JP3477046B2 - Single cylinder engine with two-axis balancer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balancer engine, and more particularly to a single cylinder engine having a two-shaft balancer.

[0002]

2. Description of the Related Art Conventionally, an engine having a two-axis balancer has been proposed for a single cylinder engine. In the two-axis balancer, balancers of the same weight are installed in two parallel axes to suppress engine vibration. In such a two-shaft balancer engine, in order to avoid the weight part of the two-shaft balancer from interfering with the weight part of the crankshaft and the large end of the connecting rod, the crankshaft crank gear and the driven gear on the balancer side are There is an idle gear between them. However, by inserting the idle gear, there is a problem that the total height becomes large in the vertical engine and the horizontal width becomes large in the horizontal engine.

In the case of a single-cylinder engine that is often required to be compact, it is difficult to adopt the method of interposing the idle gear, and the driven gear on the balancer side must be directly driven by the crank gear. FIG. 6 is a diagram showing a gear train of a biaxial balancer in which the crank gear and the driven gear on the balancer side are directly meshed with each other.

In FIG. 6, a crankshaft 45 is installed in a crankcase 44, a crank gear 46 fixed to the crankshaft 45 is meshed with a first balancer gear 47 of a biaxial balancer, and the first balancer gear is formed. The biaxial balancer is rotated by engaging 47 with the second balancer gear 48.

[0005]

However, the engine with a two-axis balancer shown in FIG. 6 has the following problems. That is, in the case of the primary balancer of the single cylinder engine as described above, that is, the balancer that cancels the frequency of the crankshaft rotation speed of one time, the rotation speed of the crankshaft 45, the rotation speed of the first balancer 49, and the second balancer 50. Since it is necessary to match the rotation speeds of the three, the gear ratio of the three plates is 1:
Must be 1: 1. On the other hand, with the configuration shown in FIG. 6, the axial distance between the crankshaft 45 and the first balancer 49 must be set to a certain extent in order to avoid interference between the balancer and the large end of the connecting rod or the crankpin arm. .

Then, the axial distance between the first balancer 49 and the second balancer 50 is the same as the axial distance, so that
There is a problem that the size of the biaxial balancer becomes large in the height h and width w directions. Since the primary vibration components of a multi-cylinder engine can be balanced among the cylinders, a secondary balancer may be used if a balancer is introduced. Since the capacity of the secondary balancer is 1/3 to 1/5 that of the primary balancer, the above problem does not occur in the multi-cylinder engine.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a single-cylinder engine with a two-axis balancer that can solve the above problems. As an example of a specific problem, there is a case where the biaxial balancer is made compact to reduce the height and width of the engine. The problems and means for solving the problems other than those described above will be described in detail in the means, actions, and embodiments of the invention for solving the problems described later.

[0008]

The present invention will be described below with reference to, for example, FIGS. 1 to 5 showing an embodiment of the present invention. A first aspect of the present invention is a single-cylinder engine with a two-axis balancer in which a pair of balancers are installed in parallel with the crankshaft 3 and the balancer is rotationally driven by a crank gear 8, and the first balancer 4 of the two-axis balancer 6 is a crankshaft. A first driven gear 9 that directly meshes with the gear 8 and transmits power from the crank gear 8, and a first driven gear 9 that is provided on the opposite side in the axial direction from the first driven gear 9
A transmission gear 12 for transmitting power to the balancer 5, the second balancer 5 has a second driven gear 13 meshing with the transmission gear 12, and the pitch circle diameter of the crank gear 8 and the first driven gear 9 The pitch circle diameter is the same, the pitch circle diameter of the transmission gear 12 and the pitch circle diameter of the second driven gear 13 are the same, and the weight portion 14 of the first balancer 4 and the weight portion 15 of the second balancer 5 are both connecting rods. The first end sub-comprising is provided with connecting rod large end escape portions 16 and 16 through which the large end passes.
The pitch circle of the transmission gear 12 is larger than the pitch circle radius of the dynamic gear 9.
The radius is set to be small, and the first driven gear 9 of the first balancer 4 is set.
The person was to be opposed to the weight portion 15 of the second balancer 5 <br/> is, the first driven gear 9 of the first balancer 4 and the second balancer 5
Of the second balancer 5 so as not to interfere with the weight portion 15 of
The weight part 15 of the
The weight portion 15 of the balancer 5 is provided with a gear passage escape portion 17 through which the first driven gear 9 passes.

The second aspect of the present invention is mainly shown in FIG. 5, in which at least the weight portion 14 of the first balancer 4 does not interfere with the crankshaft counterweight portions 30 and 30 and the crankpin arm portions 20 and 20. It is characterized by having escape portions 21, 21, 23, 23 at both left and right ends of the portion 14.

[0010]

According to the first aspect of the invention, since the weight portion of the first balancer and the weight portion of the second balancer both have the escape portion for passing the large end of the connecting rod, the first balancer and the second balancer have Each shaft can be brought close to the crankshaft, and the two-shaft balancer can be compactly arranged in the engine. Further, since the first driven gear of the first balancer does not interfere with the weight portion of the second balancer, the weight portion of the second balancer is provided with an escape portion for passing the first driven gear, so that the crank gear-first Even with a configuration in which two sets of gear trains including a driven gear train and a transmission gear-a second driven gear train are provided, it is possible to set a small axial distance between the first balancer and the second balancer. .

According to the second aspect of the invention, since the escape portions are provided at the left and right ends of at least the weight portion of the first balancer, only the portion that interferes with the crankshaft counterweight portion and the crankpin arm portion can be cut off. 1 balancer and 2nd
Even if the balancer axes are shortened, interference can be avoided without significantly reducing the weight of the weight section.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical cross-sectional view of an essential part of an engine with a biaxial balancer showing a first embodiment of the present invention. Figure 2
(A) is a diagram showing the positional relationship between the first balancer and the second balancer with a crank angle of 90 ° as viewed from the power take-off shaft side of the engine, and FIG. 2 (B) is a view taken along the line BB (right side view) Is.

FIG. 3 (A) is a diagram showing the positional relationship between the first balancer and the second balancer with a crank angle of 225 ° as seen from the power take-off shaft side, and FIG. 3 (B) is a view taken along the line BB (upper right). 45 °). FIG. 4A is a diagram showing a positional relationship between the first balancer and the second balancer with a crank angle of 246.5 ° as seen from the power take-off shaft side, and FIG.
FIG. 4C is a view of FIG. 4A viewed from below.

In this embodiment, the case where the invention is applied to a water-cooled single-cylinder vertical diesel engine is shown. As shown in FIG. 1, the engine 1 includes a crankcase 2 and a crankshaft 3 installed therein. A biaxial balancer 6 including a first balancer 4 and a second balancer 5 is installed below the crankshaft 3 in parallel with the crankshaft 3.

As shown in FIG. 2 (B), a crank gear 8 is fixed to the crank shaft 3 near the power take-off shaft side 7 of the engine.
The driven gear 9 is directly meshed with the driven gear 9. A transmission gear 12 is fixed to the opposite side 10 of the first balancer 4 in the axial direction via a weight portion 14 of the first balancer 4, and the transmission gear 12 has a second balancer as shown in FIG. 4 (C). 5
The second driven gear 13 is engaged with the second driven gear 13. Therefore, there is a gear train of the crank gear 8 and the first driven gear 9 on the power take-off shaft side 7 of the engine 1, and a gear train of the transmission gear 12 and the second driven gear 13 on the opposite side 10 to the power take-off shaft side. become.

Further, the pitch circle diameter of the crank gear 8 and the pitch circle diameter of the first transmission gear 9 have the same length (that is, 1:
1), and the pitch circle diameter of the transmission gear 12 and the pitch circle diameter of the second transmission gear 13 have the same length (that is, 1:
1), and the pitch circle diameter of the transmission gear 12 is set smaller than the pitch circle diameter of the first driven gear 9. Therefore, the shaft center 3a of the crankshaft 3 shown in FIG.
4 from the distance d1 between the shaft center 4a of the first balancer 4 and
The distance d2 between the shaft center 4a of the first balancer 4 and the shaft center 5a of the second balancer 5 shown in (C) is shorter.

In order to reduce the size of the biaxial balancer 6, the rotational trajectory of the connecting rod large end portion of the crankshaft 3 overlaps with the rotational trajectory of the weight portion 14 of the first balancer 4 and the weight portion 15 of the second balancer 5. Is set so that the first driven gear 9 of the first balancer 4 overlaps the rotation locus of the weight portion 15 of the second balancer 5. And
Both the weight portion 14 of the first balancer 4 and the weight portion 15 of the second balancer 5 have a large connecting rod escape portion 16.1.
6 (see FIG. 4 (C)) is provided, and the first balancer 4
When the first driven gear 9 is opposed to the weight portion 15 of the second balancer 5 , the first driven gear 9 of the first balancer 4 should not interfere with the weight portion 15 of the second balancer 5.
The weight portion 15 of the second balancer 5 is provided with a gear passage clearance portion 17 (see FIG. 4C) of the first driven gear 9.

Further, as shown in FIG. 2A, as compared with the position of the shaft center 4a of the first balancer 4, the shaft center 5 of the second balancer 5 is
The position a is set lower by a predetermined distance e. Figure 1 is the first
It is a figure for demonstrating the structure of the weight part of a balancer, FIG.5 (A) is the figure which looked at the 1st balancer from the lower side, FIG.
5B is a sectional view taken along the line BB of the weight portion, and FIG. 5C is a sectional view taken along the line CC of the weight portion.

As shown in FIG. 5A, the first balancer 4
The wet portion 14 of the connecting rod is provided with the above-described large-diameter relief portion 16 of the connecting rod, so that the large-diameter relief portion 16 of the connecting rod is provided.
It is divided into separation weight portions 18, 18 on both sides of. As shown in FIGS. 5 (B) and 5 (C), each of the separation weight portions 18 is a weight portion having a substantially fan-shaped cross section. Further, as shown in FIG. 5 (B), a crank pin arm escape portion that allows the crank pin arm portions 20 and 20 (see FIG. 3B) to escape to the outside predetermined regions 19 and 19 of the connecting rod large end escape portion 16. 21 ・ 21 are formed. Further, as shown in FIG. 5C, crankshaft counterweights 30 and 30 (see FIG. 3B) are released to both outermost parts 22 and 22 of the separation weights 18 and 18, respectively. The escape portions 23, 23 are formed.

The crank pin arm escape portion 2
1 and the crankshaft count weight relief portions 23, 23 do not need to be provided over the entire area of the fan-shaped edge, and the relief portion is formed only in the interfering portion. Therefore, in the first balancer 4, the connecting rod large end relief portion 16 Even if is increased, the weight required for the first balancer 4 can be secured. Further, reference numeral 24 in FIG. 5 (B) is a locus drawn by the crankpin arm portions 20 and 20, and reference numeral 25 in FIG. 5 (C) is a locus drawn by the crankshaft counterweight portions 30 and 30.

Further, as shown in FIG. 1, in this engine, a drive gear 26 having a diameter smaller than that of the crank gear 8 is fixed to the crankshaft 3 at a position 27 in FIG. 2B. The cam shaft gear 28 is meshed with. The cam shaft gear 28 is located diagonally above the crank shaft 3 and closer to the side of the crankcase 2 in FIG. 1, and the cam shaft gear 28 meshes with the governor shaft gear 29 at the lower position. The center of the governor shaft gear 29 is located laterally of the shaft center of the first balancer 4 in FIG.

The operation of the engine with the two-axis balancer having the above structure will be briefly described. By the vertical movement of the piston,
As shown in FIG. 2A, for example, the crank gear 8 rotates counterclockwise, the first balancer 4 rotates clockwise, and the second balancer 5 rotates counterclockwise. Since the first balancer 4 and the second balancer 5 rotate in the opposite directions in this manner, the weight portions 14 and 15 and the crankshaft system (the connecting rod large end portion,
The way of approaching the crankpin arm section 20 and the crankshaft counterweight section 30) is different. In particular, in the first balancer 4, the portions that may interfere with the crank pin arm portions 20 and 20 and the crankshaft counterweight portions 30 and 30 are limited to the left and right end portions of the weight portion 14 of the first balancer 4. There is. Therefore, as shown in FIG. 3B, crank pin arm escape portions 21 and 21 (see FIG. 5B) are provided so as to avoid the crank pin arm portions 20 and 20, and the crankshaft counter of FIG. Weight part 30
Crankshaft counterweight relief portions 23, 23 (see FIG. 5C) are provided so as to avoid the outer end portion of 30.

The second balancer 5 includes a crank pin arm portion 20 and a crank shaft counterweight portion 30.
Since they are set apart from each other by a distance e so as not to interfere with 30, they do not need the relief portions, and only the connecting rod large end relief portion 16 is provided. By setting in this way, the transmission gear 12 is larger than the pitch circle diameter of the first driven gear 9.
Even if the pitch circle diameter is set to be small, it is possible to prevent the biaxial balancer 6 from interfering with each part.

Further, according to this embodiment, the crankshaft 3
Is directly transmitted from the crank gear 8 to the first driven gear 9 of the first balancer 4, and the rotation of the first balancer 4 is transmitted by the transmission gear 12 to the second driven gear 13 of the second balancer 5.
Transmitted directly to. Even when the rotation of the crank gear 8 is transmitted to the biaxial balancer without passing through the idle gear, the crank gear 8-the gear train of the first driven gear 9 and the transmission gear 12-the second driven gear 13 are arranged. Since the gear train of the crank gear 8 and the first driven gear 9 are independent, the pitch circle diameter of the crank gear 8 and the first driven gear 9 is 1: 1, and the transmission gear 12 and the second driven gear 1 are
Even if the pitch circle diameter with 3 is set to 1: 1, the three gear trains of crank gear 46 → first balancer gear 47 → second balancer gear 48 shown in FIG. The size of the crankcase does not become large due to its size. That is, the gear train of the crank gear 8 and the first driven gear 9 and the gear train of the transmission gear 12 and the second driven gear 13 are arranged on the crankshaft 3 in accordance with the shape and size of the crack case required by the engine. It is possible to individually arrange the positions. Therefore, according to this embodiment, the configuration of the biaxial balancer in the crankcase can be freely set as compared with the configuration of the conventional direct drive type as shown in FIG.

Although not described in the drawings, if the pitch circle diameter of the transmission gear 12 is set larger than the pitch circle diameter of the first driven gear 9, the distance between the crankshaft 3 and the first balancer 4 is the same. Then, the weight of the biaxial balancer can be increased as compared with the conventional configuration shown in FIG.

[Brief description of drawings]

FIG. 1 is a partially longitudinal front view of an engine with a biaxial balancer according to the present invention.

FIG. 2 (A) is a diagram showing a positional relationship between a first balancer and a second balancer with a crank angle of 90 ° as viewed from the power take-off shaft side, and FIG. 2 (B) is a view taken along the line BB ( (Right side view).

FIG. 3 (A) is a diagram showing a positional relationship between a first balancer and a second balancer having a crank angle of 225 ° as viewed from the power take-off shaft side, and FIG. 3 (B) is a view taken along the line BB ( (Upper right 45 °)
Is.

FIG. 4 (A) is a diagram showing a positional relationship between a first balancer and a second balancer with a crank angle of 246.5 ° as viewed from the power take-off shaft side, and FIG. 4 (B) is a view taken along the line BB. Figure (left 23.5
FIG. 4C is a view of FIG. 4A viewed from below.

5A and 5B are views for explaining the configuration of the weight portion of the first balancer, FIG. 5A is a view of the first balancer as seen from below, and FIG. 5B is a portion B of the weight portion. -B line sectional drawing, FIG.5 (C) is CC sectional view taken on the line of a weight part.

FIG. 6 is a diagram showing a gear train of an engine in which a crank gear and a balancer drive gear are directly meshed with each other.

[Explanation of symbols]

3 ... Crankshaft, 4 ... 1st balancer, 5 ... 2nd balancer, 6 ... 2 axis balancer, 8 ... Crank gear, 9 ... 1st driven gear, 12 ... Transmission gear, 13 ... 2nd driven gear. 14 ...
Weight portion of first balancer, 15 ... Weight portion of second balancer, 16 ... Large connecting rod end relief portion, 17 ... Gear passage relief portion, 20 ... Crank pin arm portion, 21 ... Crank pin arm relief portion, 23 ... Crankshaft counterweight relief part, 30 ... Crankshaft counterweight part.

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Claims (2)

(57) [Claims] 1. A single-cylinder engine with a two-axis balancer in which a pair of balancers are installed in parallel with a crankshaft (3), and the balancer is rotationally driven by a crank gear (8). A first driven gear (9) in which the first balancer (4) directly meshes with the crank gear (8) to transmit power from the crank gear (8), and the first driven gear (9) are opposite in axial direction to the first driven gear (9). And a transmission gear (12) that is provided on the side and transmits power to the second balancer (5),
The second balancer (5) has a second driven gear (13) meshing with its transmission gear (12), and the pitch circle diameter of the crank gear (8) and the pitch circle diameter of the first driven gear (9) are the same. And the pitch circle diameter of the transmission gear (12) and the pitch circle diameter of the second driven gear (13) are the same, and the weight portion (14) of the first balancer (4) and the weight of the second balancer (5) are Both parts (15) are provided with connecting rod large end relief parts (16, 16) through which the connecting rod large end passes, and the transmission gear (1) is larger than the pitch circle radius of the first driven gear (9).
The radius of the pitch circle of 2) is set small , and the first driven gear (9) of the first balancer (4) is set to the second balancer.
When facing the weight part (15) of the support (5) ,
Make sure that the first driven gear (9) of the first balancer (4) does not interfere with the weight portion (15) of the second balancer (5) .
The intermediate portion of the weight portion (15) of the second balancer (5) in the axial direction is recessed to form the weight portion (1) of the second balancer (5).
5) A single-cylinder engine with a two-axis balancer, characterized in that a gear passing clearance (17) through which the first driven gear (9) passes is provided. 2. The single-cylinder engine with a two-axis balancer according to claim 1, wherein at least a weight portion (1) of the first balancer (4) is provided.
4) is the crankshaft counterweight part (30/30),
At the left and right ends of the weight part (14), there are relief parts (21, 21) so as not to interfere with the crankpin arm parts (20, 20).
・ A single-cylinder engine with a two-axis balancer, characterized in that