JPH0427368B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an assembled crankshaft for an engine.

FIG. 1 is an explanatory diagram showing an assembled crankshaft 1 used in a conventional V-type four-cylinder engine. The crankshaft 1 is integrally formed with both end journal parts 2 and a web 3, an intermediate journal part 4, webs 5 on both sides thereof, and left and right crank pins 6, and is integrally formed with both end journal parts 2. It is assembled by press-fitting the end of each crank pin 6 into a fitting hole 7 provided in the web 3. The crankshaft 1 has both end journal portions 2 and an intermediate journal portion 4 rotatably supported by a crankcase 9 via a main bearing 8 .

Further, a first connecting rod 11 is connected to each of the left and right crank pins 6 via a first large end bearing 10, and a second connecting rod 1 is connected via a second large end bearing 12.
3 are connected.

In such a conventional crankshaft 1, a linear oil passage 14 is provided that passes through the intermediate journal portion 4 and the left and right crank pins 6. Lubricating oil is introduced into this oil passage 14 through an oil passage 15 that is bored in the radial direction of the intermediate journal portion 4 and is able to communicate with an oil passage (not shown) provided in the crankcase 9. The lubricating oil introduced into the oil passage 14 is supplied to the first large end bearing 10 through the first oil passage 16 drilled in each crank pin 6, and is also supplied to the first large end bearing 10 through the second oil passage 1.
The second large end bearing 12 is supplied with oil via the second large end bearing 7.

However, in the conventional crankshaft 1, the oil passage 14 is formed in a straight line connecting the intermediate journal portion 4 and the left and right crank pins 6, and is extremely long and difficult to process. Also,
Since the oil passage 14 is formed in an inclined state with respect to the axis of each crank pin 6, the rotation radius R of the first oil passage 16 about the crankshaft rotation center is
1 becomes larger than the rotation radius R2 of the second oil supply path 17, causing a difference in the magnitude of the centrifugal force acting on the lubricating oil flowing out from each oil supply path, and causing a difference in the magnitude of the centrifugal force acting on the lubricant flowing out from each oil supply path, causing The amount of oil supplied is larger than the amount of oil supplied from the second oil supply path 17 to the second large end bearing 12, and seizure is likely to occur in the second large end bearing 12. Also,
At the press-fit end of each crank pin 6 into the web 3, where a large inertial force acts during engine operation,
The wall thickness t formed between the outer periphery of each crank pin 6 and the oil passage 14 is small, and each crank pin 6 is prone to fatigue failure from this part, so such a crankshaft 1 is not suitable for high-speed engines. do not have. Note that an oil passage 1 connected to an oil passage 14 from the end of each crank pin 6 as shown by a broken line in FIG.
8, and the oil passage 18 is provided with a first oil passage 19 that can supply lubricating oil to the first large end bearing 10, and the rotation radius of the first oil passage 19 with respect to the center of the crankshaft is set to the crankshaft of the second oil passage 17. If the rotation radius with respect to the shaft center is set to be the same, the amount of oil supplied to the first large bearing 10 and the second large end bearing 12 will be mutually balanced, but each crank pin 6 has a plurality of long oil passages 14 and The oil passage 18 is bored, and its strength and rigidity are greatly reduced, which is not appropriate.

Also, when installing an oil passage on the crankshaft,
It is desirable to reduce the number of parts without plugging the open end of the oil passage.

The present invention ensures the strength and rigidity required for the crankshaft when supplying oil to the big end bearing on the crankshaft from the oil passage provided on the crankshaft.
Another purpose is to facilitate the machining of the oil passage, to make the amount of oil supplied to each big end bearing the same, and to reduce the number of parts.

In order to achieve the above object, the present invention provides a connecting rod that is supported by a crankcase through both end journal parts and an intermediate journal part, and that connects each connecting rod big end to each crank pin between each journal part through a big end bearing. In an assembled crankshaft for an engine, the intermediate journal part and the webs on both sides of the engine have an H-shaped cross section. The webs on both sides are provided with concave fitting holes spaced apart from each other by 180 degrees at the crank angle, into which the crank pin is press-fitted. A hole-shaped oil passage is drilled, and a straight oil passage is bored in the intermediate journal part, with both ends facing each fitting hole, and the oil passage provided in the intermediate journal part is connected to each oil passage of the crank pin. The lubricating oil pumped from the oil pump is directly supplied to the oil passage of the intermediate journal portion.

According to the present invention, there are the following effects.

The oil passage consists of an oil passage provided on the crankpin approximately on the central axis line, and an oil passage provided on the intermediate journal with both ends facing each insertion hole in the web, so there is no need for extra machining on the crankpin. Strength and rigidity are ensured without forming holes.

The oil passages that communicate the oil passages of the crank pins are bored in the intermediate journal part in a straight line facing each of the concave fitting holes in the web, so the length of the oil passage is extremely short, and the oil passages that communicate with each of the concave fitting holes are The oil passage can be drilled at the same time as the hole is drilled, making processing easier.

The oil passage of the blind hole-shaped crank pin and the oil passage of the intermediate journal part whose both ends face the concave fitting hole are communicated by press-fitting the crank pin, so the oil passage does not have an open end and can be plugged with a plaque or the like. Since there is no need to do this, the number of parts is reduced.

The oil passage of each crank pin is connected to the oil passage of each crank pin by supplying the lubricating oil under pressure from the oil pump directly to the oil passage provided in the intermediate journal. Those connected in series (Japanese Patent Application Laid-Open No. 55-29074)
The same amount of lubricating oil is supplied without the need for special adjustment means.

Furthermore, since the oil passage for each crank pin is drilled approximately on the central axis, even if a big end bearing is supported on each crank pin, the amount of oil supplied is balanced, and eventually all the big end bearings on the crankshaft are Lubricating performance is improved because the same amount of oil is supplied to both.

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

FIG. 2 is a side view showing a motorcycle to which the present invention is applied, FIG. 3 is a plan view showing an embodiment of the present invention with main parts cut away, and FIG. 4 is a side view of a motorcycle to which the present invention is applied. FIG. 3 is a cross-sectional view showing a main part.

In the motorcycle shown in Fig. 2, the frame 2
1 is equipped with a V-type 4-cylinder engine 22, a front wheel 24 is pivotally supported at the front part of the frame 21 via a front fork 23, and a steering handle 25 is provided. A rear wheel 28 is pivotally supported by a rear arm 27 that is urged downward by a rear action 26 . The upper part of the frame 21 includes a fuel tank 29 and a seat 3.
0 is attached to the seat 30, and a passenger can sit on the seat 30. In the engine 22, as shown in FIG. 3, a crankshaft 32 is rotatably supported by a crankcase 31. crankshaft 3
2, the intermediate journal part 33 and the webs 34 on both sides thereof are integrally formed, and each journal part 3 at both ends
5. Each crank pin 36 and the web 37 sandwiched between them are integrally formed, and the intermediate journal portion 3
One end of each crank pin 36 is assembled into a fitting hole 38 provided in a web 34 integrally formed with the crank pin 3, thereby forming the entire crank pin. The crankshaft 32 has an intermediate journal portion 33 and journal portions 35 at both ends pivotally supported by the crankcase 31 via a main bearing 39 .

A first large end bearing 4 is attached to the left and right crank pins 36.
A first connecting rod 41 is connected to the first connecting rod 41 through a second large end bearing 42, and a second connecting rod 43 is connected through a second large end bearing 42. A first left piston 44 is connected to the small end of the first connecting rod 41 connected to the left crank pin 36 via the crank pin, and a second connecting rod 43 is connected to the left crank pin 36. A second left piston 45 is connected to the small end of the right side crank pin 3 via a crank pin.
A first right piston 46 is connected to the small end of the first connecting rod 41 connected to the right side crank pin 36 via a crank pin, and a small end of the second connecting rod 43 is connected to the right crank pin 36. A second right piston 47 is connected to via a piston pin. Each piston 44 , 45 , 46 , 47 reciprocates within the cylinder liner of each cylinder and is capable of transmitting rotational force to the crankshaft 32 . The rotation of the crankshaft 32 is transmitted to the rear wheel 28 through a crank gear 48, a clutch gear 49, a clutch 50, and a transmission (not shown).
It is said that it can be transmitted to

Further, the intermediate journal portion 3 of the crankshaft 32
3 and the web 34 are provided with an oil passage 51 that is inclined with respect to the crank rotation center line, and
Each crank pin 36 has an oil passage 52 formed on its axis, and the oil passage 51 and the oil passage 52 communicate with each other. Further, an oil passage 53 is bored in the intermediate journal portion 33 in the radial direction, and one end of the oil passage 53 is
An oil passage 54 that is bored in the crankcase 31 and the main bearing 39 and guides the lubricating oil pumped from the oil pump is communicated with the other end of the oil passage 53.
It communicates with the oil passage 51. In addition, each crank pin 36 has a first oil supply passage 55 that communicates with the oil passage 52 and is capable of supplying lubricating oil to the first large end bearing 40, and a first oil supply passage 55 that is capable of supplying lubricating oil to the second large end bearing 42. A second oil supply passage 56 is bored in the radial direction.

According to the above embodiment, as the engine 22 operates, lubricating oil is pumped by the oil pump to the oil passage 52 bored in each crank pin 36 via the oil passages 54, 53, and 51. Refueled. The lubricating oil guided to the oil passage 52 is transferred to the first oil supply passage 5
5 to lubricate the first large end bearing 40,
The second large end bearing 42 is lubricated via the second oil supply path 56. However, according to the above embodiment, the following ~
It has the function and effect of

The oil passage includes an oil passage 52 provided on the crank pin 36 and approximately on the central axis line, and an intermediate journal portion 33.
Since the crank pin 36 is provided with only a linear oil passage 51 whose both ends face each insertion hole 38 of the web 34, strength and rigidity can be ensured without forming extra holes in the crank pin 36 for machining. Ru. Therefore, the crankshaft 32 includes the crank pin itself, each connecting rod 41, 4 which acts on each crank pin 36 as the engine operates.
3. It becomes possible to sufficiently withstand the inertia force based on the mass of each piston 44, 45, 46, 47, and it becomes possible to increase the rotation speed.

The oil passage 51 that communicates the oil passage 52 of each crank pin 36 is bored in the intermediate journal portion 33 in a straight line facing each concave fitting hole of the web.
The length of the oil passage 51 is extremely short, and the oil passage can be drilled simultaneously with the drilling of each concave fitting hole, making processing easier.

Oil passage 52 of the crank pin 36 in the form of a blind hole
Since the oil passages 51 and 51 of the intermediate journal portion 33 whose both ends face the concave fitting hole 38 are communicated by press-fitting the crank pin, the oil passages 51 and 52 do not have open ends and need to be plugged with plugs or the like. Because there are no parts, the number of parts is reduced.

The oil passage 52 of each crank pin 36 is connected to the oil passage 52 of each crank pin 36 by supplying lubricating oil under pressure from an oil pump directly to the oil passage 51 provided in the intermediate journal part.
The same amount of lubricating oil is supplied without providing any special adjustment means, as in the case where the oil passages 52 of each crank pin 36 are connected in series (Japanese Patent Laid-Open No. 55-29074).

Furthermore, since the oil passage 52 of each crank pin 36 is bored approximately on the central axis, in particular, each crank pin 3
Even if the two big end bearings 40 and 42 are supported on the crankshaft 32, the amount of lubricating oil supplied is balanced, and eventually the same amount of oil is supplied to all the big end bearings on the crankshaft 32, improving lubrication performance. do.

In the above embodiment, the present invention is applied to a V-type 4-cylinder engine, but the present invention can also be applied to a V-type 6-cylinder engine or more.

As described above, according to the present invention, when lubricating the big end bearing on the crankshaft from the oil passage provided in the crankshaft, the strength and rigidity required for the crankshaft are ensured, and the oil passage is facilitates processing,
Furthermore, the amount of oil supplied to each big end bearing can be the same, and the number of parts can be further reduced.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an assembled crankshaft of an engine according to a conventional example, FIG. 2 is a side view showing a motorcycle to which the present invention is applied, and FIG. 3 is an assembled crankshaft of an engine according to the present invention. FIG. 4 is a cross-sectional view showing the main part of FIG. 3; FIG. 22...Engine, 31...Crankcase,
32... Crankshaft, 33... Intermediate journal portion, 34... Web, 35... Each journal portion at both ends, 36... Crank pin, 37... Web,
38... Fitting hole, 39... Main bearing, 40... First
Big end bearing, 41...First connecting rod, 42...Second big end bearing, 43...Second connecting rod, 51, 52, 5
3, 54...oil passage, 55...first oil supply passage, 56...
...Second oil supply path.

Claims (1)

[Claims] 1 It is supported by the crankcase via both end journal parts and an intermediate journal part, and each connecting rod large end part is pivotally supported via a big end bearing on each crank pin between each journal part, and the intermediate journal part and each crank In an assembled crankshaft for an engine in which the pin is provided with an oil passage that can supply lubricating oil to the big end bearing, the intermediate journal part and the webs on both sides thereof are integrally formed with an H-shaped cross section, and the webs on both sides have an H-shaped cross section. 180° apart from each other at the crank angle,
Provides a concave insertion hole into which the crank pin is press-fitted,
A blind hole-shaped oil passage is drilled in the crank pin extending approximately on the center axis from the press-fitting tip, and a linear oil passage is bored in the intermediate journal portion with both ends facing each fitting hole. A prefabricated crankshaft for an engine, characterized in that the oil passages are connected to the respective oil passages of the crank pin, and the lubricating oil pumped from the oil pump is directly supplied to the oil passages of the intermediate journal part. .