JPH0533724A - Crank shaft support structure of internal combustion engine - Google Patents

Abstract

PURPOSE:To provide a crank shaft support structure of internal combustion engine capable of optimumly suppressing the vibration in conformity with the curvi-linear deformation and the twist deformation of the crank shaft, enhanced in NVH of the power plant, and enabling simultaneous achievement of the vibration noise reduction and weight reduction of the engine. CONSTITUTION:At the rear portion of a cylinder block 1 where a flywheel 9 is mounted with respect to the center of the air-cylinder arrangement of the cylinder block 1, a bearing beam 12 is provided which has connected thereto with the bearing caps 5d, 5e of bulk heads 4d, 4e clamping a fourth air cylinder #4. At the frontward portion of the cylinder block 1, the bearing caps 5a, 5b of the bulk heads 4a, 4b clamping a first air cylinder #1 and a block skirt portion 2 located on both sides thereof are connected with use of side bolts 11. The bearing caps 5d, 5e connected with the bearing beam 12 and the bearing caps 5a, 5b connected to the block skirt portion 2 are not connected with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a crankshaft support structure for an internal combustion engine using a first bearing cap group connected to a block side wall and a second bearing cap group connected to each other.

[0002]

2. Description of the Related Art As one of the causes of vibration noise of an internal combustion engine for automobiles, there is bending deformation and torsional deformation during rotation of a crankshaft, which greatly contributes to vibration of various parts of a cylinder block. The source of this vibration is the combustion stimulating force, and since the flywheel, the crank pulley, and the like are attached to both ends of the crankshaft, the bending deformation and torsional deformation of the crankshaft itself are further excited. Regarding the actual behavior of the crankshaft, on the rear side of the crankshaft to which the flywheel is attached, the crankshaft is mainly bent and deformed due to the large flywheel mass, and the main bearing cap falls and vibrates in the front-rear direction of the engine. On the other hand, on the front side of the crankshaft to which the crank pulley and the like are attached, the torsional vibration of the crankshaft is mainly amplified by the torque fluctuation of the accessory transmitted by the belt or chain for driving the accessory that is wound around the crank pulley and the like. , The main bearing cap vibrates in the left and right and up and down directions of the engine.

Therefore, in order to suppress the bending deformation and the torsional deformation of the crankshaft, a plurality of bearing caps are integrally connected to each other by a bearing beam, and the bearing cap or the bearing beam and the block skirt are connected by bolts. Things have been proposed. (Jpn. Pat. Appln. KOKAI No. 59-88241)
Further, in order to achieve both high rigidity and light weight of the crankshaft support structure, it has been proposed to provide a bearing beam to at least the cylinders at both ends. (JP-A-60-1360)

[0004]

However, in the former structure, all the bearing caps are connected to each other by the bearing beams and are connected to the block skirts by the bolts.
The bearing beam does not have the effect of suppressing the torsional deformation that mainly occurs on the front side of the crankshaft, and the coupling with the block skirt does not have the effect of suppressing the bending deformation that mainly occurs on the rear side of the crankshaft. The weight is extremely large compared to the suppression effect, which causes a problem of deterioration of fuel efficiency. Further, since all the bearing caps are connected, the torsional deformation and the bending deformation generated on the front and rear sides of the crankshaft are transmitted to each other, and the vibration of the connecting portion by the bearing beam and the connecting portion to the block skirt portion is suppressed. This causes a problem that the actions interfere with each other and the vibration cannot be suppressed sufficiently.

Further, according to the latter structure, although the purpose is to achieve both high rigidity and light weight of the crankshaft support structure, the torsional deformation mainly generated on the front side of the crankshaft on which the crank pulley and the like are mounted is caused by the bearing beam. It is unnecessary because it can not be suppressed so much, not only the weight increases, but also
On the contrary, there arises a problem that the bearing beam acts as a resonance system to increase vibration.

Particularly, when the cylinder block is a cone block in order to improve the NVH of the power plant including the engine and the transmission, it is difficult to connect the bearing cap or the bearing beam to the block skirt on the rear side of the crankshaft to which the flywheel is attached. Not only that, but as described above, the effect of suppressing the bending deformation of the crankshaft, which is mainly caused by the connection with the block skirt portion, cannot be obtained so much, and conversely, the tilting vibration of the bearing cap due to the bending deformation in the front-rear direction can be prevented. The vibration is transmitted to the block skirt portion and further increases the vibration of the block skirt portion.

In view of the above circumstances, the present invention suppresses vibrations optimally in response to bending deformation and torsional deformation of the crankshaft, improves NVH of the power plant, and reduces vibration noise and weight of the engine. A crankshaft support structure for an internal combustion engine is provided.

[0008]

Therefore, according to the invention of claim 1, an internal combustion engine in which a crankshaft is supported by a plurality of bearing caps paired with bearing portions arranged so as to sandwich each cylinder in the lower portion of the cylinder block. In the crankshaft support structure, the bearing cap and block side wall portions extending on both sides of the bearing cap are coupled to each other, and the first bearing cap group independent from each other without coupling between adjacent bearing caps, A coupling member that couples the bearing caps to each other is provided, and the bearing cap and the block side wall portion have a second bearing cap group that is free without being coupled, and the first bearing cap group is an anti-flywheel. Side, and the second bearing cap group above And arranged separately on the side where the wheel is attached constitutes a crankshaft support structure for an internal combustion engine.

According to a second aspect of the invention, in addition to the configuration of the first aspect of the invention, the plurality of bearing caps are provided between the bearing cap groups and between the adjacent bearing caps provided between the bearing cap groups. A crankshaft support structure for an internal combustion engine, which is independent of each other and is composed of a third bearing cap group in which a bearing cap and a block side wall portion are separated without being coupled to each other. According to a third aspect of the invention, in addition to the configurations of the first and second aspects of the invention, a block side wall portion on the rear side of the cylinder block corresponding to both sides of the second bearing cap group connected by the connecting member forms a transmission case. The crankshaft support structure of the internal combustion engine is formed by being enlarged in a substantially conical shape toward the joint surface.

[0010]

According to the first aspect of the present invention, the bearing cap and the block side wall portions extending on both sides of the bearing cap are coupled to each other, and the adjacent bearing caps are independent from each other without being coupled to each other. The first bearing cap group and the second bearing cap group provided with a connecting member for connecting the bearing caps to each other and separated without the bearing cap and the block side wall portion being coupled to each other By arranging them separately for the wheel side and the side where the flywheel is mounted, the torsional deformation of the crankshaft that mainly occurs on the front side of the crankshaft where the crank pulley etc. are mounted is located on the bearing kick and the blocks located on both sides. Connect the side wall to the left and right of the bearing cap and It is possible to suppress and reduce the downward vibration, and to suppress the bending deformation of the crankshaft, which occurs mainly on the rear side of the crankshaft where the flywheel is mounted, by suppressing the tilt vibration of the bearing cap in the front-rear direction by the connecting member. it can. Further, since the first bearing cap group and the second bearing cap group are not connected to each other, it is possible to perform appropriate vibration suppression without interfering with each other's vibration suppressing action,
Since the bearing cap is not unnecessarily supported, the weight can be reduced.

According to the structure of claim 2, in addition to the operation of claim 1, since the third bearing cap group is provided between both bearing cap groups, the bending deformation occurring at both ends of the crankshaft. And the torsional deformation is suppressed by the both bearing cap groups, the crankshaft between the both bearing cap groups is relatively unlikely to be deformed, and the third bearing cap group is connected between adjacent bearing caps. Independently, the bearing cap and the block side wall can be separated without being coupled, and unnecessary support of the bearing cap is not performed, and the weight can be further reduced.

According to the structure of claim 3, claims 1 and 2
In addition to the above action, by forming the joint portion of the cylinder block with the transmission case into a substantially conical shape, the joint rigidity between the cylinder block and the transmission can be improved and bending vibration between the engine and the transmission can be reduced. In addition, the rigidity of the side wall portion of the cylinder block itself can be improved, and in particular, the opening / closing vibration of the block side wall portion which is induced by the tilt vibration of the bearing cap supporting the rear side of the crankshaft in the front-rear direction can be suppressed.

[0013]

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

FIG. 1 shows an embodiment in which the present invention is applied to a four-cylinder engine. The cylinder block 1 has a block skirt portion 2a formed by extending the lower portions of both side walls thereof in parallel with the cylinder arrangement direction. is doing. On the transmission case 3 side of the block skirt portion 2a, a substantially cone extending from the block skirt portion 2a corresponding to a bulkhead, which will be described later, installed between both side walls of the cylinder block 1 toward the outer peripheral end portion of the transmission case 3. A block skirt portion 2b having a shape is formed, and an outer peripheral end of the transmission case 3 is connected to the block skirt portion 2b of the cylinder block 1 formed in a substantially conical shape. At the bottom of this cylinder block 1, the first cylinder #
Five bulkheads 4a, 4b, 4c, 4d, and 4e are formed from the anti-transmission side so as to partition the first cylinder # 2, the third cylinder # 3, and the fourth cylinder # 4.
Each of these bulkheads 4a, 4b, 4c, 4d, 4e
Bearing caps 5a, 5b, 5c, 5d, 5e having independent shapes so as to form a pair with the bearing portion formed in
Are fixed by bolts 6 to support the crankshaft 7. A crank pulley 8 is attached to the front end of the crankshaft 7,
A flywheel 9 is attached to the rear end. The bulkheads 4a, 4 that sandwich the first cylinder # 1 at the front end
b bearing caps 5a, 5b and block skirts 2a as block side walls located on both sides thereof,
The coaxial holes 10a to 10b are formed symmetrically, and the side bolts 11 are formed in the holes 10a of the block skirt portion 2a.
Bushings, which will be described later, in which holes for inserting the holes are formed are press-fitted, and the holes 10b of the bearing caps 5a and 5b are
Has a structure in which a screw is formed to screw the side bolt 11 diagonally upward from the left and right sides of the block skirt portion 2a, and forms a first bearing cap group. (See FIG. 2) Further, a pair of bearing caps 5d and 5e are provided on the lower surface of the bearing caps 5d and 5e of the bulkheads 4d and 4e sandwiching the rear end fourth cylinder # 4, and two parallel beam portions 12a and 12b are provided. The bearing beam 12 as a connecting member that is connected to each other is fixed by a bolt 13 to form a second bearing cap group. The central bearing cap 5c is independently fastened to the bulkhead 4c to form a third bearing cap group (see FIG. 3). Next, the coupling structure between the bearing cap and the block skirt portions located on both sides of the bearing cap will be described in detail with reference to FIG.

FIG. 4 shows a side bolt 1 including a bearing cap 5b and block skirt portions 2a located on both sides thereof.
1 shows a binding structure according to 1. Block skirt part 2
A is provided with a hole 10a penetrating obliquely upward from the block outer wall side to the block inner wall side. A bush 15 having a hole 14 into which the side bolt 11 is inserted is formed in the hole 10a at the outer peripheral portion thereof. Liquid gasket is applied and press-fitted. Further, a slit 16 is cut in the bush 15 in the axial direction between both ends, and the slit 16 allows the bush 15 to expand and contract in the radial direction when the bolt is fastened. On the other hand, bearing cap 5
A connecting portion 17 for connecting to the block skirt portion 2a is provided at b, and an end surface of the connecting portion 17 is formed with a hole 10a coaxial with the hole 10a formed in the block skirt portion 2a. A screw is formed on 10b.
Then, in a state where the block skirt portion 2a and the bearing cap 5b are fastened by the side bolts 11, the bush 15 press-fitted into the block skirt portion 2a and the end surface of the coupling portion 17 of the bearing cap 5b are in contact with each other.
According to this structure, deformation of the block skirt portion 2a and the bearing cap 5b caused by the manufacturing error of the block skirt portion or the bearing cap 5b when the block skirt portion 2a and the bearing cap 5b are fastened to each other is prevented from being deformed. The bush 1 can be absorbed by the movement in the direction of the cap 5b, and the sealability between the hole 14 formed in the bush 15 and the side bolt 11 inserted in the hole 14 can be improved.
5 is secured by abutting on the end surface of the coupling portion 17 of the bearing cap 5b. Also, the block skirt part 2
The sealing property between the hole 10a formed in a and the outer peripheral portion of the bush 15 press-fitted into the hole 10a is also blocked by the slit 16 cut in the bush 15 together with the liquid gasket applied to the outer peripheral portion of the bush 15. When the skirt portion 2a and the bearing cap 5b are fastened by the side bolts 11, radial expansion of the central portion of the outer periphery of the bush 15 is allowed, so that the surface pressure between the hole 10a and the outer periphery of the bush 15 is increased. Secured.
Further, from the bearing cap 5b to the side bolt 11
The vibration transmitted to the block skirt portion 2a via the bush 15 can be damped by the bush 15.

Therefore, according to the crankshaft support structure as described above, the bearing beam 1 is provided on the front side of the crankshaft 7 to which the flywheel 9 which is largely bent and deformed when the crankshaft 7 is rotated is mounted.
2, the rear side of the crankshaft 7 to which the crank pulley 8 having a large torsional deformation is attached is firmly supported by fastening the side bolts 11 to the block skirt portion 2, so that the optimum vibration corresponding to the deformation of the crankshaft 7 is obtained. It is possible to suppress the weight, and thereby it is possible to reduce the weight because an unnecessary supporting member is not provided. Further, the central portion of the crankshaft 7 is restrained from being deformed by the first and second bearing cap groups which are connected by the bearing beams 12 arranged at both ends thereof and fastened to the block skirt portion 2 by the side bolts 11. Since it is not necessary to support the bearing cap 5c, the weight can be further reduced and the side bolt 11
It is possible to appropriately suppress vibration without interfering with the torsional deformation suppressing effect on the front side of the crankshaft 7 and the bending deformation suppressing effect on the rear side of the crankshaft 7 by the bearing beam 12.

Further, the first portion on the front side of the crankshaft 7
Fasten the side head bolts 5a and 5b of the bulkheads 4a and 4b sandwiching the cylinder # 1 by screwing side bolts 11 diagonally upward from the block skirt portions 2a located on both sides thereof toward the lower ends of the bearing caps 5a and 5b. By doing so, the deformation of the bearing caps 5a, 5b in the left-right and up-down directions can be uniformly suppressed.

On the transmission case 3 side of the block skirt portion 2a of the cylinder block 1, the block skirt portion 2a corresponding to the bulkhead 4d installed between both side walls of the cylinder block 1 extends from the outer peripheral end portion of the transmission case 3. The cylinder block 1 has a substantially cone-shaped block skirt portion 2b extending toward the cylinder block 1 and has a cone block shape.
The joint rigidity between the transmission case 3 and the transmission case 3 can be increased, and the rigidity of the block skirt portion 2 of the cylinder block 1 itself can be increased. In particular, the bearing cap 5 supporting the rear side of the crankshaft 7 can fall in the front-rear direction. Opening / closing vibration of the block skirt portion 2 induced by vibration can be suppressed, and vibration of the engine can be reduced.

In this embodiment, the block skirt portion and the bearing cap are fastened by screwing side bolts diagonally upward from the block skirt portion, but by horizontally screwing from the block skirt portion. Good. Further, when the block skirt portion is a half skirt type cylinder block that ends on both sides of the crankshaft, the reinforcing block and the bearing cap that are fastened to the lower portion thereof may be fastened. Further, although the third bearing cap group is formed by one bearing cap in this embodiment, it may be formed by any number of bearing caps. Although the present invention is applied to a 4-cylinder engine, the present invention can be applied to any multi-cylinder engine.

[0020]

As described above, according to the first aspect of the present invention, on the front side of the crankshaft to which the crank pulley and the like are attached, the torsional deformation of the crankshaft which mainly occurs is located on both sides of the bearing cap. On the rear side of the crankshaft where the flywheel is attached, the bending deformation of the crankshaft that mainly occurs is reduced only by connecting the block side wall, and the bending deformation of the crankshaft that is mainly generated is reduced only by the connecting member to provide an unnecessary supporting member. Optimum vibration suppression according to the deformation of the crankshaft can be performed, and the first bearing cap group connected to the block side wall portion and the second bearing cap group connected by the connecting member should not be connected to each other. Thus, optimal vibration suppression can be performed without mutual interference of vibration suppression actions. As a result, both high rigidity and light weight of the crankshaft support structure can be achieved, and engine noise can be reduced and fuel efficiency can be improved.

According to the invention of claim 2, claim 1
In addition to the effect of the above, since the third bearing cap group is provided between the both bearing cap groups, the bending deformation and the torsional deformation occurring at both ends of the crankshaft are suppressed by the both bearing cap groups, and the both bearing cap groups are suppressed. The crankshaft between the cap group and the cap group is relatively unlikely to be deformed, and the third bearing cap group is independent without the adjacent bearing caps being connected to each other, and the bearing cap and the block side wall portion are coupled to each other. Therefore, the engine can be lightened without unnecessarily supporting the bearing cap.

According to the invention of claim 3, claim 1
In addition to the effects of (2) and (2), the joint surface between the cylinder block and the transmission is formed in a substantially conical shape on the rear end side of the cylinder block, so that the joint rigidity between the cylinder block and the transmission can be improved and the power plant N
In addition to being able to improve VH, it is possible to improve the rigidity of the cylinder block side wall portion itself, and particularly to suppress the opening / closing vibration of the block side wall portion that is caused by the front-back vibration of the bearing cap that supports the rear side of the crankshaft. The engine noise can be reduced.

[Brief description of drawings]

FIG. 1 is a bottom view of a cylinder block showing a crankshaft support structure of a four-cylinder engine according to an embodiment of the present invention.

2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a diagram showing a detailed coupling structure of a bearing cap and block skirt portions located on both sides of the bearing cap according to the embodiment of the present invention.

[Explanation of symbols]

1 ... Cylinder block, 2 ... Block skirt part, 3 ...
Transmission case, 4 ... Cylinder, 5 ... Bearing cap, 7 ... Crank shaft, 9 ... Flywheel, 11 ... Side bolt, 12 ... Bearing beam ,.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yasuhide Tahara             3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda             Within the corporation

Claims (3)

[Claims] 1. A crankshaft support structure for an internal combustion engine, wherein a crankshaft is supported by a plurality of bearing caps that are paired with bearings arranged so as to sandwich each cylinder at the lower part of a cylinder block. A first bearing cap group that is connected to the extended block side wall portion and is independent of the adjacent bearing caps without being connected to each other, and a connecting member that connects the bearing caps to each other is provided. The bearing cap and the block side wall portion has a second bearing cap group separated without being coupled, and the first bearing cap group on the anti-flywheel side of the cylinder block,
A crankshaft support structure for an internal combustion engine, wherein the second bearing cap group is divided and arranged on a side of the cylinder block where the flywheel is attached. 2. The bearing caps according to claim 1, wherein the plurality of bearing caps are independent of each other and the adjacent bearing caps provided between the both bearing cap groups are not connected to each other. The cap and the side wall of the block are composed of a third group of bearing caps which are separated without being joined. 3. The cylinder block rear side block side wall portions corresponding to both sides of the second bearing cap group connected by the connecting member are substantially conical toward the joint surface with the transmission case. Enlarged shape.