JPH0618050Y2 - Cylinder block structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a cylinder block structure, and more particularly to a cylinder block structure in which a bearing cap mounting structure is improved.

[Prior Art] In a cylinder block configured to rotatably support a crankshaft, as shown in FIG. 3, a deformation of the block skirt b between a block skirt b of a cylinder block a and an oil pan c, The one provided with a ladder frame e to prevent the deformation of the bearing cap d, the _one provided with a bearing plate f to prevent the movement of the bearing cap d ₁ on the oil pan C ₁ side as shown in FIG.
As shown in the figure, there is one in which a bearing plate g is provided on the oil pan c ₁ side in order to prevent the movement of the block skirt b ₁ .

However, in any of the examples, there is a problem that the bearing cap is likely to be deformed by the impact load from the crankshaft, and vibration noise is generated due to the gap (backlash) due to the deformation. In addition, these ladder frames, bearing beams, and bearing plates have problems in terms of cylinder block weight, productivity, and cost.

Therefore, in the prior art, as shown in FIG. 6, a bulkhead i, which is connected to the skirt b _{1 in} a half-skirt type cylinder block a ₁ whose skirt b ₁ ends near the center of the crankshaft h, is formed by the bulkhead i. Positioned on both sides of the bearing cap d ₁ coupled to i, the retainer k reinforced by the rib j is integrally projected, and the retainer k
And bound a bearing cap d ₁ in the side bolt l "cylinder block of an internal combustion engine" (Japanese Utility Model 59-107955
No. gazette) has been proposed.

[Problems to be solved by the invention] However, in the structure in which the bearing cap is attached to the retainer with the side bolts, as the number of bolts increases, the assembly work time increases and the number of parts required for assembly increases. There is a problem that the cost reduction cannot be achieved sufficiently.

Also in terms of strength, since the side bolts are mainly structured to receive the thrust load from the crankshaft, there is a risk that the side bolts will be broken (especially the screw part) due to repeated fatigue.

[Means for Solving the Problems] The present invention is intended to solve the above problems, and a bulk having a bearing portion that covers the upper half of the crankshaft in the lower portion is hung on the inner surfaces of the left and right skirts of the cylinder block to form the crankshaft. In a cylinder block structure in which a bearing cap covering the lower half is attached to the lower part of the bulk by bolts, ribs extending to the bearing cap side are provided on the inner surfaces of the left and right skirts with the bearing cap as the center,
The extended end faces of these ribs are linear grooves that open at the upper end face and the lower end face of the rib, and the groove depth of which is the deepest at the lower end face and the shallowest at the upper end face. Wedge portions that are fitted into the fitting grooves by wedges are respectively provided on both end surfaces on the side.

[Operation] When the wedge part of the bearing cap is fitted into the fitting groove and the bearing cap is bolted to the bulk,
There is no gap (play) between the wedge part and the fitting groove. Therefore, no noise is generated due to rattling. Further, since the load in the thrust direction of the crankshaft direction is received by the rib and the skirt, the bearing cap is not deformed or collapsed.

[Embodiment] A preferred embodiment of the cylinder block structure of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, the skirt 2 forming the lower part of the cylinder block 1 has a bulk 3 laid over the inner surface 2 a of the skirt 2. The bulk 3 integrally has a bearing portion 5 that covers the upper half of the outer peripheral surface 4a of the crankshaft 4 on the lower portion thereof, and has screw portions 8 and 8 outside (on the left and right) of the bearing surface 6 respectively. There is. And bearing cap 9
Are integrally attached to the lower portion of the bulk 3 by bolts 15 and 16 screwed into the screw portions 8 and 8.

The bearing cap 9 is, as shown in FIGS. 1 and 2,
It is composed of a plate-shaped member, and has a bearing surface 10 that covers the outer peripheral surface 4a of the lower half of the crankshaft 4 at the upper part thereof, and both end surfaces 12a and 12b on the skirt side thereof have a fitting groove 1 described later.
Wedge portions 13a, 13b that are wedge-fitted with 4a, 14b
have.

These wedge portions 13 a and 13 b are provided in a V shape with respect to the bearing cap 9. And wedge part 1
The thickness of 3a, 13b is thinner than the thickness of the bearing cap 9, and the wedge portions 13a, 13b are provided at the center portion in the thickness direction with respect to the end surface of the bearing cap 9 on the skirt side.

Then, on the inner surface 2a of the skirt 2, ribs 3a are integrally formed at portions located on the left and right sides of the bearing cap 9 so as to extend toward the bearing cap 9 side.

These ribs 3a, 3b are opened at their extended end faces to the upper end face and the lower end face of the bearing cap 9, respectively.
Fitting grooves 14a and 14b for fitting the wedge portions 13a and 13b into the wedges are provided.
These fitting grooves 14a, 14b are formed in a taper shape such that the groove depth is deepest at the lower end surface and shallowest at the upper end surface.

Therefore, even after the tightening of the bolts 15 and 16 is completed and the bearing cap 9 is integrally attached to the bearing portion 5 on the bulk 3, the wedge force continues to be applied to the skirt 2 via the rib 3a. There is no play between them. Therefore, vibration noise due to rattling, which has been a problem in the past, does not occur.

Further, since the rib 3a and the skirt 2 receive a load in the thrust direction of the crankshaft 4, the rib 3a and the skirt 2
As long as the strength of the bearing cap is sufficient, the bearing cap 9 will not be deformed or fallen. Therefore, stable bearing performance is maintained. Further, only the tensile load acts on the bolts 15 and 16, and the strength thereof is guaranteed.

The wedge portions 13a and 13b are set to have a section modulus that can sufficiently oppose the load of the crankshaft 4 in the thrust direction, and the wedge portions 13a and 13b and the fitting grooves 14a and 14b are the bearing cap 9 and the bearing. The taper is set so that a predetermined wedge force is exerted between them when they are completely engaged and tightened.

Therefore, the conventional side bolts are unnecessary, and a lightweight, low cost, high rigidity and low noise cylinder block structure can be obtained.

[Effects of the Invention] As is clear from the above description, the present invention exhibits the following excellent effects.

(1) The strength of the cylinder block can be increased, and
Since the backlash can be eliminated, vibration noise can be greatly reduced.

(2) Deformation of the bearing cap can be prevented and stable bearing performance can be obtained.

(3) The number of parts can be reduced and the assembly workability can be greatly improved.

(4) The weight and cost can be reduced.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing a preferred embodiment of a cylinder block structure according to the present invention, FIG. 2 is a view taken along the line II-II of FIG. 1, and FIGS. 3 to 6 show conventional examples. FIG. In the figure, 1 is a cylinder block, 2 is a skirt, 3 is a bulk, 4 is a crankshaft, 5 is a bearing portion, 9 is a bearing cap, 13a and 13b are wedge portions, and 14a and 14b are fitting grooves.

Claims (1)

[Scope of utility model registration request] 1. A cylinder block in which a bulk having a bearing portion covering the upper half of a crankshaft is hung on the inner surfaces of the left and right skirts of a cylinder block, and a bearing cap covering the lower half of the crankshaft is attached to the lower portion of the bulk by bolts. In the structure, ribs extending toward the bearing cap side are provided on the inner surfaces of the left and right skirts centering on the bearing cap, and the extended end surfaces of these ribs are linear grooves that open at the upper end surface and the lower end surface of the rib, respectively. The groove depth is the deepest at the lower end surface and the shallowest at the upper end surface, and the bearing cap is provided with wedge portions at both end surfaces on the skirt side, which are wedge-fitted to the above-described fitting groove. And cylinder block structure.