JP2006249996A - Valve mechanism for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve mechanism for an internal combustion engine capable of suppressing deterioration due to heat of an oil seal. <P>SOLUTION: A thermal insulating part 25 having lower heat conductivity than that of a shaft part 20 of an exhaust valve 5 being one example of a valve for the internal combustion engine is provided in an end part of the shaft part 20 of the exhaust valve 5. The oil seal 50 comes into contact with the thermal insulating part 25. A valve guide 40 having higher heat conductivity than that of the shaft part 20 comes into contact with the shaft part 20. Since a hollow part 21 sealing refrigerant 30 in it is formed in the exhaust valve 5, heat received by an umbrella part 10 from a combustion chamber is transmitted to each part of the shaft part 20 by flowing-in of refrigerant 30 in the hollow part 21, and a part of heat is transmitted to the valve guide 40 from the shaft part 20 for heat radiation. Since the thermal insulating part 25 has low heat conductivity and heat is not easily transmitted, heat is not easily transmitted to the oil seal 50. As a result, deterioration due to heat of the oil seal is suppressed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a valve mechanism for an internal combustion engine. In particular, the present invention relates to a valve mechanism for an internal combustion engine that can reduce problems caused by heat.

  A conventional valve mechanism for an internal combustion engine is provided with an internal combustion engine valve having an umbrella portion that communicates an intake port or an exhaust port with the combustion chamber. However, the umbrella portion faces the combustion chamber. When the fuel burns in the combustion chamber, it is easy to receive heat generated by the combustion. For this reason, in some conventional valves for internal combustion engines, in order to transmit this heat in the direction of the shaft portion, a hollow portion is formed inside the shaft portion or the umbrella portion, and a refrigerant is sealed in the hollow portion. As a result, the internal combustion engine valve reciprocates during operation of the internal combustion engine valve mechanism, so that the refrigerant in the hollow portion flows in the hollow portion, so that the heat of the umbrella portion is transmitted to the shaft portion via the refrigerant.

  However, the shaft seal is in contact with an oil seal that prevents oil that lubricates the cylinder head from flowing into the combustion chamber through the internal combustion engine valve. This oil seal is formed from a rubber-based material. Because it is weak to heat. For this reason, when heat is applied to the oil seal, the material forming the oil seal may deteriorate and the sealing performance may be reduced. Therefore, some conventional valve mechanisms for internal combustion engines have a heat insulating coat layer formed on the shaft portion. For example, in patent document 1, the heat insulation coating layer is formed in the axial part and the oil seal is made to contact the heat insulation coating layer. Thereby, conduction of heat from the valve for the internal combustion engine to the oil seal is suppressed, and deterioration of the oil seal due to heat is suppressed.

Japanese Utility Model Publication No. 3-116711

  However, since the output of the internal combustion engine in recent years has improved as compared with the conventional internal combustion engine, the amount of heat generated is increased accordingly. For this reason, in the heat insulation coat mentioned above, since the volume of the part to insulate is too small, there was a possibility that the heat transmitted from the shaft part to the oil seal could not be sufficiently insulated.

  The present invention has been made in view of the above, and an object of the present invention is to provide a valve mechanism for an internal combustion engine that can suppress thermal deterioration of an oil seal.

  In order to solve the above-described problems and achieve the object, the valve mechanism for an internal combustion engine according to the present invention has an umbrella portion at one end of a shaft portion, and a hollow portion is formed inside the shaft portion and the umbrella portion. An internal combustion engine valve mechanism having a valve for an internal combustion engine in which a refrigerant is sealed inside the hollow portion, is connected to the shaft portion and contacts an oil seal, and is connected to the umbrella portion. It is provided with the heat insulation part which insulates heat, and the heat radiating part located between the said umbrella part and the said heat insulation part, and radiating the heat from the said umbrella part, It is characterized by the above-mentioned.

  In this invention, the oil seal is brought into contact with the heat insulating portion connected to the shaft portion, and a heat radiating portion is provided between the umbrella portion and the heat insulating portion. For this reason, since the heat from the umbrella part is insulated by the heat insulating part, it is difficult for heat to be transmitted to the oil seal. Furthermore, since the heat from the umbrella part is radiated by the heat radiating part, the heat from the umbrella part is more difficult to be transmitted to the oil seal. As a result, thermal deterioration of the oil seal can be suppressed.

  Moreover, the valve mechanism for an internal combustion engine according to the present invention is characterized in that the heat insulating portion closes the hollow portion.

  In this invention, since the hollow part is closed with the heat insulation part, the valve for internal combustion engines which has a hollow part can be manufactured easily. As a result, thermal deterioration of the oil seal can be easily suppressed.

  The valve mechanism for an internal combustion engine according to the present invention is characterized in that the heat insulating portion has a lower thermal conductivity than the shaft portion.

  In this invention, since the thermal conductivity of the heat insulating portion is lower than the thermal conductivity of the shaft portion, the heat transmitted to the shaft portion in the vicinity of the heat insulating portion is more reliably insulated by the heat insulating portion to the oil seal. Insulated more reliably. As a result, thermal deterioration of the oil seal can be suppressed more reliably.

  In the valve mechanism for an internal combustion engine according to the present invention, the heat radiating portion is formed by the shaft portion and a shaft portion contact portion in contact with the shaft portion.

  In this invention, since the heat radiating portion is formed by the shaft portion and the shaft portion contact portion in contact with the shaft portion, the heat of the shaft portion is transmitted to the shaft portion contact portion. For this reason, since the heat of the shaft portion is transmitted more reliably through the shaft portion contact portion, the heat of the umbrella portion is more reliably radiated through the shaft portion and the shaft portion contact portion. As a result, the heat transferred to the heat insulating portion is more reliably reduced, and thus the conduction of heat to the oil seal is more reliably reduced. As a result, thermal deterioration of the oil seal can be suppressed more reliably.

  Moreover, the valve mechanism for an internal combustion engine according to the present invention is characterized in that a portion of the shaft portion that contacts the shaft portion contact portion has higher thermal conductivity than the umbrella portion.

  In this invention, since the portion of the shaft portion that contacts the shaft portion contact portion has a higher thermal conductivity than the umbrella portion, the heat transmitted from the umbrella portion to this portion is more reliably transmitted to the shaft portion contact portion. Because it is transmitted to, it is more reliably radiated heat. For this reason, since the heat transmitted from the umbrella portion to the shaft portion and further transmitted toward the heat insulating portion is radiated by the heat radiating portion, the heat transmitted to the heat insulating portion is more reliably reduced. For this reason, the conduction of heat to the oil seal is more reliably reduced. As a result, thermal deterioration of the oil seal can be suppressed more reliably.

  Moreover, the valve mechanism for an internal combustion engine according to the present invention is characterized in that the shaft portion contact portion has a higher thermal conductivity than the shaft portion of the portion where the shaft portion contact portion contacts.

  In this invention, since the thermal conductivity of the shaft contact portion is higher than the thermal conductivity of the shaft contacted with the shaft contact portion, the heat of the shaft portion is more reliably supplied to the shaft contact portion. Can conduct. Thereby, the heat transmitted from the umbrella portion to the shaft portion and further transmitted in the direction of the heat insulating portion is more reliably conducted to the shaft portion contact portion through the shaft portion, and is radiated more reliably. For this reason, since the heat transmitted to the heat insulation part is more reliably reduced, the conduction of heat to the oil seal is more reliably reduced. As a result, thermal deterioration of the oil seal can be suppressed more reliably.

  The valve mechanism for an internal combustion engine according to the present invention is characterized in that the shaft contact portion also serves as a valve guide.

  In the present invention, since the valve guide also serves as the shaft contact portion, it is not necessary to newly provide the shaft contact portion, and the shaft contact portion can be easily provided. As a result, thermal deterioration of the oil seal can be easily suppressed.

  The valve mechanism for an internal combustion engine according to the present invention has an effect that thermal deterioration of the oil seal can be suppressed.

  Hereinafter, embodiments of a valve mechanism for an internal combustion engine according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same. The internal combustion engine valve mechanism of the internal combustion engine valve mechanism according to the present invention includes an intake valve and an exhaust valve. In the following description, an internal combustion engine valve mechanism having an exhaust valve will be described.

  FIG. 1 is a schematic diagram showing a valve mechanism for an internal combustion engine according to a first embodiment of the present invention. The valve mechanism 1 for an internal combustion engine shown in the figure has an exhaust valve 5, which is a valve for an internal combustion engine, a valve guide 40, and an oil seal 50. The internal combustion engine valve mechanism 1 is provided to open and close an exhaust passage (not shown) formed in a cylinder head (not shown) when the exhaust valve 5 reciprocates. FIG. 1 shows the internal combustion engine valve mechanism 1 in a state where the exhaust valve 5 closes the exhaust passage.

  The exhaust valve 5 has an umbrella part 10 and a shaft part 20. The umbrella portion 10 is formed in a shape close to a conical shape, and the bottom surface of the conical shape is formed as a valve surface 11. The valve surface 11 faces a combustion chamber (not shown) of an internal combustion engine (not shown) in which the internal combustion engine valve mechanism 1 is provided. The shaft portion 20 is located on the slope 12 side of the umbrella portion 10, one end portion of the shaft portion 20 is connected to a conical top, and the axial direction is parallel to the height direction of the conical shape. It is formed in the direction that becomes the direction.

  Further, a heat insulating portion 25 is located at the other end of the shaft portion 20. The heat insulating portion 25 is formed in a columnar shape having substantially the same diameter as the shaft portion 20. Moreover, the heat insulation part 25 is formed of a material having lower thermal conductivity than the material forming the shaft part 20 and the umbrella part 10. For example, the shaft portion 20 and the umbrella portion 10 are both formed of iron, whereas the heat insulating portion 25 is formed of titanium which is a material having a lower thermal conductivity than iron. The material forming the heat insulating portion 25 may be formed of a material other than a metal material such as a resin material as long as the material has a lower thermal conductivity than the material forming the shaft portion 20. Moreover, you may use an adhesive agent etc. for joining with the heat insulation part 25 and the axial part 20. FIG.

  The shaft portion 20 and the umbrella portion 10 are formed with a continuous cavity, and the cavity is a hollow portion 21. The hollow portion 21 is filled with a refrigerant 30 made of, for example, metallic sodium. The refrigerant 30 is in a liquid state at least during operation of the internal combustion engine.

  The valve guide 40 is fixed to the cylinder head. The valve guide 40 is provided as a shaft contact portion and is in contact with the shaft portion 20 between the heat insulating portion 25 and the umbrella portion 10. The valve guide 40 is formed with a hole having a diameter approximately the same as the diameter of the shaft portion 20, and the shaft portion 20 is inserted into the hole. For this reason, this hole serves as the valve guide contact portion 41 and is in contact with the shaft portion 20. In addition, the valve guide contact portion 41 is formed in the shape of a hole having a diameter approximately the same as the diameter of the shaft portion 20, and the shaft portion 20 is inserted through the valve guide contact portion 41. The valve guide 40 restricts movement in directions other than the axial direction. Further, the valve guide 40 is formed of a material having higher thermal conductivity than the material forming the shaft portion 20. For example, while the shaft portion 20 is made of iron as described above, the valve guide 40 is made of aluminum. In addition, the valve guide 40 thus provided as the shaft portion contact portion and the shaft portion 20 of the portion in contact with the valve guide 40 are provided together as a heat radiating portion.

  The oil seal 50 is a stationary part fixed to the cylinder head, and is in contact with the heat insulating portion 25. The oil seal 50 is formed with a hole having substantially the same diameter as the cylindrical shape that is the shape of the heat insulating portion 25, and the heat insulating portion 25 is inserted into the hole. For this reason, the hole serves as the oil seal contact portion 51 and is in contact with the heat insulating portion 25. In addition, since the oil seal contact portion 51 is formed with a hole having a diameter approximately the same as the diameter of the heat insulating portion 25 in this way, the oil seal contact portion 51 has a cylindrical shape that is a shape of the heat insulating portion 25 with a predetermined width. It is in contact over the entire circumference in the circumferential direction. Further, since the oil seal 50 is formed of a rubber-based material and has elasticity, the oil seal contact portion 51 is in contact with the heat insulating portion 25 with almost no gap. As a result, the gap between the oil seal 50 and the heat insulating portion 25 can be sealed, and the oil that lubricates the inside of the cylinder head between the shaft portion 20 and the valve guide 40 is prevented from flowing, so that this oil Flowing in the direction of the combustion chamber along the exhaust valve 5 is suppressed.

  The internal combustion engine valve mechanism 1 according to the first embodiment is configured as described above, and the operation thereof will be described below. When the internal combustion engine provided with the internal combustion engine valve mechanism 1 is operated, the valve surface 11 facing the combustion chamber of the internal combustion engine receives heat from the fuel by burning the fuel in the combustion chamber. A part of the heat received by the valve surface 11 is transmitted to the refrigerant 30 enclosed in the hollow portion 21.

  FIG. 2 is a diagram illustrating a state where the exhaust valve of FIG. 1 has moved. The exhaust valve 5 is provided so as to open and close the exhaust passage during operation of the internal combustion engine, and the exhaust passage is opened and closed by operating the exhaust valve 5 in the axial direction of the shaft portion 20. When the exhaust valve 5 moves in the direction of the heat insulating portion 25 (see FIG. 1), the exhaust passage is closed, and when the exhaust valve 5 moves in the direction of the umbrella portion 10 (see FIG. 2), the exhaust passage is opened. During operation of the internal combustion engine, the exhaust valve 5 reciprocates in the axial direction of the shaft portion 20 as described above. However, when the exhaust valve 5 reciprocates, the refrigerant 30 positioned in the hollow portion 21 is exhausted by inertia. It moves in the hollow portion 21 with a motion different from the motion of 5. The temperature of the refrigerant 30 is increased by the heat from the valve surface 11 of the umbrella part 10, but the heat of the refrigerant 30 is transmitted to the shaft part 20 as the refrigerant 30 moves in the hollow part 21. At that time, since the refrigerant 30 moves while transferring heat to the shaft portion 20 when the refrigerant 30 moves from the direction of the umbrella portion 10 toward the heat insulating portion 25, the temperature of the shaft portion 20 increases from the umbrella portion 10 side. Go.

  As described above, the valve guide 40 is in contact with the shaft portion 20 whose temperature has increased. Since the valve guide 40 is made of a material having a higher thermal conductivity than the material forming the shaft portion 20, the heat of the shaft portion 20 is easily transmitted to the valve guide 40. For this reason, the heat of the shaft portion 20 is transmitted to the valve guide 40 through the valve guide contact portion 41. Thus, a part of the heat of the shaft portion 20 is radiated to the valve guide 40.

  A heat insulating part 25 is located at the end of the shaft part 20 opposite to the end on the umbrella part 10 side, and the oil seal 50 is in contact with the heat insulating part 25. The heat insulating part 25 is formed of a material having a lower thermal conductivity than the material forming the shaft part 20. For this reason, it is difficult for the heat of the shaft portion 20 to be transmitted to the heat insulating portion 25, and even when the temperature of the shaft portion 20 becomes high, the temperature of the heat insulating portion 25 becomes difficult to increase. Further, the oil seal 50 in contact with the heat insulating portion 25 is fixed to the cylinder head as a stationary component. For this reason, when the exhaust valve 5 reciprocates during operation of the internal combustion engine, the exhaust valve 5 comes into contact with the oil seal 50 so as to slide. The oil seal 50 is always in contact with the heat insulating portion 25 even when the exhaust valve 5 closes the exhaust passage (see FIG. 1) or opens (see FIG. 2).

  The internal combustion engine valve mechanism 1 is located at one end of the shaft portion 20 and has a low thermal conductivity, and the oil seal 50 is brought into contact with the heat insulating portion 25 where the temperature does not easily rise. It is possible to suppress the rise. Moreover, since the heat radiating part which consists of the valve guide 40 and the shaft part 20 which contacts the said valve guide 40 is provided between the heat insulation part 25 and the umbrella part 10, the umbrella raised by the heat of the combustion chamber The heat of the part 10 is radiated by the heat radiating part and is not easily transmitted to the heat insulating part 25. For this reason, since it becomes difficult for the heat of the umbrella part 10 to be transmitted to the oil seal 50, it is possible to suppress the temperature of the oil seal 50 from rising. As a result, thermal deterioration of the oil seal 50 can be suppressed.

  Moreover, since the heat conductivity of the heat insulation part 25 is made lower than the heat conductivity of the shaft part 20 by making the materials different between the heat insulation part 25 and the shaft part 20, the heat transferred to the shaft part 20 is In addition, it is difficult to be surely transmitted to the heat insulating portion 25. For this reason, the heat transmitted to the shaft portion 20 in the vicinity of the heat insulating portion 25 is more reliably insulated by the heat insulating portion 25 and more reliably insulated from the oil seal 50. As a result, thermal deterioration of the oil seal 50 can be suppressed more reliably.

  Further, as described above, the heat radiating portion is formed by the valve guide 40 and the shaft portion 20 that contacts the valve guide 40. For this reason, the heat transmitted to the shaft portion 20 by the refrigerant 30 moving in the hollow portion 21 is reliably radiated through the valve guide 40 in contact with the shaft portion 20. For this reason, since the heat | fever of the umbrella part 10 is thermally radiated more reliably via the axial part 20 and the valve guide 40, the heat transmitted to the heat insulation part 25 reduces more reliably. Thereby, the heat transmitted from the heat insulation part 25 to the oil seal 50 is also more reliably reduced. As a result, thermal deterioration of the oil seal 50 can be suppressed more reliably.

  Further, since the material forming the valve guide 40 has higher thermal conductivity than the material forming the shaft portion 20, the heat of the shaft portion 20 can be more reliably transmitted to the valve guide 40. Thus, the heat received by the umbrella portion 10 during combustion of the fuel in the combustion chamber and transmitted from the umbrella portion 10 to the shaft portion 20 through the refrigerant 30 or by conduction is in contact with the shaft portion 20, and It is more reliably transmitted to the valve guide 40 having a high thermal conductivity. For this reason, since the heat received in the umbrella part 10 is radiated more reliably, the heat transmitted to the heat insulation part 25 is more reliably reduced. Thereby, the heat transmitted from the heat insulation part 25 to the oil seal 50 is also more reliably reduced. As a result, thermal deterioration of the oil seal 50 can be suppressed more reliably.

  Further, since the valve guide 40 also serves as a shaft contact portion that becomes a part of the heat radiating portion, there is no need to newly provide a shaft contact portion that contacts the shaft portion 20 and radiates the heat of the shaft portion 20. The shaft contact portion can be easily provided. As a result, the thermal deterioration of the oil seal 50 can be easily suppressed.

  This internal combustion engine has substantially the same configuration as the valve mechanism for an internal combustion engine according to the first embodiment, but is characterized in that a portion having a higher thermal conductivity than the umbrella portion is provided in the shaft portion. Since other configurations are the same as those of the first embodiment, the description thereof is omitted and the same reference numerals are given. FIG. 3 is a schematic diagram illustrating a valve mechanism for an internal combustion engine according to a second embodiment of the present invention. In the exhaust valve 65 included in the valve mechanism 60 for an internal combustion engine shown in the figure, a part of the shaft part 66 is formed of a material different from the other parts of the shaft part 66. Specifically, a sliding portion 67 that is a portion that contacts the valve guide 40 in the shaft portion 66 is formed of a material different from that of the other portions of the shaft portion 66. The portions of the shaft portion 66 other than the sliding portion 67 are made of the same material as the umbrella portion 10, whereas the sliding portion 67 is made of these materials, that is, other than the umbrella portion 10 and the sliding portion 67. The shaft portion 66 is made of a material having a higher thermal conductivity than that of the material forming the shaft portion 66. The valve guide 40 is formed of a material having a thermal conductivity equal to or higher than that of the material forming the sliding portion 67.

  Further, a convex portion 68 protruding in the direction of the shaft portion 66 is formed at a portion of the heat insulating portion 25 on the shaft portion 66 side. The convex portion 68 has a columnar shape having a diameter smaller than the diameter of the column that is the shape of the heat insulating portion 25, and protrudes in the direction of the shaft portion 66. On the other hand, a recessed portion 69 that is recessed toward the umbrella portion 10 is formed at the end portion of the shaft portion 66 on the heat insulating portion 25 side. The recess 69 is recessed in a columnar shape having substantially the same diameter as the column that is the shape of the projection 68 of the heat insulating portion 25. The heat insulating portion 25 is fixed to the shaft portion 66 by inserting the convex portion 68 into the concave portion 69 formed in the shaft portion 66.

  The internal combustion engine valve mechanism 60 according to the second embodiment is configured as described above, and the operation thereof will be described below. FIG. 4 is a diagram showing a state where the exhaust valve of FIG. 3 has moved. When the internal combustion engine provided with the internal combustion engine valve mechanism 60 is operated, the exhaust valve 65 reciprocates similarly to the exhaust valve 5 included in the internal combustion engine valve mechanism 1 of the first embodiment. At that time, the exhaust valve 65 reciprocates while the sliding portion 67 slides with respect to the valve guide contact portion 41 of the valve guide 40. Further, the sliding portion 67 when the exhaust valve 65 reciprocates in this way is always the valve regardless of whether the exhaust valve 65 closes the exhaust passage (see FIG. 3) or opens (see FIG. 4). It is in contact with the guide 40.

  In the valve mechanism 60 for an internal combustion engine described above, the thermal conductivity of the sliding portion 67 that is a portion that contacts the valve guide 40 in the shaft portion 66 is higher than the thermal conductivity of the umbrella portion 10. The heat transmitted from 10 to the shaft portion 66 is more reliably transmitted to the sliding portion 67, and is transmitted from the sliding portion 67 to the valve guide 40. For this reason, the heat received by the umbrella portion 10 during combustion of the fuel in the combustion chamber is more reliably radiated by the sliding portion 67 and the valve guide 40, so the heat transmitted to the heat insulating portion 25 is more reliably reduced. To do. For this reason, the heat transmitted from the heat insulation part 25 to the oil seal 50 is more reliably reduced. As a result, thermal deterioration of the oil seal 50 can be suppressed more reliably.

  Further, since the heat insulating portion 25 inserts the convex portion 68 into the concave portion 69 formed in the shaft portion 20 and is fixed to the shaft portion 66, when the heat insulating portion 25 is fixed to the shaft portion 66, centering or the like is performed. Positioning can be performed easily. Thereby, the heat insulation part 25 can be easily fixed to the shaft part 66. As a result, the provision of the heat insulating portion 25 facilitates the manufacture of the internal combustion engine valve mechanism 60 that suppresses the thermal deterioration of the oil seal 50, and can reduce the manufacturing cost.

  FIG. 5 is a diagram illustrating a modification of the valve mechanism for the internal combustion engine according to the second embodiment. In addition, the convex part 68 of the heat insulation part 25 formed in the exhaust valve 65 which the valve mechanism 60 for internal combustion engines which concerns on Example 2 has is provided only in order to fix the heat insulation part 25 to the axial part 66 easily. However, the convex portion 68 may be used for closing the hollow portion 21. That is, by forming the hollow portion 21 of the shaft portion 66 to the end portion on the heat insulating portion 25 side, and making the diameter of the convex portion 68 of the heat insulating portion 25 substantially the same as or slightly smaller than the diameter of the hollow portion 21, When fixing 25 to the shaft portion 66, the convex portion 68 can be inserted into the hollow portion 21. Thereby, since the hollow part 21 is closed by the heat insulation part 25, the exhaust valve 65 which has the hollow part 21 can be manufactured easily. As a result, the thermal deterioration of the oil seal 50 can be easily suppressed. Further, the umbrella portion 10 of the exhaust valve 65 is divided into a split structure, the valve surface 11 is divided from the umbrella portion 10, one end of the hollow portion 21 is closed by the heat insulating portion 25 as described above, and the other end is closed by the valve surface 11. May be. Thereby, the exhaust valve 65 having the hollow portion 21 can be manufactured more easily. As a result, the thermal deterioration of the oil seal 50 can be suppressed more easily.

  Further, in the exhaust valve 65 included in the valve mechanism 60 for an internal combustion engine according to the second embodiment, the heat insulating portion 25 is provided with a convex portion 68 and the shaft portion 66 is formed with a concave portion 69. In this case, a concave portion 69 may be formed, and a convex portion 68 may be formed on the shaft portion 66. Thus, by forming the convex part 68 and the recessed part 69 in the fixing part of the heat insulation part 25 and the axial part 66, the thermal insulation part 25 can be easily fixed to the axial part 66, and reduction of manufacturing cost can be achieved. Can be planned. Further, the convex portion 68 and the concave portion 69 formed in the fixed portion between the heat insulating portion 25 and the shaft portion 66 are formed on the shaft portion 20 like the exhaust valve 5 of the internal combustion engine valve mechanism 1 according to the first embodiment. Alternatively, it may be formed in the exhaust valve 5 in which the sliding part 67 having a different thermal conductivity from that of the other part is not formed.

  Further, the heat insulating portion 25 and the shaft portion 20 of the first embodiment, the shaft portion 20 and the valve guide 40, and the shaft portion 66 and the sliding portion 67 other than the sliding portion 67 of the second embodiment each have thermal conductivity. Although different materials are used for heat insulation or heat dissipation, these may not necessarily be formed of materials having different thermal conductivities. The same material may be used as long as heat insulation and heat dissipation can be performed depending on the shape and structure of each part.

  Further, in the first and second embodiments described above, the exhaust valves 5 and 65 are described as examples of the valves for the internal combustion engine included in the valve mechanisms 1 and 60 for the internal combustion engine. However, the valves for the internal combustion engine according to the present invention are described. The internal combustion engine valves included in the mechanisms 1 and 60 may be internal combustion engine valves other than the exhaust valves 5 and 65, or may be intake valves. Even in an internal combustion engine valve other than the exhaust valves 5 and 65, the valve surface 11 faces the combustion chamber, and the refrigerant 30 is provided in the hollow portion 21, so that the temperature of the oil seal 50 in contact with the internal combustion engine valve increases. When there is a possibility of doing so, the thermal deterioration of the oil seal 50 can be suppressed by applying the present invention.

  As described above, the valve mechanism for an internal combustion engine according to the present invention is useful for the valve mechanism for an internal combustion engine having an oil seal, and in particular, a hollow portion in which a refrigerant is sealed is formed in the valve for the internal combustion engine. Suitable for cases.

It is the schematic which shows the valve mechanism for internal combustion engines which concerns on Example 1 of this invention. It is a figure which shows the state which the exhaust valve of FIG. 1 moved. It is the schematic which shows the valve mechanism for internal combustion engines which concerns on Example 2 of this invention. It is a figure which shows the state which the exhaust valve of FIG. 3 moved. FIG. 6 is a view showing a modification of the valve mechanism for an internal combustion engine according to the second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 60 Valve mechanism for internal combustion engines 5, 65 Exhaust valve 10 Umbrella part 11 Valve surface 20, 66 Shaft part 21 Hollow part 25 Heat insulation part 30 Refrigerant 40 Valve guide 41 Valve guide contact part 50 Oil seal 51 Oil seal contact part 67 Sliding Moving part

Claims (7)

An internal combustion engine having an umbrella portion at one end of a shaft portion, a hollow portion formed in the shaft portion and the umbrella portion, and a valve for an internal combustion engine in which a refrigerant is sealed inside the hollow portion A valve mechanism,
A heat insulating part connected to the shaft part and in contact with an oil seal to insulate heat from the umbrella part;
A heat dissipating part which is located between the umbrella part and the heat insulating part and dissipates heat from the umbrella part;
A valve mechanism for an internal combustion engine, comprising:   The valve mechanism for an internal combustion engine according to claim 1, wherein the heat insulating portion closes the hollow portion.   The valve mechanism for an internal combustion engine according to claim 1 or 2, wherein the heat insulating portion has a lower thermal conductivity than the shaft portion.   The valve mechanism for an internal combustion engine according to any one of claims 1 to 3, wherein the heat radiating portion is formed by the shaft portion and a shaft portion contact portion in contact with the shaft portion.   5. The valve mechanism for an internal combustion engine according to claim 4, wherein a portion of the shaft portion that contacts the shaft portion contact portion has a higher thermal conductivity than the umbrella portion.   6. The valve mechanism for an internal combustion engine according to claim 4, wherein the shaft contact portion has a higher thermal conductivity than the shaft portion of the portion where the shaft contact portion contacts.   The valve mechanism for an internal combustion engine according to any one of claims 4 to 6, wherein the shaft contact portion also serves as a valve guide.

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