JP2001200893A - Balancer device for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce vibrations of a balancer device by suppressing the imbalance of a balancer portion in the balancer axial direction. SOLUTION: This balancer device is structured to rotate a weight portion by attaching a balancer gear 9 to a balancer shaft 15 with the weight portion and rotating the balancer gear 9 with a crank gear. In the balancer device, a first weight portion 21 and a second weight portion 22 having a weight lighter than the first weight 21 are mounted to the balancer shaft 15, and the balancer gear 9 lightened by providing an opening 23 is mounted in the second weight portion 22 having the small volume side. In this structure, the weight balance between the first weight portion 21 and the second weight portion 22 can be improved to suppress vibrations.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine balancer device.

[0002]

2. Description of the Related Art FIGS. 5 and 6 show an engine using a conventional balancer device. As shown in FIG. 5, the engine 51 has a crankshaft 53 installed in a crankcase 52, and a first shaft below the crankshaft 53.
A two-axis balancer device 56 including a balancer 54 and a second balancer 55 is installed in parallel with the crankshaft 53.

As shown in FIG. 6, a crank gear 60 is fixed to a crank shaft 53 near a power take-out shaft side 57 of an engine, and a first driven gear 59 of a first balancer 54 is directly connected to the crank gear 60. The meshing (see FIG. 6A) is performed. In this specification, the power take-out shaft side of the engine is referred to as a front side 57 of the engine, and the opposite side is referred to as a rear side 58 of the engine. FIG.
A transmission gear 62 is fixed to the rear side 58 of the engine of the first balancer 54 as shown in FIG.
2 meshes with the second driven gear 63 of the second balancer 55.

[0006] As shown in FIG. 6 (B), both the first balancer and the second balancer 55 have a configuration in which a first weight portion 65 and a second weight portion 66 are attached to a balancer shaft 64. The first weight portion 65 is a weight portion having a large volume on the front side 57 of the engine from the cylinder center axis 67. The second weight portion 66 is a weight portion located on the rear side 58 of the engine with respect to the cylinder center axis 67 and having a smaller volume than the first weight portion 65.

[0005]

The configuration of the above-mentioned conventional balancer device has the following problems. (A) Since the difference in volume between the first weight portion 65 and the second weight portion 66, that is, the difference in weight is large, the first balancer 5
4. There is a problem that vibration of the two-axis balancer device 56 in the longitudinal direction of the engine due to rotation of the second balancer 55 increases. (B) In the two-axis balancer device 56, in order to increase the moment for compensating the inertia force of the engine reciprocating portion, the first
It is conceivable to increase the volume of the weight portion 65 and the second weight portion 66. However, if the volume of the weight portions 65 and 66 is increased, the crankcase 52 accommodating the two-axis balancer device 56 becomes large, and the engine Cannot be made compact.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an engine balancer device which can solve the above problems. An example of a specific purpose is as follows. (a) In a balancer device provided with a first weight portion and a second weight portion having a smaller volume than the first weight portion, the longitudinal vibration of the balancer device is reduced. (b) To provide a balancer device that can suppress engine vibration without increasing the volume of the weight portion. It should be noted that the problems of the invention other than those described above and the means for solving the problems will be described in detail in the description in the following specification.

[0007]

The present invention will be described below with reference to, for example, FIGS. 1 to 4 showing an embodiment of the present invention. The first invention attaches a balancer gear to a balancer shaft having a weight portion,
In the engine balancer device configured to rotate the weight portion by rotating the balancer gear with a predetermined gear that is interlocked with the rotation of the engine, a lightening portion 26 is provided on the balancer gear, and the lightening portion 26 is provided. ,
Angle range θ around the balancer axis 15 where the weight portion exists
Are provided in an angle range (2π−θ) excluding.

According to a second aspect of the present invention, a first weight portion 21 and a second weight portion 22 having a smaller volume than the first weight portion 21 are provided on the balancer shaft 15, and the meat portion is provided on the second weight portion 22 side having a smaller volume. It is characterized in that a balancer gear having a cutout portion 26 is provided.

According to a third aspect of the present invention, a first weight portion 21 and a second weight portion 22 having a smaller volume than the first weight portion 21 are provided on the balancer shaft 15, and these weight portions 21 and.
A part of the balancer shaft 15 is formed on the plane portion 25 in an angle range (2π−θ) excluding the angle range θ around the balancer axis 15 in which 22 exists.

The first and second inventions will be further described. In the first invention, the configuration in which the balancer gear is lightened may be configured such that a concave portion is provided in the balancer gear.
3 or both configurations can be adopted. Second
In the present invention, the position where the balancer gear is provided may be the end of the second weight portion 22 or the center thereof. Note that the first to third inventions can be configured independently of each other, or can be combined with the configurations described in the embodiments described later.

[0011]

According to the first aspect of the present invention, the balancer gear is hollowed out in an angle range other than the angle range around the balancer axis where the weight portion exists, so that compared to a configuration in which the balancer gear is not hollowed out, More moment can be added to compensate for the inertial force of the reciprocating part of the engine. Therefore, it is possible to further suppress the vibration of the engine as compared with a balancer device having the same weight portion without increasing the volume of the crankcase.

The operation and effect of the second invention will be described.
In the balancer device, when the first weight portion and the second weight portion are provided, the volume of the first weight portion and the volume of the second weight portion cannot be designed to be substantially equal due to the internal configuration of the engine. In some cases, a second weight portion having a smaller volume than the portion has to be provided. In such a case, according to the second aspect of the invention, since the thinned balancer gear is attached to the second weight portion having a small volume, the first weight portion and the second weight portion are arranged in the balancer axial direction. The imbalance in weight balance can be suppressed. Therefore, vibration of the balancer device can be reduced.

According to the third aspect, the first weight portion and the second weight portion
In the angle range excluding the angle range around the balancer axis where the weight portion exists, since a part of the balancer shaft is formed in a flat portion, the volume of at least one of the first weight portion and the second weight portion of the balancer device is increased. Can be increased without increasing.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional view of an essential part of an engine with a two-axis balancer showing a first embodiment of the present invention, and FIG.
FIG. 2 is a vertical sectional view taken along line II. The first embodiment shows a case where the balancer device according to the present invention is incorporated in a water-cooled single-cylinder vertical diesel engine. As shown in FIG. 1, in the engine 1, a crankshaft 3 is installed in a crankcase 2, and a two-axis balancer device 6 including a first balancer 4 and a second balancer 5 is provided below the crankshaft 3. It is installed in parallel with.

As shown in FIG. 2, a balancer driving crank gear 8 is fixed to the crankshaft 3 near the rear side 7 (flywheel side) of the engine, and the balancer driving crank gear 8 is attached to the first balancer 4. Of the first driven gear 9 directly mesh with each other. The first driven gear 9 meshes with the second driven gear 11 of the second balancer 5, as shown in FIG. Therefore, the balancer driving crank gear 8, the first driven gear 9, and the second
There is a gear train of the driven gear 11.

As shown in FIG. 1, a drive gear 12 having a smaller diameter than the crank gear 8 is fixed to the front side 10 of the engine (see FIG. 2). 13 are engaged. As shown in FIG. 1, the camshaft gear 13 is
The camshaft gear 13 is meshed with the governor shaft gear 14 at a position below the camshaft gear 13. In FIG. 1, the center of the governor shaft gear 14 is located on the side of the shaft center of the first balancer 4. The pitch circle diameter of the balancer driving crank gear 8 and the pitch circle diameters of the first transmission gear 9 and the second driven gear 11 are set to the same length (that is, 1: 1: 1).

As shown in FIGS. 3 (A) and 3 (B), each of the balancers 4 and 5 is configured so that both ends of the balancer shaft 15 are laterally suspended by a power takeout shaft side bearing 16 and a flywheel side bearing 17. At the same time, a connecting rod large end escape portion 20 is provided so that a central portion 19 including the cylinder center axis 18 does not interfere with the connecting rod large end.

The balancer portion is configured to be divided in the front-rear direction when viewed from the cylinder center axis 18, and has a first weight portion 21 between the cylinder center axis 18 and the power take-out shaft side bearing 16, and a flywheel from the cylinder center axis 18. It includes a second weight portion 22 located between the wheel-side bearing 17.

In this engine, the cylinder center axis 18
Is set to be longer than the distance L2 from the cylinder center axis 18 to the flywheel side bearing 17 from the power take-out shaft side bearing 16. In addition, since the first driven gear 9 and the second driven gear 13 are provided between the distance L2, the length of the first weight portion 22 of the first balancer device 4 is very short. In such a configuration of the balancer unit, the weights of the first balancer unit 21 and the second balancer unit 22 become unbalanced, and the vibration of the balancer device tends to increase. Therefore, in the first embodiment, as shown in FIG. 4, the angle range (2π−θ) excluding the angle range θ around the balancer shaft 15 where the weight portions of the first weight portion 21 and the second weight portion 22 exist. , The balancer gear 9 is lightened.

When the lightening is performed, the opening 23 may be formed in the balancer gear 9 as shown in FIG. 3, or a concave portion (not shown) may be formed. If you want to remove meat,
As shown in FIG. 4, it is preferable to set the balancer gear 9 so that the left-right shape is symmetrical with respect to a line 24 that divides the angle range (2π−θ) into two.

In the first embodiment, the first weight portion 21 and the second weight portion 22 are provided on the opposite side of the first weight portion 21 and the second weight portion 22 except for the central portion 19 including the cylinder center axis 18. A flat portion 25 is formed such that at least one balancer shaft 15 of the second weight portion 22 is cut toward the axial center. In FIG.
The case where the plane portion 25 is formed in both the first weight portion 21 and the second weight portion 22 is shown.

Further, in the first embodiment, as shown in FIG. 2, the first driven gear 9 and the second driven gear provided with the opening 23 are arranged close to the flywheel bearing 17. Therefore, the lubricating oil scattered by the rotation of the balancer weight portion of the crankshaft 3 causes the opening 2
Since it flows into the flywheel bearing 17 of the balancer device from 3, there is an advantage that a sufficient amount of lubricating oil can be supplied even to a portion where lubricating oil is difficult to be supplied.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal front view of an engine provided with a balancer device according to the present invention.

FIG. 2 is a schematic partial longitudinal sectional view taken along line II-II of FIG.

FIG. 3A is a partial cross-sectional view of the balancer device extracted and drawn, and FIG. 3B is a perspective view of the balancer device.

FIG. 4 is a partial longitudinal sectional view for explaining a balancer gear.

FIG. 5 is a partial longitudinal front view of an engine provided with a conventional two-axis balancer device.

6 is a diagram showing a conventional two-axis balancer device, and FIG.
(A) shows the first balancer and the second balancer viewed from the power take-out shaft side.
FIG. 5B is a view showing the positional relationship of the balancer, FIG. 5B is a view taken along line BB, and FIG. 5C is a view of FIG. 5A as viewed from below.

[Explanation of symbols]

15: balancer shaft, 21: first weight portion, 22: second
Weight part, 25: flat part, 26: lightening part.

Claims (3)

[Claims] 1. A balancer device for an engine, wherein a balancer gear is mounted on a balancer shaft having a weight portion, and the weight portion is rotated by rotating the balancer gear with a predetermined gear that is interlocked with the rotation of the engine. , A lightening portion (26) is provided on the balancer gear,
The lightening portion (26) has an angle range (2π−θ) excluding the angle range (θ) around the balancer axis (15) where the weight portion exists.
A balancer device for an engine, wherein the balancer device is provided in the engine. 2. The balancer device according to claim 1, wherein the balancer shaft (15) has a first weight portion (21) and a second weight portion (22) having a smaller volume than the first weight portion (21). And a balancer gear provided with the lightening portion (26) on the side of the second weight portion (22) having a small volume. 3. The balancer device according to claim 1, wherein the first weight portion is provided on the balancer shaft (15).
(21) and a second weight portion (22) having a smaller volume than the first weight portion (21), and an angle range excluding an angle range (θ) around the balancer axis (15) where the weight portions exist. In (2π−θ), an engine balancer device in which a part of the balancer shaft (15) is formed in a plane portion (25).