JP2000104726A - Main bearing device of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit a vibration and a noise of a cylinder block by integrally forming a ladder plate, a bearing cap and a cylinder block by tightening the ladder plate to a cap-mounting surface of the cylinder block through the bearing cap by a cap bolt. SOLUTION: A ladder plate 8 and a bearing cap 6 are co-tightened to a cap-mounting surface 4 of a cylinder block 1 by penetrating a cap bolt 10 through a mounting hole 8C of the ladder plate 8 and a mounting hole 6D of the bearing cap 6 and threadedly engaged with a threaded portion 4B of a cap-mounting surface 4. A periphery end portion of the ladder plate 8 is tightened to a bottom surface 2D of a skirt portion 2 by penetrating a plurality of oil pan bolts 11 through a mounting hole 9B of the oil pan 9 and a mounting hole 8D of the ladder plate 8 respectively and threadedly engaged with a thread hole 2E of the skirt portion 2. Accordingly, a vibration in a forward/backward direction and a vertical direction of the bearing cap 6 is restricted.

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 holding a journal of a crankshaft to a cylinder block of an engine via a bearing cap.

[0002]

2. Description of the Related Art Conventionally, as a main bearing device for holding a journal portion of a crankshaft in a cylinder block of an engine, for example, there is known an independent bearing cap structure shown in Japanese Utility Model Laid-Open No. 6-60749 or FIGS. Have been. The independent bearing cap structure will be described with reference to FIGS.

In the figure, skirt portions 102, 102 are formed on both lower sides of a cylinder block 101, and a crank recess 1 is provided between both skirt portions 102, 102.
A cap mounting surface 103A is formed on the ceiling surface of the crank recess 103. A recess 104 having a semicircular cross section is formed on the cap mounting surface 103A.

[0004] A plurality (five) are provided in the concave portion 103 for the crank.
Bearing caps 105, 105, 105, 10
5, 105 are arranged at predetermined intervals along the axial direction of the crankshaft 107. A plurality (five) of the bearing caps 105, 105, 105, 105, 105 are respectively provided with bolts 106, 10 on the cap mounting surface 103A.
6 fixed. Each bearing cap 105
Is formed with a concave portion 105A having a semicircular cross section.

Each journal 107A of the crankshaft 107 is held between the recess 104 and the recess 105A. Each bearing cap 105 is attached to the cap mounting surface 103A of the cylinder block 101 by a bolt 106, By tightening at 106, each bearing cap 105 and cylinder block 101 are integrated.

[0006]

However, in the conventional independent bearing cap structure, each bearing cap 105 is fixed to the cap mounting surface 103A in a suspended state with its lower end being a free end. The vibrating force of the crankshaft 107 causes the cap 105 to vibrate in the front-rear and up-down directions (shown in FIGS. 6, 7A, 7B, and 7C). Vibration and noise are generated in the crankshaft 10
7, the lower portion of the bearing cap 105 is likely to vibrate in the front-rear direction (the direction of the axis of the crankshaft 107) (shown in FIG. 7C), which causes the cylinder block 101 to generate vibration and noise. There's a problem.

In order to reduce the vibration and noise of the cylinder block 101, a bed plate structure in which both sides of a plurality of bearing caps are integrated with side walls is disclosed in, for example, Japanese Utility Model Laid-Open No. 6-60749 (see FIGS. 8 and 9). This is disclosed in Japanese Unexamined Utility Model Publication No. 5-71430. The bed plate structure will be described with reference to FIGS. In the figure, a bed plate structure 202 is fixed to a lower surface 201A of a cylinder block 201 via a plurality of bolts (not shown). Lower surface 201A of cylinder block 201 and bed plate structure 202
And the crankshaft 203 is held.

The bed plate structure 202 includes a plurality of bearing caps 204 and side walls 205, which connect the plurality of bearing caps 204 at both ends thereof.
205. Such a bed plate structure 2
According to 02, the rigidity of the entire engine is increased, and there is an effect of suppressing vibration of the cylinder block 201 and suppressing vibration and noise of the conventional independent bearing cap. On the other hand, there are side walls 205, 205, the bearing cap 204 is large, and the explosive power of the engine is directly transmitted to the bed plate structure 202, so the bed plate structure 202 needs to be strengthened. Therefore, there is a problem that the weight increases.

In short, if the conventional independent bearing cap structure is adopted, the weight can be reduced.
Since the bearing caps 105 are suspended and are not connected to each other, a problem of vibration and noise of the cylinder block 101 occurs.
When 02 is used, the bearing caps 204 are connected to each other, so that the rigidity is increased and the vibration and noise of the cylinder block 201 can be suppressed. However, on the other hand, the weight increases and the advantage of the independent bearing cap structure is adopted. A certain weight reduction cannot be secured.

As described above, it is difficult to suppress the vibration and noise of the cylinder block and reduce the weight of the engine with respect to the main bearing device of the engine. SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an engine main bearing device capable of suppressing vibration and noise of a cylinder block and achieving weight reduction. It is.

[0011]

According to the present invention, there is provided a cylinder block having a skirt portion formed on both sides of a lower portion, and a mounting surface for a cap formed on a ceiling surface of a concave portion for a crank between both skirt portions; A plurality of bearing caps arranged at predetermined intervals along the axial direction of the crankshaft in the recess for use, and a cap top surface of the bearing cap abuts on the cap mounting surface and a cap side surface of the bearing cap. In the main bearing device of the engine, wherein a gap is formed between the bearing cap and the inner wall of the skirt, the vertical dimension from the cap top surface to the cap bottom surface of the bearing cap is from the cap mounting surface of the skirt portion to the bottom surface. It is equal to the height dimension, a ladder plate is bridged to the bottom of both skirts, and the periphery of the ladder plate is By tightening the ladder plate with tightened with oil pan bolts cap bolt to the cap mounting surface of the cylinder block through the bearing cap to the bottom of the serial skirt,
The ladder plate, the bearing cap, and the cylinder block are integrated.

(Operation) In the present invention, since the vertical dimension from the cap top surface to the cap bottom surface of the bearing cap is equal to the height dimension from the cap mounting surface of the skirt portion to the bottom surface, the bearing cap can be laddered. Together with the plate, the cap mounting surface between the two skirt portions can be tightened with the cap bolt. In this state, each bearing cap is connected via a ladder plate, and the bearing cap is no longer a suspended structure,
The vibration of the lower end is regulated by the ladder plate. Therefore,
The vibration in the front-back direction of the bearing cap is suppressed by the ladder plate. In addition, since the ladder plate has its peripheral edge fastened to the bottom surface of the skirt via an oil pan bolt, the ladder plate is firmly fixed to the skirt of the cylinder block.

Further, since a gap is formed between the side surface of the bearing cap and the inner walls of both skirt portions, the ladder plate and the plurality of bearing caps are lighter than the bed plate structure by that much. Be transformed into

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

Referring to FIGS. 1 to 4, a main bearing device for an engine according to an embodiment of the present invention will be described.
First, the components and their positional relationship will be described. In the figure, skirt portions 2 are formed on both sides of a lower portion of a cylinder block 1 made of a casting, respectively. A crank recess 3 is formed between the two skirt portions 2. The concave portion 3 for the crank is a concave portion having a trapezoidal cross section which shrinks as it goes upward, and has inner walls 2A, 2A and
Cap mounting surface 4 formed on the ceiling surface between A and 2A
And become surrounded by

A recess 4A having a semicircular cross section is formed in the cap mounting surface 4 along the axial direction of the crankshaft 7, and screw portions 4 are provided on both sides of the recess 4A of the cap mounting surface 4.
B and 4B are formed. Further, a flange portion 2C is provided at a lower end of the outer wall 2B of the skirt portion 2. Screw holes 2E, 2E are formed in each flange portion 2C.

In the crank recess 3, a plurality (five in this embodiment) of bearing caps 6, 6, 6,
6, 6, 6 are arranged at predetermined intervals along the axis of the crankshaft 7. The bearing cap 6 is a bridge member formed in a quadrangular cross section, and its width dimension L1 is smaller than the width dimension L2 of the cap mounting surface 4. Mounting holes 6D, 6D are formed in the bearing cap 6 corresponding to the screw portions 4B, 4B, and a recess 6B having a semicircular cross section is formed in a cap top surface 6A of the bearing cap 6. The vertical dimension from the cap top face 6A to the cap bottom face 6C of the bearing cap 6 is equal to the height dimension from the cap mounting face 4 of the skirt portion 2 to the bottom face 2D.

A crankshaft 7 is held between the recess 4A and the recess 6B. The cap side surface 6E of the bearing cap 6 and the inner walls 2A, 2A of both skirt portions 2, 2
Are formed between them. The cap top surface 6A of the bearing cap 6 is attached to the cylinder block 1
The cap bottom surface 6 </ b> C is flush with the bottom surface 2 </ b> D of the skirt portion 2.

A ladder plate 8 is arranged below the bearing cap 6. As shown in FIG. 4, the ladder plate 8 has a plurality of window holes 8A of a size that does not interfere with a crank mechanism (not shown), and a bridge portion 8B is formed between the window holes 8A. Have been. Mounting holes 8C, 8C are formed in the peripheral edges of the bridge portions 8B and the ladder plate 8 in the width direction. A plurality of mounting holes 8 </ b> D are formed in the longitudinal edge of the ladder plate 8. The interval between the mounting holes 8D, 8D is about half of the interval between the adjacent bridge portions 8B, 8B. The ladder plate 8 contacts the bottom surface 6C of the bearing cap 6 and the bottom surfaces 2D, 2D
Has been bridged to.

Here, the ladder plate 8 is a flat material having a small thickness, and is desirably a lightweight and high-strength material (at least a material higher in strength than cast iron), such as a light alloy or a high-tensile alloy. Further, an oil pan 9 is arranged below the ladder plate 8. A flange portion 9 </ b> A is formed on an upper peripheral portion of the oil pan 9. A mounting hole 9B is formed in the flange portion 9A so as to correspond to the mounting hole 8D.

Next, the connection structure of the above-mentioned components will be described. The cap bolts 10 and 10 are ladder plates 8
Mounting holes 8C, 8C of the bearing cap 6
D, 6D, the screw portion 4 of the cap mounting surface 4
The ladder plate 8 and the bearing cap 6 are jointly fastened to the cap mounting surface 4 of the cylinder block 1 by being screwed into B and 4B.

A plurality of oil pan bolts 11 penetrate through the mounting holes 9B of the oil pan 9 and the mounting holes 8D of the ladder plate 8, respectively, and are screwed into the screw holes 2E of the skirt portion 2, so that the periphery of the ladder plate 8 is formed. The portion is fastened to the bottom surface 2D of the skirt portion 2. The ladder plate 8 and the oil pan 9 form a three-dimensional structure, and the ladder plate 8 is
It has the function of reinforcement.

Thus, the cylinder block 1 and
The bearing cap 6 and the ladder plate 8 are integrated. In the present embodiment, since the vertical dimension of the bearing cap 6 is equal to the height dimension from the cap mounting surface 4 of the skirt portion 2 to the bottom surface 2D, the bearing cap 6 is moved together with the ladder plate 8. The cap mounting surface 4 between the two skirt portions 2 can be tightened with the cap bolts 10, 10. In this state, the bearing caps 6 are connected to each other via the ladder plate 8, and the bearing cap 6 is no longer in a suspended structure, and the vibration at the lower end is regulated by the ladder plate 8. Therefore, the vibration of the bearing cap 6 in the front-rear and up-down directions (conventional FIGS. 6 and 7A,
(Corresponding to the vibrations shown in (b) and (c)) are regulated. In particular, the vibration in the front-rear direction of the bearing cap 6 is suppressed by the ladder plate 8. In addition, the ladder plate 8 is fastened to the skirt portion 2 of the cylinder block 1 because the peripheral edge of the ladder plate 8 is fastened to the bottom surface 2D of the skirt portion 2 via a plurality of oil pan bolts 11. Fixed to

According to the above configuration, the bearing caps 6 are tightened to the cap mounting surface 4 between the two skirt portions 2 via the ladder plate 8, thereby integrating the bearing caps 6 to increase the rigidity of the entire engine. Can be higher. Moreover, since the ladder plate 8 is fastened to the bottom surface 2D of the skirt portion 2 with a plurality of oil pan bolts 11, each bearing cap 6 is firmly fixed to the skirt portion 2 of the cylinder block via the ladder plate 8, The rigidity can be increased similarly to the bed plate structure.

As a result, the vibration in the front-rear direction of each bearing cap 6 can be reduced, and the vibration and noise of the cylinder block 1 can be reduced. Further, as described above, even with a strong structure similar to the bed plate structure, the gaps 5 are formed between the cap side surfaces 6E and the inner wall 2A of the skirt portion 2 between the two skirt portions 2. Therefore, the weight can be reduced by that much as compared with the bed plate structure.

Further, since the explosive power of the engine is transmitted to the bearing cap 6 and the main bearing device of the engine according to the present embodiment is not directly transmitted to the ladder plate 8, the conventional bed plate structure 202 Has a different structure, requires less strength than the conventional bed plate structure 202, and can therefore reduce the weight.

Therefore, even if the conventional independent bearing cap 6 structure is employed, the same high rigidity of the whole engine as the bed plate structure can be achieved, and the vibration and noise of the cylinder block 1 can be reduced. Even with a high rigidity structure of the entire engine similar to the bed plate structure, the problem of an increase in the weight of the bed plate structure can be solved and the weight reduction can be ensured similarly to the conventional independent bearing cap 6 structure. In the present embodiment,
Although the ladder plate 8 has been described using a flat plate as an example, the present invention is not limited to this. For example, the ladder plate 8 includes a flat plate and a plate formed by forming a rib on the flat plate along the longitudinal direction. You can also.

[0028]

According to the present invention, the following effects can be obtained. By tightening the bearing cap on the cap mounting surface between the two skirt portions via the ladder plate, each bearing cap can be integrated to increase the rigidity of the entire engine. Moreover, since the ladder plate is fastened to the bottom of the skirt of the cylinder block with oil pan bolts, each bearing cap is firmly fixed to the skirt of the cylinder block via the ladder plate, similar to the bed plate structure. The rigidity of the whole engine can be increased.

As a result, the vibration in the front-rear direction of each bearing cap can be reduced, and the vibration and noise of the cylinder block can be reduced. Further, even with a strong structure similar to the bed plate structure, a gap is formed between the side surfaces of the cap and the inner wall of the skirt portion between the two skirt portions. As a result, the weight can be reduced.

Therefore, even if the conventional independent bearing cap structure is adopted, a structure having high rigidity similar to that of the bed plate structure can be realized to reduce the vibration and noise of the cylinder block, and the bed plate structure can be used. Even in the case of a similar high rigidity structure of the entire engine, it is possible to solve the problem of an increase in the weight of the bed plate structure and to secure the weight reduction as in the conventional independent bearing cap structure.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a main bearing device of an engine according to the present embodiment.

FIG. 2 is a side view of the engine.

FIG. 3 is a side view showing a state in which a plurality of bearing caps are attached to a ladder plate.

FIG. 4 is a bottom view of the ladder plate.

FIG. 5 is a sectional view showing a conventional stand-alone bearing cap structure.

FIG. 6 is a bottom view showing a mounting state of the bearing cap in FIG. 5;

FIG. 7 is a side view showing a mounting state of the bearing cap in FIG. 5;

FIG. 8 is a front view of a bed plate structure type engine.

FIG. 9 is a perspective view of a bed plate structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Skirt part 2D bottom surface 3 Crank recess 4 Cap mounting surface 5 Clearance 6 Bearing cap 6A Cap top surface 6C Cap bottom surface 6E Cap side surface 7 Crankshaft 8 Ladder plate 10 Cap bolt 11 Oil pan bolt

Claims (1)

[Claims] A skirt portion is formed on both sides of a lower portion, and a cylinder block having a cap mounting surface formed on a ceiling surface of a crank recess between both skirt portions; and a crankshaft in the crank recess. A plurality of bearing caps arranged at predetermined intervals along the axial direction, wherein a cap top surface of the bearing cap abuts the cap mounting surface and a cap side surface of the bearing cap and an inner wall of the skirt portion. In the main bearing device of the engine in which a gap is formed, a vertical dimension of the bearing cap from a cap top surface to a cap bottom surface is equal to a height dimension of the skirt portion from a cap mounting surface to a bottom surface. A ladder plate is bridged on the bottom surfaces of both skirt portions, and a peripheral portion of the ladder plate is provided on a bottom surface of the skirt portion. The ladder plate, the bearing cap, and the cylinder block are integrated by tightening the ladder plate to the cap mounting surface of the cylinder block through the bearing cap and tightening the ladder plate with the cap bolt. A main bearing device for an engine, comprising: