JP2015117663A - Seal structure between cylinder head and head cover - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prolong the service life of a seal member.SOLUTION: A head cover 10 has an extension part 14 opposed to the upper end 20J of a cylinder head 20, and a vertical wall part 15 extending from the extension part 14 along the inner peripheral surface of the cylinder head 20. The inner peripheral surface of the cylinder head 20 has a contact part 21 which contacts with the outer peripheral surface of the vertical wall part 15 to form a first seal part together with the head cover 10. By a seal member 30 arranged between the upper end 20J of the cylinder head and the extension part 14 of the head cover, a second seal part is formed, which is separated via the first seal part from a contact interface between the cylinder head and the head cover in a valve gear chamber 40.

Description

  The present invention relates to a seal structure between a cylinder head and a head cover provided in an internal combustion engine.

  The internal combustion engine includes a cylinder head and a head cover. A valve operating chamber is formed in a space surrounded by the cylinder head and the head cover. A valve operating mechanism including a camshaft and a rocker arm is accommodated in the valve operating chamber. Oil (lubricating oil) for smoothly operating the valve mechanism is supplied to the valve mechanism (such as a bearing) in the valve chamber.

  As disclosed in Patent Documents 1 and 2 below, a seal structure between a cylinder head and a head cover is known. In the seal structure, a seal member such as a packing or a gasket is used to prevent oil in the valve chamber from leaking to the outside of the valve chamber through the joint surface between the cylinder head and the head cover.

Japanese Utility Model Publication No. 63-186554 Special table 2008-510912 gazette

  In the seal structures disclosed in Patent Documents 1 and 2, a part of the seal member is exposed when viewed from the valve operating chamber. That is, the seal member is configured to be exposed to oil in the valve operating chamber. When the seal member repeatedly contacts the high temperature oil over a long period of time, the seal member gradually deteriorates and the sealing function of the seal member also gradually decreases. Even in a new state, even if the seal member has exhibited an appropriate seal function, oil leakage occurs when the seal member is unable to exhibit a sufficient seal function due to deterioration.

  The present invention has been made in view of the above circumstances, and it is possible to extend the life of the seal member by reducing the amount of oil contact with the seal member as compared with the conventional case. An object is to provide a seal structure between a cylinder head and a head cover.

  A cylinder head and a head cover sealing structure according to the present invention includes: a cylinder head having an opening; a head cover that is attached to the cylinder head and forms a valve operating chamber with the cylinder head; and the cylinder head and the head cover. The head cover includes an extension portion facing the upper end portion of the cylinder head, and a vertical wall portion extending from the extension portion along the inner peripheral surface of the cylinder head. And the inner peripheral surface of the cylinder head has a contact portion that forms a first seal portion together with the head cover by contacting the outer peripheral surface of the hanging wall portion, and the upper end portion of the cylinder head And the cylinder head in the valve operating chamber by the seal member disposed between the extended portion of the head cover and the head cover. The second sealing portion spaced from the contact interface between the head cover via the first seal portion is constituted.

  Preferably, the hanging wall portion of the head cover is elastically deformed by being press-fitted inside the contact portion, and the outer peripheral surface of the hanging wall portion is brought into contact with the elastic restoring force of the hanging wall portion. It is in close contact with the entire circumference.

  Preferably, the contact portion of the cylinder head has a concave shape that receives the hanging wall portion, and the inner peripheral surface of the cylinder head is positioned on the front side in the press-fitting direction of the head cover with respect to the contact portion. The inner wall of the vertical wall and the other inner circumferential surface of the cylinder head are surfaces by further arranging the inner wall of the vertical wall and the vertical wall disposed inside the contact portion. Have a relationship.

  Preferably, the outer peripheral surface of the hanging wall portion is positioned on the front side in the press-fitting direction of the head cover from the first joint surface extending in a direction parallel to the press-fitting direction of the head cover. The contact portion includes a second joint surface extending in a direction parallel to the press-fitting direction of the head cover, and a concave surface positioned on the front side in the press-fit direction of the head cover with respect to the second joint surface. Part.

  Preferably, in a cross-sectional view parallel to the press-fitting direction of the head cover, when a tangent line is drawn on the innermost portion of the boundary surface formed between the convex surface portion and the concave surface portion, the The tangent line has a shape extending in the horizontal direction or a shape extending toward the upper side from the horizontal direction from the inside toward the outside.

  According to the present invention, the life of the seal member can be extended.

It is sectional drawing which shows the seal structure of the cylinder head and head cover in embodiment. It is sectional drawing which expands and shows the area | region enclosed by the II line | wire in FIG. It is sectional drawing which shows the method for fixing a head cover to a cylinder head regarding embodiment. It is sectional drawing for demonstrating the effect | action and effect in embodiment. 5 is a cross-sectional view showing a seal structure between a cylinder head and a head cover in Comparative Example 1. FIG. 10 is a cross-sectional view showing a seal structure between a cylinder head and a head cover in Comparative Example 2. FIG. It is sectional drawing which shows the seal structure of the cylinder head and head cover in the 1st modification of embodiment. It is sectional drawing which shows the seal structure of the cylinder head and head cover in the 2nd modification of embodiment. It is sectional drawing which decomposes | disassembles and shows the seal structure of the cylinder head and head cover in the 3rd modification of embodiment. It is sectional drawing for demonstrating the effect | action and effect in the 3rd modification of embodiment. It is sectional drawing which shows the seal structure of the cylinder head and head cover in the 4th modification of embodiment. It is sectional drawing which shows the seal structure of the cylinder head and head cover in the 5th modification of embodiment.

  Hereinafter, embodiments will be described with reference to the drawings. When referring to the number, amount, etc., the scope of the present invention is not necessarily limited to the number, amount, etc., unless otherwise specified. The same parts and corresponding parts are denoted by the same reference numerals, and redundant description may not be repeated.

[Embodiment]
(overall structure)
FIG. 1 is a cross-sectional view showing a seal structure 100 (hereinafter referred to as a seal structure 100) between a cylinder head and a head cover in the embodiment. The seal structure 100 includes a cylinder head 20, a head cover 10, and a seal member 30. As a material constituting the cylinder head 20, for example, an aluminum alloy or cast iron is used. The head cover 10 is made of a resin material having high strength and high heat resistance such as polyamide or BMC (Bulk Molding Compound) resin.

  The cylinder head 20 has a substantially cylindrical shape and has an opening for forming the valve operating chamber 40. The head cover 10 includes a top plate portion 11 and a side wall portion 12 and has a cap-like shape as a whole. The head cover 10 is attached to the cylinder head 20 so as to cover the opening of the cylinder head 20. Although details will be described later, the side wall portion 12 (more specifically, the vertical wall portion 15 of the side wall portion 12) of the head cover 10 is formed on the inner peripheral surface 20N (more specifically, the cylinder head 20 forming the opening). Is press-fitted inside the recess 21) of the inner peripheral surface 20N.

  A valve operating chamber 40 is formed in the space inside the cylinder head 20 and the head cover 10. A valve operating mechanism including a camshaft and a rocker arm (not shown) is accommodated in the valve operating chamber 40. Oil (lubricating oil) for smoothly operating the valve operating mechanism is supplied to a valve operating mechanism (such as a bearing) in the valve operating chamber 40 from an oil supply means (not shown). The oil moves in the valve operating chamber 40 when the internal combustion engine is driven.

(Head cover 10)
FIG. 2 is an enlarged cross-sectional view showing a region surrounded by line II in FIG. The side wall portion 12 of the head cover 10 includes an upper wall portion 13, an extension portion 14, and a vertical wall portion 15. The upper wall portion 13 and the hanging wall portion 15 have an annular shape and extend along the vertical direction (vertical direction). The hanging wall portion 15 is a portion that is press-fitted into a concave portion 21 provided in the cylinder head 20.

  The extending portion 14 has a shape extending outward from a portion where the upper wall portion 13 and the hanging wall portion 15 are located. Both the upper end surface 14J and the lower end surface 14K of the extending portion 14 extend along the horizontal direction (horizontal direction). A bottomed hole 14 </ b> P for inserting the seal member 30 is provided in the lower end surface 14 </ b> K of the extending portion 14.

  The hanging wall portion 15 has a shape that hangs downward from the inside of the lower end surface 14 </ b> K of the extending portion 14 so as to extend along the inner peripheral surface of the cylinder head 20. The inner peripheral surface 15N of the vertical wall portion 15 is a portion that forms the valve operating chamber 40 (FIG. 1) together with the inner peripheral surface 20N of the cylinder head 20, and extends along the vertical direction (vertical direction). The outer peripheral surface 15G of the vertical wall portion 15 includes a bonding surface 15G1 (first bonding surface) and a convex surface portion 15G2.

  The joint surface 15G1 (see also FIG. 3) as the first joint surface has a flat surface shape, and is in a direction (press-fit direction) in which the vertical wall portion 15 of the head cover 10 is press-fitted into the concave portion 21 of the cylinder head 20. It extends in the parallel direction. The joint surface 15G1 is a part that is in close contact with the inner peripheral surface 21N (joint surface 21N1) of the recess 21 of the cylinder head 20 when the head cover 10 is press-fitted into the opening of the cylinder head 20.

  The convex surface portion 15G2 (see also FIG. 3) is located below the bonding surface 15G1. In other words, the convex surface portion 15G2 is located on the front side of the joint surface 15G1 in the press-fitting direction of the head cover 10. The convex surface portion 15G2 has a curved surface shape that bulges outward and downward. The convex surface portion 15G2 is a portion that is in close contact with the inner peripheral surface 21N (concave surface portion 21N2) of the concave portion 21 of the cylinder head 20 when the head cover 10 is press-fitted into the opening of the cylinder head 20.

(Cylinder head 20)
The cylinder head 20 includes an upper end surface 20J (upper end portion) and an inner peripheral surface 20N. The upper end surface 20J extends along the horizontal direction (horizontal direction). The upper end surface 20J faces the extending portion 14 (lower end surface 14K) of the head cover 10 when the head cover 10 is press-fitted into the opening of the cylinder head 20.

  The inner peripheral surface 20N of the cylinder head 20 is a part for forming an opening for press-fitting the head cover 10, and has a concave portion 21 (contact portion) on the upper side thereof. A portion of the inner peripheral surface 20N where the recess 21 is not provided (the other inner peripheral surface 20N3) is continuous with the lower end of the recess 21 and extends along the vertical direction (vertical direction).

  The other inner peripheral surface 20N3 is a part that forms the valve operating chamber 40 (FIG. 1) together with the inner peripheral surface of the head cover 10 (top plate portion 11 and side wall portion 12). In the present embodiment, when the head cover 10 is press-fitted into the opening of the cylinder head 20, the hanging wall portion 15 of the head cover 10 is disposed in the recess 21 of the cylinder head 20, so that the inner peripheral surface of the hanging wall portion 15. 15N and the other inner peripheral surface 20N3 of the cylinder head 20 have a flush relationship.

  The concave portion 21 as the contact portion has a concave shape such that an inner portion of the upper end surface 20J of the cylinder head 20 is cut out in a substantially J shape downward. The method for forming the recess 21 in the cylinder head 20 is not limited to notching (cutting), and the recess 21 may be formed by casting. The concave portion 21 receives the hanging wall portion 15 of the head cover 10 when the head cover 10 is press-fitted into the opening of the cylinder head 20. The inner peripheral surface 21 </ b> N of the recess 21 constitutes a “first seal portion” together with the outer peripheral surface 15 </ b> G of the vertical wall portion 15 by contacting the outer peripheral surface 15 </ b> G of the vertical wall portion 15. In the present embodiment, since the vertical wall portion 15 of the head cover 10 is press-fitted into the concave portion 21 of the cylinder head 20, the first seal portion includes the inner peripheral surface 21N of the concave portion 21 and the outer peripheral surface 15G of the vertical wall portion 15. Are formed in the portions that are in close contact with each other. The inner peripheral surface 21N of the recess 21 includes a bonding surface 21N1 (second bonding surface) and a concave surface portion 21N2.

  The joining surface 21N1 (see also FIG. 3) as the second joining surface has a flat surface shape, and is in a direction (press-fit direction) in which the hanging wall portion 15 of the head cover 10 is press-fitted into the recess 21 of the cylinder head 20. It extends in the parallel direction. The joint surface 21N1 has a shape (same shape) corresponding to the outer peripheral surface 15G (joint surface 15G1) of the hanging wall portion 15 of the head cover 10. When the head cover 10 is press-fitted into the opening of the cylinder head 20, the joint surface 21N1 is in close contact with the outer peripheral surface 15G (joint surface 15G1) of the hanging wall portion 15 of the head cover 10.

  The concave surface portion 21N2 (see also FIG. 3) is located below the bonding surface 21N1. In other words, the concave surface portion 21N2 is located on the front side of the joint surface 21N1 in the press-fitting direction of the head cover 10. The concave surface portion 21N2 has a curved surface shape that is recessed concavely outward. The concave surface portion 21N2 has a shape (same shape) corresponding to the outer peripheral surface 15G (convex surface portion 15G2) of the hanging wall portion 15 of the head cover 10. The concave surface portion 21N2 is in close contact with the convex surface portion 15G2 of the head cover 10 when the head cover 10 is press-fitted into the opening of the cylinder head 20.

(Seal member 30)
The seal member 30 is disposed between the cylinder head 20 and the head cover 10 and outside the hanging wall portion 15 of the head cover 10. The seal member 30 has an annular shape surrounding the hanging wall portion 15 from the outside. As shown in FIGS. 1 and 2, in a state where the head cover 10 is press-fitted into the opening of the cylinder head 20, the seal member 30 has an outer peripheral surface 15 </ b> G of the hanging wall portion 15 and an inner peripheral surface 20 </ b> N (recessed portion 21) The inner peripheral surface 21N) is located farther from the valve operating chamber 40 than the portion in close contact with each other.

  Specifically, the seal member 30 includes a pedestal portion 31 and an insertion portion 32. The pedestal portion 31 has a flat shape and is disposed between the lower end surface 14K of the extending portion 14 of the head cover 10 and the upper end surface 20J of the cylinder head 20. The insertion portion 32 stands from the pedestal portion 31 and has a shape corresponding to the bottomed hole 14 </ b> P provided in the head cover 10. Prior to press-fitting the head cover 10 into the opening of the cylinder head 20, the seal member 30 can be fitted into the bottomed hole 14P of the head cover 10 in advance (see FIG. 3).

  The lower end surface 14K of the head cover 10 and the upper end surface 20J of the cylinder head 20 are portions where the outer peripheral surface 15G of the hanging wall portion 15 and the inner peripheral surface 20N of the cylinder head 20 (the inner peripheral surface 21N of the recess 21) are in close contact with each other ( It is located on the side farther from the valve operating chamber 40 than the first seal part). The seal member 30 is disposed between the lower end surface 14K and the upper end surface 20J and is sandwiched between them. The seal member 30 exhibits a sealing function between the lower end surface 14K and the upper end surface 20J, and can block communication between the inside and the outside of the valve operating chamber 40. That is, a “second seal portion” is formed by the seal member 30 disposed between the upper end surface 20J (upper end portion) of the cylinder head 20 and the extending portion 14 (lower end surface 14K) of the head cover 10, and this second portion. The seal portion is separated from the contact interface between the cylinder head 20 and the head cover 10 in the valve operating chamber 40 via the first seal portion. Here, the contact interface between the cylinder head 20 and the head cover 10 in the valve operating chamber 40 is a portion of the contact interface between the cylinder head 20 and the head cover 10 that is located closest to the valve operating chamber 40. . Therefore, the inner peripheral surface 21N of the concave portion 21 and the outer peripheral surface 15G of the hanging wall portion 15 come into contact with each other (in close contact in the present embodiment), and the first seal portion formed at this contact portion is used to The two seal portions are separated from the valve operating chamber 40.

(Fixing method)
With reference to FIG. 3, prior to fixing the head cover 10 to the cylinder head 20, the seal member 30 is fitted in the bottomed hole 14 </ b> P of the head cover 10 in advance. In this state, the hanging wall portion 15 of the head cover 10 is press-fitted inside the concave portion 21 (inner peripheral surface 21N) of the cylinder head 20 (arrow AR1).

  Here, in order to achieve appropriate press-fitting, for example, the outer shape of the outer peripheral surface 15G of the hanging wall portion 15 and the inner shape of the inner peripheral surface 21N of the concave portion 21 are configured to have a similar relationship with each other. The outer peripheral length L1 of the outer shape of the outer peripheral surface 15G (joint surface 15G1) of the wall 15 is made slightly longer than the inner peripheral length L2 of the inner shape of the inner peripheral surface 21N (joint surface 21N1) of the recess 21. (L1> L2).

  During press-fitting, the joining surface 15G1 of the hanging wall portion 15 is in sliding contact with the joining surface 21N1 of the concave portion 21, and the hanging wall portion 15 is slightly elastically deformed inward. The head cover 10 is press-fitted inside the opening of the cylinder head 20 until the hanging wall 15 sufficiently enters the inside of the recess 21 (inner peripheral surface 21N). By completing the press-fitting, a so-called inlay structure is formed. Thereafter, the head cover 10 and the cylinder head 20 are firmly fixed to each other by a cylinder head bolt (not shown).

  When the press-fitting is completed, an elastic restoring force for returning to the original state remains in the vertical wall portion 15. Due to the action of the elastic restoring force of the hanging wall portion 15, the outer peripheral surface 15 </ b> G (joining surface 15 </ b> G <b> 1) of the hanging wall portion 15 is in close contact with the inner circumferential surface 21 </ b> N (joining surface 21 </ b> N <b> 1) of the recess 21 as the contact portion. When the inner peripheral surface 21N of the concave portion 21 and the outer peripheral surface 15G of the hanging wall portion 15 are in close contact with each other over the entire periphery, a first seal portion is formed in this close contact portion. In order to form a contact state (close contact state in the present embodiment) over the entire circumference of the first seal portion, the entire inner peripheral surface 21N of the recess 21 and the entire outer peripheral surface 15G of the hanging wall portion 15 are formed. The configuration is not limited to being in contact with each other over the entire periphery, and at least a part of the inner peripheral surface 21N of the recess 21 and at least a part of the outer peripheral surface 15G of the hanging wall portion 15 are in contact with each other over the entire periphery. This configuration can also be realized.

(Function and effect)
Referring to FIG. 4, as described above, the seal member 30 is between the cylinder head 20 (upper end surface 20 </ b> J) and the head cover 10 (lower end surface 14 </ b> K) and outside the hanging wall portion 15 of the head cover 10. Be placed. The seal member 30 is more than the portion where the outer peripheral surface 15G of the hanging wall portion 15 and the inner peripheral surface 20N of the cylinder head 20 (the inner peripheral surface 21N of the recess 21) are in contact with each other (in close contact with this embodiment). , Located on the far side from the valve train chamber 40. The second seal portion constituted by the seal member 30 has a position of the contact portion when the inner peripheral surface 21N of the recess 21 and the outer peripheral surface 15G of the hanging wall portion 15 are in contact with each other (in close contact in the present embodiment). It is separated from the valve operating chamber 40 via the first seal portion formed in the above.

  A part of the seal member 30 is not exposed when viewed from inside the valve train chamber 40. That is, the seal member 30 is not exposed to the oil in the valve operating chamber 40. The path from the valve operating chamber 40 to the seal member 30 is blocked by the close contact (first seal portion) between the outer peripheral surface 15G of the hanging wall portion 15 and the inner peripheral surface 21N of the recess 21. The oil in the valve operating chamber 40 is effectively prevented or suppressed from reaching the seal member 30, and even if the internal combustion engine is used for a long period of time, the seal member 30 does not come into contact with hot oil. Few.

  Therefore, the oil is less in contact with the seal member 30 than in the prior art, the deterioration of the seal member 30 is suppressed, and the life of the seal member 30 can be extended. Even if the oil rarely reaches the seal member 30, the deterioration of the seal member 30 is suppressed, so that the seal member 30 (second seal portion) is longer than the conventional seal member. A sufficient sealing function can be exhibited.

  As described above, in the present embodiment, when the head cover 10 is press-fitted into the opening of the cylinder head 20, the inner peripheral surface 15N of the hanging wall portion 15 and the other inner peripheral surface 20N3 of the cylinder head 20 are flush with each other. have. Most of the oil in the valve operating chamber 40 moves from the upper side toward the lower side, as indicated by an arrow AR2 in FIG. The flush structure facilitates oil to move downward through the inner peripheral surface 15N and the other inner peripheral surface 20N3 in order. Oil hardly accumulates at the joint JT between the inner peripheral surface 15N and the other inner peripheral surface 20N3, and the oil hardly enters the seal member 30 through the joint JT. Therefore, according to the flush configuration, it is possible to further suppress the oil from reaching the seal member 30. Note that the flush structure is not an essential configuration and can be appropriately adopted according to design conditions and the like.

  As described above, in the present embodiment, both the bonding surface 15G1 (FIG. 3) as the first bonding surface and the bonding surface 21N1 (FIG. 3) as the second bonding surface have a flat surface shape. The head cover 10 extends in a direction parallel to the press-fitting direction of the head cover 10. According to this configuration, when the head cover 10 is press-fitted into the opening of the cylinder head 20, the joint surface 15G1 and the joint surface 21N1 can be firmly adhered. The oil reaching the seal member 30 can also be suppressed by this configuration. Note that this configuration is not an essential configuration and can be appropriately adopted according to design conditions and the like.

  As described above, in the present embodiment, the outer peripheral surface 15G of the vertical wall portion 15 includes the convex surface portion 15G2, and the inner peripheral surface 21N of the concave portion 21 includes the concave surface portion 21N2. Since the convex surface portion 15G2 has a so-called tapered shape when viewed as a whole, the head cover 10 can be easily press-fitted into the opening of the cylinder head 20. Further, when the head cover 10 is press-fitted into the opening of the cylinder head 20, the convex surface portion 15G2 and the concave surface portion 21N2 can be firmly adhered to each other. The oil reaching the seal member 30 can also be suppressed by this configuration. Note that this configuration is not an essential configuration and can be appropriately adopted according to design conditions and the like.

[Comparative Example 1]
FIG. 5 is a cross-sectional view showing the seal structure 100Y in the first comparative example. The head cover 10 has a hanging wall portion 15 </ b> Y, and the seal member 30 also has a hanging wall portion 33. When viewed from within the valve train chamber 40, a part of the seal member 30Y is exposed. That is, the seal member 30Y is configured to be exposed to the oil in the valve operating chamber 40.

  In a new state, the sealing member 30Y can exhibit a predetermined sealing function. However, when the seal member 30Y repeatedly contacts high temperature oil over a long period of time, the seal member 30Y gradually deteriorates and the sealing function also gradually decreases. Since a configuration in which a part of the seal member 30Y is exposed is adopted, it can be said that it is difficult to extend the life of the seal member in the configuration of the comparative example 1 compared to the above-described embodiment.

  Further, in the configuration of Comparative Example 1, not only the joint surface (arrow DR1) between the seal member 30Y and the inner peripheral surface of the cylinder head 20, but also the inner peripheral surface of the seal member 30Y and the head cover 10 (the hanging wall portion 33). An oil path is also formed on the joint surface (arrow DR2). When the seal member 30Y is deteriorated, it can be said that the oil in the valve operating chamber 40 may leak to the outside through these two oil paths. On the other hand, in the above-described embodiment, the oil path is one place of the joint JT (see FIG. 4) between the inner peripheral surface 15N and the other inner peripheral surface 20N3, and oil leakage may occur. Can be said to have been reduced.

  In the configuration of Comparative Example 1, the seal member 30 </ b> Y has a hanging wall portion 33. When the head cover 10 is assembled to the cylinder head 20, the hanging wall portion 33 of the seal member 30 </ b> Y is in sliding contact with the hanging wall portion 15 </ b> Y of the head cover 10 or is in sliding contact with the inner peripheral surface of the cylinder head 20. At the time of assembly, since a vertical shearing force acts on the vertical wall portion 33 of the seal member 30Y, the seal member 30Y is likely to be displaced, and in some cases, the seal member 30Y may come off the head cover 10 or the like. . The structure itself of the seal member 30Y is also complicated. On the other hand, in the above-described embodiment, the seal member 30 (see FIG. 3) has a simple shape and can be fitted in the bottomed hole 14P of the head cover 10 in advance. A force that generates a position in the seal member 30 during assembly hardly acts on the seal member 30. Therefore, it can be said that the above-described embodiment can easily perform the manufacturing operation and the assembling operation as compared with the first comparative example.

[Comparative Example 2]
FIG. 6 is a cross-sectional view showing a seal structure 100Z in Comparative Example 2. The head cover 10 has a fitting portion 18, and the cylinder head 20 has a groove portion 28. The seal member 30Z also has a groove 38. When viewed from inside the valve operating chamber 40, a part of the seal member 30Z is exposed. That is, the seal member 30Z is configured to be exposed to the oil in the valve operating chamber 40.

  As in the case of Comparative Example 1, in a new state, the seal member 30Z can exhibit a predetermined sealing function. However, since a configuration in which a part of the seal member 30Z is exposed is adopted, it can be said that it is difficult to extend the life of the seal member even in the configuration of the comparative example 2 compared to the above-described embodiment. .

  Similar to the case of Comparative Example 1, not only the joint surface (arrow DR3) between the seal member 30Z and the inner peripheral surface of the head cover 10, but also the joint surface between the seal member 30Z and the inner peripheral surface of the cylinder head 20. An oil path is also formed in (arrow DR4). It can be said that the oil in the valve operating chamber 40 may leak outside through these two oil paths. On the other hand, in the above-described embodiment, the oil path is one place of the joint JT (see FIG. 4) between the inner peripheral surface 15N and the other inner peripheral surface 20N3, and oil leakage may occur. Can be said to have been reduced.

  The seal member 30Z is generally made of a soft member and easily deforms. Therefore, in the configuration of Comparative Example 2, when the head cover 10 is assembled to the cylinder head 20, it is not easy to properly fit the fitting portion 18 of the head cover 10 into the groove portion 38 of the seal member 30Z over the entire circumference. The structure itself of the seal member 30Z is also complicated. On the other hand, in the above-described embodiment, the seal member 30 (see FIG. 3) has a simple shape and can be fitted in the bottomed hole 14P of the head cover 10 in advance. A force that causes a displacement of the seal member 30 during assembly hardly acts on the seal member 30. Therefore, it can be said that the above-described embodiment can easily perform the manufacturing operation and the assembling operation as compared with Comparative Example 2.

[First Modification]
FIG. 7 is a cross-sectional view showing a seal structure 101 in a first modification of the embodiment. In a cross-sectional view parallel to the press-fitting direction (vertical direction) of the head cover 10, it is located on the innermost side of the boundary surface formed between the convex surface portion 15G2 of the hanging wall portion 15 and the concave surface portion 21N2 of the concave portion 21. It is assumed that a tangent line EL1 is drawn on the portion (the joint JT). In this case, the tangent line EL1 may be formed so as to extend in the horizontal direction. As described above, most of the oil in the valve operating chamber 40 moves from the upper side toward the lower side. When the tangent line EL1 extends in the horizontal direction, the oil penetrates into the seam JT as compared with the case where the tangent line EL1 extends from the inside toward the outside and below the horizontal direction. Can be suppressed.

[Second Modification]
FIG. 8 is a cross-sectional view showing a seal structure 102 in a second modification of the embodiment. As in the case of the first modified example (FIG. 7) described above, the innermost portion of the boundary surface formed between the convex surface portion 15G2 of the hanging wall portion 15 and the concave surface portion 21N2 of the concave portion 21 ( Assume that a tangent line EL2 is drawn at the joint JT). The tangent line EL2 of the present modification extends upward from the horizontal direction from the inside toward the outside. According to the said structure, compared with the case of the 1st modification, it becomes possible to suppress further the penetration | invasion of the oil into the joint line JT.

[Third Modification]
FIG. 9 is a cross-sectional view showing a seal structure 103 according to a third modification of the embodiment. The cylinder head 20 of this modification does not have the recess 21 and does not employ the flush structure in the above-described embodiment. On the other hand, the relationship of L1> L2 is also established in this modification, and the hanging wall portion 15 of the head cover 10 is press-fitted inside the inner peripheral surface 20N of the cylinder head 20 (arrow AR1). The seal member 30 as the second seal portion is on the side farther from the valve operating chamber 40 than the portion (first seal portion) where the outer peripheral surface 15G of the hanging wall portion 15 and the inner peripheral surface 20N of the cylinder head 20 are in close contact with each other. And is separated from the valve train chamber 40 via the first seal portion.

  Referring to FIG. 10, most of the oil in valve operating chamber 40 moves from the upper side toward the lower side (arrow AR2). Oil hardly accumulates at the joint JT between the hanging wall portion 15 and the cylinder head 20, and the oil hardly enters the seal member 30 through the joint JT. Therefore, it can be said that the operation and effect substantially the same as those of the above-described embodiment can be obtained also by the configuration of the present modification.

[Fourth Modification]
FIG. 11 is a cross-sectional view showing a seal structure 104 according to a fourth modification of the embodiment. Even in this modification, the flush structure in the above-described embodiment is not adopted. The other inner peripheral surface 20N3 of the cylinder head 20 has a shape that protrudes to the inner side (the valve operating chamber 40 side) than the inner peripheral surface 15N of the hanging wall portion 15. On the other hand, the relationship of L1> L2 (see FIG. 3) is also established in this modification, and the hanging wall portion 15 of the head cover 10 is press-fitted inside the inner peripheral surface 21N of the concave portion 21 of the cylinder head 20.

  Also in this modification, the seal member 30 as the second seal portion is a portion where the outer peripheral surface 15G of the hanging wall portion 15 and the inner peripheral surface 21N of the concave portion 21 of the cylinder head 20 are in close contact with each other (first seal Part) and farther from the valve operating chamber 40, and is separated from the valve operating chamber 40 via the first seal portion. Since a part of the seal member 30 is not exposed when viewed from the inside of the valve operating chamber 40, it can be said that the effect of suppressing the deterioration of the seal member 30 can be obtained even with the configuration of this modification.

[Fifth Modification]
FIG. 12 is a cross-sectional view showing a seal structure 105 according to a fifth modification of the embodiment. Even in this modification, the flush structure in the above-described embodiment is not adopted. The cylinder head 20 is further provided with a fitting portion 29 having a U-shape on the lower side of the recess 21, and the lower end of the vertical wall portion 15 is fitted into the fitting portion 29. Even in this modification, the relationship of L1> L2 (see FIG. 3) is established, and the hanging wall portion 15 of the head cover 10 is press-fitted inside the inner peripheral surface 21N of the concave portion 21 of the cylinder head 20.

  Also in this modification, the seal member 30 as the second seal portion is a portion where the outer peripheral surface 15G of the hanging wall portion 15 and the inner peripheral surface 21N of the concave portion 21 of the cylinder head 20 are in close contact with each other (first seal Part) and farther from the valve operating chamber 40, and is separated from the valve operating chamber 40 via the first seal portion. Since a part of the seal member 30 is not exposed when viewed from the inside of the valve operating chamber 40, it can be said that the effect of suppressing the deterioration of the seal member 30 can be obtained even with the configuration of this modification. From the viewpoint of the oil path, it can be said that in the case of the present modification, a higher resistance can act on the infiltration of oil than in the case of the above-described fourth modification.

[Other variations]
In the above-described embodiment and each modification, the seal member 30 is fitted into the bottomed hole 14P (see FIG. 3) provided in the cylinder head 20. Not limited to this configuration, a bottomed hole having the same shape as the bottomed hole 14P may be provided on the upper end surface 20J of the cylinder head 20, and the seal member 30 may be fitted into the bottomed hole. Alternatively, a bottomed hole may be provided in both the head cover 10 and the cylinder head 20, and the seal member 30 may be configured to fit into both the bottomed holes.

  As mentioned above, although embodiment and each modification based on this invention were described, the matter disclosed this time is an illustration and restrictive at no points. The technical scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 10 Head cover, 11 Top plate part, 12 Side wall part, 13 Upper wall part, 14 Extension part, 14J, 20J Upper end surface (upper end part), 14K Lower end surface, 14P Bottomed hole, 15 Hanging wall part, 15Y, 33 Hanging Wall part, 15G outer peripheral surface, 15G1 joint surface (first joint surface), 15G2 convex surface part, 15N, 20N, 21N inner peripheral surface, 18 fitting portion, 20 cylinder head, 20N3 inner peripheral surface (other inner peripheral surface), 21 concave portion (contact portion), 21N1 joint surface (second joint surface), 21N2 concave surface portion, 28, 38 groove portion, 29 fitting portion, 30, 30Y, 30Z seal member, 31 pedestal portion, 32 insertion portion, 40 movement Valve chamber, 100, 100Y, 100Z, 101, 102, 103, 104, 105 Seal structure, AR1, AR2, DR1, DR2, DR3, DR4 arrows, EL1, EL2 tangent, JT Technical eyes, L1, L2 length.

Claims (5)

A cylinder head having an opening;
A head cover which is attached to the cylinder head and forms a valve operating chamber with the cylinder head;
A seal member provided between the cylinder head and the head cover,
The head cover has an extending part facing the upper end part of the cylinder head, and a hanging wall part extending from the extending part along the inner peripheral surface of the cylinder head,
The inner peripheral surface of the cylinder head has a contact portion that constitutes a first seal portion together with the head cover by contacting the outer peripheral surface of the hanging wall portion,
The seal member disposed between the upper end portion of the cylinder head and the extension portion of the head cover causes the contact interface between the cylinder head and the head cover in the valve operating chamber to pass through the first seal portion. A second seal portion spaced apart is configured,
Seal structure between cylinder head and head cover. The hanging wall portion of the head cover is elastically deformed by being press-fitted inside the contact portion,
The outer peripheral surface of the vertical wall portion is in close contact with the contact portion over the entire circumference by the elastic restoring force of the vertical wall portion,
The seal structure between the cylinder head and the head cover according to claim 1. The contact portion of the cylinder head has a concave shape that receives the hanging wall portion,
The inner peripheral surface of the cylinder head further has another inner peripheral surface located on the front side in the press-fitting direction of the head cover with respect to the contact portion,
By arranging the hanging wall portion inside the contact portion, the inner circumferential surface of the hanging wall portion and the other inner circumferential surface of the cylinder head have a flush relationship.
The seal structure between the cylinder head and the head cover according to claim 1 or 2. The outer peripheral surface of the vertical wall portion includes a first joining surface extending in a direction parallel to the press-fitting direction of the head cover, and a convex portion located on the front side in the press-fitting direction of the head cover with respect to the first joining surface. Have
The contact portion includes a second joint surface extending in a direction parallel to the press-fitting direction of the head cover, and a concave portion located on the front side in the press-fit direction of the head cover with respect to the second joint surface.
A seal structure between the cylinder head and the head cover according to claim 3. In a cross-sectional view parallel to the press-fitting direction of the head cover, when a tangent is drawn on the innermost portion of the boundary surface formed between the convex surface portion and the concave surface portion, the tangent line is It has a shape extending in the horizontal direction or a shape extending upward from the horizontal direction as it goes from the inside to the outside,
The seal structure between the cylinder head and the head cover according to claim 4.

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