JP2574566Y2 - Main bearing device for internal combustion engine - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a main bearing device for an internal combustion engine.

[0002]

2. Description of the Related Art As a conventional example of a main bearing device for an internal combustion engine, there is one shown in FIG.
7, JP-B-60-39466, JP-A-3-6.
No. 4655). That is, a crankcase 2 is formed on both lower sides of the cylinder block 1 so as to protrude downward, and a bed plate 3 is attached to a lower wall of the crankcase 2 so as to extend between the two crankcases 2. A plurality of cross members 4 are formed on the bed plate 3 so as to extend between the crankcases 2.

[0003] A bearing portion 5 is formed by the lower portion of the cylinder block 1 and the upper wall of the bed plate 3, and a metal bearing portion is rotatably attached to the bearing portion 5. 6
Is a reinforcing member attached to the cylinder block 1 together with the bed plate 3 by bolts 7.

[0004]

By the way, in such a conventional main bearing device, the bed plate 3 is attached so as to extend between the two crankcases 2, so that the rigidity of the crankcase 2 is increased, and vibration and vibration are reduced. Although it is advantageous for reducing noise, the crankshaft is sandwiched between the lower part of the cylinder block 1 and the bearing cap portion of the bed plate 3, so that it is caused by the longitudinal bending vibration of the crankshaft during engine operation (see FIG. 7). The longitudinal vibration of the main bearing (Fig. 7
) Is directly transmitted to the crankcase 1, and the vibration of the wall of the crankcase 2 increases, and the engine vibration increases.

The present invention has been made in view of such circumstances, and suppresses transmission of vibration of a crankshaft to a crankcase or the like while maintaining high rigidity of the crankcase.
To provide a main bearing device for an internal combustion engine,
aimed to. Such equipment should be further improved.
This is the purpose of the present invention.

[0006]

SUMMARY OF THE INVENTION Therefore, the present invention provides a crankcase which is formed to project downward from both sides of a lower portion of a cylinder block, and a bed plate which is inserted between the crankcases and attached to a lower end of the crankcase. And a crankshaft in which a journal portion is rotatably held by a bearing holding portion and a bearing cap at a lower portion of the cylinder block via a bearing, wherein the journal portion of the crankshaft is
Cylindrical outer race that holds freely through the ring
At least a portion of the outer peripheral surface of the spherical surface portion, the spherical portion
Through which the crankshaft can swing in at least one direction
So that the outer race is
So that it is sandwiched between the holding part and the bearing cap.
I made it. Further, a key for regulating the position of the outer race in the direction of rotation of the crankshaft, wherein the key is formed concentrically with the outer peripheral surface of the outer race in a longitudinal section of the crankshaft.

[0007]

The lower end of the crankcase is held by a bed plate to increase rigidity, and the crankshaft swing during engine operation is reduced by a spherical portion provided on the outer peripheral surface of the outer race.
Absorbed by swinging the outer race through and so as to suppress the vibration of the crank case wall. Further, the key for regulating the position of the outer race in the crankshaft rotation direction, wherein in a cross section in the longitudinal direction of the crankshaft,
By providing a key formed concentrically with the outer peripheral surface of the outer race, the outer race is swingably supported while preventing rotation of the outer race due to rotation of a crankshaft. Lubricating oil supply was ensured.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show an embodiment of the present invention. In FIG. 1, crankcases 12 are formed on both lower sides of a cylinder block 11 so as to project downward, respectively.
A plurality of bearing holding portions 13 are formed at predetermined intervals between the cylinder blocks 11 in the front-rear direction (the depth direction in FIG. 1) of the cylinder block 11. The lower end of the center of the bearing holder 13 is shown in FIG.
As shown in FIG. 5, a bearing mounting hole 14 having a spherical inner peripheral wall is formed in a semicircular shape.

At the lower end of the crankcase 12, a bed plate 15 is attached across the two crankcases 12, and a cross member 16 is spread over the bed plate 15 between the two crankcases 12 as in the prior art. Are formed at predetermined intervals in the front-rear direction of the cylinder block 11. Cross member 16 of the bed plate 15
Bearing caps 17 are respectively formed in the center of each of the bearing caps 17, and a bearing mounting hole 18 whose inner peripheral wall is spherical is formed in a semicircular shape at the lower center of the center of each bearing cap 17, as shown in FIG. The bearing mounting holes 18 of the bearing caps 17 are mounted so as to face the bearing mounting holes 14 of the bearing holder 13, and these bearing mounting holes 14,
18 forms a circular mounting hole.

As shown in FIG. 2, an outer race 19 having a spherical outer peripheral wall is swingably mounted on the bearing mounting holes 14 and 18, and a journal portion of a crankshaft 21 is mounted on the outer race 19 via a metal bearing 20. Is installed so that it can rotate freely. A detent key 22 is attached across the upper part of the bearing cap 17 and the lower end of the outer race 19, so that the outer race 19 can swing in a substantially vertical plane in the bearing mounting holes 14, 18. It is configured as follows.

A lubricating oil supply passage 23 is formed in the rib member of the bearing holding portion 13, and this supply passage 23 is formed in a substantially elliptical shape whose major axis is the circumferential direction of the outer race 19, as shown in FIG. Have been. Further, a lubricating oil hole 24 for supplying lubricating oil to the metal bearing 20 is formed through the outer race 19 so as to communicate with the lubricating oil supply passage 23.
24 is formed in an oval shape having substantially the same shape as the supply passage 23.

According to this configuration, the explosive force acts on the crankshaft 21 via the piston during the operation of the engine, and the crankshaft 21
Even if vertical bending vibration (see Fig. 7) occurs in the outer case,
19 swings in a substantially vertical plane with respect to the bearing holding portion 13 and the bearing cap 17 to absorb the longitudinal bending vibration. For this reason, the transmission of the vibration to the crankcase 12 via the bearing holding portion 13 can be greatly suppressed, so that the vibration of the wall of the crankcase 12 can be significantly suppressed, and thus the engine vibration can be suppressed.

Further, the lubricating oil supply passage 23 of the bearing holding portion 13 and the lubricating oil hole 24 of the outer race 19 are made oblong to communicate with each other, and the outer race 19 is prevented from rotating by the key 22. The lubricating oil can be reliably supplied from the outside of the bearing, and the sliding portion can be lubricated well. Of course, since the lower ends of the two crankcases 12 are connected by the bed plate 15, the rigidity of the members of the crankcase 12 can be kept high as in the prior art, so that the vibration of the wall of the crankcase 12 can also be suppressed.

FIGS. 4 and 5 show another embodiment of the present invention. The same elements as those in the above-described embodiment are denoted by the same reference numerals as those in FIGS. In this embodiment, as shown in FIG. 4, a detent key 31 of the outer race 19 is mounted on the right side of the crankshaft 21, and the lateral bending vibration of the crankshaft 21 is absorbed by the outer race 19 and transmitted to the crankcase 12. Was suppressed.

Although the embodiment has been described in which the bearing cap is integrally attached to the bed plate, the present invention can be applied to a case where the bearing caps are separately provided.

[0016]

[Effect of the invention The present invention, as described above, the cylinder block lower sides of the crankcase as well as connected by a bedplate, the crankshaft mounted on the outer race via the bearing, the outer peripheral surface of the outer race
This swinging the outer race via a spherical portion provided
DOO so has to be, since it is possible to absorb the swing of the crank shaft during engine operation while maintaining a high rigidity of the crankcase in the outer race, it can be greatly suppress the vibration of the crank case wall. According to the invention of claim 2, the key is a key for restricting the position of the outer race in the crankshaft rotation direction.
Since a key formed concentrically with the outer peripheral surface of the outer race is provided, it is possible to prevent the outer race from swiveling due to rotation of a crankshaft while supporting the outer race so as to swing freely, and thus to lubricate bearings. Oil supply can be reliably performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of the above.

FIG. 3 is a view taken along the arrow III-III of FIG.

FIG. 4 is a block diagram showing another embodiment of the present invention.

FIG. 5 is a sectional view of a main part of the above.

FIG. 6 is an exploded view showing a conventional example of a main bearing device.

FIG. 7 is a diagram for explaining the operation of the above.

[Explanation of symbols]

 11 Cylinder block 12 Crankcase 13 Bearing holder 15 Bed plate 17 Bearing cap 19 Outer race 20 Metal bearing 21 Crankshaft

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-64655 (JP, A) JP-A-57-149613 (JP, A) JP-A-61-29127 (JP, A) 54945 (JP, U) Japanese Utility Model Showa 47-38240 (JP, U) Japanese Utility Model Showa 56-138217 (JP, U) Japanese Utility Model Showa 62-86412 (JP, U) Japanese Utility Model Utility Model Showa 60-39466 (JP, Y2) (58) Field surveyed (Int. Cl. ⁶ , DB name) F16C 9/02 F02F 7/00

Claims (2)

(57) [Scope of request for utility model registration] A crankcase formed to protrude downward on both sides of a lower portion of a cylinder block, a bed plate extending between the crankcases and attached to a lower end of the crankcase, and a bearing holding portion at a lower portion of the cylinder block. A crankshaft in which a journal is rotatably held by a bearing cap via a bearing; and a main bearing device for an internal combustion engine comprising:
The outer race surface of the cylindrical outer race
At least one part is spherical, and at least one of the crankshafts is formed through the spherical part.
So that the outer race can swing forward,
The bearing cap and the bearing cap
A main bearing device for an internal combustion engine, wherein the main bearing device is sandwiched . (2) The outer race in the crankshaft rotation direction
A key that regulates the position.
The outer race is formed concentrically with the outer peripheral surface of the outer race.
2. The key according to claim 1, further comprising:
Main bearing device for internal combustion engine.