JPS62279257A - Block structure of engine - Google Patents

Abstract

PURPOSE:To ensure the positioning of a block by providing a positioning means in the longitudinal direction on the transmission side end parts of a cylinder block and a skirt part block, and providing stepped parts on the mating faces of both blocks and forming a positioning part in the right-left direction. CONSTITUTION:An engine body is divided into a first block 2 which forms a head part and a cylinder part and a second block 4 which forms a skirt part. And, stepped parts 24 are formed on the mating faces of both blocks, which are bolted in a condition that both the corresponding stepped parts are engaged with each other. Also, the positioning in the right-left direction between both blocks is carried out by the side faces 37, 39 which are brought into contact with each other, of the stepped parts of the mating faces. Further, pin holes 41, 42 and a knock pin 43 as positioning means in the longitudinal direction are provided on the transmission side end parts of both blocks.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Industrial Application Field) The present invention relates to an engine block structure, particularly an engine body, which includes a block constituting a head portion and a cylinder portion, and a skirt portion. The present invention relates to an engine block structure in which the engine block is divided into two blocks, and both blocks are connected with bolts.

(Prior Art) In an engine for an automobile, etc., a head portion having an intake and exhaust boat is formed in a cylinder head, and a cylinder portion having a cylinder bore and a skirt portion forming a crank chamber are integrally formed in a cylinder block. It is customary. However, with such an engine structure, a plurality of head bolts must be installed from the top of the cylinder head to the cylinder block while avoiding interference with intake and exhaust boats, intake and exhaust valves, etc. As a result, the layout of the intake and exhaust system is constrained by the bolts mentioned above, significantly reducing its degree of freedom, and the mating surfaces of the cylinder head and cylinder block are affected by the high temperature and high pressure combustion gas. This causes problems such as deformation, and especially in high-output, high-speed engines, the sealing performance of the mating surfaces against the combustion gas is significantly deteriorated.

For example, Japanese Unexamined Patent Publication No. 5
As shown in Japanese Patent No. 6-34938, the head bolt is eliminated by integrally forming the section extending from the head part to the cylinder part as one block,
In addition, the mating surface of this block and other blocks is not located in the area corresponding to the combustion chamber, thereby increasing the degree of freedom in the layout of the intake and exhaust system and improving the sealing performance against combustion gas. A new engine block structure has been proposed. When adopting this type of block structure, in order to ensure the roundness of the cylinder bore or liner formed in the cylinder part, or when machining the head part from the cylinder part side, that is, from the bottom side of the engine, machining work must be done. For reasons such as simplification or simplification, the head part and cylinder part are integrally formed into one block, the skirt part is made into another block, and these two blocks are connected using bolts etc. It has been considered or attempted to conclude the same.

(Problems to be Solved by the Invention) As described above, the engine body is divided into a block that constitutes the head section and the cylinder section, and a block that constitutes the skirt section, and these two blocks are fastened together with bolts. Although such a block structure has the advantages of ensuring the roundness of the cylinder bore and facilitating machining of the head portion as described above, it has the following drawbacks.

In other words, in the cylinder section of one of the blocks, a piston that slides against the inner surface of the cylinder bore reciprocates, and in the skirt section of the other block, the crankshaft, which is supported via a bearing, causes the piston to reciprocate. In this case, the piston receives an explosive load from the combustion gas, and an extremely large load is intermittently applied to the crankshaft via the connecting rod. As a result, stress is repeatedly applied to the mating surfaces of the one block and the other block, and the cylinder section is at a higher temperature than the skirt section, resulting in a difference in thermal expansion between the two blocks. Furthermore, in a multi-cylinder engine, the phases of the reciprocating motion of each piston are different from each other, resulting in a situation where bending stress or shearing force is applied to the mating surfaces.

Therefore, it is necessary to ensure sufficient joint rigidity or mounting rigidity at the mating surfaces of the two blocks, but in spite of this, for example, the mating surfaces do not allow the flat flange portions to abut against each other. In cases where the two blocks are connected by bolts, etc., looseness or misalignment may occur between the two blocks, resulting in misalignment of the relative position of the piston and crankshaft, or Compression ratios may vary from cylinder to cylinder or engine to engine, and the connection between the transmission case, which is attached to the rear end of the engine body across both blocks, may become unstable, and these may cause discomfort. This results in various problems such as the generation of photographic noise. In order to prevent or suppress the occurrence of such problems, not only the mounting rigidity of the above-mentioned mating surfaces but also the positioning or positioning accuracy of both blocks are important, but simple and effective concrete measures have not been found. The reality is that this is not the case.

(Means for Solving the Problems) The present invention relates to the block structure of an engine, particularly the block structure in which both the block constituting the head portion and the cylinder portion and the block constituting the skirt portion are bolted together. The purpose is to effectively improve the mounting rigidity and positioning accuracy of both blocks using simple means or configurations, thereby reducing the impact caused by the load and heat acting on the mating surfaces of both blocks. It is an object of the present invention to provide a well-positioned engine block structure by suppressing as much as possible deformation in the vicinity of mating surfaces, as well as looseness and misalignment occurring between both blocks. In order to achieve this object, the present invention is characterized by the following configuration.

That is, an engine body consisting of a head section, a cylinder section, and a skirt section is divided into a block that constitutes the head section and cylinder section and a block that constitutes the skirt section,
In the engine block structure in which both blocks are bolted together, a means for positioning the blocks in the longitudinal direction of the engine (in the longitudinal direction of the engine) is provided at the transmission side ends (rear part of the engine) of the blocks,
A stepped portion is provided at a predetermined position on the mating surfaces of the two blocks, and the side surfaces of the two blocks that come into contact with each other in the stepped portion are used as positioning portions of the blocks in the left-right direction (engine width direction). shall be.

According to the above configuration, the head portion having the intake/exhaust boat, etc., and the cylinder portion having the cylinder bore or cylinder liner are integrally formed in one block, and this block and other blocks are not connected to each other. Since the cylinder part and the skirt part are separated, the conventional head bolts are abolished, allowing greater freedom in the layout of the intake and exhaust system, and making it possible to machine the head part from the bottom of the engine. This makes it possible to maintain the roundness of the cylinder bore with high accuracy while improving the roundness of the cylinder bore.

Particularly, according to the present invention, since the positioning of both blocks in the longitudinal direction is performed by a positioning means such as a knock bottle, which is driven across both blocks at the end on the transmission side, both blocks are positioned when the engine is operated. Even if a relatively large difference in thermal expansion occurs in the front-rear direction, that is, in the longitudinal direction of the engine due to the temperature difference between the blocks, the transmission-side ends of both blocks are firmly positioned. There is no deviation in relative position, and therefore, the connection state of the mission case, which is attached across the end faces of both blocks, is always good and reliable. In addition, because the longitudinal positioning is performed only at the end on the mission side and only that end is restrained, deformation and imaging due to the difference in thermal expansion between the two blocks are prevented. The effect of moderate absorption or suppression can also be obtained.

Furthermore, stepped portions are formed on the mating surfaces of both blocks, and both blocks are bolted together while the corresponding stepped portions are engaged, so that, for example, a flat surface can be formed. Compared to the case where bolts are fastened with the formed mating surfaces in contact with each other, the mounting rigidity is increased, and the two-dimensional structure that occurs due to the load or heat acting on the mating surfaces is improved. Shakiness and misalignment of the block, as well as vibration, etc., are effectively suppressed. In addition, positioning in the left-right direction, that is, in the engine width direction, is performed by the mutually abutting side surfaces of the stepped portions formed on the mating surfaces. Even if a shearing force is applied, the contact between the two sides prevents the blocks from shifting due to this bending stress, thereby ensuring the positioning of the blocks and eliminating variations in the compression ratio. It will be suppressed.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

In this embodiment, the present invention is applied to an in-line 4-cylinder, 4-valve engine.

First, the general structure of the engine according to the present invention will be explained based on FIG. 1. The main body of the engine 1 includes a first block 2 to which a head cover (not shown) is attached above, and an oil pan 3 below. The first block 2 is provided with a head portion 5 and a cylinder portion 6, and the second block 4 is provided with a skirt portion 7. The second blocks 2.degree. 4 are fastened together using bolts 8...8. The head portion 5 of the first block 2 includes:
An intake boat 10 and an exhaust boat 11 are opened in the ceiling of the combustion chamber 9, and intake and exhaust valve stem holes 12 are formed to correspond to these boats 10 and 11, respectively. 13, a bearing hole (lower half) 14, 15 for a camshaft that opens and closes the intake and exhaust valves, and a fitting hole 16 for a tappet interposed between the above-mentioned valves and both camshafts. .17 is provided, and the cylinder portion 6 of this first block 2 is provided with a cylinder bore 18 that fits and holds a piston.On the other hand, the second block 4 (skirt portion 7) is provided with a cylinder bore 18 that fits and holds a piston. Partition walls 19 located below between adjacent bores and formed in these walls 19 to form walls 1
A bearing hole (upper half) 21 is provided in which the journal portion of the crankshaft is fitted and held between the bearing cap 20 and the bearing cap 20 attached below the second block 9, respectively.
A crank chamber 22 is constituted by the oil pan 3 and the oil pan 3, and an inter-skirt plate 23 is provided at the lower end of the block 4 to prevent deformation of the end portion during engine operation.
is ready to be installed.

Incidentally, a squish generating surface 9' for generating squish of the air-fuel mixture in the combustion chamber 9 is formed at the peripheral edge of the ceiling surface of the combustion chamber 9 formed in the first block 2. This generated surface 9' is also used as a reference surface when machining the bearing hole 21 of the crankshaft. Furthermore, recesses 18'...18' are formed at the lower end of the cylinder bore 18 in the first block 2, and these four parts 18'...18' are the valves in the head section 5 of the block 2. This is provided to avoid interference between the tool and the end when machining the stem fitting hole 12,13.

Next, the above first feature, which is a feature of the present invention. 2nd car block 2.
4 and the positioning means will be explained based on FIG. 2 (a bottom view of the first block 2) and FIG. 3 (a plan view of the second block 4).

First, the first block 2 shown in FIG. 2 has peripheral wall portions 24...2 of each cylinder bore 18...18 at its bottom.
4 is formed to protrude downward from the lower end surface 25 of the block 2, and each of the protruding peripheral wall portions 24,
...24 are connected between adjacent bores via connecting portions 24'...24'. Further, the lower end surface 25 has screw holes 26...2 into which the tips of the bolts 8...8 are screwed into both ends thereof and both sides of the connecting portions 24'...24'.
6 are formed, and a seal member mounting groove 27 is further provided so as to surround these screw holes 26 . . . 26 and each of the peripheral wall portions 24 .

On the other hand, the second block 4 shown in FIG. 3 has a boss part 30 of a bolt insertion hole 29 on the upper wall part 28, and the upper end surface 31 of the wall part 28 is formed in a flat shape, and each bore The upper parts of the partition walls 19 .
In the first block 2, the connecting portion 24'...
A fourth portion 33 is formed corresponding to 24' (see FIG. 1). The upper part of the second block 4 is provided with holes 36 that are partitioned by the partition walls 19 and the front and rear end walls 34 and 35 and communicate with the crank chamber 22.
36 are provided.

Therefore, each bore peripheral wall portion 24 in the first block 2
. . 24 are formed with first side surfaces 37 . . . 37, respectively, and both side edges 38 .・3
7 are set to a predetermined width, and second side surfaces 39... are provided on both inner sides of the upper end surface 31 of the second block 4 in correspondence with the first side surfaces 37...37.・
39 are formed, respectively, and a predetermined width is set between the side edges 40...40 of the upper end surface 31 of the second block 4 and the three second side surfaces 39.

Then, each bore circumferential wall portion 24...24 of the first block 2 is fitted into each hole 36...36 of the second block 4, and the lower end surface 25 and upper end surface 31 of both blocks 2, 4 are inserted. With the bolts 8...8 in contact with each other, insert the bolts 8...8 into the bolt insertion holes 29...29 and screw holes 26...
26, the two blocks 2.4 are bolted together. In that case, each of the first side surfaces 37...37 of the first block 2 and the corresponding three second side surfaces of the second block 39 are brought into close contact with each other, and as a result, both blocks 2.4, positioning is performed in the left-right direction, that is, in the engine width direction.

Furthermore, a first bottle hole 41 is opened in the lower end surface 25 of the first block 2 at a part of the corner of the mission side end, that is, the rear end of the engine (the left end in the drawing), and A second bottle hole 42 is also opened in the upper end surface 31 at a position corresponding to the first bottle hole 41 . And this first one. By driving the knock pin 43 across the second pin holes 41, 42 (see FIG. 1), the two blocks 2.4 are positioned in the longitudinal direction of the engine, that is, in the longitudinal direction of the engine. Furthermore, mission flanges 44 and 45 are provided at the rear ends of the first and second blocks 2 and 4.
are formed, respectively, and a transmission case 46 shown by a chain line in FIG. 1 is attached so as to straddle both flanges 44 and 45.

According to the above structure, the head part 5 having the intake and exhaust boats 10, 11, etc., and the cylinder part 6 having the cylinder bore 18 are integrally formed in the first block 2, so that the conventional head bolt is not required. By abolishing this, it is possible to increase the degree of freedom in the layout of the intake and exhaust system, and the sealing performance around the combustion chamber 9 can be improved. Further, since the first block 2 and the second block 4 are precisely divided between the cylinder part 6 and the skirt part 7, the roundness of the cylinder bore 18 is maintained with high precision, and the first block 2 and the second block 4 are precisely divided between the cylinder part 6 and the skirt part 7. When the second block 2.4 is divided, the processing work for the head portion 5 from below is facilitated or simplified in combination with the provision of the recesses 18'...18' at the lower end of the bore 18. will be made into

Note that the machining of the crankshaft bearing hole 21 shown in FIG. This is done after assembling the second blocks 2.4 in the state shown in the figure and setting the dimension from the squish generating surface 9' at the peripheral edge of the combustion chamber 9 to the center of the bearing hole 21 to a predetermined value. , variations in the compression ratio of each cylinder can be prevented.

However, in this engine 1, the first. The second block 2.4 is connected to the lower end surface 25 of the first block 2 and the second block 2.4.
First side surfaces 37 . . . 37 formed on each bore circumferential wall portion 24 . Correspondingly, the upper wall 2 in the second block 4
Since the configuration is performed by fastening the second side surfaces 39...39 formed on the inner side of the second side surfaces 39...39 in close contact with each other using the bolts 8...8, for example, Compared to the case where the end faces of both formed blocks are brought into close contact with each other and bolted together, the joint rigidity or mounting rigidity is effectively increased. This prevents the occurrence of looseness or misalignment between the two blocks 2.4, as well as accompanying vibrations, etc., due to the load or heat acting on the joint portion of the two blocks 2.4. Furthermore, by bringing each of the first side surfaces 37...37 of the first block 2 into close contact with each of the second side surfaces 39...39 of the second block 4, the positioning of both blocks 2.4 in the left-right direction is facilitated. As a result, even if a large bending stress or shearing force is applied to the joint portion due to the linked movement between the piston and the crankshaft, the 8th 1st second both sides 37...
・37.39...The three abutments prevent the blocks 2.4 from shifting in the left-right direction due to the bending stress, improving the positioning accuracy between the blocks 2.4. .

Furthermore, the above 1. 1st and 2nd double bottle holes 4 formed at the transmission side end of the joint part of the second double blocks 2.4
By driving the knock bottle 43 across the block 1.42, the longitudinal position of both blocks 2.4 is determined.
Even if a relatively large difference in thermal expansion occurs due to the temperature difference between the two blocks (the first block 2 is in a higher temperature state than the second block 4), the mission side ends of both blocks 2.4 Since the positions of the transmission flanges 44 and 45 formed on both blocks 2.4 are firmly positioned, there is no deviation in the relative positions of the mission flanges 44 and 45 formed on both blocks 2.4, and therefore, the transmission case 46 is firmly positioned on both blocks 2.4. The bond will always be maintained in a stable state. Also 1,
In this way, the longitudinal positioning of both blocks 2.4 is performed only at the end on the transmission side, and only that end is restrained, so that both blocks 2.4 The effect of appropriately absorbing deformation, imaging, etc. due to the difference in thermal expansion will also be reduced by 1q.

In this embodiment, the oil passage of the lubricating device is configured as shown below in order to provide good lubrication to each lubricating part of the engine 1.

That is, as shown in FIGS. 4 and 5, on the negative side of the first block 2 (skirt portion 7), there is an oil discharge passage 5 through which the lubricating oil in the oil pan 3 is discharged by the oil pump P.
0 is formed on the side of the second block 4 (cylinder section 6), and an oil cooling passage 52 is formed in parallel and adjacent to the water jacket 51.
(see FIG. 1), the oil discharge passage 50 is the first communication passage 5.
3 to the oil inlet 55 provided in the oil filter mounting portion 54, and the oil cooling passage 52 communicates to the oil outlet 56 provided in the mounting portion 54, so that both the passages 50° 52 are configured to communicate through an oil filter. Furthermore, the oil filter side end of the oil cooling passage 52 is connected to the tappet fitting hole 16.17, the camshaft bearing hole 14.15, etc. via a second round passage 57 arranged close to the water jacket 51. The downstream end of the cooling passage 52 communicates with a main gear gallery 60 formed in the second block 4 via a third communication passage 59, and the main gear gallery 60 communicates with the bearing hole 21 of the crankshaft via each branch passage 61...61.

By configuring the oil passage in this way, the lubricating oil discharged from the oil pump P to the oil discharge passage 50 of the second block 4 passes through the oil cooling passage 52 of the first block 2. After being brought to a low temperature state by the cooling water in the water jacket 51, the second
It flows into the block 4, is forced into the main gear rally 60, and is further supplied from the gear rally 60 to the crankshaft bearing holes 21...21 via each branch passage 61...61. As a result, the lubrication and cooling effects on the bearing holes 21 . In addition, the tappet fitting hole 16
．． 17 etc., lubricating oil is supplied to the oil gear lary 58 through the second communication passage 57 disposed close to the water jacket 51, so that the lubrication and cooling effects on the valve mechanism are also performed satisfactorily.

In addition, in this embodiment, the cooling water passage (water jacket) of the cooling device provided in the engine 1 is configured as shown below, so that the cooling effect on the engine 1 is well performed. is taken into consideration.

That is, as shown in FIG. 6, the water jacket of this engine 1 is formed in the cylinder part 6 of the first block 2, and includes cylinder part side jackets 51 (first and second jackets) formed on both sides of the cylinder part 6 so as to surround the cylinder bore 18. (See Figure 1)
and a head side jacket 51' formed on the head part 5 of the first block 2 and whose upper part is covered by the upper deck 70, and both jackets 51
51' is above the combustion palm upper wall 9a and is partitioned off by lower decks 71...71 provided between the boat walls of the intake and exhaust ports 10.11.

Further, communication holes 72...72 are formed between the respective bores in the lower decks 71...71 to communicate the two jackets 51, 51', and the discharge lower 4 of the water pump 73 ( (See Figure 1), the cylinder side jacket 51 of the above-mentioned both jackets 51 and 51'
It is connected to the. With such a cooling water passage configuration, the cooling water discharged from the water pump 73 to the cylinder side jacket 51 is transferred to the combustion chamber located directly below the lower decks 71 . . . 71 while remaining at a low temperature. The cooling water immediately reaches the periphery of the wall 9a, and the combustion seedlings 9 are well cooled.In addition, in the areas between the bores where the cooling water flow tends to stagnate, the cooling water flows through the communication holes 72... 51 to the head side jacket 51', a smooth flow of cooling water occurs between the respective bores. As a result, the temperature of the combustion arm 9 is suitably lowered, improving the knocking resistance and heat load resistance of the engine 1, and improving the cooling performance between the bores, and further cooling the cylinders. This will prevent variations in action.

(Effects of the Invention) As described above, according to the present invention, in the engine block structure in which the engine body is divided into a block constituting a head portion and a cylinder portion, and a block constituting a skirt portion, both of the blocks are separated. Since stepped portions are formed on the mating surfaces and the bolts are connected with the corresponding stepped portions engaged, the mounting rigidity of both blocks is effectively increased and backlash that occurs between them is eliminated. This means that deviations and misalignments will be suppressed as much as possible. Furthermore, since the horizontal positioning of both blocks is performed by the mutually abutting side surfaces of the stepped portions formed on the mating surfaces, the bending stress acting on the mating surfaces causes the blocks to be positioned relative to each other in the horizontal direction. The occurrence of misalignment is repeated, and the positioning of both blocks is ensured.

Furthermore, since the means for positioning the blocks in the longitudinal direction is provided only at the end on the transmission side, while maintaining a stable connection between the blocks and the transmission case, the means for positioning the blocks in the longitudinal direction can be adjusted. It becomes possible to effectively absorb or suppress deformation, imaging, etc. caused by thermal expansion differences.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention; FIG. 1 is a longitudinal sectional front view of an engine according to the present invention, FIG. 2 is a bottom view of a single block constituting the head section and cylinder section, and FIG. 3 is a skirt section. FIG. 4 is a longitudinal sectional front view of the block that shows the configuration of the oil passage in the block that makes up the skirt part, and FIG. 5 shows the configuration of the oil passage that spans both blocks of the engine. side view,
FIG. 6 is a longitudinal sectional front view of the block constituting the head section and cylinder section, showing the configuration of cooling water passages in the block. DESCRIPTION OF SYMBOLS 1... Engine, 2... Block (first block) constituting the head section and cylinder section, 4... Block (second block) constituting the skirt section, 5... Head section, 6. ...Cylinder part, 7...Skirt part, 8.
...Bolt, 24...Stepped part (peripheral wall part), 25.31
...Matching surfaces (lower end surface of the first block, upper end surface of the second block), 37°39... Side surfaces of both blocks that come into contact with each other (first side surface, second side surface), 41.42.43.・
- Positioning means in the front and back direction (first bottle hole, second bottle hole,
knock bottle).

Claims (1)

[Claims] (1) Divide the engine body consisting of a head section, cylinder section, and skirt section into a block that constitutes the head section and cylinder section, and a block that constitutes the skirt section, and fasten these two blocks with bolts. In the engine block structure, a means for positioning the blocks in the longitudinal direction is provided at the ends of the blocks on the transmission side, and a stepped part is provided at a predetermined position on the mating surface of the blocks, An engine block structure characterized in that the side surfaces of the stepped portion where the blocks come into contact with each other serve as positioning portions of the blocks in the left-right direction.