JPH02176211A - Crankshaft support device for multi-cylinder internal combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION A9 Object of the Invention (1) Field of Industrial Application The present invention relates to a crankshaft support device for an in-line or V-type child cylinder internal combustion engine.

(2) Conventional technology In a multi-cylinder internal combustion engine, the crankshaft is rotatably supported between a plurality of journal walls formed integrally with the crankcase of the cylinder block and a bearing cap connected thereto by connecting bolts. However, a structure in which a plurality of bearing caps are integrally molded via a bridge portion to reinforce each other is conventionally known (see, for example, Japanese Utility Model Application No. 58-165241).

(3) Problems to be Solved by the Invention In the conventionally known device described above, the bearing cap assembly consisting of a plurality of bearing caps and a bridge portion that integrates them is large as a whole, and is also made of iron alloy. Since the overall weight is large, it is difficult to handle during assembly, inspection and maintenance, etc. Also, even if only the bearing surface of a part of the bearing cap is worn or damaged, the entire bearing cap assembly must be replaced. However, there were problems such as increased costs. In addition, it is necessary to reduce the weight of the bearing cap assembly (if it is made of light alloy, there will be problems with the rigidity and strength of each bearing cap, and there will be other problems such as the inability to stably support the crankshaft). occurs.

The present invention has been proposed in view of the above, and it is an object of the present invention to provide a crankshaft support device for a multi-cylinder internal combustion engine that can solve the above-mentioned problems of the conventional devices.

B0 Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, according to the present invention, a plurality of journal walls are formed integrally with the crankcase of the cylinder block at intervals from each other. In a crankshaft support device for a multi-cylinder internal combustion engine, the crankshaft is rotatably supported between a plurality of bearing caps and a plurality of bearing caps each removably fixed to the journal wall. In order to connect these bearing caps to each other, a bridge member extending in the axial direction of the crankshaft is integrally joined, and the bridge member is made of a light alloy, and each of the bearing caps is made of an iron alloy. Features.

(2) Effects In particular, by making the bridge member a light alloy, the weight of the bearing cap assembly can be reduced accordingly, and by making each bearing cap a steel alloy, the required strength and rigidity of the caps can be ensured. Can be done.

Moreover, the bearing cap assembly is easy to handle because it can be handled separately into relatively small bearing caps and bridge members during assembly, inspection and maintenance, etc. If only the bearing surface is worn or damaged, it is sufficient to replace only that part of the bearing cap.

Furthermore, the bearing cap, which has a bearing surface for the crankshaft and tends to become hot during engine operation, is made of iron alloy, and the bridge member, which is spaced apart from the bearing surface and has a relatively low temperature, is made of a light alloy with a relatively high coefficient of thermal expansion. By configuring each of them, it is possible to minimize the relative displacement between the joint surfaces of each bearing cap and the bridge member due to thermal deformation.

(3) Embodiments Hereinafter, embodiments in which the present invention is applied to a V-type 6-cylinder internal combustion engine will be described with reference to the drawings.

The cylinder block B of the internal combustion engine comprises two cylinders I11 12 and their cylinders 1. ．． It is composed of a crankcase 2 which integrally connects 12 collective lower parts.

The cylinders 11.12 each have an inclined cylinder axis, -L, , L2-L2, and three cylinder bores 31..., 3. ... are arranged in series, and the cylinder 11
．． A water jacket 41.4 is formed on the wall 12 so as to surround the cylinder pore 31.32.

A pair of left and right skirt walls 552 facing each other along the direction of the crankshaft Sc are integrally vertically provided on the crankcase 2, and these skirt walls 5, . At the lower end of 52 are mounting flanges 6, . 62 are integrally formed, these mounting flanges 61, 62 are integrally formed, and the oil pan Po is fixed to these mounting flanges 6□62.

Furthermore, four journal walls 7 are integrally formed in the crankcase 2 at intervals in the direction of the crankshaft Sc. Each journal wall 7 is connected to the left and right skirt walls 5. ，
52, and the crankshaft S is located in the center of its lower surface.
A semicircular bearing half R8 for supporting c is formed.

A recess 10 for fitting a bearing cap 11, which will be described later, is formed on the lower surface of each journal wall 7, and first female fitting surfaces 12.
12 is formed, and a second fitting female surface 13.degree. 13 is formed at a spaced interval on the lower inner surface thereof. The first female fitting surface 1212 is formed with a step on the inner side of the second female fitting surface 13.13, that is, closer to the crankshaft Sc.

The recess 10 formed below the journal wall 7
A bearing cap 11 made of an iron alloy is fitted into the bearing cap 11 .

This bearing cap 11 has a flat upper surface that joins the lower surface of the journal wall 7, and another bearing half 9 corresponding to the bearing half 8 is formed in the center of this upper surface. Furthermore, first male fitting surfaces 14.14 that fit into the first female fitting surfaces 12.12 are formed at the upper portions of both side surfaces of the bearing cap 11 along the direction of the crankshaft Sc. The first female and male surfaces 12 and 14 fit together to form a first fitting portion E1, as will be described later.

Furthermore, the second fitting female surface ta,
A second mating male surface 15.15 is formed which mates with the ia.

The second fitting female and male surfaces 13.15 fit into each other to form a second fitting part E3, as will be described later.

The fitting distance between the first female fitting surface 12 and the first male fitting surface 14 is set small, so that the first fitting part E is a tight fit, and the second fitting part E is a tight fit. The fitting distance between the female surface 13 and the second male fitting surface 15 is set to be large, and the second fitting portion E2 is loosely fitted. The lower surface of the bearing cap 11 is also formed flat.

Right skirt wall5. , 52.

The bearing cap 11 is received in the recess 10, and its first mating male surface 14.14 is connected to the first mating female surface 12.1.
2, and its second mating male surface 15.15 is
It is loosely fitted into the second fitting female surfaces 13, 13. Such a two-step tight and loose fitting allows the bearing cap 11 to fit into the journal wall 7 to increase mutual rigidity, and also makes it easy to fit the bearing cap 11 into the journal wall 7.

The bearing cap 11 is constructed by inserting a pair of short ports 16.16 into the left and right sides of the cap 11 from below, and screwing the short ports 16.16 onto the journal wall 7 to secure the bearing. The cap 11 is fixed to the journal wall 7.

A bridge member 17 made of a light alloy such as an aluminum alloy is positioned and fixed on the lower surface of the plurality of bearing caps 11, spanning the bearing caps 11.

That is, the bridge member 17 includes a main portion 171 extending in the direction of the crankshaft Sc, and a plurality of leg portions 172 erected integrally from the main portion 17 in correspondence with the plurality of bearing caps 11 . It consists of The upper surfaces of the plurality of leg portions 17□... are joined to the flat lower surface of the bearing cap 11. In this case, a positioning pin 18 that also serves as an oil passage is fitted between the bearing cap 11 and the left and right center portions of the journal wall 7, and their relative positioning is performed.

A pair of long bolts 19 are screwed into the journal wall 7 from the lower surface of the bridge member 17 through the bridge member 17 and the bearing cap 11 on the inner side of the pair of short poles 16.16, thereby connecting the bridge member 17 and the bearing cap 11. The bearing cap 11 is collinear with the journal wall 7.

Therefore, the pair of short poles) 16.16 and the pair of long poles)
Reference numerals 19 and 19 constitute main coupling poles Bm and Bm for fixing the bearing cap 11 to the journal wall 7.

A pair of auxiliary connecting poles) 20.20 are connected to the left and right skirt walls 5. ．． 5. from the outside of the skirt wall 51.5. and the second fitting portion E2. Bearing cap 11 passes through E2
is screwed onto the left and right sides of the

Main portion 17 of said bridge member 17. , a main gear rally 21 is formed in the longitudinal direction thereof, and a plurality of leg portions 1
7. . . . branch oil passages 22 branched from the main gear rally 21 extend upward, and each branch oil passage 2
2 is communicated with an oil supply passage 23 bored in the bearing cap 11 through an oil passage in the positioning pin 18, and this oil supply passage 2
3 is open to the bearing surface of the bearing half 9.

Bearing half R formed on journal wall 7 and bearing cap 11
A plurality of bearing holes 24 are formed by 8 and 9, and a journal shaft portion of the crankshaft SC is rotatably supported in these bearing holes 24 via a bearing metal 25.

Next, the operation of the embodiment of the present invention will be explained.

When the internal combustion engine using the cylinder block B is operated, the explosion pressure acting on the pistons in the cylinder bores 31 and 32 is caused by the inclined cylinder axes of the left and right cylinders 1°1, -L, L2L2. along the crankshaft Sc, and the crankshaft Sc has a vertical direction (Y-Y
Although bending force, torsional force, etc. act in the linear direction) and in the lateral direction (X-X direction in FIG. 1), the plurality of bearing caps 11
It itself is composed of a relatively high-rigidity, high-strength iron alloy, and each main connection pole consists of a pair of long and short bolts (19°16), Bm, and a pair of auxiliary connection poles)20
．． The bearing caps 11 are firmly fixed to the journal wall 7 by the bearing caps 20, and in addition, they are integrally connected via the bridge member 17, and the bearing caps 11 mutually reinforce each other. It becomes extremely large and can significantly increase the supporting force of the crankshaft Sc, and even if external forces such as bending and torsion forces that act on the crankshaft SC become large as the engine output increases, it can sufficiently resist the external forces. be able to.

Further, the bearing cap 11 is placed in the recess 10 of the journal wall 7.
The tight fitting of the first fitting part E1 and the loose fitting of the second fitting part E2 result in two-stage fitting, which increases the assembly strength between the journal wall 7 and the bearing cap 11. Make assembly easier.

Furthermore, during inspection and maintenance, etc., the bearing cap assembly should be removed from each of the relatively small bearing caps 11 and bridge member 1.
7 can be handled separately, making it easy to handle and maintenance such as cleaning of the main gear rally 21 etc. is easy. In such a case, only some of the bearing caps 11 need to be replaced, and it is not necessary to replace all the bearing caps 11 in their entirety, which can contribute to cost reduction.

Furthermore, the bearing cap 11, which has a bearing half 9 for the crankshaft SC and tends to become hot during engine operation, is made of iron alloy, and the bridge member 17, which is spaced apart from the bearing half 9 and is relatively low temperature, is heated to a relatively low temperature. Since each bearing cap 11 and bridge member 17 are made of a light alloy with a high coefficient of expansion, the relative displacement between the joint surfaces of each bearing cap 11 and bridge member 17 due to thermal deformation can be minimized. Even though they are made of different materials with different coefficients of thermal expansion, the generation of thermal stress at the joint between the two can be reduced as much as possible.

In the above embodiments, the present invention was applied to a V-type child cylinder internal combustion engine, but it goes without saying that the present invention can also be applied to an in-line multi-cylinder internal combustion engine.

C0 Effects of the Invention As is clear from the above embodiments, according to the present invention, a plurality of journal walls are formed integrally with the crankcase of the cylinder block at intervals from each other, and each of the journal walls is removable. In a crankshaft support device for a multi-cylinder internal combustion engine, in which a crankshaft is rotatably supported between a plurality of bearing caps fixed to a In order to achieve this, the bridge member extending in the axial direction of the crankshaft is integrally joined, and the bridge member is made of light alloy.
Furthermore, since each of the bearing caps is made of iron alloy, the iron alloy bearing cap ensures the required rigidity and strength of the cap, while the light alloy bridge member reduces the overall weight of the bearing cap assembly. Therefore, it is possible to reduce the weight of the engine without significantly reducing the support rigidity and strength for the crankshaft. Furthermore, during assembly, inspection and maintenance, etc., the bearing cap assembly can be handled separately into the relatively small parts of the bearing cap and bridge member, which improves handling. If only the bearing surface is worn or damaged, only that part of the bearing cap needs to be replaced, which can contribute to cost reduction. Furthermore, the bearing cap, which has a bearing surface for the crankshaft and tends to become hot during engine operation, is made of iron alloy, and the bridge member, which is spaced apart from the bearing surface and has a relatively low temperature, is made of a light alloy with a relatively high coefficient of thermal expansion. By configuring each of them, it is possible to minimize the relative displacement between the joint surfaces of each bearing cap and the bridge member due to thermal deformation.
Therefore, even though each bearing cap and the bridge member are made of different materials having different coefficients of thermal expansion, it is possible to suppress the occurrence of thermal stress at the joint between the two as much as possible.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal sectional view thereof, FIG. 2 is a sectional view taken along the line ■-■ in FIG.
It is a sectional view taken along the line shown in FIG.

Claims (1)

[Claims] A plurality of journal walls (
7) and a plurality of bearing caps (11) each removably fixed to the journal wall (7), the crankshaft (Sc) is rotatably supported for a multi-cylinder internal combustion engine. In the device, the lower surface of the plurality of bearing caps (11) includes the bearing caps (11).
In order to connect them, a bridge member (17) extending in the axial direction of the crankshaft (11) is integrally joined, and the bridge member (17) is made of light alloy, and each of the bearing caps (11) is made of iron. A crankshaft support device for a multi-cylinder internal combustion engine, characterized in that each is constructed from an alloy.