JPH0434251A - Method for changing vibratory direction of internal combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention A1 Object of the Invention (1) Industrial Field of Application The present invention mainly relates to a single-cylinder internal combustion engine, in which vibrations are used to change the direction of vibrations caused by inertia of reciprocating parts including pistons. This invention relates to a direction conversion method.

(2) Conventional technology In an internal combustion engine, in order to change the direction of vibration caused by the inertial force of the reciprocating part including the piston, a centrifugal force is provided at the crank part of the crankshaft that balances part or all of the inertial force. It has been widely practiced in the past to provide a balance weight that generates a force.

(3) Problems to be solved by the invention However, in the case where the balance weight is provided in the crank part, it is necessary to secure a volume in the crankcase that allows the rotation of this balance weight. This becomes an obstacle when trying to downsize the device. In addition, if you try to obtain multiple types of internal combustion engines with different vibration directions, you will have to prepare multiple types of expensive rank shafts with different mounting positions of the balance weights, so it is not possible to provide the desired engine at a low cost. This becomes difficult.

The present invention was made in view of the above circumstances, and utilizes a flywheel that is attached to the crankshaft outside the crankcase, so that it can be used without the need for a balance weight on the crankshaft.
It is an object of the present invention to provide a method for converting the vibration direction of an internal combustion engine, which makes it possible to easily and inexpensively obtain a plurality of types of internal combustion engines having different vibration directions.

B3 Structure of the Invention (1) Means for Solving the Problems The present invention includes a crankshaft having a crank part that interlocks with a piston is supported in a crankcase, and a fly is attached to the end of the crankshaft that protrudes outside the crankcase. At the same time as the boss of the wheel is fitted, a key mounted at a fixed position on the crankshaft is engaged with the keyway of the boss, and the flywheel is provided with a part or all of the inertia of the reciprocating part including the piston. A method for changing the vibration direction of an internal combustion engine equipped with a weight that generates a balanced centrifugal force, in which multiple types of flywheels with different keyway phases relative to the weight are prepared, and the flywheel selected from these flywheels is It is characterized by being attached to the same type of crankshaft.

(2) Effect According to the feature of the present invention, the flywheel is given a balance function by the weight, and balances part or all of the inertia of the reciprocating part including the piston, thereby reducing vibrations caused by the inertia. The direction can be changed to a direction different from the direction of reciprocation of the piston.

Moreover, by simply attaching flywheels whose keyways have different phases relative to the weight to the same type of crankshaft, an internal combustion engine with different vibration directions can be obtained.

(3) Examples An embodiment of the present invention will be described below with reference to the drawings.

First, in FIG. 1, a crankcase 2 of a single-cylinder internal combustion engine 1 is composed of a case body 2a with an open right side surface and a side cover 2b joined to the open end of the case body 2a, which is attached to the end wall of the case body 2a. ball bearing 3 and
2 with a bearing boss 4 integrally formed on the side cover 2b.
The crankshaft 5 is supported horizontally at the point.

The crank portion 5a of the crankshaft 5 is connected to the crank case 2.
The small end of the connecting rod 6 is connected to the piston 7.

The piston 7 is housed in a cylinder hole 9 of a cylinder block 8 that is integrally connected to the upper part of the case body 2a.

A cylinder head 10 joined to the upper end of the cylinder block 8 is formed with a combustion chamber 11 and intake and exhaust ports 12.13 opening into the chamber 11. Intake and exhaust valves 14 and 15 for opening and closing are installed. These intake and exhaust valves 14 and 15 are driven to open and close by a known valve operating device 16 that is linked to the crankshaft 5.

Both left and right ends of the crankshaft 5 protrude outward from the crankcase 2, a flywheel 17 is fixed to the left end, and a driven device (not shown) is connected to the right end.

The crank portion 5a of the crankshaft 5 is not equipped with a balance weight, and the crankcase 2 is configured so that the bottom wall 2C of the crankcase 2 is brought closer to the rotation locus of the large end of the connecting rod 6.

The flywheel 17 includes a boss 18, a rim 19 concentrically surrounding the boss 18, and a rim 19 that surrounds the boss 18 and the rim 1.
9 and a disk 20 connecting the two.

A first weight 21 is provided on the back side of the disk 20 in such a manner that a portion of the rim 19 is thickened, and a second weight 22 is provided on the front side in a similar manner. At that time, the weight 21.22
are the respective centers of gravity G,.

G2 occupy opposite positions across the axis A of the crankshaft 5, and are arranged at a certain distance from each other along the axis A.

The boss 18 has a tapered center hole 23.
A keyway 24 is provided on the inner surface of 3.

Thus, the boss 18 fits the center hole 23 into the tapered shaft portion 25 formed at the left end of the crankshaft 5, and
By screwing the nut 26 onto the tip of the crankshaft 5
is fixed to. At this time, by engaging the key groove 24 with the key 27 attached to the fixed position of the tapered shaft part 25, the first and second weights 21 and 22 are attached to the crank part 5a.
The phase of is determined.

When attaching the flywheel 17 to the crankshaft 5,
As shown in (a) to (c) of FIG. One of the flywheels 17 of a plurality of types having different phases of the keyway 24 with respect to the second weight 21, 22 is selected according to the usage conditions of the engine l.

When the flywheel 17 shown in FIG. 2(A) is attached to the crankshaft 5, the engagement between the keyway 24 and the key 27 causes the first weight 21 to be held between the axis A of the crankshaft 5 and the crank portion 5a. It now occupies the exact opposite position.

In case (a) of Fig. 2, the first and second weights 21.
The weight and mutual position of 22 are determined so that the following equations (1) and (2) hold true.

F −m + °r+ ' ω” m+ °r
z °ω2−(m,・r,−m,・r2)G2・
・・・・・・・・・(1) ml 'r 1' (
IJ" °1.=m, -r, °ω2 °!2=m
l - rl ・11 = mz 'r2'
It ”” (2) (see Fig. 3), F: Inertia force m1 of the reciprocating part including the piston 7: Mass m of the first weight 21 at the center of gravity G1,: Second weight 22
Mass at the center of gravity G2 of the crankshaft 5 ",: Distance from the axis A of the crankshaft 5 to the center of gravity G1 rt: Distance ω from the axis A of the crankshaft 5 to the center of gravity G2: Angular velocity of the crankshaft 5!,: Any point on the axis A Axial distance from the point to the center of gravity G1!t: Axial distance from the arbitrary point above to the center of gravity G!Next, regarding the effect when the flywheel 17 shown in FIG. 2 (A) is attached to the crankshaft 5 explain.

When the flywheel 17 rotates together with the crankshaft 5,
By establishing the above equation <1), the centrifugal force acting on the center of gravity G of the first weight 21 and the center of gravity G of the second weight 22.

The resultant force with the centrifugal force acting on (m + ・r+ mz
・R ω2 balances the inertial force F of the reciprocating portion including the piston 7, and vibrations caused by the inertial force F can be removed.

However, the resultant force of the centrifugal force (m, ・rl−m
, ·r, )C2 causes vibration in a direction perpendicular to the axis of the cylinder hole 9 when the piston 7 reaches the midpoint of its stroke. In this way, all the vibrations in the vertical direction due to the inertial force F are converted into vibrations in the horizontal direction.

Such a 90'' conversion of the vibration direction is effective when horizontal vibration is allowed depending on the usage conditions of the engine I.

Therefore, the keyway 24 as shown in (b) and (c) in FIG.
It will be understood from the above-mentioned operation that if flywheels 17 with different positions are attached to the same type of crankshaft 5, an engine with different vibration conversion directions can be easily obtained.

C0 Effects of the Invention As described above, the present invention provides a plurality of types of flywheels in which the keyway that engages with the key mounted at a fixed position on the crankshaft has different phases with respect to the first and second weights. By simply preparing and attaching these to the same type of crankshaft, it is possible to easily and inexpensively obtain multiple types of engines with different vibration directions.

Furthermore, since the flywheel exhibits a balancing function, there is no need to provide a balance weight on the crank portion of the crankshaft, and the crankcase can be made smaller.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; Fig. 1 is a longitudinal sectional front view of a single-cylinder internal combustion engine, and Fig. 2 (A), (B), and (C) are all prepared for the same engine. , a front view of the flywheel with different keyway positions, Figure 3 is the same as Figure 2 (
FIG. 3 is a schematic diagram of the vibration system when the flywheel of (a) is attached to the crankshaft. 1... Internal combustion engine, 2... Crank case, 5...
Crankshaft, 5a... Crank part, 7... Piston, 17... Flywheel, 18... Boss, 21.
22... Weight, 24... Keyway, 27... Key procedure amendment (1 button November 12, 1990 1, Indication of incident Patent application No. 2-140729 2, Title of invention Internal combustion Engine vibration direction conversion method 3, relationship with the case of the person making the amendment Name of patent applicant (532) Honda Motor Co., Ltd. 4, Agent
Person: 105 Address: 3-12-10-5 Nishi-Shinbashi, Minato-ku, Tokyo Subject of amendment Contents of amendment 1, page 9, line 17 of the specification, after “(a)”, add “no” do. 2. In the third line of page 10 of the specification, "ml ・r2 ・ω2" is corrected to "m2 ・rt ・ω2". 3. Specification, page 10, line 6, “=m1 ・rl ・z, J, r , °, m
, ・r, ・L J. 4. On page 10, line 16 of the specification, "any point" is corrected to "center of cylinder hole 9." 5. In the first line of page 11 of the specification, the phrase "any point" is corrected to "center of cylinder hole 9." 6. On page 12 of the specification, line 4, after the words ``It becomes effective,'' add the following on a new line. "Also, while the flywheel 17 is rotating, the first and second weights 2
The centrifugal forces acting on the centers of gravity C, , C, of the units 1 and 22 each exert a couple on the crankshaft 5, but both of these couples are as described in (2) above.
Since the formula is established, there is a balance on the crankshaft 5, so no rocking vibration is generated on the crankshaft 5 due to the couple.''

Claims (1)

[Claims] A crankshaft (5) having a crank part (5a) interlocked with a piston (7) is supported by a crankcase (2),
The boss (18) of the flywheel (17) is fitted to the end of the crankshaft (5) that protrudes outside the crankcase (2), and the key ( 27) is engaged with the keyway (24) of the boss (18), and the flywheel (17) is provided with a centrifugal force that balances part or all of the inertia of the reciprocating part including the piston (7). A method for changing the direction of vibration of an internal combustion engine equipped with generated weights (21, 22), which uses multiple types of flywheels (17) whose keyways (24) have different phases with respect to the weights (21, 22). A method for changing the direction of vibration of an internal combustion engine, which comprises preparing a flywheel (17) and attaching one selected from these flywheels (17) to a crankshaft (5) of the same type.