JPH0417760A - Cylinder block for engine - Google Patents

Abstract

PURPOSE:To substantially increase rigidity against bending and torsion by bulging both sides of a cylinder block in such a way as to increase the extent of the bulge toward the rear end of the cylinder block for forming a cone section, and extending the lower deck of the cylinder block up to the aforesaid cone section. CONSTITUTION:In an engine cylinder block 1 having a flange 3 at the rear end thereof for connection to a housing at the side of a transmission gear, both sides of the cylinder block 1 are bulged over a range from a position forward of a bulkhead 4 between an extreme rear cylinder (d) and the next cylinder 2c, to the rear end of the cylinder block 1. A cone section 6 is formed with the bulge gradually increased toward the rear end of the cylinder block 1, and the lower deck 11 of the cylinder block 1 is extended to the cone section 6. According to the aforesaid construction, the rigidity of a section for connecting the cylinder block 1 to a housing at the side of a transmission gear is substantially increased, and the vibration of a power plant can be sufficiently restrained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cylinder block of an engine connected to a transmission or the like and mounted on a vehicle.

C. Prior Art] In general, an engine cylinder block has a cylinder wall forming a plurality of cylinders, a lower crankcase, a bulkhead arranged at both front and rear ends of the crankcase, and between each cylinder. The cylinder head and other parts are combined to form an engine. and,
A clutch housing and a transmission case are connected to the rear end of the cylinder block to form a power plant, and this power plant is subject to bending forces, especially in front-wheel drive vehicles where the engine and transmission are placed horizontally. In some cases, forces such as bending and twisting in the front-rear direction, up-down direction, etc. act. In order to reduce vibration noise, etc.
It is required to increase the rigidity of the connection between the cylinder block, clutch housing, etc. against the above-mentioned forces.

Conventionally, as a structure that takes this point into consideration, for example, as shown in Japanese Utility Model Application Publication No. 62-87150, in a structure in which a housing for accommodating a clutch and a differential gear is connected to the rear end of the cylinder block, the cylinder It is known that ribs projecting outward are provided on the rear half of both sides of the block and on the housing, and the ribs reinforce the connection between the cylinder block and the housing, thereby increasing the connection rigidity. .

[Problem to be solved by the invention]

The use of ribs alone as shown in the above-mentioned publication may not necessarily improve rigidity sufficiently against forces in various directions.

Therefore, instead of the above-mentioned ribs, both sides of the rear part of the cylinder block are made to bulge outward, and the amount of bulge becomes larger toward the rear end, thereby increasing the rigidity of the connecting part to the transmission side. An effective reinforcing structure has been considered, but even with such a structure, there is still room for improvement in terms of improving the rigidity of the cone-shaped reinforcing portion itself. Furthermore, when a heavy component such as a starter is attached to the rear end side of the cylinder block, it is also required to increase the rigidity of the attached portion to prevent vibration caused by this component.

In addition, a bearing section for the crankshaft is formed in the bulkhead disposed in the crankcase of the cylinder block, but in order to suppress the vibration of the flywheel attached to the rear end of the crankshaft, it is necessary to It is required to increase the rigidity of the bulkhead on the near side. On the other hand, as the pistons of each cylinder move up and down, compression and expansion of air occur in the space below them, causing a pumping loss. Although it is desirable to make the communication hole free in order to reduce the pumping loss, there is a problem in that if a large communicating hole is formed near the bearing part of the bulkhead, the rigidity of the bulkhead decreases.

In view of these circumstances, the present invention provides an engine cylinder block that can significantly increase the rigidity against bending and torsion at the portion where the cylinder block and the transmission housing are connected, and further provides While increasing the rigidity of the Nohulk head on the side closer to the
An object of the present invention is to provide an engine cylinder block that can reduce bombing loss.

[Means to solve the problem]

In order to achieve the above-mentioned object, a first invention provides a cylinder block for an engine that has a connection part to a transmission-side housing at the rear end, and a bulkhead between the rear end cylinder and the next cylinder. A cone portion is formed in a range extending from a position forward to the rear end of the cylinder block by bulging both sides of the cylinder block and increasing the amount of bulge toward the rear end,
The lower deck of the cylinder block is extended to the cone section.

Further, the second invention provides a cylinder block for an engine having a connecting portion to a transmission-side housing at a rear end portion of the cylinder block from a position forward of a bulkhead between the rear end cylinder and the next cylinder. A cone portion is formed in a range extending to the rear end by bulging both sides of the cylinder block, and the amount of the bulge becomes larger toward the rear end. A communication part is provided that communicates the lower parts of both cylinders with each other through a space inside the part.

[Effect]

According to the first invention, the connecting portion of the cylinder block to the transmission housing is reinforced by the cone portion, and the cone portion itself is strengthened by the lower deck extending to the cone portion. The rigidity of the connection between the block and the transmission housing is increased.

According to the second aspect of the invention, the cone portion reinforces the connecting portion of the cylinder block to the transmission-side housing, and the space within the cone portion between the rear end cylinder and the next cylinder. The communication section using the airflow allows sufficient air circulation and reduces pumping loss.

〔Example〕

1 to 5 show an embodiment of the present invention, and a cylinder block 1 in this embodiment has four cylinders 2a to 2d, numbered 1 to 4 in order from the front side of the engine. A flange 3 is attached to the rear end of the cylinder block 1 as a connection part to the housing on the transmission side.
is formed. A crankcase is formed in the lower part of the cylinder block 1, and a bulkhead 4 extending in a direction perpendicular to the cylinder row is integrally provided inside the crankcase at both front and rear ends and at a position between each cylinder. A bearing portion 5 is provided at the center of the lower end of each bulkhead 4, and this bearing portion 5
A bearing cap (not shown) is fixed to the bearing portion 5 with bolts, and a crankshaft (not shown) is supported by this bearing portion 5 and the bearing cap.

A cone portion 6 is provided on the rear side of the cylinder block 1 to increase the rigidity of connection with the transmission side. This cone portion 6 bulges out both sides of the cylinder block 1 so that the amount of the bulge becomes larger toward the rear end. In other words, a cone-shaped outer wall that expands toward the rear end is formed on both sides of the cylinder block 1. The cylinder at the rear end (
It is formed in a range extending from a position forward of the bulkhead 4 between No. 4 cylinder) 2d and the next cylinder (No. 3 cylinder) 2c to the rear end of the cylinder block 1, and in the illustrated example, No. 2 and No. 3 cylinders. No. cylinder 2b.

It is formed in a range extending from around 20 to the rear end of the cylinder block 1. Inside this cone part 6, an inner wall 10 is formed at the basic shape position of the cylinder block (the position of the side wall when the cone part 6 is not provided), and a double wall formed by this inner wall 10 and the outer wall of the cone part 6 is formed. The wall structure provides sufficient reinforcement.

The cone portion 6 at the rear end of the cylinder block 1
The flange 3 is connected to the outer periphery of the flange 3.

A clutch housing or a transmission case (not shown) serving as a housing on the transmission side is connected to this flange 3 by bolting. Further, a starter mounting portion 7 connected to the flange 3 is provided at the rear end of the cone portion 6 on one side of the cylinder block 1, and a starter 8 is fixed to the starter mounting portion 7. Note that the lower end of the cylinder block 1 is connected to a reinforcing member and an oil pan (not shown) that connect both sides of the cylinder block and each bearing cap.

A lower deck 11 is provided in the cylinder block 1 at a predetermined height position corresponding to the lower end of the cylinder.

This lower deck 11 is connected to both side walls of the cylinder block 1, is provided over almost the entire cylinder block 1 from the front end side to the rear end side, except for the portions corresponding to the cylinders 28 to 2d, and is provided on the rear side of the cylinder block 1. In this case, both sides of the lower deck 11 extend beyond the inner wall 10 to reach the outer wall of the cone portion 6.

At the rear end of one side of the cylinder block 1, a lower deck 11 reaches the starter mounting portion 7.

Further, the space below the third cylinder 2c and the space below the fourth cylinder 2d are communicated via a cone inner space 12 that exists between the inner wall 10 and the outer wall of the cone portion 6. That is, on the inner wall 10, the cylinder 2c,
A communication hole 13 is formed to communicate the lower space 2d with the cone inner space 12, and a communication hole 13 is formed in the partition portion located in the cone inner space 12 at the side part of the bulkhead 4, which serves as a communication section between the cylinders. A hole 14 is formed.

According to the structure of this embodiment, the rear part of the cylinder block 1 is reinforced by the cone part 6, and this cone part 6 serves as the third and fourth cylinders 2c.

The reinforcing effect is enhanced by being formed relatively large from the front of the bulkhead 4 between 2d to the rear end of the cylinder block 1. Furthermore, since the lower deck 11 that contributes to the rigidity of the cylinder block 1 extends to the cone portion 6, the cone portion 6 is further strengthened. In this way, the cone portion 6 and the lower deck 11 greatly increase the rigidity against forces in the bending and torsion directions when the transmission is connected to the rear end of the cylinder block 1, and vibrations are sufficiently suppressed.

The cone portion 6 and the lower deck 11 extending to this portion also have a vibration suppressing effect when the starter 8 is attached to the cylinder block 1. In other words, when a heavy object such as a starter is attached to the cylinder block 1, this tends to become a source of vibration, but since the lower deck 11 is extended to the cone portion 6 and reaches the starter mounting portion 7,
This partial rigidity will also be sufficiently increased.

Furthermore, since the space below the third cylinder 2C and the space below the fourth cylinder 2d are communicated via the cone inner space 12, the rigidity of the bulkhead 4 between the third and fourth cylinders 2c and 2d is increased. Pumping loss is reduced without causing a decrease in performance.

In other words, the space below the No. 3 cylinder 2c and the space below the No. 4 cylinder 2d are in a relationship such that when one of them is compressed by the downward movement of the piston, the other expands by the upward movement of the piston. If they are widely communicated, air will flow freely between them and pumping loss will be reduced; however, if a large communication hole is provided near the bearing portion 5 of the bulkhead 4 inside the inner wall 10,
The support rigidity of the crankshaft decreases. Therefore, in this embodiment, a communication hole 13.1 is provided between the inner wall 10 and the cone portion 6.
4, No. 3 and No. 4 cylinders 2c.

2d are communicated with each other via the inner cone space 12, which allows sufficient air circulation and reduces pumping loss. There is no need to provide a large communication hole in the bulkhead 4, and the support rigidity of the crankshaft is increased.

〔Effect of the invention〕

As described above, the invention according to claim 1 provides a structure in which the 71 housing on the transmission side is connected to the rear end of the cylinder block, and the structure is located in front of the bulkhead between the rear end cylinder and the next cylinder. A cone part is formed in the range extending from the position to the rear end of the cylinder block by bulging both sides of the cylinder block and the amount of the bulge becomes larger toward the rear end, and the lower deck of the cylinder block is extended to the above cone part. Because it is extended, the synergy between the cone section and the lower deck that extends to this section greatly increases the rigidity of the section where the cylinder block and transmission housing are connected, and sufficiently suppresses power plant vibration. can do.

Further, the invention according to claim 2 forms the cone portion in a range extending from a position in front of the bulkhead between the rear end cylinder and the next cylinder to the rear end of the cylinder block, and Since a communication part is provided that communicates the lower parts of the two cylinders with each other through the space inside the cone part, it is possible to avoid providing a large communication hole near the crankshaft support part of the bulkhead and improve the crankshaft support rigidity. While increasing the height, it is possible to reduce pumping loss by allowing air to flow between the spaces below the two cylinders.

[Brief explanation of drawings]

Fig. 1 is a plan view of a cylinder block according to an embodiment of the present invention, Fig. 2 is an elevational view of one side of the cylinder block, and Fig. 3 is a cross section taken along the line ■-■ in Fig. 1. 4 is an elevational view of the rear end surface of the cylinder block, and FIG. 5 is an enlarged partially cutaway bottom view of the cylinder block. DESCRIPTION OF SYMBOLS 1... Cylinder block, 2a-2d... Cylinder, 3... Flange, 4... Bulkhead, 6...
Cone part, 1...Lower deck 1 4...Communication hole. 2... Cone internal space, 13°

Claims (1)

[Scope of Claims] 1. In an engine cylinder block having a connection part to the transmission housing at the rear end, the cylinder block is inserted from a position forward of the bulkhead between the rear end cylinder and the next cylinder. In addition to forming a cone portion extending to the rear end by bulging both sides of the cylinder block and increasing the amount of bulge toward the rear end, the lower deck of the cylinder block is extended to the cone portion. Characteristic engine cylinder block. 2. In an engine cylinder block that has a connection part to the transmission housing at the rear end, the range extends from the position forward of the bulkhead between the rear end cylinder and the next cylinder to the rear end of the cylinder block. In addition, a cone portion is formed by bulging both sides of the cylinder block and the amount of the bulge becomes larger toward the rear end, and a lateral portion of the bulkhead between the two cylinders is formed.
A cylinder block for an engine, characterized in that a communication part is provided that communicates the lower parts of the two cylinders with each other through a space within the cone part.