JPS6335830B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises a cylinder block having cylinders arranged in a V-shape, and a crankcase integrally connected to the lower part of the cylinder block.
The present invention relates to an engine block for a V-type multi-cylinder internal combustion engine.

Generally, such an engine block has two roof-shaped cylinder head joint surfaces on both sides of the upper end, and conventionally, when cutting and finishing these cylinder head joint surfaces, the lower surface of the crankcase, which is far away from the joint surfaces, was used as a reference point. Therefore, a high degree of skill was required to obtain high accuracy.

The present invention has been proposed in view of the above, and an object of the present invention is to provide the above-mentioned engine block that can be manufactured easily and with high precision.

In order to achieve the above object, the present invention provides V
It consists of a cylinder block with cylinders arranged in a shape, and a crankcase that is integrally connected to the lower part of the cylinder block, and the lower peripheral edge of the crankcase is formed on the oil pan joint surface to which the oil pan is joined. In the engine block for a V-type multi-cylinder internal combustion engine, the lower surface of the crankcase is provided with a bearing cap joint for joining a bearing cap that supports a crankshaft journal in cooperation with a semi-annular bearing formed on the lower surface of the crankcase. a surface is formed on the same plane as the oil pan joint surface, a center portion of the upper surface of the cylinder block is formed on a processing reference surface parallel to both the joint surfaces and spaced apart from the joint surfaces by a predetermined distance; Both sides of the upper surface of the cylinder block are formed into cylinder head joint surfaces that are inclined downwardly and outward from both ends of the processing reference surface, and the upper end of each cylinder is opened at these cylinder head joint surfaces. Features.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. As particularly shown in _FIG . ₂ are arranged in a V-shape.

A common crankcase 3 is integrally connected to the lower ends of the cylinder blocks 2 of both cylinder rows C ₁ and C ₂ , and the engine block is
Eb is constructed. The peripheral edge of the lower surface of the crankcase 3 is formed as an oil pan joint surface A ₁ to which the oil pan 70 is joined, and the lower surface A of the crankcase 3 is formed in cooperation with a semi-annular bearing 41 formed on the lower surface A. and crankshaft journal part 4a
The bearing cap joint surface A2 to which the upper surface of the bearing cap 42 that supports the oil pan joint surface _A2 is the oil pan joint surface.
It is formed on the same horizontal plane as A ₁ .

As clearly shown in FIG. 4, the engine block Eb has a machining reference plane B in which the center portion of the upper surface of the cylinder block 2 is spaced a predetermined distance from and parallel to both the joint surfaces A ₁ and A ₂ of the lower surface A of the crankcase. Furthermore, both sides of the upper surface of the cylinder block 2 are formed with cylinder head joint surfaces C that are inclined outwardly and downwardly from both ends of the machining reference surface B, and the upper end of the cylinder 1 is formed on each cylinder head joint surface C. It's open.

The bearing cap 42 includes at least one pair of long shaft bolts 43 arranged to sandwich the journal portion 4a.
and at least a pair of short shaft bolts 44 disposed on both outer sides of the long shaft bolts 43, which are fixed to the crankcase 3.

A piston 5 that slides into each cylinder 1 is connected to a crank pin 4b of the crankshaft 4 via a connecting rod 6.

A cylinder head 7 is fixed to each cylinder joint surface C of the cylinder block 2. Each cylinder head 7 includes a main combustion chamber 8 defined by the piston 5, a sub-combustion chamber 9 communicating with the combustion chamber 8 via a torch nozzle 10, a main intake port 11 opening into the main combustion chamber 8, and a main combustion chamber 9 communicating with the combustion chamber 8 via a torch nozzle 10. An exhaust port 13 and a sub-intake port 12 opening into the sub-combustion chamber 9 are formed, respectively.The main intake port 11 is connected to the main intake valve 14, the sub-intake port 12 is connected to the sub-intake valve 15, and the exhaust port 13 is They are opened and closed by exhaust valves 16, respectively. These valves 14, 15, 16 are provided with valve closing springs 35, 3 that bias them in the closing direction.
6 and 37 are attached.

An ignition plug 17 screwed onto the cylinder head 7 has an electrode facing the auxiliary combustion chamber 9.

An intake manifold 18 installed between the cylinder heads 7 and 7 of both cylinder rows C ₁ and C ₂ is fixed to the machining reference plane B of the engine block Eb, and a carburetor 19 is attached to the upper surface of the intake manifold 18. . The carburetor 19 can simultaneously generate a lean mixture and a rich mixture, and the intake manifold 18 supplies the lean mixture to all main intake ports 11 and the rich mixture to all sub-intake ports 12. can be distributed.

A camshaft 20 is disposed as close as possible to the crankshaft 4 in the center between both cylinder rows C ₁ and C ₂ . This camshaft 20 is supported by a cylinder block 2, and a timing transmission device 2 includes a pair of gears 21, 22 and a chain 23 suspended between them.
4, and is connected to the crankshaft 4 via the crankshaft 4, and is then driven at a reduction ratio of 1/2.

Further, a pair of left and right follower shafts 25 are arranged between the camshaft 20 and the cylinder rows C ₁ and C ₂ so as to sandwich the camshaft 20 . The exhaust follower shaft 27 is connected to each follower shaft 2.
5 as a base point and extend away from the adjacent cylinder 1, and the inner surfaces of their swinging ends engage with the intake cam 20a and the exhaust cam 20b of the camshaft 20, respectively, and their outer The inner ends of an intake push rod 30 and an exhaust push rod 31 are spherically connected to the side surfaces.

On the other hand, an intake rocker arm 33 and an exhaust rocker arm 34 are pivotally supported on the rocker shaft 32 supported by each cylinder head 7. The upper ends of the main intake valve 14 and the auxiliary intake valve 15 abut on the intermediate portion, and the outer end of the intake push rod 30 is spherically connected to the tip of the outer arm of the rocker arm 33. Further, the upper end of the exhaust valve 16 contacts the tip of the outer arm of the exhaust rocker arm 34, and the outer end of the exhaust push rod 31 is spherically connected to the tip of the inner arm of the rocker arm 34. The intake rocker arm 33 is provided with valve head gap adjustment bolts 38 and 39 at the spherical joint with the push rod 30 and at the contact portion with the sub-intake valve 15, and the exhaust rocker arm 34 is not provided with such bolts. However, instead, a hydraulic tappet mechanism 40 is installed inside the exhaust rocker follower 27.

In the figure, 50 is a head cover, and 51 is an exhaust manifold connected to the exhaust port 13.

Next, to explain the operation of this embodiment, the camshaft 20 is rotated from the crankshaft 4 via the timing transmission 24, and the intake and exhaust cams 20a and 20b of the camshaft 20 are rotated from the crankshaft 4 via the timing transmission 24.
When the lift action starts, the suction and exhaust rocker followers 26 and 27 are respectively swung upward and push up the suction and exhaust push rods 30 and 31. According to this pushing up of the intake push rod 30, the intake rocker arm 33 swings and the main
When the auxiliary intake valves 14 and 15 are opened against the valve closing springs 35 and 36, and when the exhaust push rod 31 is pushed up, the exhaust rocker arm 34 swings to open the exhaust valve 16 against the valve closing spring 37. Open it. Then, when the lifting action of the cams 20a, 20b is finished, each valve 14, 15, 16 is released by its respective valve closing spring 35,
It can be closed by the elastic force of 36 and 37.

When the main and auxiliary intake valves 14 and 15 are opened, this corresponds to the intake stroke of the piston 5 in the corresponding cylinder 1, so the lean mixture passes through the main intake port 11 into the main combustion chamber 8, and the rich mixture Air is supplied to the sub-combustion chambers 9 through the sub-intake ports 12, respectively. Then, in the next compression stroke, the rich air-fuel mixture in the auxiliary combustion chamber 9 is ignited by the discharge of the spark plug 17, and the flame is injected into the main combustion chamber 8 through the torch nozzle 10, igniting the lean air-fuel mixture in the chamber 8. Ignite and burn. As a result, combustion of a mixture with a lean overall air-fuel ratio becomes possible. In this way, the piston 5 moves to the expansion stroke, and in the next exhaust stroke, the exhaust valve 16 is opened as described above, so that the burned gas flows into the exhaust port 1.
It is discharged to 3.

When a load is applied from the crankshaft 4 to the bearing cap 42 from a direction oblique to the mating surface of the crankcase 3 and the bearing cap 42 due to the expansion stroke of the piston 5, the component of the load perpendicular to the mating surface is:
The tensile force mainly acts on the pair of long-axis bolts 43 adjacent to the journal portion 4a, and the component force parallel to the mating surface acts on both the long-axis and short-axis bolts 43, 44.
acts as a bending force and a shear force. By the way, the long-axis bolt 43 can generate a high stress especially in response to tensile force, so it can sufficiently withstand the former component force, and the short-axis bolt 44 has high rigidity and
Since the long shaft bolt 43 receives the weakened bending force and shearing force, it is possible to resist the force and prevent the bearing cap 42 from shifting from its normal position.

As described above, the present invention includes a cylinder block having cylinders arranged in a V-shape, and a crankcase that is integrally connected to the lower part of the cylinder block, and the lower peripheral edge of the crankcase is covered with oil. In an engine block for a V-type multi-cylinder internal combustion engine, which is formed on an oil pan joint surface to which a pan is joined, a crankshaft journal portion is formed on the lower surface of the crankcase in cooperation with a semi-annular bearing formed on the lower surface. A bearing cap joint surface to which a bearing cap for supporting the cylinder block is joined is formed on the same plane as the oil pan joint surface, and the center portion of the upper surface of the cylinder block is parallel to both the joint surfaces and at a predetermined distance from both the joint surfaces. The cylinder head is formed on separate machining reference surfaces, and both sides of the upper surface of the cylinder block are formed with cylinder head joint surfaces that are inclined toward the outside from both ends of the machining reference surface, and the cylinder head joint surfaces are formed on the cylinder head joint surfaces. Since the upper end of each cylinder is opened, just by cutting the bottom surface of the crankcase into a single plane, the oil pan joint surface and bearing cap joint surface on the bottom surface of the case can be easily and precisely formed in one process using the same tool. This can greatly contribute to improving the processing efficiency of these joint surfaces. Also, while machining the machining reference plane at the center of the upper surface of the cylinder block, which is parallel to the oil pan joint surface and the bearing cap joint surface at a predetermined distance, the large cutting load applied to the cylinder block is transferred to the two joint surfaces of the wide pressure receiving surface. Since it can be stably received through the joint, there is no risk that the two joint surfaces will be locally distorted, and in addition, the processing reference surface is machined parallel to the two joint surfaces that form one plane as a reference plane. Therefore, even if the machining reference surface and both joint surfaces are relatively far apart, the machining reference surface can be precisely cut while maintaining the distance therebetween. Using the above machining reference plane as a reference, the adjacent cylinder head joint surface can also be easily and accurately cut, and as a result, the cylinder head joint is inclined at a constant angle at a constant distance from the lower surface of the crankcase. Since the surface can be obtained extremely easily and accurately, a highly accurate engine block can be easily manufactured without requiring a high degree of skill, and this can contribute to improving mass productivity.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional front view of a V-type multi-cylinder internal combustion engine equipped with the engine block of the present invention, FIG. 2 is a vertical cross-sectional side view thereof, FIG. 3 is an enlarged plan view of one cylinder row with the head cover removed, and FIG. The figure is a front view of the engine block. A...Crankcase bottom surface, _A1 ...Oil pan joint surface, _A2 ...Bearing cap joint surface, B...Machining reference surface, C...Cylinder head joint surface, 1...Cylinder,
2...Cylinder block, 3...Crank case, 4
...Crankshaft, 4a...Journal part, 18...Intake manifold, 41...Bearing, 42...Bearing cap, 70...Oil pan.

Claims (1)

[Claims] 1. Consists of a cylinder block 2 having cylinders 1 arranged in a V-shape, and a crankcase 3 integrally connected to the lower part of the cylinder block 2,
In an engine block for a V-type multi-cylinder internal combustion engine, the peripheral edge of the lower surface A of the crankcase 3 is formed at an oil pan joint surface A ₁ to which an oil pan 70 is joined.
has a bearing cap joint surface to which a bearing cap 42 which cooperates with a semi-annular bearing 41 formed on the lower surface A and supports the crankshaft journal portion 4a is joined.
A ₂ is formed on the same plane as the oil pan joint surface A ₁ , and the center portion of the upper surface of the cylinder block 2 is parallel to both the joint surfaces A ₁ and _{A 2 .} Processing reference plane B separated by a predetermined distance
Both sides of the upper surface of the cylinder block 2 are formed with cylinder head joint surfaces C that are inclined downwardly and outward from both ends of the processing reference surface B, and these cylinder head joint surfaces C
An engine block for a V-type multi-cylinder internal combustion engine, characterized in that the upper end of each cylinder 1 is opened. 2. In what is stated in claim 1,
The processing reference surface B is an engine block for a V-type multi-cylinder internal combustion engine that also serves as a mounting surface for an intake manifold.