Valve support structure for internal combustion engine

Abstract

To provide a valve support structure for an internal combustion engine that can suppress abrasion of a valve and a valve guide by preventing inclination of a valve provided in the vicinity of an opening during sliding.SOLUTION: A valve support structure for an internal combustion engine 1 includes: an opening 2D that is open on a rear wall 2C of a cylinder head 2 and is in communication with a water jacket 21; a boss part 2A for an air discharge valve guide, the boss part facing the opening 2D in a cylinder row direction A and extending in a vertical direction through the water jacket 21; and an air discharge valve 7 provided on the boss part 2A for an air discharge valve guide via the air discharge valve guide 7A in a slidable manner. A reinforcement rib 23 is provided in the water jacket 21. The reinforcement rib 23 extends from the boss part 2A for an air discharge valve guide to the side of the opening 2A, and extends from a ceiling wall 21A of the water jacket 21 to a bottom wall 21B.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a valve support structure for an internal combustion engine. [Background technology]

[0002] BACKGROUND ART In an exhaust valve provided in a cylinder head, a valve support structure is known that reduces wear on a valve guide that occurs when the valve moves up and down (see Patent Document 1).

[0003] The valve support structure described in Patent Document 1 movably supports an exhaust valve on a cylinder head.

[0004] The exhaust valve is arranged to pass through a through hole provided in the cylinder head, and is equipped with a cylindrical valve guide that movably guides the shaft of the exhaust valve, and a cylindrical buffer material arranged between the valve guide and the cylinder head.

[0005] With this valve support structure, when the valve stem tilts relative to the valve guide, the valve guide also tilts to match the stem, increasing the contact area between the valve stem and the valve guide, thereby reducing wear on the valve guide caused by the valve moving up and down. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-80879 Summary of the Invention [Problem to be solved by the invention]

[0007] Incidentally, one of the factors that causes the valve stem and valve guide to tilt is the rigidity of the cylinder head.

[0008] The cylinder head is formed with a water jacket, and an opening is formed in the wall of the cylinder head that communicates with the water jacket. Because the rigidity of the cylinder head is low near the opening, if a valve guide is located near this opening, there is a problem that the valve stem and valve guide are more likely to tilt than in other parts.

[0009] The present invention has been made in response to the above-mentioned problems, and aims to provide a valve support structure for an internal combustion engine that can prevent a valve arranged near an opening from tilting when sliding, thereby suppressing wear on the valve and valve guide. [Means for solving the problem]

[0010] The present invention provides a valve support structure for an internal combustion engine including: a water jacket formed in a cylinder head; an opening that opens into a wall portion located at an end of the cylinder head in the cylinder row direction and communicates with the water jacket; a valve guide boss portion that faces the opening in the cylinder row direction and extends vertically through the water jacket; and a valve that is slidably attached to the valve guide boss portion via a valve guide, wherein a reinforcing rib is disposed within the water jacket, and the reinforcing rib extends from the valve guide boss portion toward the opening side and also extends from the ceiling wall to the bottom wall of the water jacket. [Effects of the Invention]

[0011] As described above, according to the present invention, the valve disposed near the opening can be prevented from tilting during sliding, and wear of the valve and valve guide can be suppressed. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a rear view of a cylinder head equipped with a valve support structure according to one embodiment of the present invention. [Figure 2]FIG. 2 is a vertical cross-sectional view of a cylinder head equipped with a valve support structure according to one embodiment of the present invention. [Figure 3] FIG. 3 is a plan view of a cylinder head provided with a valve support structure according to one embodiment of the present invention. [Figure 4] 4 is a cross-sectional view taken along the line IV-IV in FIG. [Figure 5] 5 is a cross-sectional view taken along the arrows VV in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] A valve support structure for an internal combustion engine according to one embodiment of the present invention is a valve support structure for an internal combustion engine comprising: a water jacket formed in a cylinder head; an opening that opens into a wall portion located at the end of the cylinder head in the cylinder row direction and communicates with the water jacket; a valve guide boss portion that faces the opening in the cylinder row direction and extends vertically through the water jacket; and a valve that is slidably attached to the valve guide boss portion via a valve guide, wherein a reinforcing rib is arranged within the water jacket, and the reinforcing rib extends from the valve guide boss portion toward the opening side and also extends from the ceiling wall to the bottom wall of the water jacket.

[0014] As a result, the valve support structure for an internal combustion engine according to one embodiment of the present invention can prevent the valve arranged near the opening from tilting when sliding, thereby suppressing wear on the valve and valve guide. [Example]

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a valve support structure for an internal combustion engine according to the present invention will be described with reference to the drawings.

[0016] 1 to 5 are diagrams showing a valve support structure for an internal combustion engine according to one embodiment of the present invention. In Figures 1 to 5, the up / down, front / rear, left / right directions are based on the internal combustion engine installed in a vehicle, and the front / rear direction of the vehicle is the front-rear direction, the left / right direction of the vehicle (vehicle width direction) is the left / right direction, and the up / down direction of the vehicle (vehicle height direction) is the up / down direction.

[0017] 1 and 2, an internal combustion engine 1 includes a cylinder head 2 and a cylinder block 3 connected to the lower part of the cylinder head 2 via a head gasket 4.

[0018] The head gasket 4 has a sealing function to prevent leakage of combustion gas, cooling water, engine oil, etc. from the connecting portion between the cylinder head 2 and the cylinder block 3.

[0019] As shown in FIG. 2, the cylinder head 2 includes an exhaust camshaft 5, an exhaust cam 6, an exhaust valve 7, an exhaust-side rocker arm 8, and an exhaust-side hydraulic lash adjuster (HLA) 9.

[0020] The exhaust camshaft 5 extends in the front-rear direction, and the exhaust cam 6 is attached to the exhaust camshaft 5 so as to be rotatable integrally with the exhaust camshaft 5 .

[0021] One end of the rocker arm 8 is disposed so as to come into contact with the upper end of the pivot 9A of the HLA 9, and a circular pressed roller 8A is supported in the center of the rocker arm 8.

[0022] The pressed roller 8A protrudes from the upper surface of the rocker arm 8, and the pressed roller 8A is in contact with the exhaust cam 6.

[0023] The other end of the rocker arm 8 is in contact with the upper end of the exhaust valve 7. The exhaust valve 7 is provided so as to be able to move back and forth in the axial direction relative to the cylinder head 2, and is biased by a valve spring 10 in a direction to close an exhaust hole 11A that communicates between an exhaust port 11 and a combustion chamber 12 (exhaust valve closed state). The exhaust valve 7 of this embodiment constitutes a valve.

[0024] The cylinder block 3 is provided with a plurality of cylinders 3A each housing a piston (not shown), and the combustion chamber 12 is formed from the space above the cylinder 3A. In other words, the combustion chamber 12 is formed from the space surrounded by the piston located at top dead center and the cylinder.

[0025] The cylinders 3A in this embodiment are arranged in a row in the front-rear direction, and the direction in which the cylinders are arranged is referred to as a cylinder row direction A. The number of cylinders is not limited.

[0026] When the rocker arm 8 is pushed by the exhaust cam 6, the exhaust valve 7 is pushed down (lifted) against the biasing force of the valve spring 10, and the exhaust port 11A opens (exhaust valve open state).

[0027] An exhaust port 11 is connected to the cylinder 3A, and exhaust gas burned in the combustion chamber 12 is discharged from the cylinder 3A to the outside of the cylinder head 2 through the exhaust port.

[0028] An exhaust valve guide boss 2A is formed on the cylinder head 2, and the exhaust valve 7 is slidably disposed on the exhaust valve guide boss 2A via an exhaust valve guide 7A. The exhaust valve guide boss 2A in this embodiment constitutes the valve guide boss.

[0029] The cylinder head 2 includes an intake camshaft 13, an intake cam 14, an intake valve 15, an intake-side rocker arm 16, and an intake-side hydraulic lash adjuster (HLA) 17.

[0030] The intake camshaft 13 extends in the front-rear direction (cylinder row direction A) parallel to the exhaust camshaft 5, and the intake cam 14 is attached to the intake camshaft 13 so as to rotate integrally therewith.

[0031] One end of the rocker arm 16 is disposed so as to come into contact with the upper end of the pivot 17A of the HLA 17, and a circular pressed roller 16A is supported in the center of the rocker arm 16.

[0032] The pressed roller 16A protrudes from the upper surface of the rocker arm 16, and the pressed roller 16A is in contact with the intake cam .

[0033] The other end of the rocker arm 16 is in contact with the upper end of the intake valve 15. The intake valve 15 is provided so as to be movable axially back and forth relative to the cylinder head 2, and is biased by a valve spring 18 in a direction to close an intake hole 19A that connects an intake port 19 and the combustion chamber 12 (intake valve closed state).

[0034] When the rocker arm 16 is pushed by the intake cam 14, the intake valve 15 is pushed down (lifted) against the biasing force of the valve spring 18, and the intake port 19A opens (intake valve open state).

[0035] An intake port 19 is connected to the cylinder 3A, and intake air is supplied to the cylinder 3A through the intake port 19.

[0036] An intake valve guide boss portion 2B is formed on the cylinder head 2, and an intake valve 15 is slidably disposed on the intake valve guide boss portion 2B via an intake valve guide 15A.

[0037] As shown in FIG. 3, a spark plug hole 2H is provided between the exhaust valve guide boss portion 2A and the intake valve guide boss portion 2B, and an ignition plug (not shown) is inserted into the spark plug hole 2H.

[0038] 4 and 5, a water jacket 21 through which cooling water flows is formed in the cylinder head 2. The water jacket 21 is formed on the exhaust port 11 side, in the lower part of the cylinder head 2, and extends along the cylinder row direction A of the cylinder head 2. The cooling water flowing through the water jacket 21 cools the combustion chamber 12 and the cylinder head 2 around the exhaust port 11.

[0039] 1, openings 2D and 2E for discharging cooling water are formed in a rear wall 2C of the cylinder head 2. The rear wall 2C of this embodiment forms a wall portion.

[0040] The opening 2D communicates with the water jacket 21, and the cooling water flowing through the water jacket 21 is discharged to the outside of the cylinder head 2 through the opening 2D.

[0041] The opening 2E communicates with the water jacket 22 (see FIG. 4), and the cooling water flowing through the water jacket 22 is discharged from the opening 2E to the outside of the cylinder head 2. The water jacket 22 forms a cooling water passage on the intake port 19 side, which is different from the water jacket 21, and cools the intake port 19 side and the bottom of the cylinder head 2.

[0042] 4 and 5, the exhaust valve guide boss portion 2A faces the opening 2D in the cylinder row direction A and extends in the vertical direction through the water jacket 21. In other words, the exhaust valve guide boss portion 2A forms part of the outer wall of the water jacket 21.

[0043] 2 and 5, a valve train chamber 31 is formed in the cylinder head 2 above the water jacket 21, and in the valve train chamber 31, an exhaust camshaft 5, an exhaust cam 6, a rocker arm 8, and an HLA 9 are arranged.

[0044] 4, a reinforcing rib 23 is provided inside the cylinder head 2. The reinforcing rib 23 extends from the exhaust valve guide boss portion 2A along the cylinder row direction A toward the opening 2D side.

[0045] As shown in FIG. 5, the water jacket 21 includes a top wall 21A and a bottom wall 21B, and the reinforcing ribs 23 extend from the top wall 21A to the bottom wall 21B and connect the top wall 21A and the bottom wall 21B together.

[0046] 4, a pair of head bolt holes 2a, 2b are formed in the rear of the cylinder head 2, and bolts (not shown) are inserted into the head bolt holes 2a, 2b to fasten the cylinder head 2 to the cylinder block 3. A pair of head bolt holes (not shown) are also formed in the front of the cylinder head 2.

[0047] That is, the cylinder head 2 is attached to the cylinder block 3 by inserting bolts into the head bolt holes 2a, 2b and fastening the bolts to the cylinder block 3.

[0048] The head bolt holes 2a, 2b are located on the rear wall 2C side of the exhaust valve guide boss portion 2A in the cylinder row direction A of the cylinder head 2.

[0049] The head bolt holes 2a, 2b are arranged along an imaginary straight line X that extends in a direction intersecting the cylinder row direction A, and the reinforcing rib 23 extends from the exhaust valve guide boss portion 2A toward the rear wall 2C beyond the imaginary straight line X in the cylinder row direction A.

[0050] The water jacket 21 has an outlet passage portion 21C. The outlet passage portion 21C has a left inner wall 21D and a right inner wall 21E that extend vertically and face each other in a direction intersecting the cylinder row direction A, and allows the cooling water to flow from the periphery of the exhaust valve guide boss portion 2A toward the opening 2D.

[0051] The left inner wall 21D and the right inner wall 21E have a passage width narrowing portion 21a where the distance between them narrows toward the opening 2D in the flow direction of the cooling water.

[0052] Specifically, a bent portion 21b is formed on the right inner wall 21E, and the right inner wall 21E located upstream of the bent portion 21b in the direction of cylinder row A in the flow direction of the cooling water is closer to the left inner wall 21D in the left-right direction than the right inner wall 21E located downstream of the bent portion 21b in the direction of cylinder row A in the flow direction of the cooling water.

[0053] In other words, the right inner wall 21E located downstream of the bend 21b in the direction of cylinder row A in the flow direction of the cooling water is spaced apart from the left inner wall 21D in the left-right direction, compared to the right inner wall 21E located upstream of the bend 21b in the direction of cylinder row A in the flow direction of the cooling water.

[0054] The reinforcing rib 23 has a tip 23a on the opening 2D side that is positioned closer to the exhaust valve guide boss 2A than the passage width narrowing portion 21a in the flow direction of the coolant. In this embodiment, the left inner wall 21D and the right inner wall 21E form a pair of side walls.

[0055] Next, the effects of the valve support structure of the internal combustion engine 1 of this embodiment will be described. The valve support structure of the internal combustion engine 1 of this embodiment includes a water jacket 21 formed in the cylinder head 2, and an opening 2D that opens into a rear wall 2C located at the rear end of the cylinder head 2 in the cylinder row direction A and communicates with the water jacket 21.

[0056] In addition, the valve support structure of the internal combustion engine 1 includes an exhaust valve guide boss portion 2A that faces the opening 2D in the cylinder row direction A and extends vertically through the water jacket 21, and an exhaust valve 7 that is slidably arranged on the exhaust valve guide boss portion 2A via an exhaust valve guide 7A.

[0057] A reinforcing rib 23 is disposed within the water jacket 21, and extends from the exhaust valve guide boss portion 2A toward the opening 2D, and also extends from the ceiling wall 21A of the water jacket 21 to the bottom wall 21B.

[0058] As a result, even when the exhaust valve 7 is disposed near the opening 2D, which has low rigidity, the reinforcing rib 23 can improve the supporting rigidity of the exhaust valve guide boss portion 2A.

[0059] This prevents the exhaust valve 7 and the exhaust valve guide 7A from tilting in the cylinder row direction A when the exhaust valve 7 slides. As a result, wear on parts such as the exhaust valve 7 and the exhaust valve guide 7A when the exhaust valve 7 slides can be suppressed.

[0060] In addition, the reinforcing ribs 23 can improve the rigidity of the cylinder head 2, thereby strengthening the compressive force of the head gasket 4 and improving the sealing function that prevents leakage of combustion gases, cooling water, engine oil, etc. from the connection between the cylinder head 2 and the cylinder block 3.

[0061] Furthermore, according to the valve support structure for the internal combustion engine 1 of this embodiment, the cylinder head 2 has head bolt holes 2a and 2b into which bolts are inserted to fasten the cylinder head 2 to the cylinder block.

[0062] The pair of head bolt holes 2a, 2b are located on the rear wall 2C side of the exhaust valve guide boss portion 2A in the cylinder row direction A of the cylinder head 2, and are arranged along an imaginary straight line X extending in a direction intersecting the cylinder row direction A.

[0063] In addition, the reinforcing rib 23 extends from the exhaust valve guide boss portion 2A toward the rear wall 2C beyond the imaginary line X in the cylinder row direction A.

[0064] Here, the areas of the cylinder head 2 around the head bolt holes 2a and 2b form the connecting portion to the cylinder block 3, and therefore have higher rigidity than other portions of the cylinder head 2.

[0065] Therefore, by extending the tip portion 23a of the reinforcing rib 23 outward from the position of the head bolt holes 2a, 2b, the exhaust valve guide boss portion 2A can be reinforced by the surrounding areas of the head bolt holes 2a, 2b, and the support rigidity of the exhaust valve guide boss portion 2A can be more effectively increased.

[0066] This more effectively prevents the exhaust valve 7 and the exhaust valve guide 7A from tilting in the cylinder row direction A when the exhaust valve 7 slides, and more effectively prevents wear on parts such as the exhaust valve 7 and the exhaust valve guide 7A when the exhaust valve 7 slides.

[0067] Furthermore, according to the valve support structure of the internal combustion engine 1 of this embodiment, the water jacket 21 has an outlet passage portion 21C that allows cooling water to flow from the periphery of the exhaust valve guide boss portion 2A toward the opening 2D, and the outlet passage portion 21C has a left inner wall 21D and a right inner wall 21E that extend in the vertical direction opposite each other in a direction intersecting the cylinder row direction A.

[0068] The left inner wall 21D and the right inner wall 21E have passage width narrowing portions 21a where the distance between them narrows toward the opening 2D in the flow direction of the cooling water, and the tip portion 23a of the reinforcing rib 23 on the opening 2D side is positioned closer to the exhaust valve guide boss portion 2A than the passage width narrowing portion 21a in the flow direction of the cooling water.

[0069] As a result, the tip end 23a of the reinforcing rib 23 is positioned upstream (toward the exhaust valve guide boss 2A) of the passage width narrowing portion 21a where the passage width of the outlet passage 21C narrows, and therefore the reinforcing rib 23 is prevented from obstructing the flow of cooling water flowing through the outlet passage 21C toward the opening 2D, thereby maintaining the cooling performance of the cylinder head 2.

[0070] While an embodiment of the present invention has been disclosed, it will be apparent to those skilled in the art that modifications may be made without departing from the scope of the invention, and all such modifications and equivalents are intended to be encompassed by the following claims. [Explanation of symbols]

[0071] 1. Internal combustion engine 2. Cylinder head 2A Exhaust valve guide boss (valve guide boss) 2a, 2b Head bolt holes 2C Rear wall (wall part) 2D opening 7 Exhaust valve (valve) 21 Water Jacket 21A Ceiling wall 21a Passage width reduction section 21B Bottom wall 21C Exit passage section 21D Left inner wall (pair of side walls) 21E Right inner wall (pair of side walls) 23 Reinforcing rib A Cylinder row direction X imaginary line

Claims

1. a water jacket formed on the cylinder head; an opening portion that opens into a wall portion located at an end portion of the cylinder head in a cylinder row direction and that communicates with the water jacket; a valve guide boss portion that faces the opening in the cylinder row direction and extends in a vertical direction through the water jacket; a valve slidably attached to the valve guide boss portion via a valve guide, A reinforcing rib is disposed within the water jacket, a valve support structure for an internal combustion engine, wherein the reinforcing rib extends from the valve guide boss portion toward the opening and also extends from a ceiling wall to a bottom wall of the water jacket.

2. the cylinder head has a pair of head bolt holes into which bolts are inserted to fasten the cylinder head to a cylinder block, the pair of head bolt holes are located closer to the wall portion than the valve guide boss portion in the cylinder row direction of the cylinder head, and are arranged along an imaginary straight line extending in a direction intersecting the cylinder row direction, 2. The valve support structure for an internal combustion engine according to claim 1, wherein the reinforcing rib extends from the valve guide boss portion toward the wall portion beyond the imaginary straight line in the cylinder row direction.

3. the water jacket has an outlet passage portion through which cooling water flows from the periphery of the valve guide boss portion toward the opening, the outlet passage portion has a pair of inner walls extending in a vertical direction and facing each other in a direction intersecting the cylinder row direction, the pair of inner walls have passage width narrowing portions whose spacing narrows toward the opening in the flow direction of the cooling water, 3. The valve support structure for an internal combustion engine according to claim 1, wherein the reinforcing rib has a tip end on the opening side that is positioned closer to the valve guide boss portion than the passage width narrowing portion in the flow direction of the cooling water.

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