JPH0650387A - Balancer device for single cylinder engine - Google Patents

Abstract

PURPOSE:To obtain a small-sized and simple constitution by installing a balance weight sliding cylinder installed integrally with a cylinder, balance weight which is made of the material having a large specific gravity and moves in reciprocation in the sliding cylinder, with a phase difference of 180 deg. for a piston, and a return passage to the inside of a crankcase which communicates to the sliding cylinder. CONSTITUTION:A balance weight sliding cylinder 33 is installed integrally in close to and in parallel to a cylinder 31, and a balance weight 35 is gently fitted inside the sliding cylinder 33, and the product of the weight of the weight 35 and the revolution radius of a crank pin 32b is made equal to the product of the weight of a piston 34 and the revolution radius of a crank pin 32a. In order to obtain the compact constitution of the sliding cylinder 33 and the balance weight 35, the weight 35 is made of the material having a large specific gravity. A communication hole 43 permits the communication between the upper part of the sliding cylinder 33 an the inside of a crank case 36. The primary vibration due to the reciprocating movement of the piston 34 can be absorbed by the weight 35 which moves in reciprocation, having the phase shifted by 180 deg.. With this constitution, a balancer device can be accommodated in small-sized and compact form, and also the whole of an engine can be made small-sized and compact.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balancer device for a general purpose single cylinder engine and a crankcase compression type two cycle single cylinder engine.

[0002]

2. Description of the Related Art A conventional crank engine has a small number of cylinders (1-2
An example of a mechanical balancer in the case of a cylinder will be described with reference to FIG. FIG. 6 is a schematic vertical sectional view of a conventional balancer device for a two-cycle engine. This example is an in-line two-cylinder engine, and the pistons of the first cylinder and the second cylinder have a phase difference of 180 °. That is, when the piston of the first cylinder is at the top dead center, the piston of the second cylinder is at the bottom dead center. Both pistons are connected to the crankshaft by a connecting rod. In the figure, A is a known crankcase compression type two-cycle in-line two-cylinder engine. 1 is the first cylinder,
The second cylinder 2 is provided in series with the first cylinder 1. Three
Is fitted into the first cylinder 1 by the first piston. 4 is the second
The piston is fitted in the second cylinder 2. Reference numeral 7 denotes a crankshaft, which has a crank angle of 180 ° and four cranks and three bearings. A first connecting rod 5 connects the first piston 3 to the crankshaft 7. A second connecting rod 6 connects the second piston 4 to the crankshaft 7. A bearing 8 supports the crankshaft 7. A crankcase 9 supports the crankshaft and also supports the entire engine. 1
Reference numeral 1 denotes a first crank chamber, which is below the first cylinder 1. A second crank chamber 12 is located below the second cylinder 2. A seal ring 10 is provided on the crankshaft 7 between the first crank chamber 11 and the second crank chamber 12. Reference numeral 13 denotes an opposed cylinder, which is provided in one body with the crankcase 9 so as to face the first cylinder 1. Reference numeral 14 denotes an opposed cylinder which is provided integrally with the crankcase 9 so as to face the second cylinder 2.

Reference numeral 15 is a balancer, which is fitted into the opposing cylinder 14 in the shape of an upwardly opening cup. A connecting rod 16 connects the balancer 15 and the piston 3 to the crankshaft 7 with a phase difference of 180 °. Reference numeral 17 is a balancer, which is fitted into the opposing cylinder 14 in the shape of an upward-opening cup. Reference numeral 18 is a connecting rod, and the balancer 17 is connected to the second piston 4 and 18
It is connected to the crankshaft 7 with a phase difference of 0 °. 19 is a chamber of the opposed cylinder 13, and 20 is a chamber of the opposed cylinder 14. Reference numeral 21 denotes an escape passage, which connects the chamber 19 of the opposing cylinder 13 and the chamber 20 of the opposing cylinder 14 at the back of the cylinder.
Each cylinder has an intake hole and an exhaust hole scavenging hole (neither shown), the intake hole is connected to the air cleaner through the carburetor, the exhaust hole is connected to the muffler by the exhaust pipe, and the scavenging hole is connected to the crank by the scavenging passage. It is connected to the chambers 11 and 12.

Next, the operation of the conventional example will be described. The operation relating to the power generation of the crankcase compression type two-cycle in-line two-cylinder engine A is well known and will not be described. Balancer 1
5 is the opposed cylinder 1 with a phase difference of 180 ° with the first piston 3.
3, the balancer 17 has a phase difference of 180 degrees with the second piston 4.
It reciprocates in the opposing cylinder 14 at an angle of °. Crankshaft 7
During the rotation, the primary vibration associated with the reciprocating motion of the first piston 3 and the second piston 4 is absorbed by the balancers 15 and 17. Since the balancers 15 and 17 have a phase difference of 180 °, the chamber 19 of the opposed cylinder 13 and the chamber 20 of the opposed cylinder 14
The back pressure generated on the balancers 15 and 17 is offset through the relief passage 21, and the balancers 15 and 17 operate smoothly.

[0005]

However, the conventional balancer device for an engine has many components and has a complicated structure and a large size, resulting in a high cost. When a mixed fuel / lubricating oil is used in a two-cycle engine, there is almost no replacement of the old and new lubricating oil in the sliding portion of the balancer, and seizure or wear may occur as a result of deterioration of the lubricating oil. The object of the present invention is to provide a balancer device for a single-cylinder engine which solves the problems of the prior art, is small and compact, and therefore the entire engine can be small and compact, and can be lubricated smoothly even when applied to a two-cycle engine. is there.

[0006]

A first aspect of the present invention is a single-cylinder engine, in which a balance weight sliding cylinder provided in parallel with the cylinder and laterally approaching the cylinder, and a piston driven by a crankshaft A balance weight made of a material that reciprocates in the balance weight sliding cylinder with a phase difference of °, and a crankcase provided on the side of the balance weight sliding cylinder so as to communicate with the sliding cylinder and the upper side. And a return passage to.

According to a second aspect of the present invention, in a crankcase compression type two-cycle compression type single cylinder engine, a balance weight sliding cylinder provided in one body in parallel with and laterally adjacent to the cylinder and driven by a crankshaft. A balance weight that reciprocates in the balance weight sliding cylinder with a phase difference of 180 ° with a piston and communicates with a balance weight having a communication hole in the axial direction and a cylinder provided at the upper end of the balance weight sliding cylinder. It is characterized by having a passage.

[0008]

According to the first aspect of the present invention, in a single cylinder engine, the primary vibration accompanying the reciprocating motion of the piston during engine operation is absorbed by the balance weight which is driven by the crankshaft and reciprocates with a 180 ° phase shift. Moment vibrations that tilt the crankshaft up and down due to the distance between the points of action of the piston inertial force and the balance weight inertial force on the crankshaft remain, but this adjusts the weight of the balance weight fixed to the crankshaft. Can be reduced. A second aspect of the invention is a crank chamber compression type two-stroke single-cylinder engine, in which the primary vibration associated with the reciprocating movement of the piston is driven by the crankshaft and is reciprocally moved 180 degrees out of phase with the balance weight as in the first aspect. Moment vibration that is absorbed and tilts the crankshaft up and down remains, but this can be reduced by adjusting the balance weight fixed to the crankshaft, and in the exhaust / scavenging stroke of the engine, a mixed gas of fuel / lubricant and air It is possible to lubricate the sliding portion of the balance weight by passing through the communication hole of the balance weight, the balance weight sliding cylinder, and the passage of the cylinder.

[0009]

EXAMPLE A first example will be described with reference to FIGS. The first embodiment is an example applied to a 4-cycle single cylinder engine. FIG. 1 is a sectional view of a four-cycle single cylinder engine of an embodiment, and FIG. 2 is a sectional view taken along line BB of FIG. In the figure, 30 is a 4-cycle single cylinder engine. A crankcase 36 supports the entire engine. Reference numeral 37 denotes a crankcase lid, which is attached to the side surface of the crankcase 36 to form a lid. 32 is a crankshaft, a crank angle of 180 °,
Two cranks and two bearings. Two bearings 38 are attached to the crankcase 36 and the crankcase lid 37 to support the crankshaft 32. Reference numerals 32a and 32b are crankpins. Reference numeral 31 is a cylinder, which is a known element of an engine, and is attached to a crankcase 36. A piston 34 is fitted in the cylinder 31. A piston pin 41 is fitted into the piston 34. A connecting rod 39 connects the piston pin 41 and the crank pin 32a. Reference numeral 33 denotes a balance weight sliding cylinder, which is a cylinder provided in parallel with and close to the cylinder 31. Three
A balance weight 5 is loosely fitted in the balance weight sliding cylinder 33. 42 is a pin fitted into the balance weight 35. A connecting rod 40 connects the pin 42 and the crank pin 42b. The product of the weight of the balance weight 35 and the turning radius of the crank pin 32b is equal to the product of the weight of the piston 34 and the turning radius of the crank pin 32a. In order to make the balance weight sliding cylinder 33 and the balance weight 35 compact, the material of the balance weight 35 is selected to have a large specific gravity.

Reference numeral 43 is a communication hole, which is a balance weight sliding cylinder 3
The upper part of 3 and the inside of the crankcase 36 communicate with each other. Three
A balance weight 2c is fixed to the crankshaft 32. 32d is a balance weight fixed to the crankshaft 32. Next, the operation of the first embodiment will be described.
The operation of generating power of the four-cycle single-cylinder engine 30 is well known and will not be described. The primary vibration accompanying the reciprocating motion of the piston 34 during the operation of the 4-cycle single cylinder engine 30 can be absorbed by the balance weight 35 which reciprocates with a 180 ° phase shift. Moment vibrations that tilt the crankshaft 32 up and down due to the distance between the point of action of the inertial force of the piston 34 on the crankshaft 32 and the point of action of the inertial force of the balance weight 35 remain, but this is fixed to the crankshaft 32. Balance weight 32
It can be reduced by adjusting the weights of c and 32d.

Next, a second embodiment will be described with reference to FIGS. 3 is a sectional view of a crankcase compression type two-cycle single cylinder engine, and FIG. 4 is a sectional view taken along the line CC of FIG. FIG. 5 is a diagram in which the crankshaft of FIG. 3 is rotated 180 °. In the figure, 50 is a two-cycle single cylinder engine. Reference numeral 56 is a starter-side crankcase, 57 is a fan-side crankcase, which is attached to the starter-side crankcase 57 to assemble the crankcase and supports the two-cycle single-cylinder engine 50 as a whole together with the starter-side crankcase 56. Reference numeral 52 denotes a crankshaft, which is a known engine component, which has a crank angle of 180 °, two cranks, and two bearings. A ball bearing 58 supports the crankshaft 52. A cylinder 51 is a known element of the engine. A piston 54 is fitted in the cylinder 51. A crank pin 52a is provided on the crank shaft 52. Reference numeral 52b is a crank pin, and the crank shaft 52 has a phase difference of 18 from that of the crank pin 52a.
It is set at 0 °. A connecting rod 59 connects the piston pin 54 and the crank pin 52a. Reference numeral 53 is a balance weight sliding cylinder, which is a cylinder provided in parallel with and close to the cylinder 51. 55 is a balance weight and is a piston type balance weight sliding cylinder 5
3 is loosely fitted. A connecting rod 60 connects the balance weight 55 and the crank pin 52b. Weight of balance weight 55 and crank pin 52
The product of the turning radius of b, the weight of the piston 54 and the turning radius of the crank pin 52a are equal. In order to make the balance weight sliding cylinder 53 and the balance weight 55 compact, the material of the balance weight 55 is selected to have a large specific gravity. 53a is a passage for connecting the rear end of the balance weight sliding cylinder 53 and the cylinder 51. A communication hole 55a is opened in the axial direction of the balance weight 55. 52c is a balance weight fixed to the crankshaft 52. Reference numerals 62 and 63 denote scavenging ports, which are provided in the cylinder 51 and communicate with the crank chamber. 61
Is an exhaust port provided in the cylinder 51 and communicates with a muffler. A muffler 64 communicates with the outside air. F indicates the flow direction of the mixed gas with an arrow.

Next, the operation of the second embodiment will be described. Two
The operation of generating power of the cycle single-cylinder engine 50 is publicly known and will not be described. The primary vibration associated with the reciprocating motion of the piston 54 during the operation of the two-cycle single cylinder engine 50 can be absorbed by the balance weight 55 that reciprocates with a 180 ° phase shift. Crankshaft 5
The moment vibration that tilts the crankshaft 52 in the vertical direction due to the distance between the point of action of the inertial force of the piston 54 and the point of action of the inertial force of the balance weight 55 remains, but this adjusts the weight of the balance weight 52c. Can be reduced. In the exhaust / scavenging stroke of the engine, the balance weight 55 slides by passing a mixed gas of fuel / lubricant and air through the communication hole 55a of the balance weight 55, the balance weight sliding cylinder 53, and the passage 53a of the cylinder 51. The parts can be lubricated. In the exhaust / scavenging stroke of the engine in which the piston 54 is pushed down, the scavenging ports 62 and 63 communicate the crank chamber and the cylinder 51 and blow out a mixed gas of fuel / lubricant and air compressed in the crank chamber in a direction indicated by an arrow F. The cylinder 51 is scavenged. The exhaust gas is sent from the exhaust port 61 to the muffler 64 by the exhaust pipe.

[0013]

The balancer device can be housed in a compact size by providing a cylinder and one balance weight sliding cylinder. Therefore, the entire engine can be kept small and compact. Even when applied to a 2-cycle engine, smooth lubrication can be achieved. Therefore, the present invention can provide a balancer device for a single-cylinder engine that is small and compact, and therefore the entire engine can be made compact and compact, and can be lubricated smoothly even when applied to a two-cycle engine.

[Brief description of drawings]

FIG. 1 is a sectional view of a 4-cycle single cylinder engine of a first embodiment.

FIG. 2 is a sectional view taken along line BB of FIG.

FIG. 3 is a sectional view of a two-cycle single cylinder engine of a second embodiment.

FIG. 4 is a sectional view taken along line CC of FIG.

FIG. 5 is a diagram in which the crankshaft of FIG. 3 is rotated 180 °.

FIG. 6 is a schematic sectional view of a two-cycle engine showing a conventional balancer device.

[Explanation of symbols]

30 ... 4-cycle single cylinder engine, 31 ... Cylinder, 34 ... Piston, 32 ... Crank shaft, 33 ... Balance weight sliding cylinder, 35 ... Balance weight, 50 ... 2
Cycle single cylinder engine, 51 ... Cylinder, 52 ...
Crankshaft, 53 ... Balance weight sliding cylinder, 53a ...
Passage, 54 ... piston, 55 ... balance weight, 55
a ... communication hole, 52c ... balance weight.

Claims (2)

[Claims] 1. In a single cylinder engine (30),
A balance weight sliding cylinder (33) provided in parallel with the cylinder (31) and adjacent to the side of the cylinder (31).
And the piston (3
4) and a balance weight (35) made of a material that is reciprocally moved in the balance weight sliding cylinder (33) with a phase difference of 180 °, and a balance weight sliding cylinder (3).
A balancer device for a single-cylinder engine, which has a return passage (43) into the crankcase, which is provided on the side of 3) so as to communicate with the sliding cylinder above. 2. A crankcase compression type two-stroke single-cylinder engine (50), a balance weight sliding cylinder (53), which is provided in one body in parallel with and adjacent to the cylinder (51) and a crankshaft. A balance weight (55) which is driven by (52) and reciprocates in the balance weight sliding cylinder (53) with a phase difference of 180 ° with the piston (54);
A balancer device for a single cylinder engine, comprising: a passage (53a) provided at an upper end of the balance weight sliding cylinder (53) and communicating with a cylinder.