JPH08121459A - Bearing structure for diesel engine - Google Patents

Abstract

PURPOSE: To secure the reliability of a bearing metal by providing a lube oil passage groove along a reverse surface of an upper side bearing metal in a cylinder block partition, and preparatively providing an oil groove and an oil path hole drilled inside a lower side bearing metal, so as to reduce vibration and produced noise. CONSTITUTION: By providing an oil groove 22a and an oil path hole 22 in a lower side bearing metal 4 supported by a metal cap 2, in the case that setting the lower side bearing metal 4 and upper side bearing metal 5 is rotated with a crankshaft 1 by any shock of an engine, lube oil from a lube oil path 20 of a cylinder block can be supplied to a crankshaft oil hole 21 of the crankshaft 1 and a tilt lube oil path through the oil groove 22a and the oil path hole 22. Shielding the lube oil path between the cylinder block and the crankshaft 1 by the lower side bearing metal 4 is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder block of an internal combustion engine, a bearing portion of a crankshaft and a camshaft.

[0002]

2. Description of the Related Art In a conventional engine, in the main bearing portion of a crankshaft, when the main bearing metal rotates together with the crankshaft due to some cause of the engine, the oil to the main bearing metal is blocked and the main bearing metal is blocked. The crank pin metal or piston located downstream of the lubrication oil passage was seized. Further, in the conventional arrangement of the balance weight of the crankshaft, there is a large difference between the bearings regarding the oil film thickness of the bearing metal of the crankshaft. Further, in the conventional engine, in the case of the main bearing metal or the half-bearing metal of the cam bearing, since it was constructed symmetrically as shown in Japanese Patent Publication No. 52-7484, if it is installed in reverse when assembled. The bearing could not maintain the perfect circle, and seizure occurred. Further, in the bearing portion of the cam shaft, there is a separate main oiling pipe, and the bearing of the cam shaft is lubricated. Further, in the conventional engine, the anti-vibration rubber that supports the cylinder block is not directly attached to the installation leg of the cylinder block, but is attached via the engine base as shown in Japanese Utility Model Publication No. 6-39083.

[0003]

DISCLOSURE OF THE INVENTION The present invention makes it possible to reduce the vibration and noise generated in an internal combustion engine and to ensure the reliability of the bearing metal for a long time.

[0004]

The problem to be solved by the present invention is as described above. Next, the means for solving the problem will be described. A metal cap 2 in which a lower bearing metal 4 is fitted on the lower surface of the bearing portion of the cylinder block partition wall 3.
Is suspended by a suspending bolt 18 and fitted into the lower surface of the cylinder block partition wall 3 to form a semi-arcuate upper bearing metal 5
And the lower bearing metal 4 having a semi-circular shape fitted on the upper surface of the metal cap 2 supports the crankshaft 1 as a bearing, and from the lubricating oil passage 20 in the cylinder block partition wall 3 to the oil passage hole 25 of the bearing metal 5. As a result, the lubricating oil is supplied to the crankshaft oil hole 21 in the crankshaft 1 via the oil groove 24 inside the upper bearing metal 5, and the crankshaft oil hole 21 is supplied with the lubricating oil through the inclined lubricating oil passage 19. A lubricating oil passage groove 23 is provided along the rear surface of the upper bearing metal 5 of the cylinder block partition wall 3, and a preliminary oil groove is provided inside the lower bearing metal 4. 22a and the oil passage hole 22 are bored.

In the crankshaft 1 in which one throw weight is provided for each throw, the balance weight is arranged on the crank arm on the center O side of each throw and the balance is provided on the crank arm having the thrust bearing surface on the flywheel side. The weight attachment was stopped and the height of the lower part of the crank arm was increased by the distance a.

In the bearing structure of a diesel engine, suspension bolts 18 for fixing the metal cap 2 to the cylinder block partition wall 3 are arranged at a distance asymmetric with respect to the axial center of the crankshaft 1, and the metal cap and the cylinder block are arranged. A rib that also serves as the boss of the metal cap side bolt was provided for each partition wall, and a vibration-proof rubber was attached to the installation leg of the cylinder block having a structure in which the metal cap and the rib were fastened with the metal cap side bolt.

In the bearing structure of the diesel engine, an oil passage is provided in the cylinder block B on the cam bearing side that supports the cam shaft 9.

[0008]

Next, the operation will be described. According to claim 1, since the lower bearing metal 4 supported by the metal cap 2 is provided with the oil groove 22a and the oil passage hole 22, the lower bearing metal 4 and the upper bearing metal 5 are set. , When the engine rotates with the crankshaft 1 due to some impact of the engine, the lubricating oil from the lubricating oil passage 20 of the cylinder block B is transferred to the crankshaft oil hole 2 of the crankshaft 1.
1 or the inclined lubricating oil passage 19 can be supplied through the oil groove 22a and the oil passage hole 22, and the lower bearing metal 4 shields the lubricating oil passage between the cylinder block B and the crankshaft 1. There is nothing to do.

According to the second aspect of the present invention, in the crankshaft 1, a balance weight is attached to the crank arm on the side of the engine center O of each of the throws, so that the variation in the oil film thickness of the main bearing metal between the bearings is caused. By making it smaller, the minimum oil film thickness of each bearing could be averaged. In addition, with the above balance weight arrangement, it is not necessary to attach a balance weight to the outermost crank arm 15, and the portion in contact with the thrust bearing 17 can be lengthened by the distance a. It was possible to obtain a sufficient contact area during.

According to the third aspect, the suspension bolt 1 for attaching the metal cap 2 to the cylinder block partition wall 3 is used.
Since the left and right distances are different from each other with respect to the rotation center of the crankshaft 1, the mounting position of the metal cap 2 with respect to the cylinder block partition wall 3 is determined in one direction, which is the reverse of the co-machined state. No longer attached to. As a result, it was possible to reduce seizure accidents of the bearing metal in the lower bearing metal 4 and the upper bearing metal 5. Also, with the metal cap 2,
The strength of the installation leg of the cylinder block B to which the anti-vibration rubber that is not placed on the engine base is directly attached by screwing the metal block side bolts 6 and 6 to the installation leg reinforcing rib 7 of the cylinder block B. Could be maintained.
Further, by directly attaching the anti-vibration rubber to the cylinder block, the engine installation height was suppressed and the vibration amplitude could be reduced.

According to the fourth aspect, as in the conventional case, the cam shaft 9
It is possible to solve the problem that the lubricating oil pressure decreases in the bearings located downstream of the piping, as in the case where oil is supplied to the bearing metal from outside the cylinder block B via piping. It was. Further, the complicated assembly process of piping could be reduced.

[0012]

EXAMPLES Next, examples will be described. FIG. 1 is an overall front sectional view of a diesel engine of the present invention, and FIG. 2 is a side view showing a cylinder block 3, a crankshaft 1, a metal cap 2, and a metal cap side bolt 6 of a bearing structure of the diesel engine of the present invention. 3, FIG. 3 is a front sectional view of the cylinder block partition wall 3, the metal cap 2, and the crankshaft 1, and FIG. 4 is a side sectional view of FIG.
Is an overhead view of the lower bearing metal 4, and FIG. 6 is the upper bearing metal 5.
FIG. 7 is an overhead view showing the arrangement of the crankshaft 1 and the balance weight, and FIG. 8 is a difference in the length a of the outermost crank arm 15 of the crankshaft 1 and the other crank arm 14 from the distance a. Side view showing the structure provided with,
FIG. 9 is a side view showing the difference in the distance a between the seat surface 15a of the crank arm and the seat surface 14a of the other crank arm.

FIG. 10 is a front sectional view showing a state in which the metal cap side bolts 6 are screwed from the installation leg reinforcing rib 7 portion of the cylinder block B to the metal cap 2, and FIG. Bearing part and cylinder block B
12 is a front sectional view showing a bearing portion of the cam shaft 9 and a lubricating oil passage, FIG. 13 is a side view showing an oil passage of a bearing portion of the cam shaft 9, and FIG. 14 is a cylinder block. B is a side view showing a portion where the supercharger mounting base E for mounting the supercharger A is mounted on B, and FIG. 15 is a side view showing a mounting portion for the intercooler mounting base D for mounting the intercooler C on the cylinder block B. FIG. 16 is a plan view of the supercharger A, supercharger mounting base E, and cylinder block B, FIG. 17 is a plan view of the intercooler C and intercooler mounting base D, and FIG. 18 is the cylinder block B.
FIG. 19 is a plan view showing a mounting support S between the intercooler mounting base D and the supercharger mounting base E, and FIG. 19 is a front view of the mounting support S.

This will be described with reference to FIGS. 1 and 2. Piston P
The crankshaft 1 and the crankshaft 1 are connected by a connecting rod F. Further, unlike the conventional structure, the engine base is arranged below the cylinder block B, and the engine base is supported by the anti-vibration rubber. Instead of interposing the engine base below the cylinder block B, An anti-vibration rubber 8 is directly provided on the lower part. In order to make the engine height as low as possible, it is necessary to avoid providing an engine stand. 10 is an oil pan.

Since the leg width of the cylinder block B is widened by the above structure, the installation leg reinforcing rib 7 is provided, and the metal cap side bolts 6, 6 are screwed between the installation leg reinforcing rib 7 and the metal cap 2. ing.

Next, referring to FIG. 3, FIG. 4, FIG. 5, and FIG.
The invention of claim 1 will be described. From the lubricating oil pump, the bearing metal on the side of the cylinder block partition wall 3 of the crankshaft 1 and the connecting rod F of the crankshaft 1
It is necessary to supply lubricating oil to both bearing metals on the side of. Therefore, the lubricating oil passage 2 inside the cylinder block B is
After 0, the lubricating oil is supplied to the back surface of the upper bearing metal 5 from above the cylinder block partition wall 3.

On the lower surface of the cylinder block partition wall 3, there is formed a metal fitting recess into which the semi-circular upper bearing metal 5 is fitted, and the upper bearing metal 5 is fitted into this metal fitting recess. The metal cap 2 is fixed to the lower side of the lower surface of the cylinder block partition wall 3 by a hanging bolt 18, and the upper surface of the metal cap 2 is also provided with a fitting recess for fitting the lower bearing metal 4. Has been done. A lubricating oil passage groove 23 is formed as a groove-shaped oil passage along the upper bearing metal 5 on the lower surface of the cylinder block partition 3 corresponding to the back surface of the upper bearing metal 5. Also, inside the upper bearing metal 5, an oil groove 2 is formed as a groove-shaped oil passage.
4 are configured. Further, the upper bearing metal 5 is provided at its central portion with an oil passage hole 25 penetrating the front and back sides as shown in FIG.

The lower bearing metal 4 is fitted into the fitting recess on the upper surface of the metal cap 2 so as to face the upper bearing metal 5. The upper bearing metal 5 and the lower bearing metal 4
Due to this, the crankshaft 1 rotates inside a perfect circle. Then, the lubricating oil pumped from the lubricating oil passage 20 collects in the lubricating oil passage groove 23 on the back surface of the upper bearing metal 5, and at the same time from the oil passage hole 25 to the oil groove 24 between the crankshaft 1 and the upper bearing metal 5. And a crankshaft oil hole 21 penetrating the crankshaft 1 is formed.

Crankshaft oil hole 2 of the crankshaft 1
1 communicates with the inclined lubricating oil passage 19 shown in FIG. 4 from the central portion, and the inclined lubricating oil passage 19 supplies lubricating oil to the inside of the metal in the bearing portion of the connecting rod F of the crankshaft 1. There is.

In the above-mentioned structure, the lower bearing metal 4 and the upper bearing metal 5 are normally always in the positions, and the lower bearing metal 4 and the upper bearing metal 5 are rotated together with the rotation of the crankshaft 1. Does not rotate around, but if a large load is applied to the lower bearing metal 4 and the upper bearing metal 5 due to some accident, the lower bearing metal 4 and the upper bearing metal 5 will rotate. Then, the lower bearing metal 4 may be on the upper side and the upper bearing metal 5 may be on the lower position. In this way, the lower bearing metal 4
When the upper bearing metal 5 rotates and the lower bearing metal 4 does not have the lubricating oil passage groove 23, the oil groove 22a, or the oil passage hole 22, the lubricating oil from the lubricating oil passage 20 is discharged. The passage is closed by the lower bearing metal 4, and a situation occurs in which the oil does not flow from the crankshaft oil hole 21 to the inclined lubricating oil passage 19.

In order to prevent such a situation, in the present invention, as shown in FIG. 5, the oil passage hole 22 and the oil groove 22 are formed on the side of the lower bearing metal 4, which is not necessary at all when there is no accident.
That is, a is bored. As a result, the lower bearing metal 4
Even when the upper bearing metal 5 is rotated and the upper and lower bearings are rotated, the minimum amount of lubricating oil is supplied to the crankshaft oil hole 21 and the inclined lubricating oil passage 19 from the oil passage hole 22 and the oil groove 22a. Has become possible.

Next, description will be given with reference to FIGS. 7, 8 and 9. In the conventional diesel engine, the arrangement of the balance weights is determined from the relationship of the dynamic balance for reducing vibration and noise, and the arrangement of the balance weights of the respective bearings in forming the lubricating oil film between the bearing metal and the crankshaft 1 is determined. It was not arranged from the viewpoint of averaging the minimum oil film thickness. That is, when attaching the balance weights at both ends throw, it is advantageous to attach the balance weights to the crank arm outside the engine, because it is easier to obtain dynamic balance, and at the ends throw, the balance weights are attached to the outside crank arm.

However, if balance weights are attached to the outside at the throws at both ends, it is disadvantageous in terms of the formation of an oil film in the metal part, the oil film thickness becomes thinner than other bearings, and it is the second in the 6-cylinder. 5
There were many accidents of seizure of the metal on the number side. In the present invention, such a defect of the prior art is improved, and in the both-end throw, the inner crank arm is
The balance weight was attached.

When the balance weight is attached to the inner crank arm at both ends of the throw, the balance weight is not attached to the crank arm (outermost part) having the thrust bearing, so that the distance a can be secured to secure the thrust bearing area. Can be freely

That is, in FIG. 7, the balance weights 26, 27 and 28 are all mounted on the mounting surface of the crank arm on the engine center O side, and the balance weight 31.
・ 30 and 29 are also located inside the center O of the engine. As described above, by attaching the balance weight to the crank arm on the engine center O side, it is disadvantageous in terms of ease of dynamic balance, but the formation of the oil film on the bearing metal can be averaged over all the bearings. At the same time,
As shown in FIGS. 8 and 9, the distance a can be freely set so as to secure the thrust bearing area.

Next, description will be made with reference to FIG. In the conventional bearing structure of a diesel engine, the suspension bolt 18 for screwing the metal cap 2 on the cylinder block partition wall 3 is
The crankshaft 1 is arranged at a position symmetrical with respect to the center of rotation. Therefore, when the metal cap 2 is attached to the cylinder block partition wall 3, it is possible to attach the metal cap 2 to the cylinder block partition wall 3 even if they are attached by mistake. When the metal cap 2 is attached to the left and right, the roundness of the bearing inner diameter cannot be secured.

In the present invention, the distances between the left and right suspension bolts 18 and the rotation center of the crankshaft 1 are made different from each other as X and Y in order to solve the above-mentioned problems of the prior art.

Next, referring to FIGS. 11, 12, and 13, the lubrication structure of the cam shaft 9 will be described. In the bearing portion of the cam shaft 9 as well, the metal cap 11 is fixed to the cylinder block B side by the screw bolts 40. The screw bolts 40 are also mounted on the left and right with respect to the axial center of the cam shaft 9. They are different. Further, conventionally, the lubrication of the bearing metal of the camshaft 9 is supplied from the lubricating oil main gallery 43 to the bearing portion of the camshaft 9 by providing piping that passes outside the cylinder block B. However, in this conventional piping system, the pressure of the lubricating oil decreases as the bearing is located downstream of the piping, and the lubricating oil may not be supplied to the cam shaft 9. Further, as shown in FIG. 12, the position dimension of the bolt for attaching the metal cap of the cam shaft is X '.
And Y'and different sizes of X'and Y'can prevent misassembly.

In the present invention, in order not to make a difference in the lubricating oil pressure between the cam bearings, between the large-diameter lubricating oil holes 47 of the cam shaft 9, the inside of the cylinder block B for each cam bearing,
The lubrication oil passage 44, the lubrication oil passage 20 and the lubrication oil passage 45 are used for supply. That is, the lubricating oil passage 44 from the lubricating oil main gallery 43 allows the above-mentioned upper bearing metal 5
The lubricating oil passage 20 to the lower bearing metal 4 is supplied to the lubricating oil passage 45, and the upwardly extending portion of the lubricating oil passage 20 is supplied to the lubricating oil passage 45 provided in the cylinder block partition wall 46 of the camshaft 9. However, the cylinder block partition wall 3 and the cam shaft 9
Since the position is slightly shifted back and forth between the cylinder block partition wall 46 and the cylinder block partition wall 46, the large-diameter lubricating oil hole 47 has a large diameter, and the displaced lubricating oil passage 45 is disposed therein. The same lubricating oil passage 20 could be used both as an oil passage for lubricating the camshaft 9 and as an oil passage for lubricating the upper bearing metal 5.

Next, referring to FIGS. 14 to 19, for the cylinder block B, the supercharger A and the intercooler C are provided.
The configuration of the part to which the is attached will be described. The supercharger mounting base E for mounting the supercharger A and the intercooler mounting base D for mounting the intercooler C also serve as lifting metal fittings when lifting the diesel engine upward. Therefore, if the fastening between the cylinder block B and the supercharger mount E and the intercooler mount D is not sufficient, a dangerous state will occur during lifting.

Conventionally, in order to mount the supercharger mounting base E and the intercooler mounting base D on the cylinder block B,
There was a problem that a large bolt diameter was required and the bolt hole diameter was also large, the intercooler mount D and the turbocharger mount E could not be positioned during assembly, and the attached duct piping could not be mounted during reassembly. .

In the present invention, the mounting support S constructed as shown in FIGS. 18 and 19 is first fixed to the upper surface of the cylinder block B, and the intercooler mounting base D and the supercharger mounting are attached to the mounting support S. The part of the hanging metal fitting of the stand E was fixed. For the mounting support S, bolts are inserted from above to fix the bolt holes 38 to the upper surface of the cylinder block B, and the mounting support S.
A horizontal bolt hole 37 for fixing the supercharger mounting base E and the intercooler mounting base D is screwed. Also,
A knock pin hole 3 for determining the position between the supercharger mounting base E, the intercooler mounting base D, and the mounting support S.
9.39 is drilled horizontally.

By mounting the mounting support S on the cylinder block B and fixing the supercharger mounting base E and the intercooler mounting base D to the mounting support S in this manner,
It was possible to minimize the deviation of the attachment between the two and to strengthen the strength of the hanging metal fitting.

[0034]

Since the present invention is constructed as described above, it has the following effects. As described in claim 1, the oil groove 2 is formed in the lower bearing metal 4 supported by the metal cap 2.
By providing 2a and the oil passage hole 22, when the lower bearing metal 4 and the upper bearing metal 5 are set together with the crankshaft 1 due to some impact of the engine, the cylinder block B The lubricating oil from the lubricating oil passage 20 is fed to the crankshaft oil hole 21 of the crankshaft 1.
And the inclined lubricating oil passage 19 can be supplied via the oil groove 22a and the oil passage hole 22, and the lubricating oil passage between the cylinder block B and the crankshaft 1 is shielded by the lower bearing metal 4. It's gone.

According to the second aspect of the present invention, in the crankshaft 1, by providing a balance weight to the crank arm on the engine center O side, it becomes difficult to keep the dynamic balance a little, but the oil film on the inner surface of the bearing metal is different from each other. It was possible to average the bearings, and it was possible to improve the reliability against the seizure of the metal part. Further, since the outermost crank arm 15 is arranged so that no balance weight is attached, the portion in contact with the thrust bearing 17 can be lengthened by the distance a.
It was possible to obtain a sufficient contact area between and.

According to the third aspect of the invention, the hanging bolt 18 for attaching the metal cap 2 to the cylinder block partition wall 3 is used.
Since the left and right distances are made different from the rotation center of the crankshaft 1, the mounting position of the metal cap 2 to the cylinder block partition wall 3 is determined in one direction, which is contrary to the case of co-machining. It was possible to prevent seizure of the bearing due to a mistake in the assembly of the bearing, since it was not necessary to install it, and the roundness of the bearing was not rounded. Further, the metal cap 2 and the installation leg reinforcing rib 7 of the cylinder block B are screwed and fastened by the metal cap side bolts 6 to directly attach the vibration isolating rubber not mounted on the engine base. The strength of the installation leg of the cylinder block B could be maintained. Moreover, by directly attaching the vibration-proof rubber to the cylinder block, the engine installation height was kept low, and the vibration amplitude could be reduced.

Since the bearing metal of the camshaft 9 is lubricated from the outside of the cylinder block B via piping as in the conventional case, the bearing metal of the camshaft 9 is positioned downstream of the piping. It was possible to eliminate the problem that the pressure of the lubricating oil decreased as the bearing became wider. Moreover, the complicated assembly process of piping could be reduced.

[Brief description of drawings]

FIG. 1 is an overall front sectional view of a diesel engine of the present invention.

FIG. 2 is a side view showing a cylinder block 3, a crankshaft 1, a metal cap 2, and a metal cap side bolt 6 of the bearing structure of the diesel engine of the present invention.

FIG. 3 is a front sectional view of a cylinder block partition wall 3, a metal cap 2, and a crankshaft 1.

4 is a side sectional view of FIG.

FIG. 5 is an overhead view of the lower bearing metal 4.

FIG. 6 is an overhead view of the upper bearing metal 5.

FIG. 7 is an overhead view showing the arrangement of the crankshaft 1 and the balance weight.

FIG. 8 is a distance a in the dimension length between the outermost crank arm 15 of the crankshaft 1 and another crank arm 14.
The side view which shows the structure which provided the difference.

FIG. 9 is a side view showing a difference in distance a between a seat surface 15a of a crank arm and a seat surface 14a of another crank arm.

FIG. 10 is a front cross-sectional view showing a state in which metal cap side bolts 6, 6 are screwed from the installation leg reinforcing rib 7 portion of the cylinder block B to the metal cap 2.

11 is a front cross-sectional view showing the relationship between the bearing portion of the cam shaft 9 and the cylinder block B. FIG.

FIG. 12 is a front sectional view showing a bearing portion of the camshaft 9 and a lubricating oil passage.

FIG. 13 is a side view showing an oil passage of a bearing portion of a cam shaft 9.

FIG. 14 is a side view showing a portion where a supercharger mounting base E for mounting the supercharger A is attached to the cylinder block B.

FIG. 15 is a side view showing a mounting portion of an intercooler mount D for mounting an intercooler C on a cylinder block B.

FIG. 16 is a plan view of a supercharger A, a supercharger mount E, and a cylinder block B.

FIG. 17 is a plan view of an intercooler C and an intercooler mount D.

FIG. 18 is a drawing showing a mounting support S between a cylinder block B and an intercooler mounting base D or a supercharger mounting base E.

FIG. 19 is a front view of the mounting support S.

[Explanation of symbols]

 A Supercharger B Cylinder block C Intercooler D Intercooler mounting base E Supercharger mounting base F Connecting rod 1 Crankshaft 2 Metal cap 3 Cylinder block partition wall 4 Lower bearing metal 5 Upper bearing metal 6 Metal cap side bolt 7 Installation leg reinforcement Rib 8 Anti-vibration rubber 9 Cam shaft 14, 15 Crank arm

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuki Maetani 1-32, Chaya-cho, Kita-ku, Osaka-shi, Osaka Yanmar Diesel Co., Ltd. No. Yanmar Diesel Co., Ltd.

Claims (4)

[Claims] 1. A cylinder block partition wall 3 is obtained by suspending a metal cap 2 having a lower bearing metal 4 fitted on a lower surface of a bearing portion of the cylinder block partition wall 3 with a suspension bolt 18.
The upper bearing metal 5 having a semi-arcuate shape fitted on the lower surface of the upper side and the lower bearing metal 4 having a semi-arcuate shape fitted on the upper surface of the metal cap 2 support the crankshaft 1 as a bearing, and From the lubricating oil passage 20 to the bearing metal 5
Oil groove 24 inside the upper bearing metal 5 from the oil passage hole 25 of
Through the crankshaft oil hole 21 in the crankshaft 1.
Is supplied to the crank pin bearing of the crankshaft 1 from the crankshaft oil hole 21 via the inclined lubricating oil passage 19, and is arranged along the back surface of the upper bearing metal 5 of the cylinder block partition wall 3. To form a lubricating oil passage groove 23, and to further preliminarily provide the oil groove 22 inside the lower bearing metal 4.
A bearing structure for a diesel engine, wherein a and an oil passage hole 22 are provided. 2. In a crankshaft 1 having one balance weight for each throw, the balance weights are arranged on the crank arm on the center O side of the engine for each throw, and on the crank arm having a thrust bearing on the flywheel side. A crankshaft for a diesel engine, characterized in that the balance weight is not attached and the lower height of the crank arm is increased by a distance a. 3. The bearing structure for a diesel engine according to claim 1, wherein the hanging bolts 18 for fixing the metal cap 2 to the cylinder block partition wall 3 are arranged at a distance asymmetric with respect to the axis of the crankshaft 1. A rib that also serves as the boss of the metal cap side bolt is provided for each partition wall of the metal cap and the cylinder block, and the metal cap and the rib are fastened with the metal cap side bolt to prevent the installation leg of the cylinder block from being damaged. Bearing structure for diesel engines, which is equipped with vibrating rubber. 4. A bearing structure for a diesel engine according to claim 1, wherein an oil passage is provided in a cylinder block B on a cam bearing side for bearing the camshaft 9.