, the clutch shoe 27 is swingably supported around a pin 29 provided on the flywheel 19, and
At the time of rotation, it is oscillated in the outward direction by centrifugal force and is pressed against the inner diameter surface of the clutch bell 26.

As described above, the clutch bell 26 is fixed to the intermediate portion of the pilot shaft 21, and both ends of the pilot shaft 21 are supported by the pair of bearings 22 and 24. When a bending moment is generated in the clutch bell 26 due to the difference in the pressing force that presses the inner circumference of the clutch 26, the bending moment is received by the intermediate portion of the pilot shaft 21 that supports the clutch bell 26.

Therefore, the moment load does not act directly on the pair of bearings 22 and 24 that support the pilot shaft 21, and the moment load does not act on the pair of bearings 2.
Since they are received by the bearings 2 and 24, the moment load acting on the respective bearings 22 and 24 is small, and it is possible to effectively prevent the bearings 22 and 24 from being damaged.

Further, the bearing 24 is provided in the vicinity of the drive gear 28.
Therefore, the drive gear 28 is less likely to rotate with runout, and the power transmission efficiency can be improved.

FIG. 2 shows another embodiment of the present invention. This embodiment is different from the above-described embodiment in that a drive gear 28 is attached to the tip of the pilot shaft 21 penetrating the bearing housing 23.

Instead of the drive gear 28, a toothed pulley for a timing belt may be used.

Also in the above-mentioned embodiment, the same effect as that of the above-mentioned embodiment is obtained.

[0027]

As described above, in the present invention, the pilot shaft is inserted into the axial shaft insertion hole formed in the crankshaft, and both ends of the pilot shaft are rotatably supported by the bearings. Since the clutch bell of the centrifugal clutch is attached to the intermediate part of the pilot shaft between the bearings, even if there is an imbalance in the pressing force of the clutch shoes that press the inner circumference of the clutch bell, the bending moment that acts on the pair of bearings Is small, there is little damage to the bearing, and the life of the bearing can be improved.

Further, since the drive gear that rotates together with the clutch bell is supported by bearings in its vicinity, the runout of the drive gear during rotation is extremely small, and power transmission efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view of an engine according to the present invention.

FIG. 2 is a sectional view showing another example of the same engine.

FIG. 3 is a sectional view showing a conventional engine.

FIG. 4 is a sectional view showing another conventional engine.

[Explanation of symbols]

 11 Cylinder Block 12 Cylinder Chamber 13 Piston 15 Crankshaft 19 Flywheel 20 Shaft Insertion Hole 21 Pilot Shaft 22 Bearing 24 Bearing 26 Clutch Bell 27 Clutch Shoe 28 Drive Gear

Claims (1)

[Claims] 1. A tip portion of a crankshaft, which is slidably incorporated in a cylinder formed in a cylinder block and is rotated in one direction by reciprocating movement of the piston, penetrates through the cylinder block and faces the outside. A flywheel is attached to the crankshaft, and a shaft insertion hole extending in the axial direction from the tip end surface is formed in the crankshaft. A clutch bell is mounted between the bearings of the pilot shaft, which faces the flywheel in the axial direction, and the plurality of clutch shoes that are swingably supported by the flywheel and swing outward by centrifugal force are provided. It is placed in the clutch bell and one of the clutch bell and pilot shaft is used for torque transmission. Model engine equipped with a dynamic wheel.