Cylinder cover sealing gasket

Abstract

The invention provides a cylinder head seal for improving the sealing performance among a cylinder block, a cylinder head and a cover member. A first substrate having a cylinder axial direction as a thickness direction, a second substrate disposed on one side of the first substrate in the cylinder axial direction, and a third substrate disposed on one side of the second substrate in the cylinder axial direction are provided, and a protrusion is provided on at least one of the first substrate, the second substrate, and the third substrate. The protrusion protrudes toward one side or the other side in the cylinder axial direction and has a ridge line extending toward the mating surface of the cover member when viewed in the cylinder axial direction. The second substrate and the third substrate are each provided with a through-hole which is formed in the vicinity of the protruding portion when viewed in the cylinder axial direction, passes through the front and back surfaces of each substrate, and overlaps each other when viewed in the cylinder axial direction, and the hole diameter of the through-hole of the second substrate is made smaller than the hole diameter of the through-hole of the third substrate.

Description

Technical Field

[0001] This invention relates to a cylinder head sealing gasket. Background Art

[0002] In an internal combustion engine with a cylinder block and a cylinder head, a protrusion that extends axially to one side of the cylinder, known as a cylinder head gasket with a raised section, is placed between the cylinder block and the cylinder head to seal them together.

[0003] Furthermore, as disclosed in Patent Document 1, it is known that in an internal combustion engine having a cover component (chain housing in Patent Document 1), the so-called three-sided mating portions of the three components are sealed by a liquid sealant (liquid gasket in Patent Document 1), the cover component having a mating surface that engages with the end faces of the cylinder block and cylinder head in a direction orthogonal to the cylinder axis.

[0004] Specifically, Patent Document 1 discloses an engine assembly method in which liquid sealant is applied to both sides of the cylinder head gasket along the cylinder axis, and then the liquid sealant is applied to the three mating parts by fastening the cylinder head and cylinder block.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent No. 5978918

[0008] Technical problem to be solved by the invention

[0009] In the structure of Patent Document 1, when the cylinder head gasket is a multilayer gasket consisting of multiple stacked substrates, there is a concern that the sealing performance of the three mating parts cannot be adequately ensured. Specifically, in the multilayer cylinder head gasket, if liquid sealant is only applied to the two sides along the cylinder axial direction, there is a concern that when the cylinder head is fastened to the cylinder block, air in the passageway defined between the protrusions and surrounding portions of the specified substrates and the opposing substrates is squeezed out towards the cover component side, thereby blowing away the liquid sealant in the three mating parts, and insufficient liquid sealant cannot be ensured in the three mating parts. Summary of the Invention

[0010] The present invention was made in view of the above circumstances, and its object is to provide a cylinder head gasket that can improve the sealing performance between the cylinder block, cylinder head and cover components.

[0011] Technical solutions for solving technical problems

[0012] To solve the above-mentioned technical problems, the present invention provides a cylinder head gasket, which is inserted between the cylinder block and the cylinder head in an engine. The engine includes: the cylinder block, the cylinder head, and a cover component. The cylinder block and the cylinder head coincide in the cylinder axial direction. The cover component has a mating surface that abuts against end faces of the cylinder block and the cylinder head in a direction orthogonal to the cylinder axial direction. Lubricating oil is used inside the cover component. The cylinder head gasket includes: a first base plate with the cylinder axial direction as its thickness direction; a second base plate disposed on one side of the first base plate in the cylinder axial direction; and a third... The three substrates are arranged on one side of the cylinder axial direction of the second substrate. At least one of the first substrate, the second substrate, and the third substrate includes a protrusion that protrudes toward one or the other side of the cylinder axial direction and has a ridge extending toward the mating surface of the cover component when viewed in the cylinder axial direction. The second substrate and the third substrate each have a through hole that is formed near the protrusion when viewed in the cylinder axial direction and penetrates the front and back of each substrate and overlaps with each other when viewed in the cylinder axial direction. The diameter of the through hole in the second substrate is smaller than the diameter of the through hole in the third substrate.

[0013] In this invention, through holes are formed in both the second and third substrates of the multi-layer cylinder head gasket. Therefore, liquid sealant can be introduced through each through hole into the vicinity of the protrusion between the third and second substrates and the protrusion between the second and first substrates, thereby sealing a portion of the passageway formed around the protrusion. Furthermore, the through holes in the second and third substrates overlap, and the diameter of the through hole in the second substrate is smaller than that in the third substrate. Therefore, liquid sealant flowing into the through hole of the third substrate can be reliably introduced into the through hole of the second substrate and even between the second and first substrates, and a portion of the liquid sealant passing through the through hole of the third substrate can be blocked by the second substrate and introduced into the space between the second and third substrates, reliably sealing a portion of the aforementioned passageway.

[0014] As described above, according to the present invention, when the cylinder block and cylinder head are fastened, air can be prevented from being forcefully squeezed from the end of the cylinder head gasket toward the cover component side through the aforementioned passage, thereby blowing away the liquid sealant disposed around the end, thus improving the sealing performance between the cylinder block, cylinder head and cover component.

[0015] In the above structure, preferably, the through hole of the second substrate is located inside the through hole of the third substrate when viewed in the axial direction of the cylinder (Technical Solution 2).

[0016] According to this structure, since the overlap area between the through holes of the second substrate and the through holes of the third substrate can be increased, the liquid sealant can be reliably introduced between the second substrate and the first substrate.

[0017] In the above structure, preferably, the through hole of the second substrate is configured such that the center of the through hole coincides with the center of the through hole of the third substrate (Technical Solution 3).

[0018] In this structure, the second substrate extends inward from the periphery of the through-hole covering the entire circumference of the third substrate. Therefore, liquid sealant can be introduced between the second and third substrates through the entire circumference of the through-hole covering the third substrate, and the gap between the second and third substrates can be reliably sealed by the liquid sealant.

[0019] In the above structure, it is preferable that the periphery of the through hole in the second substrate has a guide portion that is bent radially inward toward one side of the cylinder axis (Technical Solution 4).

[0020] According to this structure, the liquid sealant can be guided to the space between the second substrate and the third substrate through the guide portion, and the gap between them can be reliably sealed by the liquid sealant.

[0021] In the above structure, preferably, the first substrate has a shape that closes the through hole of the second substrate from the other side of the cylinder axis (Technical Solution 5).

[0022] According to this structure, by blocking the liquid sealant with the first substrate, more liquid sealant can be introduced between the substrates.

[0023] In the above structure, preferably, a fourth substrate is further provided, which is disposed between the first substrate and the second substrate. The fourth substrate has a through hole that penetrates the front and back of the fourth substrate and overlaps with the through hole of the second substrate when viewed in the axial direction of the cylinder (Technical Solution 6).

[0024] According to this structure, by setting four base plates between the cylinder head and the cylinder block and introducing liquid sealant between each base plate, the sealing performance between the cylinder head and the cylinder block can be further improved reliably.

[0025] Effects of the Invention

[0026] As described above, the cylinder head gasket according to the present invention can improve the sealing performance between the cylinder block, cylinder head, and cover components. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic side view showing the structure of the engine.

[0028] Figure 2 Yes Figure 1 A schematic cross-sectional view of a portion of the section along line II-II.

[0029] Figure 3 It is magnification Figure 2 A diagram representing a portion of something.

[0030] Figure 4 This is a rough top view of the cylinder head gasket.

[0031] Figure 5 It is a schematic three-dimensional view representing a portion of the front end of the cylinder head gasket.

[0032] Figure 6 yes Figure 5 A rough cross-sectional view at line VI-VI.

[0033] Figure 7 Figures (a) through (d) are schematic representations of the engine assembly process, and are... Figure 5 A rough cross-sectional view at line VII-VII.

[0034] Figure 8 Figures (a) through (c) are schematic representations of the engine assembly process, and are related to... Figure 6 The corresponding diagram.

[0035] Figure 9 This is a schematic side view showing the assembled cylinder head gasket of the engine body.

[0036] Figure 10 This diagram schematically illustrates the engine assembly process when using the cylinder head gasket involved in the comparative example, and is related to... Figure 7 The diagram corresponding to (c).

[0037] Figure 11 This is a schematic diagram illustrating the engine assembly process when using the cylinder head gasket according to an embodiment of the present invention, and is related to... Figure 7 The diagram corresponding to (c).

[0038] Figure 12 This is a schematic cross-sectional view of the cylinder head gasket involved in the modified example, and is related to... Figure 6 The corresponding diagram.

[0039] Explanation of symbols

[0040] 1 engine

[0041] 2 Engine body

[0042] 10 cylinder head

[0043] 20-cylinder block

[0044] 30 chain guard

[0045] 32. Rear end face (mating face)

[0046] 50 Cylinder Head Sealing Gasket

[0047] 150 First sealing gasket substrate (first substrate)

[0048] 151 First protrusion (protrusion)

[0049] 152 ridge line

[0050] 153 edge line

[0051] 250 Second sealing gasket substrate (second substrate)

[0052] 254 Second Through Hole (Through Hole)

[0053] 256 Guiding Department

[0054] 350 Third Sealing Gasket Substrate (Third Substrate)

[0055] 351 Third protrusion (protrusion)

[0056] 352 ridge line

[0057] 353 ridge line

[0058] 354 Third Through Hole (Through Hole)

[0059] 450 Fourth Sealing Gasket Substrate (Fourth Substrate)

[0060] 451 Fourth protrusion (protrusion)

[0061] 452 edge line

[0062] 453 edge line

[0063] 454 Fourth through hole (through hole). DETAILED DESCRIPTION

[0064] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. Figure 1 This is a schematic side view illustrating the structure of an engine 1 with a cylinder head gasket 50 according to an embodiment of the present invention.

[0065] Engine 1 includes: a cylinder block 20 having cylinders 23, an engine body 2 including a cylinder head 10 and a cylinder head gasket 50, and a chain cover 30 assembled to the engine body 2. The engine body 2 is, for example, a tandem six-cylinder engine, with six cylinders 23 arranged, for example, in a row, formed in the cylinder block 20. The chain cover 30 is disposed on one side of the engine body 2 in the direction of the cylinders 23.

[0066] Hereinafter, the arrangement direction of the cylinders 23 will be referred to as the front-rear direction, with the side relative to the chain cover 30 of the engine body 2 designated as the front and the opposite side as the rear. Furthermore, in this embodiment, the cylinder head 10 is fastened to the upper surface of the cylinder block 20, and the axial direction of the cylinders 23, i.e., the cylinder axis, is aligned with the vertical direction. Therefore, the arrangement direction of the cylinder head 10 and the cylinder block 20, and the axial direction of the cylinders 23, will be referred to as the vertical direction, with the side of the cylinder head 10 relative to the cylinder block 20 designated as the upper and the opposite side as the lower. Additionally, the left-right direction, which is perpendicular to both the front-rear and vertical directions and faces forward, will be referred to as the left-right direction. Furthermore, the lower side in the vertical direction corresponds to "one side of the cylinder axis" in this invention, and the upper side corresponds to "the other side of the cylinder axis". Additionally, the view along the cylinder axis, i.e., along the vertical direction, will be appropriately referred to as a top view.

[0067] At the front of the engine body 2, a timing chain 40 driven to rotate by a crankshaft (not shown) connected to the pistons (not shown) fitted into each cylinder 23 is arranged along the front end face 2A of the engine body 2.

[0068] The chain cover 30 is a component that covers accessories such as the timing chain 40. The chain cover 30 has a rear end face 32 that abuts against the front end face 2A of the engine body 2, and a rear end face 32 that abuts against the front end face 12 of the cylinder head 10 and the front end face 22 of the cylinder block 20. The chain cover 30 is fastened to the engine body 2 with the front end face 2A and the rear end face 32 abutting against each other, and a chain receiving portion 39 for accommodating the timing chain 40 is divided between the chain cover 30 and the engine body 2. Specifically, the central portion of the front end face 2A of the engine body 2 (i.e., the front end face 12 of the cylinder head 10 and the front end face 22 of the cylinder block 20) ​​in the left-right direction is recessed rearward. The central portion of the rear end face 32 of the chain cover 30 in the left-right direction is recessed forward. The engine body 2 and the chain cover 30 are fastened together with the left and right ends of the front end face 2A of the engine body abutting against the left and right ends of the rear end face 32 of the chain cover 30. A chain receiving portion 39 is divided between the central portion of the front end face 2A of the engine body 2 and the central portion of the rear end face 32 of the chain cover 30 in the left and right directions. Inside the chain cover 30, specifically inside the chain receiving portion 39, lubricating oil for lubricating the timing chain 40, etc., is used. The chain cover 30 is equivalent to the "cover component" in this invention, and the rear end face 32 of the chain cover 30 is equivalent to the "mating surface" in this invention.

[0069] The cylinder head gasket 50 is used to prevent combustion gases and lubricating oil from leaking to the outside between the cylinder head 10 and the cylinder block 20, and is inserted between the cylinder head 10 and the cylinder block 20. That is, the cylinder head gasket 50 is configured to seal the gap X1 between the lower surface 11 of the cylinder head 10 and the upper surface 21 of the cylinder block 20, and the cylinder head 10 and the cylinder block 20 are fastened to each other with the cylinder head gasket 50 sandwiched between them.

[0070] (Structure of cylinder head gasket)

[0071] Next, the structure of the cylinder head gasket 50 according to the embodiment will be described in the direction in which the cylinder head gasket 50 is placed on the upper surface 21 of the cylinder block 20. Figure 2 Yes Figure 1 A schematic cross-sectional view of the front part of engine 1 at the II-II line section. Figure 3 It is magnification Figure 2 The diagram shows a portion of the engine 1, specifically the front and right side of the section along line II-II. Figure 4 This is a schematic top view of the cylinder head gasket 50. Figure 5 This is a perspective view of the right side of the front end of the cylinder head gasket 50, viewed from below. Figure 6 yes Figure 5 A rough cross-sectional view at line VI-VI.

[0072] The cylinder head gasket 50 has a generally plate-like shape extending in both the front-rear and left-right directions. Cylinder holes 53 are formed in the cylinder head gasket 50 at positions corresponding to each cylinder 23, penetrating its surface. As described above, six cylinders 23 are formed in the cylinder body 20 arranged in the front-rear direction, and six cylinder holes 53 are formed in the cylinder head gasket 50 arranged in the front-rear direction.

[0073] The cylinder head gasket 50 is a multi-layer gasket, having multiple plate-shaped gasket substrates with their thickness directions being vertical. In this embodiment, the cylinder head gasket 50 is a four-layer gasket with four gasket substrates 150, 250, 350, and 450. Specifically, the cylinder head gasket 50 includes: a first gasket substrate 150 forming the uppermost layer; a second gasket substrate 250 disposed below the first gasket substrate 150 and forming the third layer from the top; a third gasket substrate 350 disposed below the second gasket substrate 250 and forming the fourth layer from the top, i.e., the lowest layer; and a fourth gasket substrate 450 disposed between the first gasket substrate 150 and the second gasket substrate 250 and forming the second layer from the top. Each gasket substrate 150, 250, 350, and 450 is made of metal, such as SUS material.

[0074] The thickness, i.e. the vertical dimension, of the first sealing gasket substrate 150, the third sealing gasket substrate 350, and the fourth sealing gasket substrate 450 is set to be approximately the same. On the other hand, the thickness of the second sealing gasket substrate 250 is set to be smaller than that of the other sealing gasket substrates 150, 450, and 350.

[0075] The shapes of each sealing gasket substrate 150, 250, 350, and 450 when viewed from above are roughly the same. The shapes of each sealing gasket substrate 150, 250, 350, and 450 when viewed from above are roughly the same as the upper surface 21 of the cylinder body 20. At the center of the left-right direction of each leading edge of each sealing gasket substrate 150, 250, 350, and 450, a rearward recessed portion 59 is formed corresponding to the chain receiving portion 39.

[0076] On the other hand, the longitudinal dimensions of each sealing gasket substrate 150, 250, 350, and 450, i.e., the longitudinal length of the cylinder head sealing gasket 50, are set to be slightly smaller than the longitudinal length of the upper surface 21 of the cylinder block 20. Thus, as... Figure 1 As shown, with the cylinder block 20 and cylinder head 10 fastened together and the chain cover 30 fastened to the cylinder block 20 and cylinder head 10, a gap X2 is defined between the front end 51 of the cylinder head sealing gasket 50 and the rear end face 32 of the chain cover 30.

[0077] With the aforementioned gap X2 open, lubricating oil and other fluids can leak from the inside of the chain receiving section 39, between the cylinder block 20 and the cylinder head 10, to the outside of the engine 1 through the gap X2. Therefore, the gap X2 is sealed by a liquid sealant S during the assembly of the engine 1. The liquid sealant S is a fluid sealant, such as a silicone-containing sealant.

[0078] The first sealing gasket substrate 150, the second sealing gasket substrate 250 and the fourth sealing gasket substrate 450 are respectively formed with protrusions that protrude upward or downward.

[0079] A first protrusion 151 is formed at the front end of the first sealing gasket substrate 150. The first protrusion 151 extends along the protrusion line L1. The protrusion line L1 is a line that extends substantially parallel to the inner periphery of the recess 59 in a top view at a position that moves radially outward from the inner periphery of the recess 59 (chain receiving portion 39).

[0080] Specifically, the protrusion line L1 is composed of a right line L11 extending rearward from the front end of the right side portion of the first sealing gasket substrate 150, a left line L12 extending rearward from the front end of the left side portion of the first sealing gasket substrate 150, and a central line L13 extending in a left-right direction between the rear ends of the right line L11 and the left line L12. Furthermore, the first protrusion 151 is composed of a right protrusion 151B extending rearward from the front end of the right side portion of the first sealing gasket substrate 150 along the right line L11, a left protrusion 153B extending rearward from the front end of the left side portion of the first sealing gasket substrate 150 along the left line L12, and a central protrusion 152B extending in a left-right direction between the rear ends of the right protrusion 151B and the left protrusion 153B along the central line L13.

[0081] In this embodiment, the first protrusion 151 is inclined downwards as it approaches the radially outer side of the recess 59 (chain receiving portion 39). That is, in this embodiment, the portion of the front end of the first sealing pad substrate 150 that is radially (radially) outside the recess 59 and the chain receiving portion 39 is positioned below the inner portion, and it is bent downwards in a radially outward direction to form the first protrusion 151. As a result, two ridges 152 and 153 are formed at the front end of the first protrusion 151 along the protrusion line L1, and these two ridges 152 and 153 extend forward toward the rear end face 32 of the chain cover 30.

[0082] A third protrusion 351 is formed at the front end of the third sealing gasket substrate 350. When viewed from above, the third protrusion 351 extends along the first protrusion 151 and the protrusion line L1, and is vertically opposite to the first protrusion 151. That is, similar to the first protrusion 151, the third protrusion 351 also has a portion extending rearward from the front end of the right side portion of the third sealing gasket substrate 350, a portion extending rearward from the front end of the left side portion of the third sealing gasket substrate 350, and a portion extending horizontally along the central line L13. Furthermore, two ridges 352 and 353 are formed at the front end of the third protrusion 351, extending along the protrusion line L1 when viewed from above. These two ridges 352 and 353 extend forward, i.e., towards the rear end face 32 of the chain cover 30. The width dimension of the third protrusion 351, i.e., the spacing between the two ridges 352 and 353, is approximately the same as the width dimension of the first protrusion 151, i.e., the spacing between the two ridges 152 and 153. The third protrusion 351 has the same structure as the first protrusion 151, but is inclined downwards as it gets closer to the outer side of the radial direction (the radial direction of the recess 59 and the chain receiving portion 39).

[0083] A fourth protrusion 451 is formed at the front end of the fourth sealing gasket substrate 450. When viewed from above, the fourth protrusion 451 extends along the first protrusion 151, the third protrusion 351, and the protrusion line L1, and is vertically opposite to the first protrusion 151 and the third protrusion 351. That is, similar to the first protrusion 151 and the third protrusion 351, the fourth protrusion 451 also has a portion extending rearward from the front end of the right side portion of the fourth sealing gasket substrate 450, a portion extending rearward from the front end of the left side portion of the fourth sealing gasket substrate 450, and a portion extending horizontally along the central line L13. Furthermore, two ridges 452 and 453 are formed at the front end of the fourth protrusion 451, extending along the protrusion line L1 when viewed from above, and these two ridges 452 and 453 extend forward toward the rear end face 32 of the chain cover 30. The width dimension of the fourth protrusion 451, i.e., the distance between the two ridges 452 and 453, is approximately the same as the width dimension of the first protrusion 151 and the third protrusion 351, i.e., the distance between the two ridges 152 and 153 and the distance between the two ridges 352 and 353. On the other hand, the fourth protrusion 451 has a structure that is symmetrical to the first protrusion 151 in the vertical direction, and is inclined in such a way that the position closer to the radial (radial direction of the recess 59 and the chain receiving portion 39) is located on the upper side.

[0084] Here, the first sealing gasket substrate 150 described above corresponds to the "first substrate" of the present invention, the second sealing gasket substrate 250 corresponds to the "second substrate", the third sealing gasket substrate 350 corresponds to the "third substrate", and the fourth sealing gasket substrate 450 corresponds to the "fourth substrate". In addition, the first protrusion 151 and the third protrusion 351 respectively correspond to the "protrusions" of the present invention.

[0085] In addition to the first protrusion 151, the third protrusion 351, and the fourth protrusion 451, the first sealing gasket substrate 150, the third sealing gasket substrate 350, and the fourth sealing gasket substrate 450 are also provided with protrusions 58 that protrude upwards or downwards. For example, each sealing gasket substrate 150, 350, and 450 is provided with a protrusion along the periphery of each cylinder hole 53, and a protrusion extending along the outer periphery of each sealing gasket substrate 150, 350, and 450.

[0086] Next, the detailed structure of the left and right ends 50R and 50L of the front end of the cylinder head gasket 50 will be described. The structures of the right end 50R and the left end 50L of the front end of the cylinder head gasket 50 are roughly symmetrical to each other. Hereinafter, the structure of the right end 50R of the front end of the cylinder head gasket 50 will be described as representative.

[0087] On the right side end 50R of the front end of the second sealing gasket substrate 250, the third sealing gasket substrate 350, and the fourth sealing gasket substrate 450, through holes 254, 354, and 454 are respectively formed, which, when viewed from above, penetrate the surface and back of each substrate along their thickness direction near the first protrusion 151, the third protrusion 351, and the fourth protrusion 451, and overlap with each other. In this embodiment, each through hole is a circular hole.

[0088] Specifically, a second through hole 254 penetrating the back of the second sealing gasket substrate 250 is formed near the first protrusion 151, the third protrusion 351, and the fourth protrusion 451 when viewed from above, at the right end of the front end of the second sealing gasket substrate 250. A third through hole 354 penetrating the back of the third sealing gasket substrate 350 is formed near the third protrusion 351 at the right end of the front end of the third sealing gasket substrate 350. A fourth through hole 454 penetrating the back of the fourth sealing gasket substrate 450 is formed near the fourth protrusion 451 at the right end of the front end of the fourth sealing gasket substrate 450. The diameter of the fourth through hole 454 is set to be smaller than the diameter of the second through hole 254, and the diameter of the second through hole 254 is set to be smaller than the diameter of the third through hole 354.

[0089] In this embodiment, the second through hole 254, the third through hole 354 and the fourth through hole 454 are respectively disposed on the left side of the first protrusion 151, the third protrusion 351 and the fourth protrusion 451, that is, on the side close to the recess 59 and the chain receiving portion 39 and disposed on the radial inner side of the recess 59 and the chain receiving portion 39.

[0090] Here, the term "nearby of the protrusion" as used in this specification refers to a region where the shortest distance between the protrusion and the protrusion is less than half the diameter of the largest through hole 354, i.e., less than the radius. When viewed from above, each through hole 254, 354, and 454 is formed at a position where the distance between its right end and the first protrusion 151, the third protrusion 351, and the fourth protrusion 451 is less than the radius of the third through hole 354. In this embodiment, the third through hole 354 is formed at a position where the distance between its right end and the third protrusion 351 is approximately 1 / 5 of the radius of the third through hole 354. For example, the distance between the right end of the third through hole 354 and the third protrusion 351 is set to approximately 1 mm. Furthermore, this distance is approximately half the width (left-right dimension) of the third protrusion 351. Furthermore, when viewed from above, the second through hole 254 is formed at a position where the distance between the right end of the second through hole 254 and the first protrusion 151, the third protrusion 351, and the fourth protrusion 451 is approximately 2 / 5 of the radius of the third through hole 354. The fourth through hole 454 is formed at a position where the distance between the right end of the fourth through hole 454 and the fourth protrusion 451 is approximately 4 / 5 of the radius of the third through hole 354.

[0091] Furthermore, in this embodiment, the distance between the front end of each through hole 254, 354, and 454 and the front edge of each sealing gasket substrate 250, 350, and 450 is below the diameter of the third through hole 354. For example, the distance between the front end of the third through hole 354 and the front edge of each sealing gasket substrate 250, 350, and 450 is set to approximately 3 mm.

[0092] In this embodiment, the second through hole 254, the third through hole 354, and the fourth through hole 454 are configured such that, when viewed from above, the second through hole 254 is located inside the third through hole 354, and the fourth through hole 454 is located inside the second through hole 254. Furthermore, the centers of the second through hole 254, the third through hole 354, and the fourth through hole 454 are aligned when viewed from above, and these centers are located on the same line L20 extending in the vertical direction.

[0093] According to the above structure, in this embodiment, when viewed from below, the lower surface 255 of the second sealing pad substrate 250 covers the entire circumference of the third through hole 354 and extends from the periphery of the third through hole 354 toward the radially inward side of the third through hole 354; the lower surface 455 of the fourth sealing pad substrate 450 covers the entire circumference of the second through hole 254 and extends from the periphery of the second through hole 254 toward the radially inward side of the second through hole 254.

[0094] A guide portion 256, bent radially inward toward the lower side and toward the inner side of the second through hole 254, is provided around the periphery of the second through hole 254 in the second sealing gasket substrate 250. The guide portion 256 is provided all around the circumference of the second through hole 254. In this embodiment, as... Figure 6 As shown, the guide portion 256 is formed at the top of the third through hole 354.

[0095] As described above, through holes 254, 354, and 454 are formed near the first protrusion 151, the third protrusion 351, and the fourth protrusion 451 on the second sealing gasket substrate 250, the third sealing gasket substrate 350, and the fourth sealing gasket substrate 450 among the four sealing gasket substrates 150, 250, 350, and 450. On the other hand, no holes are formed on the first sealing gasket substrate 150 at positions opposite to these through holes 254, 354, and 454. When viewed from above, the fourth through hole 454 is closed by the first sealing gasket substrate 150. That is, the first sealing gasket substrate 150 has a shape that closes each through hole 254, 354, and 454 from above when viewed from above.

[0096] Furthermore, as described above, the structures of the left and right ends 50R and 50L at the front end of the cylinder head gasket 50 are approximately symmetrical. At the left end of the front end of the second gasket substrate 250, the third gasket substrate 350, and the fourth gasket substrate 450, respectively, to the right of the first protrusion 151, the third protrusion 351, and the fourth protrusion 451, and near these protrusions 151, 351, and 451, through holes 259, 359, and 459 are formed, similar to the through holes 254, 354, and 454 on the right side, respectively, penetrating their surfaces. Additionally, a guide portion (not shown) bent inwards towards the lower side and radially towards the through hole 259 is provided around the periphery of the through hole 259 on the left side of the second gasket substrate 250.

[0097] (Engine assembly steps)

[0098] The steps for assembling engine 1 as described above will be explained. Figure 7 、 Figure 8 It is a diagram that schematically illustrates the process of assembling an engine. Figure 7 (a) to (d) are Figure 5 A schematic cross-sectional view at line VII-VII, arranged chronologically. Figure 7 The order of (a), (b), (c), and (d). Figure 8 (a) to (c) are related to Figure 6 The corresponding graphs are arranged in chronological order. Figure 8 The order of (a), (b), and (c).

[0099] In this embodiment, such as Figure 7(a) and Figure 8 As shown in (a), with the liquid sealant S applied to the front end of the upper surface 21 of the cylinder block 20, a cylinder head gasket 50 is placed on the upper surface 21 of the cylinder block 20. Furthermore, the liquid sealant S is applied to the upper surface of the placed cylinder head gasket 50.

[0100] Next, as Figure 7 (b) and Figure 8 As shown in (b), the cylinder head 10 is placed on the cylinder head gasket 50 from above.

[0101] Next, as Figure 7 (c) and Figure 8 As indicated by arrow Y10 in (c), while pressing the cylinder head 10 downwards towards the cylinder block 20, they are tightened using bolts or the like. At this time, as... Figure 7 As shown in (c), a portion of the liquid sealant S is pushed or pressed forward of the cylinder head gasket 50, covering the cylinder head gasket 50 from the front. Additionally, a portion of the liquid sealant S extends along the upper surface 21 of the cylinder block 20 and the lower surface 11 of the cylinder head 10. Furthermore, a portion of the liquid sealant S flows into the inner sides of the third through-hole 354, the second through-hole 254, and the fourth through-hole 454. Further, a portion of the liquid sealant S flowing into these through-holes 254, 354, and 454 enters the gaps between the gasket substrates 150, 250, 350, and 450 and extends along these gaps.

[0102] Next, as Figure 7 As shown in (d), while the rear end face 32 of the chain cover 30 abuts against the front end face 2A of the engine body 2 (the front end face 12 of the cylinder head 10 and the front end face 22 of the cylinder block 20), the chain cover 30 is fastened to the engine body 2 using bolts or the like.

[0103] As described above, the cylinder head 10, cylinder block 20, and chain cover 30 are interconnected. Furthermore, a liquid sealant S disposed in front of the cylinder head gasket 50 seals the gap X2 between the front end 51 of the cylinder head gasket 50 and the rear end face 32 of the chain cover 30.

[0104] (Functions, etc.)

[0105] According to the embodiment configured as described above, the cylinder head gasket 50 can reliably seal the gap X2 between the front end 51 of the cylinder head gasket 50 and the rear end face 32 of the chain cover 30. Figure 9This is a schematic side view of the cylinder head gasket 50 after the engine body 2 has been assembled, i.e., with the cylinder block 20 and cylinder head 10 fastened together. It is also a front view of the right side end 50R of the front portion of the cylinder head 10, cylinder block 20, and cylinder head gasket 50. Furthermore, in Figure 9 The illustration of liquid sealant S is omitted in the text. Figure 10 This is a comparative example, that is, using a cylinder head gasket 50 from the above embodiment where the second through hole 254, the third through hole 354, and the fourth through hole 454 are omitted. Figure 7 The diagram corresponding to (c) is a diagram showing the assembly of engine 1. Figure 11 This diagram schematically illustrates the assembly of engine 1 using the cylinder head gasket 50 of the above embodiment, and is related to... Figure 7 The diagram corresponding to (c). Furthermore, Figure 10 and Figure 11 This refers to the situation before the cylinder head 10 is fastened to the cylinder block 20 and the chain cover 30 is fastened to the engine body 2. Figure 10 and Figure 11 The chain guard 30 is represented by an imaginary line (dotted line).

[0106] As described above, when the cylinder block 20 is fastened to the cylinder head 10, the cylinder head gasket 50 is pressed against the upper surface 21 of the cylinder block 20 by the lower surface 11 of the cylinder head 10. Under this pressing force, the protrusions, including the first protrusion 151, the third protrusion 351, and the fourth protrusion 451, elastically deform, generating elastic force. Consequently, the protruding portions of each gasket substrate 150, 250, 350, and 450 are tightly pressed against adjacent gasket substrates, the lower surface 11 of the cylinder head 10, or the upper surface 21 of the cylinder block 20, sealing the gap X1 between the cylinder block 20 and the cylinder head 10. However, as... Figure 9 As shown, the peripheral portions of the protrusions of each sealing gasket substrate 150, 250, 350, and 450 cannot be completely closed. Therefore, around the first protrusion 151, the third protrusion 351, and the fourth protrusion 451, a passage X3 extending along the protrusion line L1 and opening at the front end face of the cylinder head sealing gasket 50 is defined by each sealing gasket substrate 150, 250, 350, and 450.

[0107] In the cylinder head gasket involved in the comparative example, since the second through hole 254, the third through hole, and the fourth through hole 454 are not formed, therefore... Figure 10As shown, no liquid sealant S is introduced into the inner side of the cylinder head gasket, i.e., between the gasket base plates 150, 250, 350, and 450. Therefore, the inner space of the aforementioned passage X3 extending along the raised line L1 becomes a cavity throughout its approximately entire length. Consequently, when the cylinder head 10 is pressed towards the cylinder block 20, applying a downward pressing force to the cylinder head gasket, as... Figure 10 As indicated by arrow Y11, most of the air in the passage X3 and the air in the gaps between the sealing gasket substrates 150, 250, 350, and 450 connected to the passage X3 is forced forward from the opening at the front end of the passage X3, i.e., towards the chain cover 30 side. As a result, in the comparative example, a portion of the liquid sealant S disposed in front of the cylinder head gasket, i.e., a portion of the liquid sealant S disposed in the gap X2, is blown away, forming a void X10 inside the liquid sealant S. Therefore, in the cylinder head gasket involved in the comparative example, there is a concern that lubricating oil may leak from the chain receiving portion 39 side to the outside of the engine 1 through the void X10. That is, there is a concern that the gap X2 cannot be properly sealed.

[0108] In contrast, in the cylinder head gasket 50 of the above embodiment, as described above, the liquid sealant S is introduced into the gap between the gasket substrates 150, 250, 350, and 450 through the second through hole 254, the third through hole 354, and the fourth through hole 454.

[0109] Specifically, the second through hole 254, the third through hole 354, and the fourth through hole 454 are formed at overlapping positions. That is, these through holes 254, 354, and 454 are interconnected. Therefore, a portion of the liquid sealant disposed between the cylinder head gasket 50 and the cylinder block 20 moves upward through the third through hole 354 toward the third gasket substrate 350, upward through the second through hole 254 toward the second gasket substrate 250, and upward through the fourth through hole 454 toward the fourth gasket substrate 450 as the cylinder head gasket 50 is pressed toward the cylinder block 20 side. In particular, in the above embodiment, when viewed from above, the second through hole 254 is located inside the third through hole 354, and the fourth through hole 454 is located inside the second through hole 254. Therefore, the liquid sealant S can be reliably moved above each sealing pad substrate 250, 350, 450 through each through hole 254, 354, 454.

[0110] Furthermore, in the above embodiment, the diameters of the third through hole 354, the second through hole 254, and the fourth through hole 454 are set to decrease in this order. Consequently, in the cylinder head gasket 50 according to the above embodiment, viewed from below, the lower surface 255 of the second gasket base plate 250 extends radially inward from the periphery of the third through hole 354, and the lower surface 455 of the fourth gasket base plate 450 extends radially inward from the periphery of the second through hole 254. Therefore, as... Figure 6 As indicated by arrow Y1, a portion of the liquid sealant S, after passing through the third through-hole 354, moves along the lower surface 255 of the second sealing pad substrate 250 and is introduced between the second sealing pad substrate 250 and the third sealing pad substrate 350. Additionally, as... Figure 6 As indicated by arrow Y2, a portion of the liquid sealant S, after passing through the second through-hole 254, moves along the lower surface 455 of the fourth sealing pad substrate 450 and is introduced between the fourth sealing pad substrate 450 and the second sealing pad substrate 250. Furthermore, in the above embodiment, the first sealing pad substrate 150 closes the fourth through-hole 454 from above. Therefore, the first sealing pad substrate 150 restricts the further upward movement of a portion of the liquid sealant S after passing through the fourth through-hole 454, preventing it from being introduced between the first sealing pad substrate 150 and the fourth sealing pad substrate 450.

[0111] Here, each through hole 254, 354, 454 is located near the first protrusion 151, the fourth protrusion 451, and the third protrusion 351, i.e., near the protrusion line L1. As a result, liquid sealant S is introduced between the sealing gasket substrates 150, 250, 350, 450 and is introduced into the portion near the protrusion line L1.

[0112] The above results indicate that, in the above embodiments, as Figure 11 As shown, the middle portion of the aforementioned passage X3 is sealed by a liquid sealant S. When the middle portion of passage X3 is sealed by the liquid sealant S, as... Figure 11As indicated by arrow Y21, air passing through passage X3 is prevented from flowing towards its front opening, thus reducing the amount of air squeezed forward from the opening of passage X3. Therefore, according to the cylinder head gasket 50 of the above embodiment, the liquid sealant S disposed in the gap X2 can be prevented from being blown away by air within passage X3, preventing the formation of voids in the liquid sealant S in the gap X2, i.e., between the front end 51 of the cylinder head gasket 50 and the rear end face 32 of the chain cover 30, thereby improving the sealing performance of the gap X2. Furthermore, air flowing forward through passage X3 squeezes the liquid sealant S introduced into the middle of passage X3 forward, i.e., towards the gap X2. Therefore, according to the cylinder head gasket 50 of the above embodiment, by ensuring the amount of liquid sealant S filled into the gap X2 along with the squeezing out of the liquid sealant S, the sealing performance of the gap X2 can also be improved.

[0113] In particular, in the above embodiment, as described above, the centers of the second through hole 254, the third through hole 354, and the fourth through hole 454 are aligned. The lower surface 255 of the second sealing gasket substrate 250 covers the entire circumference of the third through hole 354, extending radially inward from the periphery of the third through hole 354. The lower surface 455 of the fourth sealing gasket substrate 450 covers the entire circumference of the second through hole 254, extending radially inward from the periphery of the second through hole 254. Therefore, it is possible to cover the entire circumference of each through hole 254, 354, and 454, so that the liquid sealant S is directed radially outward towards each through hole 254, 354, and 454, reliably introducing the liquid sealant S into the gaps between each sealing gasket substrate 150, 250, 350, and 450. Therefore, the passage X3 can be reliably sealed, and the sealing performance of the gap X2 can be reliably improved.

[0114] Furthermore, in the above embodiment, a guide portion 256 is provided around the periphery of the second through hole 254, which bends downward and radially inward toward the second through hole 254. Therefore, the liquid sealant S can be guided along the guide portion 256 to the gap between the second sealing pad substrate 250 and the third sealing pad substrate 350. Through the gap between them and even through the passage X3 between the second sealing pad substrate 250 and the third sealing pad substrate 350, more liquid sealant S can be introduced, and the passage X3 can be reliably sealed further.

[0115] Furthermore, in the above embodiment, by forming at the positions of each through hole 254, 354, 454 and near the front end 51 of the cylinder head gasket 50, such as Figure 11As shown, the area from the middle of the passage X3 to the front end 51 of the cylinder head gasket 50 is filled with liquid sealant S. Therefore, it is possible to reliably prevent air in the passage X3 from blowing away the liquid sealant S in the gap X2. Furthermore, as the through holes 254, 354, and 454 separate from the front end 51 of the cylinder head gasket 50, even if the liquid sealant S does not fill to the vicinity of the front end of the passage X3, as long as the middle part of the passage X3 is closed by the liquid sealant S, the amount of air ejected from the front end of the passage X3 toward the gap X2 is reduced, thus improving the sealing performance of the gap X2.

[0116] (Modified Example)

[0117] In the above embodiment, although the first protrusion 151, the third protrusion 351 and the fourth protrusion 451 are described as being radially inclined along the recess 59 and the chain receiving portion 39, the specific structure is not limited to the above structure as long as these protrusions 151, 351 and 451 protrude upward or downward.

[0118] In the above embodiment, although it has been described that the through holes 254, 354, 454 are formed in the radial direction of the recess 59 and the chain receiving portion 39 at a position that is inside the protrusions 151, 351, 451 and the protrusion line L1, it is acceptable that the through holes 254, 354, 454 are near the protrusions 151, 351, 451 and the protrusion line L1 when viewed from above, or they may be provided in the radial direction that is further outside the recess 59 (chain receiving portion 39).

[0119] In the above embodiments, although the case where the center positions of each through hole 254, 354, and 454 are the same has been described, these center positions may not be the same. Furthermore, in the above embodiments, although the case where the center positions of each through hole 254, 354, and 454 are the same, and the second through hole 254 is located inside the third through hole 354, and the fourth through hole 154 is located inside the second through hole 254 has been described, it is sufficient that at least a portion of these through holes 254, 354, and 454 are arranged such that they overlap when viewed from above.

[0120] In the above embodiment, although the case in which the first sealing pad substrate 150 has a shape that closes each through hole 254, 354, 454 from above has been described, it is also possible to provide holes opposite to each through hole 254, 354, 454 in the first sealing pad substrate 150.

[0121] In the above embodiments, although the case where each through hole 254, 354, and 454 is a circular hole has been described, the shape of these through holes 254, 354, and 454 may not be circular.

[0122] In the above embodiment, although the case where a guide portion 256 is provided around the second through hole 254 has been described, the guide portion 256 can be omitted.

[0123] In the above embodiments, although it has been described that the first sealing gasket substrate 150, the third sealing gasket substrate 350 and the fourth sealing gasket substrate 450 are respectively formed with protrusions, the protrusions can be formed on any one of the first sealing gasket substrate 150, the second sealing gasket substrate 250 and the third sealing gasket substrate 350.

[0124] In the above embodiments, although the thickness of the second sealing gasket substrate 250 is thinner than that of the other sealing gasket substrates 150, 350, and 450, and the second sealing gasket substrate 250 does not have protrusions, it is also possible to make the thickness of the second sealing gasket substrate 250 the same as that of the other sealing gasket substrates.

[0125] In the above embodiment, although the case where the cylinder head gasket 50 is a four-layer gasket has been described, the cylinder head gasket can be any multi-layer gasket having three or more gasket substrates, and the number of layers can be five or more.

[0126] In addition, the cylinder head gasket can also be like Figure 12 That's how it's structured. Specifically, in Figure 12 In the cylinder head gasket 550 shown, the fourth gasket substrate 450 is omitted, and the cylinder head gasket 550 is a three-layer gasket. Additionally, in Figure 12 In the example, similar to the above embodiment, a guide portion 556 is formed around the second through hole 554 of the second sealing pad substrate 551. On the other hand, the thickness of the second sealing pad substrate 551 is set to be the same as the thickness of the first sealing pad substrate 150 and the third sealing pad substrate 350, and a protrusion 552 is formed on the second sealing pad substrate 551.

[0127] In the above embodiments, although the case where the engine body 2 is a tandem six-cylinder engine has been described, the number of cylinders and the arrangement of cylinders in the engine body 2 are not limited to this.

Claims

1. A cylinder head gasket, inserted between a cylinder block and a cylinder head in an engine, the engine comprising: the cylinder block, the cylinder head and a cover component, the cylinder block and the cylinder head overlap in the cylinder axial direction, the cover component has a mating surface, the mating surface abuts against the end surfaces of the cylinder block and the cylinder head in a direction orthogonal to the cylinder axial direction, respectively, and lubricating oil is used inside the cover component, characterized in that: have: A first substrate, wherein the first substrate has the axial direction of the cylinder as a thickness direction; a second substrate, the second substrate being arranged on one side of the first substrate in the axial direction of the cylinder; as well as A third substrate, the third substrate is arranged on one side of the second substrate in the axial direction of the cylinder, At least one of the first substrate, the second substrate, and the third substrate includes a protrusion that protrudes toward one side or the other side of the cylinder axial direction and has a ridgeline extending toward the mating surface of the cover component when viewed in the axial direction of the cylinder, The second substrate and the third substrate each have a through hole, which is formed near the protrusion when viewed in the axial direction of the cylinder, penetrates the front and back of each substrate, and overlaps with each other when viewed in the axial direction of the cylinder. The through hole of the second substrate has a smaller diameter than the through hole of the third substrate.

2. The cylinder head gasket according to claim 1, characterized in that: The through hole of the second substrate is arranged inside the through hole of the third substrate when viewed in the axial direction of the cylinder.

3. The cylinder head gasket according to claim 2, characterized in that: The through hole of the second substrate is arranged so that the center of the through hole coincides with the center of the through hole of the third substrate.

4. The cylinder head gasket according to claim 2, characterized in that: The second substrate has a guide portion on the periphery of the through hole that is bent toward one side in the axial direction of the cylinder and radially inward.

5. The cylinder head gasket according to claim 1, characterized in that: The first substrate has a shape that closes the through hole of the second substrate from the other side in the axial direction of the cylinder.

6. The cylinder head gasket according to any one of claims 1 to 5, characterized in that: A fourth substrate is further provided, the fourth substrate being arranged between the first substrate and the second substrate, The fourth substrate has a through hole that penetrates the front and back of the fourth substrate and overlaps with the through hole of the second substrate when viewed in the axial direction of the cylinder.

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