JPS5936759Y2 - Primary paransor device for 4-stroke in-line 2-cylinder engine - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a primary balancer device for a 4-cycle in-line 2-cylinder engine, and particularly relates to a primary balancer device in which the balancer shaft located below is disposed above the lubricating oil level in the oil pan. It is something.

Conventionally, as shown in FIG.
Those equipped with book balancer shafts 2 and 3 were generally used.

However, in such a balancer device, when the inclination angle α of the engine increases, that is, when the orientation of the cylinder 4 approaches the horizontal, the balancer shaft 3 located below becomes immersed in the lubricating oil 6 in the oil pan 5. There is a problem.

The present invention is based on the inventions of JP-A-53-125506 and JP-A-54-16009, which were previously proposed by the applicant, and the balancer shaft can be moved to any position by selecting the phase and mass of the weight provided on the balancer shaft. By taking advantage of the fact that the engine can be installed at a large angle,
In addition to installing the lower balancer shaft above it without soaking it in the lubricating oil in the oil pan, we have added an additional twist to the design by making the bearing of the lower balancer shaft separate from the crankshaft bearing cap. By fixing it to the bearing cap, a balancer shaft like the one described above can be provided without changing the crankcase, and space can be used effectively, and the degree of freedom in designing the balancer shaft bearing can be increased. It is an object of the present invention to provide a primary balancer shaft for a four-stroke, in-line, two-cylinder engine that is capable of increasing the strength of the bearing portion.

In addition, as a related prior art, there is a technology that prevents the balancer shaft from being immersed in the lubricating oil in the oil pan.
-12404, and another one in which two balancer shafts are arranged on one side of the crankshaft is published in Japanese Patent Application Laid-Open No. 49-122.
Seen in Publication No. 12.

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings.

In FIGS. 2 to 4, reference numeral 1 indicates a crankshaft, 2,
3 is a balancer shaft. These balancer shafts 2.3 are installed parallel to the crankshaft 1, and driven gears 8 and 9 provided on the balancer shaft 2.3 mesh with a drive gear 7 provided on the crankshaft 1, respectively. As a result, both balancer shafts 2 and 3 are configured to move in the same direction and in the opposite direction to the crankshaft 1 at the same speed as the crankshaft 1.

Eccentric weights 10.11 are provided on the balancer shafts 2 and 3, and the weights 10.11 are set at positions 7<position of the balancer shafts 2 and 3 so as to cancel out the primary excitation force due to the reciprocating mass traveling all over the area from the engine. It has a phase and mass that are correlated with each other.

The above configuration is similar to the invention disclosed in Japanese Patent Application Laid-Open No. 125506/1983, which was previously proposed by the applicant of the present invention.

The balancer shafts 2 and 3 as described above have weights 10,
By selecting the phase and mass of 11, it can be placed at any position on both sides of the crankshaft 1, so the balancer shaft 3 located below can be placed close to the extension of the line connecting the axis of the cylinder 4 and the center of the crankshaft 1. Place the crankcase 1 in the
It is disposed above the surface of the lubricating oil 6 in the oil pan 5 fixed to the oil pan 2.

Further, as shown in FIGS. 2 to 5, the bearings 13 on the drive gear 7 side and the opposite side of the crankshaft 1 are respectively attached to the crankcase 1 by bolts 15.
2, it is fixed to the case 12.

Both ends of the balancer shaft 3 located below are rotatably supported by bearings 16, and these bearings 16 are constructed separately from the bearing cap 14 of the crankshaft 1, and each end is attached to the cap 14 with a bolt 17. Tightening is fixed.

The balancer shaft 2 located above is rotatably supported by a bearing attached to the crankcase 12 by appropriate means.

Further, in the figure, reference numeral 18 is a piston, and 19 is a connecting rod.

In the present invention, the balancer shaft is constructed by utilizing the invention of JP-A-54-16009, which was previously proposed by the applicant of the present invention. A numerical value may be given to any condition among the positions of , and the remaining values may be determined so that the primary excitation force and the primary excitation moment become zero at a specific rotation speed and load.

Further, the bearing of the balancer shaft may be fixed by passing a bolt through the bearing cap of the crankshaft and tightening it to the crankcase.

As explained above, the primary balancer device for a 4-cycle in-line 2-cylinder engine according to the present invention allows the lower balancer shaft to be installed above the lubricating oil level in the oil pan, even in engines with large inclination angles. Therefore, there is no problem such as splashing of lubricating oil by the balancer shaft, and the two balancer shafts can be installed asymmetrically with respect to the crankshaft, and the crankshaft bearing cap is separate from the crankcase. Since the bearing of the lower balancer shaft, which is separate from the cap, is fixed to the crankcase through the cap, there is no need to change the crankcase because the bearing is installed in the space inside the oil pan. To,
The housing space for the balancer shaft located below in the crankcase can be omitted or can be made small, and the space can be used effectively.

Moreover, since the bearing cap and the balancer shaft bearing are separate bodies, tightening bolts on the part of the balancer shaft that is supported by the bearing must be made large in diameter so that the part is not affected by deformation. It has the advantage of having a large degree of freedom in design, being able to increase its strength, and being easy to assemble.

[Brief explanation of the drawing]

Figure 1 shows a conventional 4-stroke in-line 2-cylinder engine.
FIG. 2 is a schematic cross-sectional explanatory view showing the primary balancer device according to an embodiment of the present invention; FIG. 3 is a side cross-sectional development view of the same side; FIG. -IV
FIG. 5 is a front view showing the bearing cap and the bearing portion of the balancer shaft. 1... Crankshaft, 2, 3... Balancer shaft, 4... Cylinder, 5... Oil pan, 6... Lubricating oil , 7... Drive gear, 8, 9... Driven gear, 10.11.
...Weight, 12...Crankcase,
13...Bearing, 14...Bearing cap, 15...Bolt, 16...Bearing, 1
7...Bolt, 18...Piston, 1
9... Conrod.

Claims (1)

[Scope of utility model registration request] Two balancer shafts are provided parallel to the crankshaft, and these balancer shafts are connected to the crankshaft via a transmission means so as to move in the same direction and in the opposite direction to the crankshaft at the same speed as the crankshaft, In a system in which each balancer shaft is provided with a weight whose phase and mass are correlated with the position of the balancer shaft so as to cancel the primary excitation force due to the reciprocating mass generated from the engine, the lower balancer shaft is connected to the oil pan. The bearing is placed above the lubricating oil level in the
1. A primary balancer device for a 4-cycle in-line 2-cylinder engine, characterized in that it is constructed separately from a bearing cap of a crankshaft and is fixed to the bearing cap.