Cylinder cover structure

Abstract

The invention provides a cylinder head structure, which can increase the rigidity of a part corresponding to a cylinder hole when the sealing force between a cylinder block and a cylinder head is strengthened and the output of an engine is improved, and can reasonably improve the sealing force of a cylinder hole corresponding part located at the upper side between adjacent cylinders. The cylinder head structure is provided with: insertion walls (24, 24) through which left and right fastening bolts disposed between adjacent cylinders pass; a cylinder head upper wall (25) that connects the upper ends of the pair of insertion walls (24, 24) to each other; and a cylinder head bottom wall (26), and a cylinder head cooling water path (2W) enclosed by the four walls (insertion walls (24, 24), the cylinder head upper wall (25), and the cylinder head bottom wall (26)) is formed, a vertical wall (27) is formed between the pair of insertion walls (24, 24), and the vertical wall (27) is formed in a state of bridging the cylinder head upper wall (25) and the cylinder head bottom wall (26) and extending in the left-right direction to shield the cylinder head cooling water path (2W). The vertical wall (27) is present in a central region between the pair of insertion walls (24, 24).

Description

Technical Field

[0001] The invention relates to a cylinder head which is assembled on a cylinder block by a plurality of fastening bolts. Background Art

[0002] In a water-cooled multi-cylinder diesel engine, for example, as disclosed in Patent Document 1, the following structure is generally adopted: cooling water discharged from a water pump is transported to the cooling water path of the cylinder block (cylinder), and in the cooling water path of the cylinder head, the cooling water rises from the cooling water path around each cylinder hole of the cylinder block.

[0003] The cylinder block and the cylinder head are assembled with a gasket interposed therebetween. However, since the width between the cylinders, that is, between the cylinder holes, is narrow, the width of the gasket is inevitably narrowed, so the sealing force of the combustion gas is easily reduced.

[0004] In addition, the space between adjacent fastening bolts in the cylinder head becomes a hollow cross-section due to the presence of the cooling water channel, which easily reduces the rigidity. In particular, between a pair of fastening bolts sandwiching adjacent cylinder holes in the cylinder block (see Patent Document 2), Figure 4 ), the axial force of the fastening bolts is difficult to be transmitted to the gasket through the cylinder head, and the pressing force of the gasket is reduced, which may lead to a decrease in the sealing force.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2003-97347

[0008] Patent Document 2: Japanese Patent Application Publication No. 2015-108346 ( Figure 4 ) Summary of the invention

[0009] Problem that the invention aims to solve

[0010] With the recent high performance, if the output of the engine is increased without changing the interval between cylinders or the cylinder diameter, the combustion pressure will increase. Therefore, it is necessary to further improve the sealing force between adjacent cylinders, but there is a limit in the above-mentioned existing technology, and further research is needed.

[0011] The object of the present invention is to provide a cylinder head structure which can increase the rigidity of the corresponding parts between cylinder holes on the upper side between adjacent cylinders in the cylinder head while strengthening the sealing force between the cylinder block and the cylinder head to achieve an increase in the output of the engine, thereby reasonably improving the sealing force of the corresponding parts between the cylinder holes.

[0012] Means used to solve problems

[0013] The present invention provides a cylinder head structure, characterized in that:

[0014] The cylinder head is assembled on the cylinder block by a plurality of fastening bolts.

[0015] The cylinder head is provided with: an insertion wall for passing fastening bolts on both sides between adjacent cylinders arranged in the cylinder body; a cylinder head upper wall connecting the upper ends of a pair of the insertion walls to each other; and a cylinder head bottom wall.

[0016] A vertical wall is provided in the cooling water passage surrounded by the pair of the insertion walls, the cylinder head upper wall, and the cylinder head bottom wall. The vertical wall straddles the cylinder head upper wall and the cylinder head bottom wall.

[0017] Regarding claims 2 to 6 following the second invention, reference is made to the claims.

[0018] Effects of the Invention

[0019] According to the present invention, since a longitudinal wall is newly provided between a pair of insertion walls, the length between the pair of insertion walls is greatly shortened (the length of the beam when the cylinder head upper wall is regarded as a double support beam is greatly reduced), thereby being able to greatly improve the strength and rigidity of the corresponding portion between the cylinder holes on the upper side between adjacent cylinders in the cylinder head.

[0020] The axial force generated by tightening the fastening bolts passing through the pair of insertion walls is guided not only through the insertion walls but also through the cylinder head upper wall and the cylinder head bottom wall, and the axial force is transmitted to the cylinder head as evenly as possible compared to the existing structure without the longitudinal wall. Therefore, the axial force guided between the pair of fastening bolts is substantially increased, so that the sealing between the cylinder block and the cylinder head can be greatly improved.

[0021] As a result, a cylinder head structure can be provided which can increase the rigidity of the corresponding parts between cylinder holes on the upper side between adjacent cylinders in the cylinder head while strengthening the sealing force between the cylinder block and the cylinder head to increase the output of the engine, thereby reasonably improving the sealing force of the corresponding parts between the cylinder holes. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic side view of the engine showing a cooling water conveying structure.

[0023] Figure 2 This shows the schematic structure of the cylinder bore. Figure 2 (A) is a longitudinal section view. Figure 2 (B) is Figure 2 The BB line cross-sectional view of (A) Figure 2 (C) is Figure 2 (A) CC line cross-sectional view.

[0024] Figure 3 It is a top view of the cylinder head.

[0025] Figure 4 yes Figure 3 ZZ line sectional view (a cross-sectional view showing the corresponding part between cylinder holes)

[0026] Figure 5 A partially cutaway perspective view showing the corresponding portion between the cylinder holes of the cylinder head, viewed from obliquely above DETAILED DESCRIPTION

[0027] Hereinafter, an embodiment of the cylinder head structure of the present invention in the case of an industrial diesel engine will be described with reference to the accompanying drawings. It should be noted that in the industrial diesel engine (hereinafter referred to as the engine) E, the side having the cooling fan 10 is the front, the side having the inertia wheel 7 is the rear, the side having the intake port 30 (the side having the intake manifold (not shown)) is the right, and the side having the exhaust port 28 (the side having the exhaust manifold (not shown)) is the left. Figure 5 In the present invention, a longitudinal wall 27 is added to the existing structure by an imaginary line.

[0028] like Figure 1 As shown, in an inline 4-cylinder (multi-cylinder) engine E, a cylinder head 2 is assembled on a cylinder block 1, a cylinder head cover 3 is assembled on the cylinder head 2, and an oil pan 4 is assembled below the cylinder block 1. Reference numeral 5 is a crankshaft, reference numeral 6 is a piston, reference numeral 7 is an inertia wheel, reference numeral 8 is a transmission belt, reference numeral 9 is a water pump, reference numeral 10 is a cooling fan, and reference numeral 11 is a radiator. The upper portion of the cylinder block 1 is formed as a cylinder portion 1A in which the piston 6 is embedded.

[0029] The cooling water w in the cooling device of the engine E flows roughly in the following order. Figure 1 As shown, water pump 9 → cylinder portion 1A of cylinder block 1 → cylinder head 2 → thermostat 12 → upstream hose 13 → radiator 11 → downstream hose 14 → water pump 9. In addition, there is a path in which a part of the cooling water w is cooled in the oil cooler 16 through the supply path 15 of the dedicated path from the cylinder head 2, and then returns to the water pump 9 through the discharge path 17.

[0030] The cooling water w entering the cylinder unit 1A from the front basically flows backward and also flows upward along each cylinder 1a. Therefore, the cooling water w flows upward from the water jacket of the cylinder unit 1A, i.e., the cylinder cooling water path 1W, into the water jacket of the cylinder head 2, i.e., the cylinder head cooling water path 2W, and also flows from the rear to the front (the water pump 9 at the front).

[0031] like Figure 2As shown in (A), between the adjacent cylinders 1a, 1a of the cylinder unit 1A, a lower connecting wall 18, a middle connecting wall 19, and an upper connecting wall 20 are provided to connect and integrate the adjacent cylinders 1a, 1a in a state of crossing the cylinder cooling water path 1W. The cylinder head cooling water path 2W of the cylinder head 2 and the cylinder cooling water path 1W of the cylinder unit 1A are connected at multiple locations on the outer side of each cylinder 1a, and are connected between the adjacent cylinders 1a, 1a (between cylinder holes) through two connecting holes 21 and 22 at left and right locations.

[0032] like Figure 1 and Figure 5 As shown in FIG. 1 , a cylinder head cooling water passage 2W for cooling water w to pass through is formed inside the cylinder head 2, and a cylinder bore corresponding portion (also referred to as an "inter-cylinder portion") 2b located on the upper side between the adjacent cylinders 1a, 1a in the cylinder head 2 is formed as shown in FIG. Figure 2 (A) and Figure 4 In the cylinder bore corresponding portion 2b, a cylinder head cooling water passage 2W is formed between a pair of left and right insertion walls 24 having insertion holes 2c through which the fastening bolts 23 pass and surrounded by the cylinder head bottom wall 26 and the cylinder head upper wall 25.

[0033] The bottom surface 26a of the cylinder head bottom wall 26 is placed on the upper surface 1b of the cylinder portion 1A via the gasket G, and the cylinder head upper wall 25 is the upper wall of the cylinder head on which the cylinder head cover 3 is placed. Figure 3 to Figure 5 Reference numeral 28 in the figure denotes an exhaust port, and cylinder head cooling water passages 2W are also formed at upper and lower portions thereof and on the right side of the right insertion wall 24 .

[0034] That is to say, Figure 2 to Figure 5 As shown, the cylinder head 2 assembled on the cylinder block 1 by a plurality of fastening bolts 23 is provided with: insertion walls 24, 24, which are used for the fastening bolts 23, 23 on both sides between the adjacent cylinders 1a, 1a arranged in the cylinder block 1 to pass through; a cylinder head upper wall 25, which connects the upper ends of a pair of insertion walls 24, 24 to each other; and a cylinder head bottom wall 26, and a cylinder head cooling water path 2W is formed by the pair of insertion walls 24, 24, the cylinder head upper wall 25 and the cylinder head bottom wall 26, and a longitudinal wall 27 is formed between the pair of insertion walls 24, 24, and the longitudinal wall 27 is formed to: bridge the cylinder head upper wall 25 and the cylinder head bottom wall 26, and extend in the direction connecting the pair of insertion walls 24, 24 to block the cylinder head cooling water path 2W.

[0035] like Figure 2 (A) Figure 3 , Figure 4As shown, the longitudinal wall 27 is continuously connected to the left end of the insertion wall 24 on the right side (the air inlet side) and integrated, and the left-right position i of the left end (the end on the side not connected to the insertion wall 24) 27a of the longitudinal wall 27 is formed to exist in the central area C between the pair of insertion walls 24, 24. As an example of the range of the central area C, when the center-to-center distance between the left and right insertion walls 24 is set to D, ±10% (C: 0.4D≤I<0.6D) of the left and right centers can be cited, but other than this (a range of 30% to 70%, etc.) is also possible.

[0036] If the left-right width of the longitudinal wall 27 is set to the length d between the center of the right insertion wall 24 and the left end 27a, the length d of the longitudinal wall 27 is set to the distance between the pair of insertion walls 24, 24, that is, the length of about half of the center-to-center distance D (0.4D≤d≤0.6D). Figure 4 As shown, it is advantageous if a reinforcing wall 29 is formed on the cylinder head bottom wall 26 of the cylinder bore corresponding portion 2b so as to be rib-shaped and protrude upward and extend leftward and rightward (in a direction connecting the pair of insertion walls 24, 24 to each other).

[0037] The left end of the reinforcement wall 29 rises obliquely upward and is connected to the insertion wall 24 on the left side. A vertical hole water channel (hole-shaped cooling water channel) 21A is formed in the oblique reinforcement wall portion 29a (see Figure 2 (A) Figure 2 (C) and Figure 4 The vertical hole water passage 21A is connected to the communication hole 21 on the left side of the cylinder portion 1A via a gasket G. The cylinder cooling water passage 1W and the cylinder head cooling water passage 2W are connected vertically by the vertical hole water passage 21A and the communication hole 21.

[0038] like Figure 2 (A) Figure 2 (B) and Figure 4 As shown in FIG. 1 , the cylinder head cooling water passage 2W on the front side (one side) of the longitudinal wall 27 is connected to the bottom surface 26a just below the longitudinal wall 27 by means of an inclined hole water passage 22A formed by extending from the bottom surface 26a toward the front and upward. That is, the inclined hole water passage 22A (an inclined hole-shaped cooling water passage) is provided at the lower part of the longitudinal wall 27, and the inclined hole water passage 22A bridges the cylinder head cooling water passage 2W on one side separated by the longitudinal wall 27 and the lower end of the longitudinal wall 27 or the bottom surface 26a of the cylinder head bottom wall 26 on the other side. The cylinder cooling water passage 1W and the cylinder head cooling water passage 2W are also connected vertically by means of the inclined hole water passage 22A connected via the gasket G and the connecting hole 22 on the right side.

[0039] [About the effect]

[0040] Conventionally, although not shown in the figure, the cylinder head has a cylinder bore corresponding portion 2b which is provided with no vertical wall 27 in order to expand the cylinder head cooling water passage 2W (see Patent Document 1). Figure 4 ), which is disadvantageous in terms of strength and rigidity, and there is a tendency that the axial force generated by tightening the fastening bolts 23 is difficult to be uniformly transmitted to the cylinder head bottom wall 26. Therefore, attempts have also been made to provide a rib wall (a wall such as the reinforcing wall 29) protruding upward on the cylinder head bottom wall 26, but the improvement in strength and rigidity is not sufficient and there is a limit.

[0041] Therefore, in the present invention, a longitudinal wall 27 is formed between the pair of insertion walls 24, 24, and the longitudinal wall 27 is formed so as to span the cylinder head upper wall 25 and the cylinder head bottom wall 26, and to extend in the direction connecting the pair of insertion walls 24, 24 to block the cylinder head cooling water channel 2W. By newly providing the longitudinal wall 27, the length between the insertion walls 24, 24 is greatly shortened (the length (span) of the beam when the cylinder head upper wall 25 is regarded as a double-support beam extending left and right is greatly reduced), so the strength and rigidity of the corresponding portion 2b between the cylinder holes can be greatly improved.

[0042] That is, the axial force of the fastening bolts 23, 23 passing through the pair of insertion walls 24, 24 is guided by the vertical wall 27 in contact with the bolt seat surface, and thus can be transmitted to the cylinder head 2 as evenly as possible compared to the conventional structure without the vertical wall 27. Therefore, the axial force guided between the pair of fastening bolts 23, 23 is substantially increased, and the effect of greatly improving the sealing performance between the cylinder portion 1A and the cylinder head 2 can be obtained.

[0043] If the left end 27a of the vertical wall 27 integrated with the right insertion wall 24 is set to exist in the central area C between the pair of insertion walls 24, 24 (refer to Figure 4 ), the interval between the pair of insertion walls 24, 24 is approximately halved (the length of the beam is halved), so the strength and rigidity of the corresponding portion 2b between the cylinder holes can be greatly improved.

[0044] Since the inclined hole water channel 22A inclined forward or backward is formed at the lower part of the vertical wall 27, the lower side (bottom surface 26a) of the vertical wall 27 can be reasonably connected with the cylinder head cooling water channel 2W on the front side or rear side of the vertical wall 27 despite the vertical wall 27, so that a smooth flow of cooling water w can be obtained. In addition, the vertical hole water channel 21A that connects the lower side (bottom surface 26a) of the vertical wall 27 with the cylinder head cooling water channel 2W is formed in the reinforcing wall portion 29a on the side of the cylinder bore corresponding portion 2b where the vertical wall 27 is not present, so that the strength and rigidity are not reduced due to the provision of the vertical hole water channel 21A.

[0045] In addition, since the longitudinal wall 27 is disposed biased toward the right side of the engine E, that is, the intake port side (the intake manifold configuration side), there is no longitudinal wall 27 on the exhaust port side where the temperature is likely to rise, and the cooling water w can easily move in the cylinder head cooling water path 2W along the front-to-back direction (cylinder arrangement direction), thereby also having the advantage of being able to efficiently absorb heat from the exhaust side.

[0046] [Other embodiments] (1) The longitudinal wall 27 may be provided on the left side in an integrated manner with the insertion wall 24 on the left side (exhaust port side). (2) The longitudinal wall 27 may be provided independently at the left and right central portions between a pair of insertion walls 24, 24. In this case, the hole-shaped cooling water passages may be provided along the longitudinal direction (up and down direction) between the longitudinal wall 27 and the left and right sides of each insertion wall 24, 24.

[0047] (3) The inclined hole water channel 22A may be formed as an inclined hole that connects the cylinder head cooling water channel 2W on the rear side of the vertical wall 27 and the bottom surface 26a on the front side of the vertical wall 27. (4) The rib-shaped reinforcement wall 29 may be formed as an inclined hole that connects the cylinder head cooling water channel 2W on the rear side of the vertical wall 27 and the bottom surface 26a on the front side of the vertical wall 27. Figure 2 Not shown in (A), Figure 4 It is also possible not to have the reinforcing wall 29, but it is advantageous if it is present.

[0048] Description of reference numerals:

[0049] 1 Cylinder block

[0050] 1a Cylinder

[0051] 2 Cylinder head

[0052] 2W Cylinder head cooling water circuit

[0053] 21A Cooling water channel with holes

[0054] 22A Slanted hole cooling water channel

[0055] 23 Fastening bolts

[0056] 24 penetration wall

[0057] 25 Cylinder head upper wall

[0058] 26 Cylinder head bottom wall

[0059] 26a Bottom

[0060] 27 Vertical Wall

[0061] 27a end

[0062] 29a Reinforced wall

Claims

1. A cylinder head structure, wherein: The cylinder head assembled on the cylinder block by a plurality of fastening bolts is provided with: an insertion wall for passing the fastening bolts on both sides between adjacent cylinders arranged in the cylinder block; a cylinder head upper wall connecting the upper ends of a pair of the insertion walls to each other; and a cylinder head bottom wall. A cylinder head cooling water channel is formed which is surrounded by a pair of the insertion walls, the cylinder head upper wall and the cylinder head bottom wall. A vertical wall is formed between the pair of insertion walls. The vertical wall is formed so as to straddle the cylinder head upper wall and the cylinder head bottom wall and extend in a direction connecting the pair of insertion walls to shield the cylinder head cooling water channel.

2. The cylinder head structure according to claim 1, wherein: The vertical wall is formed so as to be present in a central region between the pair of insertion walls.

3. The cylinder head structure according to claim 1, wherein: The vertical wall is connected to and integrated with any one of the pair of insertion walls.

4. The cylinder head structure according to claim 3, wherein: The end of the vertical wall that is not connected to the insertion wall is formed so as to be present in a central region between the pair of the insertion walls.

5. The cylinder head structure according to any one of claims 1 to 4, wherein: An inclined hole-shaped cooling water channel is provided at the lower portion of the vertical wall, and the inclined hole-shaped cooling water channel bridges the cylinder head cooling water channel on one side separated by the vertical wall and the bottom surface of the cylinder head bottom wall directly below the vertical wall or on the other side.

6. The cylinder head structure according to any one of claims 1 to 4, wherein: The cylinder head bottom wall is formed with a rib-shaped reinforcement wall portion extending in a direction connecting the pair of insertion walls and projecting upward, and a hole-shaped cooling water channel is formed that vertically penetrates the reinforcement wall portion.

Images