JPH0643483Y2 - Integral bearing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a bearing cap called an integral bearing in which the bearing caps are integrally connected by a beam member for the purpose of reducing noise.

(Prior Art) Conventionally, in order to prevent vibration noise caused by reciprocating motion of a piston between cylinders, each bearing cap is integrally connected by a beam member, and an integral bearing having high rigidity is provided as a third embodiment. An integral bearing 2 connected by one lower beam member 1 as shown in the figure, and an integral bearing 2 connected by two lower beam members 3 and 4 as shown in FIG. 4 in order to have rigidity higher than that of the integral bearing 2. Lu bearing 5, etc. are known,
The shape of the integral bearing to be used is determined as a result of considering interference with the components arranged around (specifically, downward or obliquely downward). Here, the integral bearing is assembled to the cylinder block as shown in FIGS. In the figure, the piston 8 arranged in each bore space 7 of the cylinder block 6 is supported by a connecting rod 9 so as to be slidable in the vertical direction in the figure, and each connecting rod 9 is positioned on both sides of a balance weight 30. Along with it, it is attached to the crankshaft 20 that is bent in a U shape. Incidentally, the piston 8, the connecting rod 9, the crankshaft 20, and the balance weight 30 are shown in phantom lines because they are complicated when they are shown in solid lines. The crankshaft 20 includes an upper rib 21 provided substantially below the partition wall 10 existing between the bores of the cylinder block 6,
The bearing portion 11 is provided at the lower end of the skirt portion 22 below the cylinder block 6, and the upper portion and the lower portion are fixed to the cylinder block 6 by an upper rib 21 and a lower rib 23 that is on the same plane. Two beam members 1 with bearing caps 12 that are linear to each other
It is supported in a state of being inserted between the integral bearing 15 connected by 3,14. Each bearing portion 11 and the corresponding bearing cap 12 are fixed to each other by a bolt 16 for connection, and the beam members 13 and 14 are outside the outer envelope M of the crank rotation locus indicated by phantom lines and have rigidity. It is provided as close to M as possible in order to raise the height.

Below the cylinder block 6, an undercase 25 having a thin wall thickness is fixed as an oil tray, and the bottom plate cannot be made to be convex so much due to a problem such as interference with other parts. Is shallowed to the point where it does not come into contact with, and is substantially parallel to the beam member.

(Problems to be solved by the invention) The cylinder block adopting the above-mentioned integral bearing has a stronger collapse strength in the axial direction of the crankshaft and a higher torsional strength with respect to the center of rotation of the crank, as compared with those in which the bearing caps are not connected by beam members. Since the bending strength around the cylinder bore axis was improved, vibration noise was somewhat reduced, but it was not as expected. In addition, since the vibration is transmitted to the thin undercase fixed to the lower part of the cylinder block and vibrates together, there is a problem that the noise is further increased. Here, it is conceivable to simply increase the thickness of the beam member and / or the undercase to increase the rigidity and absorb the vibration, but if this is done, the position of the bottom plate bottom surface of the undercase should not be displaced further downward. This is not preferable because there is a problem of interference with other parts located below, as described above, and the layout or the like must be changed significantly.

(Means for Solving Problems) In order to solve the above problems, the present invention has a structure in which the beam member in the central portion between the integral bearings is convex downward and the bottom surface of the bearing cap and the beam member near the bearing cap are upward. The beam member and the bottom surface of the bearing cap are formed in a corrugated shape so as to be convex in the direction. The beam member at the central portion is located slightly outside the outer envelope of the rotational trajectory of the connecting rod, and the bearing cap is located at the central portion. The beam member on the side is located slightly outside the outer envelope of the rotational trajectory of the balance weight, and the bottom plate upper surface of the under case located below the integral bearing is formed by following the corrugation, so that Undercase and integral bearing without extending the bottom surface of the bottom plate of the undercase The rigidity of the vibration is increased, and thereby the vibration noise is further reduced.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

1 and 2 show an integral bearing and an undercase according to the present invention. The difference from the prior art is that the bearing caps 112 are connected to each other and the beam members 113 and 114 located below the left and right sides of the bearing caps 112.
, So that the bottom surface of each bearing cap 100 and the beam member 115 in the vicinity of each bearing cap 112 are convex upwards at the central portion between the bearings (dashed line A in FIG. 1), that is, the beam The curved surface connecting the lower surfaces of the members 113 and 114 and the bottom surface 100 of the bearing cap has a downward peak at the center portion between the bearings, and the bearing portion cap 112
There is a point where a waveform 200 is formed so as to have a peak at the above portion, and a point where the upper surface 201 of the undercase bottom plate undulates along the waveform 200. The wavy beam members 113, 114 here are slightly outside the outer envelope M of the crank rotation locus described above at the central portion between the bearings (dashed line A in FIG. 1), and on the bearing cap side from A. Is slightly outside the outer envelope of the rotation trajectory of the balance weight 30. That is, the beam members 113 and 114 have a waveform that is as close as possible to the connecting rod 9 and the balance weight 30 within a range in which the connecting rod 9 and the balance weight 30 do not hit even if they rotate. According to this structure, the beam member 115 (that is, at the coupling portion) near the bearing cap 112 can be arranged higher than before, so that the rigidity of the bearing cap 112 in the axial direction of the crankshaft can be naturally increased. Moreover, the rigidity of the beam members 113 and 114 can be increased by corrugating the beam members. In addition, since the bottom plate upper surface 201 of the under case 125 is corrugated along the waveform 200 formed by the bottom surface 100 of the bearing cap and the lower surfaces of the beam members 113 and 114, the under case at a position below the bottom surface 100 of the bearing cap is formed. Since the thickness H of the bottom plate can be made considerably thicker than the conventional one as shown in the drawing, the rigidity of the undercase 125 can be increased without lowering the position of the bottom plate lower surface 210 of the undercase 125 from the conventional one. Under case 125
By increasing the rigidity of the integral bearing 150, it is possible to further reduce vibration noise. In addition, the connecting bolt 1 for connecting the bearing portion 11 and the bearing cap 112
In order to prevent 6 from being projected downward, in this embodiment, the bearing cap 112 is provided with a spot facing for the bolt so as not to be projected downward as much as possible.

(Effect of the Invention) As described above, according to the present invention, the beam member is formed in a corrugated shape as close as possible to the connecting rod and the balance weight, and the bottom surface of the undercase is formed following this corrugated shape. Without increasing the height
Since the rigidity of the integral bearing and the undercase can be increased, vibration noise can be further reduced without changing the structure and layout of other components.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional side view showing a part of an embodiment of the present invention,
FIG. 2 is a sectional view taken along the line AA of FIG. 1, FIGS. 3 and 4 are schematic views of respective conventional integral bearings, and FIG. 5 is a partial sectional schematic side view showing a conventional technique, and FIG. Is B in FIG.
It is a -B sectional view. 1,3,4,13,14,113,114 …… Beam members, 2,5,15,150 ……
Integral bearing, 6 ... Cylinder block, 7
…… Bore, 11 …… Bearing part, 12,112 …… Bearing cap, 20 …… Crankshaft, 25,125 …… Undercase, 100 …… Bearing cap bottom, 115 …… Beam member near the bearing cap, 200 …… Waveform, 201
...... Upper surface of bottom plate of the under case, A, B …… Center between bearings.

Claims (1)

[Scope of utility model registration request] 1. An integral bearing in which each bearing cap, which is paired with a bearing portion arranged between each bore of a cylinder block and supports a crankshaft, is integrally connected to each other by a beam member, wherein the beam member is The beam members are respectively connected to the left and right lower portions of the bearing caps, and the beam members at the central portion between the bearing caps are convex downward, and the bottom surface of the bearing cap and the beam members near the bearing cap are convex upward. As described above, the beam member and the bottom surface of the bearing cap are formed in a corrugated shape, and the beam member at the central portion is located slightly outside the outer envelope of the rotational trajectory of the connecting rod, and at the bearing cap side from the central portion. The beam member is an outer envelope of the rotation trajectory of the balance weight. An integral bearing, characterized in that an upper surface of a bottom plate of an under case located slightly outside the tangential line and below the integral bearing is formed in a manner following the corrugations.