JP3173214B2 - Oil passage structure of crankshaft assembly - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil passage structure for an engine crankshaft assembly.

[0002]

2. Description of the Related Art In a motorcycle, as shown in FIG. 8, an engine unit 2 as a power unit is connected to a lower portion of a rear portion of a body frame 1 by an engine suspension portion 3, and the center of the crankcase when the center stand is turned off and when the center stand is UP. As shown by a and b, the axis is swung about the center O of the crankshaft, and the engine unit 2
The rotation of the engine 6 is transmitted through a transmission mechanism in the engine unit 2 to a rear wheel 5 that is pivotally supported by the rear part.

[0003] The engine unit 2 has a crankshaft driven by the operation of a piston cylinder arranged substantially horizontally, and this crankshaft is rotatably supported by bearings provided in a crankcase. A crankpin is attached to the crankshaft at an eccentric position between the crankwheels to form a crankshaft assembly, and an oil passage from an oil tank extends to the crankshaft assembly. The oil passage communicates with an oil passage in a crankshaft through an oil reservoir, and the oil passage in the crankshaft communicates with a sliding portion of a crankpin or a starter clutch mechanism through an oil outlet passage in a radial direction.

In a single cylinder engine, it has been found that the position at which the crankshaft stops when the engine is stopped is stopped at the following position from the relationship with the compression top dead center. This data is for a 4 cycle 100 CC single cylinder engine.

In this single-cylinder engine, it is assumed that the engine stops at a position around 120 ° before the piston top dead center (around a rotation position 240 ° from the top dead center), and around 180 ° before the piston top dead center (180 °). Assuming a case where the motor stops at around the rotational position) and a case where the motor stops at approximately 40 ° before the piston top dead center (near the 320 ° rotational position from top dead center), the test results for 30 times indicate that

[Outside 1] Met.

[0006]

Therefore, in the case of a single-cylinder engine, if the positions of the oil inlet and the oil outlet to the oil passage in the crankshaft are not taken into account, the position of the oil inlet and the oil outlet depends on the formation of the oil inlet and the oil outlet. There is a possibility that not only the oil in the crankshaft but also the oil in the oil sump may partially flow out. For example, if the oil inlet to the crankshaft is inclined downward toward the ground surface, most of the oil in the oil passage of the crankshaft will flow into the oil sump and the crankcase, and will also be formed on the crankshaft. If both the oil inlet and the oil outlet facing the ground surface, not only the oil in the oil passage of the crankshaft but also the oil in the oil sump flows out into the crankcase via the oil passage of the crankshaft 10. The oil outflow is shown in FIG.

When the engine is started when there is no oil in the oil passage of the crankshaft or when the amount of oil in the oil reservoir is small, the crankpin and the starter are not provided with sufficient oil immediately after the engine is started. Since the sliding portion of the clutch mechanism rotates, the durability tends to decrease, and in the worst case, the engine may stop. In particular, when the engine was not used for a long time, the tendency was further strengthened.

The present invention has been made in consideration of the above-described circumstances, and has an oil passage structure of a crankshaft assembly capable of eliminating oil runoff after the engine is stopped and sufficiently lubricating the oil immediately after the engine is started. The purpose is to provide.

[0009]

According to a first aspect of the present invention, there is provided an oil passage structure for a crankshaft assembly in which a cylinder is disposed substantially horizontally. A crankshaft assembly is disposed in a crankcase of an engine, and a driving force from a piston is transmitted to the crankshaft assembly by a connecting rod to rotate the crankshaft. A pair of crank wheels are connected by a crank pin to form an oil passage for supplying lubricating oil into the crank shaft assembly, and the crank case and the crank shaft assembly are provided at an oil inlet to the crank shaft assembly. The oil passage structure of the crankshaft assembly having an oil reservoir formed between the crankshaft assembly and the center of the crankshaft of the crankshaft assembly. X a plane substantially parallel with the ground surface through
XY two-dimensional coordinates in an engine side view state where an axis orthogonal to the X axis is set as a Y axis, and an oil passage on the crankcase side communicating with an oil inlet of the crankshaft assembly is connected to the crankshaft assembly. The oil pin extends from below the solid body toward the oil sump, and the inlet to the oil sump regulates the liquid level of the oil sump. It is positioned above the oil level of the oil reservoir from a position near 240 ° before the point to a position near 120 ° before the point.

According to another aspect of the present invention, there is provided an oil passage structure for a crankshaft assembly in which a cylinder is disposed substantially horizontally. A crankshaft assembly is disposed inside the crankshaft assembly, and a driving force from a piston is transmitted to the crankshaft assembly by a connecting rod to rotate the crankshaft. On the other hand, the crankshaft assembly includes a pair of left and right crankwheels having a crankshaft. And an oil passage for supplying lubricating oil to the crankshaft assembly. An oil inlet between the crankcase and the crankshaft assembly is provided at an oil inlet to the crankshaft assembly. In the oil passage structure of the crankshaft assembly in which the reservoir is formed, the oil passage structure passes through substantially the center of the crankshaft of the crankshaft assembly. An X-Y two-dimensional coordinate in an engine side view state is set in which a plane substantially parallel to the surface is an X axis and an axis orthogonal to the X axis is a Y axis, and an oil inlet and an oil outlet of the crankshaft assembly are When the single-cylinder engine is stopped, it is arranged so as to be located on the Y-axis positive direction side higher than the axis of the crankshaft.

[0011]

[Function] In the oil passage structure of the crankshaft assembly,
While the oil level in the oil sump is regulated by the inlet to the oil sump, when the engine is stopped, the oil inlet of the oil passage of the crankshaft is located in the Y axis positive direction position (upper position) from the oil sump oil level. Therefore, no matter what position and direction the oil hole of the oil port is located, the oil level of the oil sump does not become lower than the inlet position of the crankcase side oil passage, so that the oil of the oil sump flows down. Can be prevented. Further, since the oil inlet and the oil outlet of the crankshaft assembly are formed at positions higher than the axis of the crankshaft when the engine is stopped, a required amount of oil is always secured in the crankshaft assembly even when the engine is stopped.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an engine unit of a motorcycle to which the present invention is applied. The engine unit 10 generates the rotational driving force of the rear wheel 11
2 and a transmission 13 that transmits the rotational driving force from the engine 12 to the rear wheel 11.

The engine 12 has a cylinder device 15 provided on a crankcase 14 which is an engine case.
A piston 17 is slidably provided in a cylinder block 16 of the cylinder device 15, and a driving force from the piston 17 is transmitted to a crankshaft 20 via a crankpin 19 by a piston rod (conrod) 18,
The crankshaft 20 is driven to rotate. The crankpin 19 is provided at an eccentric position of the crankwheels 21 and 21 forming a pair with the crankshaft 20 to form a crankshaft assembly 22.

The crankshaft 20 is rotatably supported by the crankcase 14 via bearings 24, 24, while one side of the crankshaft 20 protrudes sideways through the crankcase 14, and a flywheel A magnet 26 and a blower fan 27 are provided. Sign 2
8 is a case cover. The other side of the crankshaft 20 is provided with a drive pulley 31 of a V-belt speed change mechanism 30 that constitutes the transmission 13 and protrudes laterally with the other crankcase 14 placed thereon. This transmission 13 is a case extension 14a extending rearward from a crankcase 14 shown in FIG.
Attached to

The driven pulley 3 of the V-belt transmission mechanism 30
2 is rotatably supported by a drive shaft 34 of a transmission mechanism 33, and a V-belt 35 is stretched between the driven pulley 32 and the drive pulley 31. This V
The continuously variable speed is automatically changed by the belt speed change mechanism 30. The driven pulley 32 is connected to a drive shaft 34 via a centrifugal clutch mechanism 36, and transmits the driving force from the engine 12 from the V-belt transmission mechanism 30 to the drive shaft 34 of the transmission mechanism 33 via the centrifugal clutch mechanism 36. I have.

The transmission mechanism 33 constitutes a reduction gear mechanism by a gear train in which gears are combined. The driving force transmitted to the drive shaft 34 is transmitted to the rear wheel shaft 37 which is a driven shaft via the transmission mechanism 33, Wheel 11
Is rotationally driven.

A starter clutch mechanism 4 having a starter gear 40 is mounted on a crankshaft 20 rotatably supported by a bearing 24 on the crankcase 14.
1 is provided. An oil passage 44 from an oil tank (not shown) extends through the oil filter 45 as shown in FIG. The oil passage 44 is communicated with an annular oil sump 46 formed around the crankshaft 20. The oil sump 46 has an oil seal 47 between the crankshaft 20 and the crankcase 14.
48.

The oil sump 46 is connected to the crankshaft 20.
An oil passage 50 formed in an axial direction inside the oil passage 50 is communicated via an oil inlet passage 51 in a radial direction.
The oil outlet passages 53 and 54 from 0 are bifurcated, one of which extends through the crank pin 19 into the crank chamber 55 and the other extends to the rotating (lubricating) portion of the starter clutch mechanism 41. Reference numeral 56 denotes an oil plug.

In the oil passage structure of the crankshaft assembly 22, as shown in FIGS.
Through the center of the X-axis (X-
X-Y two-dimensional coordinates are set as the Z plane), and when the crank pin 19 is on the lower dead center side from the upper dead center, the crank shaft 20
The oil inlet port (oil inlet) 51a of the oil inlet passage 51 of the oil passage 50 provided in the
It is located in the Y-axis positive direction (upper position) from the oil level OL of the oil inside.

The oil level OL of the oil in the oil sump 46 is
It is regulated by an inlet of an oil passage 44 extending from an oil tank (not shown) via an oil filter 45. In the stop test of the single cylinder engine, the engine 1
When the crankshaft 20 is stopped, the crankshaft 20 does not stop at the top dead center position, but stops at a position near the crankpin position 120 ° before the top dead center of the piston 17 (240 ° rotation position) as shown in FIG. And the crank pin 19 is moved 18 degrees from the top dead center of the piston as shown in FIG.
It may stop near the position rotated by 0 °, or may stop near 240 ° (120 ° rotation position) before the top dead center of the piston as shown in FIG.

In the oil passage structure of the crankshaft assembly, in any of the cases shown in FIGS. 4 and 5, a plane passing substantially through the center of the crankshaft and substantially parallel to the ground surface is defined as an X-axis (XZ). XY two-dimensional coordinates in an engine side view state are set, and an oil passage 50 into the crankshaft 20 is set.
Port position (oil inlet) 51 of oil inlet passage 51
a is located in the positive direction of the Y axis from the liquid level OL of the oil reservoir 46. Connect the oil inlet 51a to the oil sump 46
No matter what position and direction the oil holes of the oil outlet passages 53 and 54 are located, the oil sump 46 does not become lower than the oil level OL of the oil sump 46. The oil 46 does not flow toward the oil outlet passages 53 and 54.

When the engine is of a substantially horizontal type, as shown in FIGS. 4 and 5, the oil inlet 51a and the oil outlet of the crankshaft are located within the range in the Y-axis positive direction.

By doing so, oil does not flow out to a probability of 90% or more based on the above experimental results, and oil is secured. Therefore, in the oil passage structure of the crankshaft assembly, even when the engine is stopped, the oil inlet passage 51 leading to the oil passage 50 of the crankshaft 20 is inclined downward so as to face the ground surface as shown in FIG. Also, the oil inlet passage 51 and the oil outlet passages 53 and 54 can be reliably and in advance prevented from inclining down so as to face the ground surface side.

[0025]

As described above, according to the present invention, the required amount of lubricating oil is always ensured in the oil sump and the crankshaft assembly, so that the oil lubrication can be sufficiently performed immediately after the engine is started. Problems such as a decrease in the durability of the pin and the rotating portion of the starter clutch mechanism can be solved. Further, since the oil passage on the crankcase side is pressure-fed from below the crankshaft assembly toward the oil sump, it is possible to stably supply the lubricating oil, while the lubricating oil is supplied into the oil passage of the crankshaft assembly. Since the oil filling time is shortened, the lubricating oil spreads quickly and lubricity can be improved. Since there is no need for additional components or special processing in terms of structure, the cost and the manufacturing process are not affected, and the durability of the crank system components can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an engine unit of a motorcycle to which the present invention is applied.

FIG. 2 is a side view of a crankcase provided in the engine unit.

FIG. 3 is a sectional view of a crankshaft assembly showing one embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a positional relationship of an oil passage at a crankpin position 120 ° from a top dead center.

FIG. 5 is an explanatory diagram showing a positional relationship of an oil passage at a crankpin position 180 ° from a top dead center.

FIG. 6 is an explanatory diagram showing a positional relationship of an oil passage at a crankpin position 240 ° from a top dead center.

FIG. 7 is an explanatory diagram at the time of oil outflow.

FIG. 8 is a side view showing an example of a motorcycle to which the present invention is applied.

[Explanation of symbols]

 Reference Signs List 10 engine unit 11 rear wheel 12 engine 19 crank pin 20 crankshaft 22 crankshaft assembly 41 starter clutch mechanism 44 oil passage 45 oil filter 46 oil sump 50 oil passage 51 oil inlet passage 53, 54 oil outlet passage

Claims (2)

(57) [Claims] A crankshaft assembly is provided in a crankcase of a single cylinder engine having cylinders arranged substantially horizontally, and a driving force from a piston is transmitted to the crankshaft assembly by a connecting rod to rotate the crankshaft. While
The crankshaft assembly is configured by connecting a pair of left and right crankwheels having a crankshaft with crankpins,
An oil passage for supplying lubricating oil is formed in the crankshaft assembly, and an oil sump is formed between the crankcase and the crankshaft assembly at an oil inlet to the crankshaft assembly. In the passage structure, an X-axis is a plane passing substantially through the center of the crankshaft of the crankshaft assembly and substantially parallel to the ground surface, and an X-axis perpendicular to the X-axis is a Y-axis. Y2
Dimensional coordinates are set, and a crankcase-side oil passage leading to the oil inlet of the crankshaft assembly is extended from below the crankshaft assembly toward the oil sump, and the oil sump is formed at the inlet to the oil sump. While the oil inlet to the crankshaft assembly is adjusted so that the crankpin is positioned above 240 ° near the top dead center of the piston and near 120 ° near the piston above the oil level of the oil sump. An oil passage structure for a crankshaft assembly, wherein the oil passage structure is located. 2. A crankshaft assembly is disposed in a crankcase of a single-cylinder engine having cylinders arranged substantially horizontally, and a driving force from a piston is transmitted to the crankshaft assembly by a connecting rod to rotate the crankshaft. While
The crankshaft assembly is configured by connecting a pair of left and right crankwheels having a crankshaft with crankpins,
An oil passage for supplying lubricating oil is formed in the crankshaft assembly, and an oil sump is formed between the crankcase and the crankshaft assembly at an oil inlet to the crankshaft assembly. In the passage structure, an X-axis is a plane passing substantially through the center of the crankshaft of the crankshaft assembly and substantially parallel to the ground surface, and an X-axis perpendicular to the X-axis is a Y-axis. Y2
Dimensional coordinates are set, and an oil inlet and an oil outlet of the crankshaft assembly are disposed so that the oil inlet and the oil outlet are located on the Y axis positive direction side higher than the axis of the crankshaft when the single cylinder engine is stopped. Oil passage structure for shaft assembly.