JPH04303167A - Joining structure of engine and transmission - Google Patents

Abstract

PURPOSE:To improve rigidity of the joining part of an engine main body and a transmission, and reduce vibration in association with operation of the engine. CONSTITUTION:An integrated engine block 1 in which a cylinder head part, a cylinder part, and a crank case part, are cast together in one body is employed. A mission jointing boss part 1a whose root part is formed up to a cylinder head part, is projecting-formed in one body on the end part of the block 1. The end part 5a of a transmission case 5 is combined with the end part of the engine block 1 while using the boss part 1a so as to clamp both of them, together.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a structure for coupling the main body of a reciprocating piston engine to a transmission, and more particularly to a technique for increasing the strength of the coupling and reducing unnecessary vibrations.

0002

[Prior Art] In a power unit consisting of an engine and a transmission, a transmission case is combined with the cylinder block of the engine body.
Both are connected with multiple bolts. Since the lower part of the coupling end (clutch case part) of the transmission case protrudes below the lower end of the cylinder block, that part is generally fastened to the end of the oil pan. The oil pan has considerably lower rigidity than the cylinder block, so relying on this part to connect the transmission case will not provide sufficient joint strength and rigidity.

[0003] If the rigidity of the engine body and transmission joint is insufficient, bending mode vibrations and torsional mode vibrations are likely to occur in the joint as the engine operates.
These vibrations are transmitted into the passenger compartment through the vehicle body and become muffled noise. Therefore, Japanese Patent Application Publication No. 1-185655,
-As seen in Publication No. 87937, etc., the engine
Various reinforcing members have been developed to increase the joint rigidity on the lower side (oil pan side) of the transmission joint.

0004

[Problem to be solved by the invention] If the coupling area between the highly rigid cylinder block and the transmission case is sufficiently large, there is no need to rely on the oil pan side at the bottom.
Therefore, there is no need to use reinforcing members that increase the number of parts and assembly man-hours. However, the structure of a typical engine is
Since the cylinder block and the upper cylinder head are constructed separately, even if the connection surface with the transmission is expanded to the cylinder head side, the rigidity of the connection between the cylinder block and the cylinder head is not very high. Therefore, it is not very effective in increasing the coupling stiffness of the transmission.

This invention was made in view of the above-mentioned conventional problems, and its purpose is to increase the joint rigidity of the engine and transmission without increasing the number of parts, assembly man-hours, and overall weight as much as possible. The goal is to provide a structure that allows for this.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention uses an integrated engine block in which a cylinder head portion, a cylinder portion, and a crankcase portion are integrally cast. At the end of this integrated engine block, a boss part for connecting the transmission whose root part extends to the cylinder head part is integrally formed to protrude, and when the end part of the transmission case is combined with the end part of the engine block, the boss part is formed. The structure is also used to connect the two.

[0007]

[Operation] Since the cylinder head, cylinder, and crankcase are integrally cast, the rigidity of the engine block is extremely high, and the area where it connects to the transmission case can be made sufficiently large. Above this joint (i.e. the end face of the cylinder head)
By integrally forming the boss portion and adding it as a means for fastening the transmission, the rigidity of the connection between the integrated engine block and the transmission case can be greatly increased.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a first embodiment of the present invention. Reference numeral 1 indicates an engine block that is the main body of an in-line four-cylinder engine. This engine block 1 is an integrated engine block in which a cylinder head portion, a cylinder portion, and a crankcase portion are integrally cast. The engine block 1 is attached with a head cover 2, an intake manifold 3, an exhaust manifold 4, and the like. Reference numeral 5 designates a transmission case, and the clutch case portion 5a at the end of this is combined with the end of the integrated engine block 1 and firmly fastened.

In this embodiment, a boss portion 1a is formed protruding from the transmission mounting surface of the integrated engine block 1. This boss portion 1a is cast integrally with the engine block 1. As shown in the figure, the position of the root portion of the boss portion 1a extends from near the center of the end of the engine block 1 to the upper cylinder head portion. The clutch case portion 5a and the boss portion 1a at the end of the transmission case 5 are shaped to fit and join together when both are assembled in a proper position. In addition to firmly fastening the peripheral portion of the clutch case portion 5a to the substantially perpendicular end surface of the engine block 1 with a plurality of bolts, the boss portion 1a and the clutch case portion 1a are also firmly fastened with bolts 6 in a substantially vertical direction. It has been concluded.

A second embodiment of the invention is shown in FIGS. 2, 3, and 4. In this embodiment, the boss portion 1a in the embodiment shown in FIG. 1 is formed to protrude greatly into a canopy shape to form a canopy portion 1b. The eaves portion 1b is also provided with a plurality of reinforcing ribs 1c. The eaves portion 1b and the reinforcing ribs 1c are cast integrally with the integrated engine block 1. On the other hand, as shown in FIG. 2, the upper half of the clutch case portion 5a of the transmission case 5 is cut out, and the eaves portion 1b of the engine block 1 is combined with that portion, so that the two are integrated. It forms the clutch case part. Note that the base portions of the eaves portion 1b and reinforcing ribs 1c are integrated into the engine block 1.
It extends to the top of the cylinder head (cylinder head).

Then, as shown in FIG. 4, the transmission case 5 is assembled into the integrated engine block 1,
The periphery of the lower part of the clutch case 5b is fastened to the oil pan 7 with bolts, and the joint surface with the eaves part 1b from the middle to the upper part of the clutch case part 5a is also firmly fastened with a plurality of bolts. As shown in FIG. 4, the engine-transmission coupling surface spans three planes curved at approximately right angles, and the coupling rigidity is greatly improved compared to simply coupling to one plane at the end of the engine.

0012

[Effects of the Invention] As explained in detail above, in this invention, the engine body is an integrated engine block in which the cylinder head part, the cylinder part, and the crankcase part are integrally cast. A boss part for connecting the transmission that extends to the cylinder head part is integrally formed to protrude, and the end of the transmission case is combined with the end part of the engine block, and the boss part is also used to firmly fasten the two. , the joint rigidity between the two becomes extremely high, making it possible to reduce bending mode vibrations and torsional mode vibrations associated with engine operation.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the configuration of a first embodiment of the present invention.

FIG. 2 is an exploded perspective view showing the configuration of a second embodiment of the invention.

FIG. 3 is a perspective view of a second embodiment of the present invention in a coupled state.

FIG. 4 is a schematic front view of a second embodiment of the invention.

[Explanation of symbols]

1 Integrated engine block 1a
Boss part 1b Hisashi part
1c Reinforcement rib 5 Transmission case 5a Clutch case part

Claims (2)

[Claims] Claim 1: A boss part for connecting a transmission, whose root part extends to the cylinder head part, is integrated into the end of an integrated engine block in which a cylinder head part, a cylinder part, and a crankcase part are integrally cast. 1. A coupling structure for an engine and a transmission, characterized in that an end of the transmission case is formed protruding from the end of the engine block, and the end of the transmission case is combined with the end of the engine block, and the two are fastened together using the boss. 2. An engine-transmission coupling structure, characterized in that the boss portion according to claim 1 is formed into a canopy shape, and is combined with an end portion of the transmission case to constitute a clutch case portion.