JPH05340420A - Body structure of multicylindered engine - Google Patents

Abstract

PURPOSE:To provide a body structure of a multicylindered engine that is able to reduce the extent of vibration to be transferred to a cylinder block from a crankshaft so favorably. CONSTITUTION:A slit 14 striding a bulkhead 6' exclusive of both front and rear ends of an engine and a bearing cap 7' in contact with this bulkhead is installed in space between a skirt 4 and a cap bolt 9 and adjacent bearing caps 7 are connected tight to each other by a bearing beam 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a main body structure of a multi-cylinder engine.

[0002]

2. Description of the Related Art Conventionally, for example, as shown in FIG. 6 is known for the purpose of reducing the sound emitted from a skirt (see Japanese Utility Model Laid-Open No. 64-22849).

This is because a skirt 102 that defines a crankcase 101 and a bulkhead 103 that divides the crankcase 101 into cylinders are integrally formed at the lower end of a cylinder block 104 in cooperation with the bulkhead 103. A ladder frame 105 that rotatably supports the shaft is fastened with a plurality of cap bolts 106, and a crescent-shaped space 107 is formed between the skirt 102 and the cap bolts 106.

The deformation (deflection) of the crankshaft due to the combustion pressure causes the main bearing 108, which rotatably supports the combustion shaft, to collapse, which acts as a vibrating force to vibrate the cylinder block 104. But cap bolt 10
Since a crescent-shaped space 107 is opened between 6 and the skirt 102, the main bearing portion 108 can swing in the engine front-rear direction independently of the skirt 102. The vibration transmission path is cut, and the sound emitted from the skirt 102 can be reduced.

[0005]

However, in such a conventional engine main body structure, II of FIG. 6 is used.
As well shown in the -II cross section, a crescent-shaped space 107 is formed in all the bulkheads 103 and the ladder, including the front and rear ends of the engine, so that the main bearing portion 108 falls in the front-rear direction of the engine. The decrease in rigidity is unavoidable, and the crankshaft is deformed due to the combustion pressure received by the piston, so that the main bearing 108 swings too much in the front-rear direction of the engine.・ It was a cause of vibration.

The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a main body structure of a multi-cylinder engine which can favorably reduce vibration transmitted from a crankshaft to a cylinder block. Is.

[0007]

In order to solve the above problems, the present invention provides a skirt that defines a crankcase at the lower end of a cylinder block, a bulkhead that partitions the crankcase into cylinders, and a bulkhead. In a main structure of a multi-cylinder engine, a front and rear ends of the engine are provided in a body structure of a multi-cylinder engine that includes a bearing cap that rotatably supports a crankshaft and a pair of cap bolts that tighten the bearing cap to a bulkhead on both sides of the crankshaft. On the removed bulkhead and the bearing cap that abuts on it, a slit that spans both of them is opened between the skirt and the cap bolt, and the bearing cap located at the front and rear ends of the engine and the bearing cap where the slit is opened It is characterized in that and are rigidly connected with a bearing beam.

[0008]

According to the above construction, the bulkhead excluding the front and rear ends of the engine and the bearing cap abutting against the bulkhead are formed with slits extending over both of them, so that the portion supporting the crankshaft is deformed by the crankshaft. It becomes possible to swing independently from the skirt due to (deflection), and the main vibration transmission path from the crankshaft to the skirt is cut. Moreover, since the bearing cap having the slits is rigidly coupled to the bearing caps fastened to the front and rear ends of the engine by the bearing beam, the bearing cap having the slits and the collapse rigidity of the bulkhead are relatively small. Can be increased. Therefore, it is possible to prevent the generation of new noise due to the bearing cap falling too much, and at the same time, it is possible to reduce the sound emitted from the skirt. Further, the crankshaft support rigidity at the front and rear ends of the engine is high because no slits are formed, and the box rigidity of the crankcase composed of the bulkhead and skirt located at the front and rear ends of the engine is significantly enhanced,
The sound emitted from the skirt is synergistically improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment according to the present invention will be described below with reference to FIGS. 1 is a sectional view taken along the line AA of FIG. 3, and FIG. 2 is a sectional view taken along the line BB of FIG.

Reference numeral 1 is a cylinder block having four cylinders 2 in series. A skirt 4 defining a crankcase 3 is formed at the lower end of the cylinder block 1 so as to face both sides of a crankshaft 5. A bulkhead 6 partitions the crankcase 3 into cylinders, and is formed in a direction perpendicular to the crankshaft 5 with opposite skirts 4 at both ends.

A bearing cap 7 for rotatably supporting the crankshaft 5 in cooperation with the lower end 6a of the bulkhead 6 is tightened. The tightening of the bearing cap 7 is performed by a pair of cap bolts 9 arranged on both sides of the crankshaft 5, and a main bearing portion that rotatably supports the crankshaft 5 between the bulkhead 6 and the bearing cap 7. 10 are configured. Main bearing part 10
Between the bearing and the crankshaft 5 is a bearing metal 11
Is provided to facilitate smooth rotation of the crankshaft 5.

A collar 12 is driven between the bearing cap 7 and the bulkhead 6 that abuts against the bearing cap 7, straddling them. The color 12 is driven in
Both ends 7a of each bearing cap 7 and both ends 6a of each bulkhead 6 are rigidly connected to the bearing beam 13 (described later) and the skirt 4, and the box rigidity of the crankcase 3 is enhanced.

Bulkhead 6 excluding the front and rear ends of the engine
(Hereinafter referred to as a bulkhead 6 ') and a bearing cap 7 (hereinafter, referred to as a bearing cap 7') that abuts on the bulkhead 6 '.
The slit 14 is formed over both of them. The slit 14 is formed between the cap bolt 9 and the skirt 4, and also between the collar 12 and the cap bolt 9, and extends in the cylinder axis direction. The depth of the slit 14 cut into the bulkhead 6 ′ is deeper than the end portion 9 a of the cap bolt 9, that is, the cylinder 2
Is cut to the side close to. The cap bolt 9 is disposed between the slit 14 and the crankshaft 5 as follows.
The slit 14 is cut deeper than the end portion 9a of the cap bolt 9 in order to prevent the moment load caused by the tilting of the bearing cap 7 from being transmitted to the cylinder block 1, and this is more effective. This is to prevent it.

FIG. 2 is a view showing the front and rear ends of the engine. A bulkhead 6 (hereinafter referred to as bulkhead 6 ") fastened to the front and rear ends of the engine and a bearing abutting on the bulkhead 6 are shown in FIG. The slit 12 is not opened between the cap 7 (hereinafter, referred to as a bearing cap 7 "), the collar 12 is driven therein, and the box rigidity of the crankcase 3 including the skirt 4 and the bulkhead 6" is improved. Considered to improve.

FIG. 3 is a vertical cross-sectional view of the cylinder 2 in the direction of arrangement (C-C cross-sectional view of FIG. 1). Is rigidly connected with the two bearing beams 13. The bearing beam 13 connects the adjacent bearing caps 7 with each other.
It is formed integrally with the lower end of the bearing cap 7 and extends in the arrangement direction of the cylinders 2.

The partial cross section shown in FIG. 3 is the DD cross section of FIG. 1, but the slit 14 is formed in the bulkhead 6'and the bearing cap 7 ', and the bulkhead 6 "and the bearing cap are formed. It is understandable that it is not opened on 7 ".

Reference numeral 15 is a main oil gallery, and 16
Is a water jacket and 17 is a flywheel.

Next, the operation will be described based on such a configuration.

Since a slit 14 is formed between the bulkhead 6'excluding the front and rear ends of the engine and the bearing cap 7'which abuts against the bulkhead 6 ', the crankshaft 5 is rotatably supported. The main bearing portion 10 that is capable of freely swinging in the engine front-rear direction independently of the skirt 4 along with the deformation (deflection) of the crankshaft 5 has a main vibration from the crankshaft 5 to the skirt 4. The transmission path is cut. Moreover, since the bearing cap 7'having the slit 14 is rigidly coupled to the bearing cap 7 "fastened to the front and rear ends of the engine by the bearing beam 13, the bulkhead 6'and the bearing cap 7'are formed. It is possible to relatively increase the falling rigidity, and thus it is possible to prevent the generation of new noise due to the excessive falling of the bulkhead 6 ′ and the bearing cap 7 ′, and at the same time, reduce the sound emitted from the skirt 4.

Further, the supporting rigidity of the crankshaft 10 at the front and rear ends of the engine is high because the slits 14 are not formed, and the box of the crankcase 3 composed of the bulkhead 6 "and the skirt 4 located at the front and rear ends of the engine. The rigidity is remarkably enhanced, and the bearing beam 13 connecting the front and rear ends of the engine rigidly connects the bulkheads 6 ″ located at the front and rear ends of the engine, so that the box rigidity of the crankcase 3 is made even stronger. Therefore, the sound emitted from the skirt 4 is synergistically improved.

Since both ends 6a of the bulkhead 6 and both ends 6a of the bearing cap 7 which do not allow shake due to deformation (deflection) of the crankshaft are rigidly connected by the collar 12, the bearing beam Reference numeral 13 complements the box rigidity of the crankcase 3.

Next, a second embodiment according to the present invention will be described with reference to FIGS.
It will be explained based on.

In this embodiment, the slits formed on both sides of the crankshaft have different lengths on the left and right sides. In FIG. 4, the direction of rotation of the crankshaft 31 is clockwise as indicated by the arrow in the figure. Then, the rotation direction of the crankshaft 31, that is, the slit 32a opened on the right side in the drawing is formed longer than the slit 32b opened on the left side in the drawing.

That is, with reference to the contact surface 35 between the bulkhead 33 and the bearing cap 34, the bulkhead 3
The depth of cut to the 3 side is the left and right slits 32a, 32
Although both b are the same, the depths of cut into the bearing cap 34 side are different between the left and right slits 32a and 32b, that is, the slit 32a formed on the right side in the drawing is the length L ₁ from the contact surface 35. While being cut,
The slit 32b formed on the left side in the drawing is cut from the contact surface 35 by the length L ₂ and has a relationship of L ₁ > L ₂ . Other configurations are the same as those in the first embodiment, and the description thereof will be omitted.

Next, the operation will be described based on the above configuration.

Generally, the in-cylinder pressure generated in the cylinder 37 is maximized with the phase of θ after top dead center as shown in FIG. 5, so that the vibration (load) transmitted from the crankshaft 31 to the cylinder block 38 is , It will greatly affect the left side of the figure. However, since the slit 32a having a small cut amount is provided on the side where the vibration (load) largely acts (on the left side in the figure), the vibration which largely acts on the left side in the figure is appropriately suppressed, and the crankshaft The main bearing portion 39 that supports the bearing is relieved from torsional vibration in the left-right direction. As a result, the torsional vibration of the bearing cap 34 is mitigated, and the torsional vibration of the crankcase is also mitigated, so that the sound emitted from the skirt can be further reduced.

In each of the above embodiments, the half skirt type main body structure in which the crankcase is cut to the center of the crankshaft has been described.
The present invention is not limited to this, and can be applied to a deep skirt type main body structure extending to the bearing cap.

[0028]

As described above, according to the present invention, the vibration transmission path from the crankshaft to the skirt can be cut while appropriately increasing the tilting rigidity of the bearing cap and the bulkhead in which the slit is formed. Moreover, since the rigidity of the crankcase box is remarkably enhanced, it is possible to synergistically improve the radiated sound from the skirt and at the same time prevent the generation of new noise due to the bearing cap falling too far.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a main body structure according to a first embodiment (a sectional view taken along the line AA of FIG. 3).

FIG. 2 is a vertical sectional view showing a main body structure according to the first embodiment (a sectional view taken along the line BB of FIG. 3).

FIG. 3 is a vertical cross-sectional view showing a main body structure according to the first embodiment (C-C cross-sectional view of FIG. 1).

FIG. 4 is a vertical sectional view showing a main body structure according to a second embodiment.

FIG. 5 is a diagram illustrating in-cylinder pressure with respect to a crank angle.

FIG. 6 is a view showing a main body structure of a conventional engine.

[Explanation of symbols]

 1 Cylinder Block 3 Crankcase 4 Skirt 5 Crankshaft 6 Bulkhead 7 Bearing Cap 9 Bearing Beam 13 Bearing Beam 14 Slit

Claims (1)

[Claims] 1. A skirt that defines a crankcase at the lower end of a cylinder block, a bulkhead that partitions the crankcase into cylinders, and a bearing cap that cooperates with the bulkhead to rotatably support a crankshaft.
In a main body structure of a multi-cylinder engine including a pair of cap bolts for tightening the bearing cap to the bulkhead on both sides of the crankshaft, the bulkhead excluding the front and rear ends of the engine and the bearing cap abutting on the bulkhead A multi-cylinder characterized in that a slit extending across the skirt is opened between the skirt and the cap bolt, and the bearing caps located at the front and rear ends of the engine and the bearing cap in which the slit is opened are rigidly connected by a bearing beam. Body structure of the engine.