JPH0746754Y2 - Engine block of multi-cylinder engine - Google Patents

Description

[Detailed Description of the Invention] A. Purpose of the Invention (1) Field of Industrial Application In the present invention, both outer walls along the crank axis direction are formed in a lattice shape by a frame of an aggregate, and are formed on the outer surface of the outer wall. Relates to an engine block of a multi-cylinder engine configured by joining plate-shaped rigid film members, respectively.

(2) Conventional Technology A conventional engine block having a frame structure is known in which a plurality of openings are formed in the outer wall of a cylinder block and a crankcase, and these openings are covered with a vibration-proof panel. -43486 gazette).

(3) Problems to be Solved by the Invention In the conventional engine block described above, since the vibration isolation panel is substantially parallel to the axis of the cylinder bore,
As shown in FIG. 12, when the engine is in operation, bending force acting on the engine block, external force F due to vibration around the crankshaft, etc. acts as a shearing force between the joint surface between the outer wall W of the engine block and the vibration isolation panel P, As a result, there is a problem in that those joint surfaces are subject to excessive shear stress S and cause damage or peeling of the vibration-proof panel P.

The present invention has been made in consideration of such circumstances, and it is effective while suppressing the increase in block weight as much as possible while reducing the joint area between the aggregate forming the outer wall of the engine and the rigid membrane member joined to the outer surface. It is an object of the present invention to provide an engine block for a multi-cylinder engine in which the shear stress acting on the joint surfaces can be effectively reduced and the problems mentioned above are solved.

B. Configuration of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention is directed to a structure in which both outer walls along the crankshaft direction are formed in a lattice shape by a framework of aggregate, and the outer wall is formed. In an engine block of a multi-cylinder engine configured by bonding the back surface of a plate-shaped rigid film member to the outer surface of, respectively, outside the aggregate, extending from one side along the back surface of the rigid film member, A flange portion thinner than the aggregate is integrally extended, and an outer surface of the aggregate and an outer surface of the flange portion together form a joint surface with the rigid film member.

(2) Operation According to the above configuration, the substantial joint area between the rigid membrane member and the aggregate is effectively expanded by the special provision of the flange portion extending from one side of the aggregate along the back surface of the rigid membrane member. Therefore, the shear stress acting on the joint surface between the aggregate and the rigid membrane member is effectively reduced, and the flange itself is thinner than the aggregate, which greatly increases the total weight of the aggregate. Therefore, the strength of the joint between the aggregate and the rigid film member is not required even if the aggregate is made thicker than necessary or the rigid film member is made thicker than necessary to increase their rigidity. The durability is enhanced, and peeling and damage of the rigid membrane member are effectively avoided.

(3) Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall side view showing a longitudinal section of a main portion of an in-line four-cylinder engine incorporating the engine block of the present invention, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. Is Fig. 1 III
Enlarged sectional view taken along -III line is shown, the engine block E in these figures, the cylinder block B _c, a cylinder head H _c which is bonded via the gasket 2 on the deck surface 1, the cylinder block It is composed of a lower case C _L attached to the lower surface of B _c . A head cover C _H is attached to the upper surface of the cylinder head H _c , and an oil pan P _o is joined to the lower surface of the lower case C _L. The crankshaft 3 is rotatably supported on the mating surface between the cylinder block B _c and the lower case C _L, and the four _first to _fourth cylinder barrels 10 ₁ to 10 _{4 of the} cylinder block B _c are supported.
Pistons 5 ... Are slidably fitted in the cylinder bores 4 ...
And are connected via connecting rods 6 ...

Next, the structure of the cylinder block B _c will be described mainly with reference to FIGS. 1 to 3 and FIGS. 4, 5, 8, 9, and 10.

FIG. 4 is a top view of the cylinder block B _{c taken} along line IV-IV in FIG. 2, and FIG. 5 is a bottom view taken along line VV in FIG.
FIG. 8 is a side view of the cylinder block B _{c taken} along line V in FIG. 2, FIG. 9 is an enlarged view of the IX portion in FIG. 2, and FIG. 10 is a perspective view of the cylinder block B _c .

The cylinder block B _c is a rigid film member 9 ₁ , 9 _{2 which} will be described in detail later.
Except for Fe, Al, Mg, or other light alloy material is integrally formed by casting, and as shown in FIG. 10, the whole has a rectangular parallelepiped shape. And this is the cylinder barrel assembly block 7, skeleton frame 8 and rigid membrane members 9 ₁ , 9 ₂ (Fig. 11).
The three are integrated into a lightweight, high-strength, high-rigidity structure.

The cylinder barrel assembly block 7 is a cylinder block.
The four cores that form the core part that is the main strength member of B _c
Configured as a fourth cylinder barrel 10 _1, 10 _2, 10 _3, 10 ₄ units body provided continuously in a row. And the first to fourth
The cylinder barrel 10 ₁ to 10 ₄ are formed cylindrical hollow portion 11 ... respectively, the boundary portion of the hollow portion 11, 11 that are adjacent mutually are communicated with each other. A cylinder liner having an outward flange portion 12 ₁ at the upper end, that is, a wet liner 12, is inserted into each hollow portion 11 to attach the vertical cylinder axis l to the first to fourth cylinder barrels 10 ₁ to 10 _{4. 1-} l ₁
And the cylinder bore 4 is formed. Further, the front and rear end walls 21 ₁ and 21 ₂ of the cylinder barrel assembly block 7 and the adjacent boundary walls 19 of the _first to _fourth cylinder barrels 10 ₁ to 10 ₄ are formed thick, and the cylinder barrel assembly block 7 is formed. The high strength of itself is secured. The piston 5 is slidably fitted in the cylinder bore 4 of the wet liner 12, and the refrigerant jacket 13 is provided between the inner peripheral surfaces of the _first to _fourth cylinder barrels 101 to 104 and the wet liner 12. (FIG. 2) is formed, so that the first to fourth cylinder barrel 10 ₁ to 10 ₄ and the wet liner 12 ... is forcibly cooled by flowing a coolant such as water to the refrigerant jacket 13 There is.

In addition, the front and rear end walls 21 ₁ and 21 _{2 of the} wall thickness in the longitudinal direction of the cylinder barrel assembly block 7 and the lower surface of the wall boundary wall 19 between the adjacent cylinder bores 4 and 4 of the assembly block 7 are bearing upper half supporting the journal shaft portion 3 ₁ ... on a half of the crank shaft 3 22 ... it is formed.

Next, the structure of the three-dimensional lattice-like skeleton frame 8 will be described. It mainly serves as a strength member of the cylinder block B _c , and is made of the same material as the assembly block 7 so as to surround the outer periphery of the cylinder barrel assembly block 7. Are integrally cast and formed as shown in FIGS. 2 to 5, 8 and 10, and a plurality of horizontal beam aggregates 15, vertical beam aggregates 16 and column aggregates 17 ... It is formed into a rectangular parallelepiped by being framed integrally with. Then these aggregates 15…, 16… and 1
In order to explain the structure of 7 ... in more detail, as clearly shown in FIGS. 2, 3, and 10, the cylinder bores 4 of the cylinder barrel assembly block 7 are arranged along the arrangement direction (crank axis direction l ₁ -l ₁ ) on the left, On the outer surface of the right side walls 18 and 18, a plurality of rectangular cross-sections are formed at substantially equal intervals in the vertical direction from the front and rear end walls 21 ₁ and 21 _{2 of the} collective block 7 and the boundary wall 19 ... The horizontal beam aggregates 15 of the book are integrally provided so as to stand upright, and these horizontal beam aggregates 15 are horizontally crossed from the cylinder barrel assembly block 7 substantially orthogonal to the crank axis l ₂ -l ₂ direction. It is overhanging in the direction. Thus, the lowermost ones of the horizontal beam aggregates 15 arranged in the vertical direction are formed thicker than the remaining ones, and the lower surface of the cylinder block B _c , that is, the lower case described later.
The joint surface with C _L (the supporting portion of the crankshaft 3) is made to have higher rigidity.

At the outer ends of the plurality of horizontal beam aggregates 15 ...
The longitudinal beam aggregates 16 having a square cross section and the column aggregates 17 which form a lattice-shaped integral structure and which form both side walls in the longitudinal direction are integrally coupled. The plurality of vertical beam aggregates 16 ... Extend in parallel with each other in the longitudinal direction of the cylinder barrel assembly block 7 at substantially equal intervals in the vertical direction, and also the plurality of column aggregates.
17 extend in parallel with each other in the vertical direction of the cylinder barrel assembly block 7 at substantially equal intervals in the longitudinal direction.

As described above, the skeletal frame 8 has horizontal beam aggregates 15 ..., vertical beam aggregates.
By constructing 16 ... and pillar aggregates 17 ... in a three-dimensional lattice form, high bending and torsional strength is ensured while being lightweight.

Further, the transverse beam aggregates 15 ... And the column aggregates 17 ... are the end walls 21 ₁ , 21 _{2 in} the longitudinal direction of the cylinder barrel assembly block 7 and the boundary wall 1 between the adjacent cylinder bores 4, 4 of the assembly block 7.
Aligned on the left and right extensions of 9 ..., As will be described later, it is possible to effectively counter as a strength member against the load from the bearing portion of the crankshaft 3. The left and right outer surfaces of the skeleton frame 8 formed of the plurality of vertical beam aggregates 16 and column aggregates 17 along the direction of the crank axis l ₂ -l ₂ are lower than the upper end reaching the deck surface 1 of the cylinder block B _c. It is formed as a straight surface substantially parallel to the cylinder bore axis l ₁ -l ₁ direction over the entire length in the vertical direction up to the lower end of the case C _L that reaches the joint surface 23.

As shown in FIGS. 4, 5 and 10, the left and right outer surfaces of the skeleton frame 8 have rear portions, that is, the third and fourth cylinder barrels 1.
Left and right expansion protrusions 25, 25 that are enlarged in a divergent manner from the outer end portion of the transverse beam aggregate 15 located on the boundary wall 19 of 0 ₃ , 10 ₄ toward the rear end surface of the skeletal frame 8 are integrally formed, As a result, the longitudinal rear end face of the skeleton frame 8 is formed in a quadrangle having a larger area than the front end face thereof. The left and right expansion extension 25
Is the left and right cross beam aggregates located on the rear end surface of the skeletal frame 8, that is, on the side of the cylinder block side mission mating surface 26.
15,15, longitudinal beam aggregates 16,16, and extended transverse beam aggregates 15 ₁ , 15 ₁ extending laterally outward from the intersection 27 of the column aggregates 17,17,
3rd and 4th cylinder barrels 10 ₃ and 10 _{4 of} vertical beam aggregates 16, 16 ...
Of the boundary wall 19 of the inclined vertical beam aggregate 16 ₁ , 16 ₁ …, which extends from the lateral direction of the boundary wall 19 to the rear, and the extended horizontal beam aggregates 15 ₁ , 15 ₁ …, and the inclined vertical beam aggregates 16 ₁ , 16 ₁ …. Of the outer column aggregates 17 ₁ , 17 _1, ... And the triangular and prismatic left and right flared extension 25,2
The inclined outer surface of 5 is the vertical direction, that is, the cylinder bore axis l
₁ −l Formed in a straight line parallel to the ₁ direction.

Further, a transmission case mounting frame 28 of the same shape is integrally formed on the rear surfaces of the left and right expansion extensions 25, 25. The frame 28 includes a horizontal frame 28 ₁ and left and right vertical frames 2
8 ₂ and 28 ₂ form a gate shape with the lower surface open, and the rear surface is formed as the cylinder block side mission mating surface 26.

As described above, the cylinder block side mission mating surface 26 of the rear end surface of the cylinder block B _c has a quadrangular shape, and the span in the lateral direction orthogonal to the crank axis l ₂ −l ₂ is enlarged, and the mission mating surface 26 of the mission mating surface 26 is expanded. Bending and torsional rigidity are enhanced.

Cylindrical upper bolt insertion bosses 30, 30 for mounting the mission case C _M are integrally provided at the upper edge corners of the left and right widening extension portions 25, 25.

As shown in FIGS. 2 to 5,11, on the skeleton frame 8 at the rear ends of the left and right outer side surfaces and the left and right expansion bulges 25, 25 which are linear and substantially parallel to the cylinder bore axis l ₁ -l _1. The left and right rigid film members 9 ₁ are made of a steel plate, a metal plate such as an aluminum plate, or a single plate of a reinforced synthetic resin material such as FRP or FRM on the left and right outer surfaces that spread toward the divergent direction toward each other. , 9 ₂ adhesive 63 (Figure 9)
Is directly bonded with.

A heat-resistant epoxy resin as a main component as the adhesive 63
FM-300 (American Cyanamid) is used.

Therefore, the rigid film members 9 ₁ and 9 ₂ can be formed of a straight plate material, and it becomes easy to manufacture them as a high rigidity material and a vibration damping material. Since the rigid film member 9 has a straight line shape substantially parallel to the cylinder bore axis line l ₁ -l ₁ , the rigid film member 9 is mainly subjected to bending acting on the cylinder block B _c and torsional vibration around the crankshaft 3 as shear stress.

The rigid film members 9 ₁ and 9 ₂ may be integrally formed by a single plate. In this case, the rigid film members 9 ₁ and 9 ₂ are bent at the refraction portion on the outer surface of the skeletal frame 8, that is, at the base end of the expansion bulge portion 25.

Thus, as shown in FIGS. 2 and 8 to 10, a plurality of vertical beam aggregates 16 forming the outer wall of the cylinder block B _c and the upper and lower vertical beam aggregates 16 of the column aggregates 17 ... , 16 and front and rear pillar aggregates 17,17
A flange portion fl that continuously extends from one side thereof along the joint surface (that is, the back surface) of the rigid film member 9 ₁ is integrally provided on the outer side portion of the flange portion fl. It is formed thinner than the aggregates 16 and 17. Therefore, according to the special provision of the flange portion fl, as shown in FIG.
..., 17 ... of substantial to the joint surface enlargement is achieved of the bonding surface via the adhesive 63 as mentioned above made of a synthetic resin rigid film member 9 ₁ for rigid film member 9 ₁ is bonded.

Adhesion area between the outer wall and the bonding surface of the rigid film member 9 _1, shear force P is acts longitudinal beam bone members 16 and the pillar aggregate 17 and the rigid film member 9 ₁ of the cylinder block B _c during operation of the engine Is increased, the maximum shear stress S that the joint surfaces are subjected to is reduced.

In addition, as shown in Figs.
The outer side wall of the upper and lower vertical beam aggregates 16 ₁ , 16 ₁ and the outer side portions of the front and rear column aggregates 17 ₁ , 17 ₁ are also joined from one side to the joint surface of the rigid membrane member 9 ₂ . A flange portion fl continuously extending along (that is, the back surface) is integrally extended, and the flange portion fl is formed thinner than the corresponding aggregates 16 ₁ and 17 ₁ . Therefore, even if the flange fl is specially provided, each aggregate 16
_The substantial joint surface of ₁ and 17 ₁ to the rigid membrane member 9 ₂ is enlarged, and the rigid membrane member 9 ₂ is bonded to this joint surface. In this case as well, the joint stress between the longitudinal beam aggregate 16 ₁ and the column aggregate 17 ₁ and the rigid membrane member 9 ₂ is increased, so that the shear stress S received on the joint surface is reduced.

As shown in FIG. 3, on the lower surface of the cylinder block B _c , there are a plurality of lower case C _L inner and outer connecting bolts 32, ...
It is fixed by 3 ...

Next, regarding the structure of this lower case C _L , the first to third, sixth, seventh,
Explaining with reference to Fig. 10 and 11, this lower case C
_L is a rectangular parallelepiped lower case frame whose planar shape is substantially the same as the planar shape of the cylinder block B _c , and the lower case frame 34 in the longitudinal direction (crank axis l ₂ −
Directly bonded to both left and right sides along the ( ₂ direction) 2
Like the rigid film members 35 _1, 35 _2, and a more rigid bottom plate 36 which is bonded to the bottom surface of the lower casing frame 34.

The lower case frame 34 includes a plurality of horizontal beam aggregates 37, vertical beam aggregates 37 like the frame frame 8 of the cylinder block B _c.
38 ... and pillar aggregates 39 ... are frame-connected in a three-dimensional lattice form. The plurality of cross beams aggregate 37 ... are in the longitudinal direction two rows spaced (crankshaft axis l ₂ -l ₂ direction) are rows, these transverse beams aggregate of the lower case C _L
A plurality of vertical beam aggregates 38 ... And column aggregates 39 ... Are integrally connected to the left and right ends of 37 ... in the longitudinal direction and the vertical direction of the lower case C _L. When the cylinder block B _c is joined to the lower case C _L as shown in FIGS. 1 to 3, the horizontal beam aggregates 37, ..., Vertical beam aggregates of the lower case C _L are connected.
38 ... and trabecular bone material 39 ... is the cylinder block B _c, crossbeam bone members 15 ..., match the longitudinal beams aggregate 16 ... and trabecular bone material 17 ... and in the vertical direction, the cylinder block B _c and the lower case C _L The front and rear end surfaces and the left and right side surfaces of the engine block E are formed into a rectangular parallelepiped which is straight in the vertical direction.

Further, the middle part of the upper and lower horizontal beam aggregates 37 of the lower case C _L has a pair of reinforcing columns 40, 40 extending in the vertical direction with a space left and right.
Are joined together by. And these reinforcement columns
A semicircular bearing lower half 42 for supporting the lower half of the crankshaft 3 is formed on the upper surface of each transverse beam aggregate 37 between 40 and 40.

As shown in FIG. 3, when the cylinder block B _c is coupled to the lower case C _L , the pair of reinforcing columns 40, 40
Is vertically aligned with the thick front and rear end walls 21 ₁ and 21 ₂ and the boundary wall 19 of the cylinder barrel assembly block 7 of the cylinder block B _c , and the bearing lower half 42 is the cylinder. A plurality of bearing parts b of the crankshaft 3 are formed so as to coincide with the bearing upper half parts 22 of the lower surface of the block B _c.
... journal shaft portion 3 ₁ of the crank shaft 3 through a bearing metal 43 ... as shown in the first to third drawing is rotatably supported by.

Further, at the rear parts of both outer side surfaces of the lower case C _{L in the} longitudinal direction, an expanding bulge portion 45 is formed integrally with the rear end surface of the lower case C _L , which spreads outward in a divergent manner toward the rear end face. The (transmission case mounting side end surface) is formed wider than the front end surface thereof, and a lower case side mission mating surface 46 having a concave end surface shape is formed on the wide rear end surface thereof. The lower case side mission mating surface 46 cooperates with the cylinder block side mission mating surface 26 of the cylinder block B _c to form a square mission mating surface f, which is shown in FIG. The mission case C _M is connected to.

The widening protruding portion 45 and the extended crossbeam bone members 37 ₁ extending from the crossbeam bone members 37 of the rearmost end, inclined to bind to extended crossbeam bone members 37 ₁ of the outer end is branched from a rear portion of the longitudinal beam bone members 38 Vertical beam aggregate 38 ₁ ,
The extended transverse beam aggregates 37 ₁ and 37 ₁ and the longitudinal beam aggregates 38 ₁ and 38 ₁ are composed of column aggregates 39 ₁ that connect the outer ends of the aggregates in the upward and downward directions. In the left and right corners of the lower edge of the left and right expansion extension 45,
A lower bolt insertion boss 47 for connecting the mission case C _M to the lower case C _L is formed.

Thus, as shown in FIGS. 1 to 3, when the cylinder block B _c and the lower case C _L are connected, the outside of the expansion protrusion 25 of the cylinder block B _c and the expansion protrusion 45 of the lower case C _L. The side surfaces are flush with each other, and the rear end surfaces thereof are formed in a quadrangular shape with their outer peripheral edges being coincident with each other, and a mission mating surface f is formed on the end surface. Then, upper and lower bolt insertion bosses 30, 30, 47, 47 are arranged at the four corners of the mission mating surface f.

Lower case frame 3 as shown in Figures 2, 3 and 10
Steel plates, metal plates such as aluminum plates, reinforced synthetic resin plates such as FRP, FRM, etc. on the left and right outer surfaces of the straight surfaces 4 and the left and right inclined outer surfaces of the expansion bulge 45 of 4 Rigid film members 35 ₁ and 35 ₂ are directly bonded with an adhesive.
The rigid film members 35, 35 are arranged on the left side of the cylinder block B _c ,
It is flush with the right rigid membrane members 9 ₁ and 9 ₂ .

The rigid film members 35 ₁ and 35 ₂ may be integrally formed by a single plate. In this case, the rigid film members 35 ₁ and 35 ₂ are bent at the bending portions on the left and right outer side surfaces of the lower case frame 34, that is, at the base end of the expansion bulge portion 45. It

As shown in FIGS. 2, 6, 10, and 11, the cylinder block B _c is provided outside the plurality of vertical beam aggregates 38 ... And the front and rear column aggregates 39, 39 that constitute the outer wall of the lower case 34. Rigid membrane member similar to
Flange fl towards the inwardly along the joint surface 35 ₁ is integrally extended, each aggregate 38 ..., 39 ..., the joint surface of the large area in cooperation with the flange portion fl respectively formed , rigid film member 35 ₁ are bonded together via the adhesive 63 as described above in the joint surface.

Further, as shown in FIGS. 2, 7, and 11, vertical beam aggregates 38 ₁ and 38 ₁ that form the outer side walls of the left and right expansion bulges 45 and 45, and the front and rear column aggregates 39.
_A flange portion fl that extends inward along the joint surface of the rigid film member 35 ₂ is integrally extended also on the outer side of ₁ , 39 ₁ to form a joint surface having a large area. ₂ is glued. In this case also enlarged bonding area between the longitudinal beam bone members 38 ₁ and trabecular bone material 39 ₁ and the rigid film member 35 _2, thereby the shear stress is reduced to receive their the joint surface.

As shown in FIGS. 1 to 3, a rigid bottom plate 36 as a baffle plate made of a flat plate such as a metal plate and a synthetic resin plate is bonded to the flat bottom surface of the lower case C _{L by} an adhesive, and the lower surface of the rigid bottom plate 36 is further joined. The oil pan P _o is connected to. As shown in FIGS. 7 and 9, the rigid bottom plate 36 is provided with a plurality of oil holes 50. Lubricating oil flows between the cylinder block B _c and the oil pan P _o through these oil holes 50. .

As shown in FIGS. 1 to 3, a rectangular parallelepiped cylinder block B _c composed of a cylinder barrel assembly block 7, a skeleton frame 8, and left and right rigid film members 9 ₁ and 9 ₂ has a lower case frame 34 on the flat bottom surface. , left, consisting of the right rigid film members 35 _1, 35 ₂ and a rigid bottom plate 36 the flat upper surface of the lower case C _L is polymerized, and a plurality of inserted through the lower case C _L from the lower surface of the lower case C _L are those , The inner connecting bolts 32 are screwed to the cylinder block B _c , whereby the cylinder block B _c and the lower case C _L are integrally connected. Furthermore the flat lower surface of the lower case C _L is polymerized oil pan P _o, the oil pan P _o is fixed by a plurality of outer connecting bolts 33 ... together with the lower case C _L to the cylinder block B _c. And the coupling of the cylinder block B _c and the lower case C _L, in their bearing portion b formed on the mating surface, the journal shaft portion 3 ₁ of the crank shaft 3 is rotatably supported by a bearing metal 43.

Further on the flat deck surface 1 of the cylinder block B _c, as shown in the first to third drawing, a plurality of long, short connecting bolt 51 ..., 52
The cylinder head H _c is integrally bound by. Then, as shown in FIG. 2, in the longitudinal direction of the cylinder head H _c ,
Nachi Suwa crankshaft direction l ₂ outer surface S ₂ along -l _2, S ₂ is
The cylinder block B _c and the lower case C _L are located inside the outer surfaces S ₁ and S ₁ extending in the same direction in the same direction.

Note in the cylinder head H _c, 53 a combustion chamber, 54,5
5 is an intake / exhaust port, 56 and 57 are intake / exhaust valves.

As shown in FIG. 1, a water pump W _P is provided on the front end wall of the cylinder block B _c , and an oil pump O _P is connected to the end of the crankshaft 3 on the front end wall side. Further the second and third one side of the cylinder block B _c, as shown in FIG been bound oil filter O _F, cleaning oil from the oil filter O _F is a cylinder block B _c in the skeletal frame 8
Oil is supplied to the lubricated portion such as the bearing portion b of the crankshaft 3 through the oil gallery 58 formed in the above.

As described above, the joint surface of the mission case C _M is superposed on the rectangular transmission mating surface f formed on the rear end surface of the cylinder block B _c and the lower case C _L which are integrally bonded to each other. B _c and lower case
The four connection bolts 59 ... Inserted in the bolt insertion bosses 30, 30, 47, 47 provided at the corners of C _L are screwed to the mission case C _M to be integrally connected. The combination of the cylinder block B _c and the lower case C _L and the transmission case C _M can be connected by only four connecting bolts 59, and the connecting work is easy, which can contribute to the overall weight reduction. .

Note the In can be implemented even this has been described for other multi-cylinder engine in the case where the present invention was performed in series four-cylinder engine embodiment of course, the cylinder block B _c and the lower case C _L constitutes the engine block The aggregate forming the left and right outer walls along the crank axis l ₂ -l ₂ direction may be provided with a flange portion fl at a part thereof as in the above embodiment, and the flange portion fl is provided at the front portion thereof. It may be provided.

C. Effects of the Invention As is apparent from the above embodiments, according to the present invention, both outer walls along the crankshaft direction are formed in a lattice shape by a frame of aggregate, and the outer surfaces of the outer walls have plate shapes. In the engine block of the multi-cylinder engine configured by joining the back surfaces of the rigid film members, the outside of the aggregate extends along one side of the back surface of the rigid film member and is thinner than the aggregate. Since the flange portion is integrally extended, and the outer surface of the aggregate and the outer surface of the flange portion together form a joint surface with the rigid membrane member, the substantial joint area between the rigid membrane member and the aggregate. Can be effectively expanded by the special provision of the flange portion, and the shear stress acting on the joint surface between the aggregate and the rigid membrane member can be effectively reduced. Furthermore, the flange portion itself is aggregate. Thinner than that and significantly increase the overall weight of the aggregate As a result, the aggregate and the rigid membrane member are joined together without increasing the rigidity by thickening the aggregate more than necessary or thickening the rigid membrane member more than necessary. Since the strength and durability of the portion can be increased, it is possible to effectively prevent peeling and damage of the rigid film member while reducing the block weight.

[Brief description of drawings]

FIG. 1 shows an embodiment of an engine block of the present invention. FIG. 1 is an overall side view of an engine shown by longitudinally cutting a main portion along line II in FIG. 2, and FIG. 2 is FIG. A longitudinal sectional view of the engine taken along line II-II, FIG. 3 is a partially enlarged longitudinal sectional view of the engine taken along line III-III of FIG. 4, and FIG. 4 is FIG.
A top view of the cylinder block along the line IV-IV, and FIG.
2 is a bottom view of the cylinder block taken along the line VV in FIG.
The figure is a top view of the lower case along the line VI-VI in FIG. 2, FIG. 7 is a bottom view of the lower case along the line VII-VII in FIG. 2, and FIG. FIG. 9 is a side view of a cylinder block of FIG. 9, FIG. 9 is an enlarged view of a portion IX of FIG. 2, FIG. 10 is an exploded perspective view of a cylinder block and a lower case, and FIG. 11 is an exploded perspective view of a rigid membrane member and a rigid bottom plate. FIG. 12 is a partially enlarged view of a conventional engine block. fl… Flange part 9 ₁ , 9 ₂ , 35 ₁ , 35 ₂ … Rigid membrane member, 16,16 ₁ … Vertical beam aggregate as aggregate, 17,17 ₁ … Column aggregate as aggregate, 38,38 ₁ … Vertical beam aggregate as aggregate, 39,39 ₁ … Column aggregate as aggregate

Claims (1)

[Scope of utility model registration request] 1. Outer side walls along the crankshaft direction are formed in a lattice shape by a framework of aggregates (16,17; 16 ₁ , 17 ₁ ; 38,39; 38 ₁ , 39 ₁ ). In an engine block of a multi-cylinder engine, the back surfaces of plate-shaped rigid membrane members (9 ₁ ; 9 ₂ ; 35 ₁ ; 35 ₂ ) are joined to the outer surfaces of the aggregates (16, 17; 16 ₁ , 17 ₁ ; 38,39; 38 ₁ , 39 ₁ ) on the outer side of the rigid membrane member (9 ₁ ; 9 ₂ ; 35 ₁ ; 35 ₂ ) from one side thereof.
Of the aggregate (16,17; 16 ₁ , 17 ₁ ; 38,3 extending along the back surface of the
9; 38 ₁ , 39 ₁ ) The flange (fl), which is thinner than that of 9; 38 1,39 1), is integrally extended, and the aggregate (16,17; 16 ₁ , 17 ₁ ; 38,39; 38 ₁ , 39 ₁ )
And the outer surface of the flange portion (fl) together form a joint surface with the rigid membrane member (9 ₁ ; 9 ₂ ; 35 ₁ ; 35 ₂ ), an engine block of a multi-cylinder engine.