JP3246225B2 - Assembled crankshaft - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an assembling crankshaft, and more particularly, to increasing the press-fitting length of a crank journal and increasing torsional torque without increasing the pitch between cylinders. The present invention relates to an assembling crankshaft that can be easily processed and can have a long service life.

[0002]

2. Description of the Related Art As an engine, there is a two-stroke engine that generates power by performing intake, compression, explosion, and exhaust during one rotation of a crankshaft. This two-stroke engine is frequently used in, for example, motorcycles, outboard motors, snowmobiles, and the like.

As this two-stroke engine, for example, there is one shown in FIGS.

That is, in FIG. 4, 102 is a two-cycle engine for a multi-cylinder engine, 104 is a cylinder wall, 106 is a cylinder, 108 is a cylinder head, 110 is an upper crankcase, 112 is a lower crankcase, 114 is a crankshaft, 116 is a connecting rod, 11
8 is a piston and 106c is a cylinder center line.

[0005] The crankshaft 114 is supported by an upper crankcase 110 and a lower crankcase 112.

The crankshaft 114 is of an assembling type. A crank journal 120 is supported by a plurality of bearings 122 held by an upper crankcase 110 and a lower crankcase 112 to press-fit the crank journal 120 and a crankpin. A crank web 126 is provided for connection of the crank web 126. Each bearing 12
2 are all in direct contact with the crank journal 120. The connecting rod 1 is connected to the crank pin 124.
One end of 16 is pivotally supported. On the other end side of the connecting rod 116, a piston 118 is provided.

[0007] In two-cycle engine 102 of FIG. 4, the cylinder pitch is the pitch between adjacent cylinder center line 106c is set to a predetermined length P _10.

In FIG. 5, 202 is a two-cycle engine for a multi-cylinder engine, 204 is a cylinder wall, 206 is a cylinder, 208 is a cylinder head, 210 is an upper crankcase, 212 is a lower crankcase, 214 is a crankshaft, and 216 is a crankshaft. The connecting rod 218 is a piston, and 206c is a cylinder center line.

The crankshaft 214 is supported by an upper crankcase 210 and a lower crankcase 212.

The crankshaft 214 is of an assembling type. A crank journal 220 is supported by a plurality of bearings 222 held by an upper crankcase 210 and a lower crankcase 212. 224 are connected to each other. Each bearing 22
2 are all in direct contact with the crank journal 220. Connecting rod 2 is connected to crank pin 224.
One end of 16 is pivotally supported. A piston 218 is provided on the other end of the connecting rod 216.

In the two-stroke engine 202 shown in FIG.
In order to obtain a press-fit length into the
It has extended the sleeve 228 of the length L ₁₁ in the axial direction of the crankshaft 214 in. Therefore, the cylinder pitch P ₁₁ between the cylinder center line 206c adjacent is set larger by a length L ₁₁ of the cylinder between the pitch P ₁₀ shown in FIG.

In FIG. 6, reference numeral 302 denotes a two-cycle engine for a multi-cylinder engine, 304 denotes a cylinder wall, 306 denotes a cylinder, 308 denotes a cylinder head, 310 denotes an upper crankcase, 312 denotes a lower crankcase, 314 denotes a crankshaft, and 316 denotes a crankshaft. The connecting rod 318 is a piston, and 306c is a cylinder center line.

The crankshaft 314 is supported by an upper crankcase 310 and a lower crankcase 312.

The crankshaft 314 is of an assembling type, and a crank journal 320 is supported by a plurality of bearings 322 held by an upper crankcase 310 and a lower crankcase 312 to press-fit the crank journal 320 and a crankpin. 324 is connected to the crank web 326. Each bearing 32
2 are all in direct contact with the crank journal 320. The connecting rod 3 is connected to the crank pin 324.
One end of 16 is pivotally supported. On the other end side of the connecting rod 316, a piston 318 is provided.

In the two-stroke engine 302 shown in FIG.
In order to obtain a press-fit length into the
Thereby extending the sleeve 328 of the length L ₁₂ in the axial direction of the crankshaft 314, a sleeve 328
And an oil seal member 330 is fitted therein. Therefore, the cylinder pitch P ₁₂ between the adjacent cylinder center line 306c is set to be larger by a length L ₁₂ of the cylinder between the pitch P ₁₀ shown in FIG. 4, the oil seal member 3
Since the fitted 30 to the sleeve 328, the cylinder pitch P ₁₂ is one as small as possible.

In FIG. 7, 402 is a two-cycle engine for a multi-cylinder engine, 404 is a cylinder wall, 406 is a cylinder, 408 is a cylinder head, 410 is an upper crankcase, 412 is a lower crankcase, 414 is a crankshaft, and 416 is a crankshaft. The connecting rod 418 is a piston, and 406c is a cylinder center line.

The crankshaft 414 is supported by an upper crankcase 410 and a lower crankcase 412.

The crankshaft 414 is of an assembling type. A crank journal 420 is supported by a plurality of bearings 422 held by an upper crankcase 410 and a lower crankcase 412 to press-fit the crank journal 420 and to insert the crankpin. 424 is connected to the crank web 426. Each bearing 42
2 are all in direct contact with the crank journal 420. The connecting rod 4 is connected to the crank pin 424.
One end of 16 is pivotally supported. On the other end side of the connecting rod 416, a piston 418 is provided.

In the two-stroke engine 402 shown in FIG.
In order to obtain the press-fit length into the
Thereby extending the sleeve 428 of the length L ₁₃ in the axial direction of the crankshaft 414, a sleeve 428
And a labyrinth seal member 330 is fitted therein. Therefore, the cylinder pitch P ₁₃ between the cylinder center line 406c adjacent is set to be larger by a length L ₁₃ of the cylinder between the pitch P ₁₀ shown in FIG. 4, fitting the Rabbi lance sealing member 430 to the sleeve 428 since the instrumentation, the cylinder pitch P ₁₃ is one as small as possible.

In FIG. 8, 502 is a two-cycle engine for a multi-cylinder engine, 504 is a cylinder wall, 506 is a cylinder, 508 is a cylinder head, 510 is an upper crankcase, 512 is a lower crankcase, 514 is a crankshaft, and 516 is a crankshaft. The connecting rod 518 is a piston, and 506c is a cylinder center line.

The crankshaft 514 is supported by an upper crankcase 510 and a lower crankcase 512.

The crankshaft 514 is of an assembling type. The crank journal 520 is supported by a plurality of bearings 522 held by an upper crankcase 510 and a lower crankcase 512, and the crank journal 520 is press-fitted and the crank pin 520 is pressed. 524 is connected to the crank web 526. One end of a connecting rod 516 is supported by the crank pin 524. A piston 518 is provided on the other end of the connecting rod 516.

In the two-stroke engine 502 of FIG. 8, adjacent crank journals 520 are connected by connecting tubes 528, respectively.
The bearing 522 is fitted in the connecting tube 528.

Japanese Patent Application Laid-Open No. 58-158 discloses such a two-stroke engine assembly type crankshaft.
JP-A-28009, JP-A-2-42207, JP-A-58-16421, JP-A-59-43715.
No. 6,086,045. Japanese Unexamined Patent Publication (Kokai) No. 58-28009 discloses that a large end of a continuous rod, in which a flat bearing is inserted, is connected to a crank pin assembled to a crank web, and the large end of the continuous rod is connected. It is intended to reduce the weight of the part. Japanese Unexamined Patent Publication No. 2-42207 discloses that a flat bearing is inserted into a large end of a connecting rod, the large end is connected to a crankpin of a crankshaft, and the flat bearing is integrated. The inner diameter of the inner periphery is maximized at a portion perpendicular to the axis connecting the small end and the large end, to reduce the weight of the large end of the connecting rod and reduce the finished mass, and to prevent seizure Is what you do. Japanese Unexamined Utility Model Publication No. 58-16421 discloses a crankcase in which a crankshaft is rotatably supported on a crankcase via a plurality of ball bearings, and is fixed to a journal portion of the ball bearing by press-fitting or the like. A biasing member such as a spring that fits into a bearing hole of the crankcase and biases the outer race in one axial direction on one side of at least one ball bearing is provided. A stopper piece against the force is provided. Showa 59-437
Japanese Patent Application Publication No. 15-150, No. 15, discloses a method in which one of the half members forming the outer ring is provided with a counterbored hole, and the half members forming the outer ring are tightened with a polygonal cross-sectional hole on the upper surface of the head. The bolt is connected from the counterbore hole by a bolt having the above, and the bolt head is stored in a state of sinking into the counterbore hole.

[0025]

However, conventionally, in the case of the crankshaft 114 shown in FIG. 4, in the case of the crankshaft 114 shown in FIG. 4, if the torsion torque at the press-fitted portion of the crank journal is insufficient, the thickness of the crank web is increased. Or it must be configured in a crankshaft 214 as shown in FIG.

[0026] When the crankshaft 214 of FIG. 5, the cylinder pitch P ₁₀ of FIG cylinder pitch P ₁₁ is the length L ₁₁ of the sleeve with a crank web of the stage 4
The problem that it became larger than that occurred.

The problem of the crankshaft 214 shown in FIG. 5 can be solved by the configuration of the crankshafts 314 and 414 shown in FIGS. 6 and 7. In the case of the crankshafts 314 and 414 shown in FIGS. When the press-fitting length of the journal is required to be longer, there is an inconvenience that it is difficult to cope with it.

Further, in the case of the structure of the crankshaft 514 shown in FIG. 8, there are two places where the torsion torque is received, and there is an inconvenience that the entire structure is weaker than the crankshaft 114 shown in FIG.

Further, the crankshaft 3 shown in FIGS.
In Nos. 14 and 414, since the bearing is sealed from the crankcase, lubrication by the air-fuel mixture cannot be expected, and there has been a disadvantage that this portion needs to be supplied with an oil pump.

[0030]

In order to eliminate the above-mentioned disadvantages, the present invention is supported between an upper crankcase and a lower crankcase of an engine to press-fit a crank journal and connect a crankpin. In the assembled crankshaft provided with a crank web, a step sleeve into which the crank journal is press-fitted is provided in the crank web so as to extend in the axial direction of the crankshaft, and one bearing is fitted to the step sleeve. And the outer diameter of this one bearing is formed to be substantially the same as the outer diameter of another bearing provided other than the step sleeve.

[0031]

According to the structure of the present invention, since the bearing is fitted on the step sleeve, the press-fit length of the crank journal can be increased without increasing the pitch between cylinders, thereby increasing the torsional torque. In addition, since the outer peripheral surfaces of the bearings are located at the same level, the machining of the crankcase is facilitated. Further, since the bearings are arranged close to the cylinder center line, The moment of the bearing is reduced, and the service life can be extended.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. 1 to 3 show an embodiment of the present invention. 1 and 3, 2 is a two-stroke engine for a multi-cylinder engine, 4 is a cylinder wall, 6 is a cylinder,
8 is a cylinder head, 10 is an upper crankcase, 1
2 is a lower crankcase, 14 is a crankshaft, 1
6 is a connecting rod, 18 is a piston, and 6c is a cylinder center line.

The crankshaft 14 is supported by the upper crankcase 10 and the lower crankcase 12.

The crankshaft 14 is of an assembling type and has a crank web 24 for press-fitting the crank journal 20 and connecting the crankpin 22. The connecting rod 1 is connected to the crank pin 22.
6 is supported at one end. On the other end side of the connecting rod 16, a piston 18 is provided.

As shown in FIGS. 1 and 2, a stepped sleeve 26 into which the crank journal 20 is press-fitted is provided on the two crank webs 24 on the center side of the two-cycle engine 2 by a length L in the axial direction of the crankshaft 14. Each is extended and provided. This step sleeve 26 is, as shown in FIG.
An inner diameter D ₁ , an outer diameter D ₂ , and a thickness T are formed in an annular body.

The step-side sleeve 26 is provided with a sleeve-side bearing 28 as one of the bearings. The sleeve-side bearing 28 has a width substantially equal to the length L of the stepped sleeve 26, and has an inner diameter D <b> _{3 that} is large enough to fit on the outer peripheral surface of the stepped sleeve 26.

The crankshaft 14 is supported by a direct support bearing 30, which is another bearing directly in contact therewith. This direct support bearing 30 is formed in a size that the inner diameter D ₅ is fitted on the outer peripheral surface of the crank journal 20, the size of the outer diameter D ₆ is fitted upper, the inner peripheral surface of the lower crankcase 10 and 12 Is formed.

In this embodiment, the outer diameter D ₄ of the sleeve-side bearing 28 is formed to be substantially the same as the outer diameter D ₆ of the direct support bearing 30, that is, the inner diameter of the upper and lower crankcases 10 and 12. The outer peripheral surfaces are formed to have the same level and to have the same size as the peripheral surfaces.

Next, the operation of this embodiment will be described.

In the two-cycle engine 2, the reciprocating motion of the piston 18 is converted into the rotational motion of the crankshaft 14 by the connecting rod 16, and the driving force is obtained.

In this embodiment, since the step sleeve 28 is provided on the crank web 24 and the sleeve-side bearing 28 is provided on the step sleeve 26, the press-fit length of the crank journal 20 is sufficiently ensured. In comparison with the conventional crankshafts shown in FIGS. 6 and 7, the press-fitting length is sufficient, and thereby the torsional torque can be increased.

As described above, the crank journal 2
Even if the length of 0 is increased, the adjacent cylinder center line 6c
In FIG.
7 can be shortened as compared with the crankshaft of No. 7.

Further, since the outer peripheral surfaces of the bearings 28 and 30 are located at the same level, the upper and lower crankcases 10 and 12 may be machined to the same cylinder, and thus the upper and lower crankcases 10 and 12 may be formed. Processing becomes easy.

Furthermore, since the sleeve-side bearing 28 is closest to the cylinder center line 6c, the moment of the bearing is reduced and the service life can be extended.

Further, since the sleeve-side bearing 28 is structured to be lubricated with oil cyst, it is not necessary to supply oil separately by an oil pump for the sleeve-side bearing 28.
The configuration can be simplified.

[0046]

As is apparent from the above detailed description, according to the present invention, a step sleeve into which the crank journal is press-fitted is provided on the crank web so as to extend in the axial direction of the crankshaft. Bearings are fitted and the outer diameter of one bearing is formed to be substantially the same as the outer diameter of the other bearings provided other than the step sleeve, so that the press-fit length of the crank journal can be increased without increasing the pitch between cylinders. The bearings can be made stronger, thereby increasing the torsional torque. Also, since the outer peripheral surfaces of the bearings are located at the same level, the machining of the crankcase is facilitated. , The bearing moment is reduced and the service life can be extended.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a two-cycle engine.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a configuration diagram of a two-cycle engine.

FIG. 4 is a sectional view of a conventional two-stroke engine.

FIG. 5 is a cross-sectional view of a conventional two-stroke engine.

FIG. 6 is a sectional view of a conventional two-stroke engine.

FIG. 7 is a sectional view of a conventional two-stroke engine.

FIG. 8 is a sectional view of a conventional two-stroke engine.

[Explanation of symbols]

 2 2 cycle engine 10 Upper crankcase 12 Lower crankcase 14 Crankshaft 20 Crank journal 22 Crank pin 24 Crank web 26 Stepped sleeve 28 Sleeve side bearing 30 Direct support bearing

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16C 3/10

Claims (1)

(57) [Claims] An assembled crankshaft provided with a crank web that is supported between an upper crankcase and a lower crankcase of an engine and press-fits a crank journal and connects a crankpin, wherein the crankweb includes the crank. A step sleeve into which a journal is press-fitted is provided extending in the axial direction of the crankshaft, a bearing is fitted to the step sleeve, and an outer diameter of the one bearing is provided other than the step sleeve. An assembled crankshaft characterized in that it is formed to have substantially the same outer diameter as another bearing.