JP2007056800A - Valve train of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide technology for eliminating reduction of airtightness of a valve element and a valve seat in a valve train of an internal combustion engine provided with the valve element opening while tilting in a specific direction and the valve seat for allowing seating of the valve element. <P>SOLUTION: In this valve train of the internal combustion engine for opening the valve element 5 while it is inclined in the specific direction S for the valve seat 13, a section on a terminal side in the specific direction S in the valve seat 13 is formed by a member 131 having lower hardness than that of the other section 130 so that the valve element 5 and the valve seat 13 adhere closely and equally by utilizing deformation of the low hardness member 131 even when parallelism of the valve element 5 and the valve seat 13 becomes low to suppress reduction of airtightness (sealing property) of the valve element 5 and the valve seat 13. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a valve mechanism for an internal combustion engine.

As a valve operating mechanism for an internal combustion engine, an intake valve stem and a valve head part (valve body) are separately formed, and the stem (valve shaft) and the valve head part are movably connected to each other. (For example, refer to Patent Document 1).
Japanese Utility Model Publication No. 63-48821 JP-A-8-61024 Special table 2003-509622 gazette Japanese Utility Model Publication No. 2-2595 Japanese Patent Laid-Open No. 10-14026

  By the way, in the conventional valve operating mechanism as described above, the valve head portion may not be seated parallel and coaxially (concentrically) with respect to the valve seat (valve seat) due to initial tolerance, assembly tolerance, change with time, or the like. In such a case, it becomes difficult for the valve head portion to be in close contact with the entire circumference of the valve seat.

  In the case of a normal poppet valve, rotation of the valve head in the circumferential direction is allowed, so even if the parallelism and concentricity (concentricity) between the valve head and the valve seat are somewhat low, Will rotate properly and come into close contact with the entire circumference of the valve seat.

  However, when the rotation of the valve head portion in the circumferential direction is restricted as in the conventional valve mechanism described above, if the parallelism or concentricity (concentricity) between the valve head portion and the valve seat decreases, the valve head portion However, it becomes difficult to adhere evenly to the entire circumference of the valve seat.

  If the valve head part is not evenly adhered to the entire circumference of the valve seat, the air tightness of the valve head part and the valve seat will be reduced, causing problems such as a reduction in the compression ratio in the compression stroke and a reduction in the combustion pressure in the expansion stroke. there is a possibility.

  The present invention has been made in view of the various circumstances as described above, and an object thereof is to include a valve body that opens a valve while inclining in a specific direction and a valve seat on which the valve body is seated. Another object of the present invention is to provide a technique capable of eliminating a decrease in airtightness of a valve body and a valve seat in a valve operating mechanism of an internal combustion engine.

  In order to solve the above-described problems, the present invention provides a valve operating mechanism for an internal combustion engine in which a valve body (valve portion) is opened while tilting in a specific direction with respect to a valve seat. By forming the part located at the base end side or the tip end side in the specific direction in at least one of the parts with lower hardness than the other parts, the deformation of the low hardness part is utilized to improve the airtightness of the valve body and the valve seat I tried to make it.

  Specifically, the present invention is a valve operating mechanism of an internal combustion engine provided with a valve body that opens a valve while inclining in a specific direction with respect to the valve seat, wherein the specific body is at least one of the valve body and the valve seat. The part located on the proximal end side or the distal end side in the direction is formed with lower hardness than other parts.

  In a valve mechanism that opens and closes while the valve body is tilted in a specific direction, if the parallelism or concentricity (concentricity) between the valve body and the valve seat is low, the valve body is not parallel to the valve seat or Sit beyond the state parallel to the seat.

  If the valve body is seated before it becomes parallel to the valve seat, the valve body is inclined in the specific direction with respect to the valve seat, so that the valve body and the valve seat are difficult to adhere to each other at the distal end side in the specific direction. . On the other hand, if the valve body is seated beyond the state parallel to the valve seat, the valve body is inclined in the direction opposite to the specific direction with respect to the valve seat. And the valve seat becomes difficult to adhere.

  When the valve body is seated before being parallel to the valve seat, when the part located on the base end side in the specific direction in at least one of the valve body and the valve seat is formed with lower hardness than the other parts, The low hardness portion is deformed (including elastic deformation and plastic deformation) to such a degree that the valve body and the valve seat are in close contact with each other at the tip side in the specific direction. As a result, the valve body is in close contact with the entire circumference of the valve seat, so that the airtightness between the valve body and the valve seat is improved.

  When the valve body is seated beyond the state parallel to the valve seat, at least one of the valve body and the valve seat is located at the tip side in the specific direction with a lower hardness than the other parts. The low hardness portion is deformed (including elastic deformation and plastic deformation) to the extent that the valve body and the valve seat are in close contact with each other on the base end side in the specific direction. As a result, the valve body is in close contact with the entire circumference of the valve seat, so that the airtightness between the valve body and the valve seat is improved.

  In the present invention, as a method of lowering the hardness of the part located on the distal end side or the proximal end side in the specific direction in at least one of the valve body and the valve seat, the member having a low hardness is press-fitted into the part. A method is conceivable.

  At that time, since the low-hardness member is easily deformed by the heat in the combustion chamber, only the low-hardness member is press-fitted into a portion located on the distal end side or the proximal end side in the specific direction in at least one of the valve body and the valve seat. Then, there is a possibility that the residual stress of the low hardness member is reduced by the thermal deformation of the low hardness member. When the residual stress of the low-hardness member decreases, the low-hardness member may drop from the press-fitted member. Furthermore, since the low-hardness member has low wear resistance, if the low-hardness member comes into direct contact with the valve body or the valve seat when the valve body opens and closes, unnecessary wear as well as the desired deformation described above may occur. There is sex.

  Therefore, in the valve operating mechanism for an internal combustion engine according to the present invention, a high-hardness member, a low-hardness member, You may make it press-fit the laminated body which laminated | stacked the member of hardness in order.

  In this case, a high-hardness member is disposed in a portion of the laminate that is in direct contact with the press-fitting destination member. Since the high-hardness member is difficult to be thermally deformed, even if the high-hardness member receives heat from the combustion chamber, the residual stress at the time of press-fitting can be kept large. As a result, it becomes difficult for the laminate to fall off from the press-fitted member.

  In addition, high hardness members with excellent wear resistance are placed in the parts of the laminate that are in direct contact with the valve body or the valve seat, so that wear of the laminate is suppressed even when the opening and closing operation of the valve body is repeated. Is done.

  When the parallelism and concentricity (concentricity) between the valve body and the valve seat are low, the low hardness member arranged in the intermediate layer of the laminate is deformed, so that the valve body and the valve seat are evenly adhered. Is realized.

  The laminated body described above is provided not only on the base end side or the tip end side in the specific direction but on the entire circumference of the part that contacts the other of the valve body and the valve seat in at least one of the valve body and the valve seat. It may be. At that time, as the low hardness member, it is preferable to use an elastically deformable member such as a rubber material or a damping steel material.

  According to such a configuration, even when the parallelism and the coaxiality of the valve seat and the valve body are low, the above-described laminated body is deformed so as to be in close contact with the valve seat or the valve seat, so that the airtightness is lowered. Is suppressed. Furthermore, when the valve body is seated in an inclined state with respect to the valve seat, a relatively large force acts on the part where the valve body and the valve seat first contact, and the valve body and the valve seat contact each other last. Although a relatively large acceleration acts on the part that performs, the low hardness member of the laminate functions as a cushioning material, so that uneven wear and sound generation at the part where the valve body and the valve seat contact first or last occur. Can be suppressed.

  In the present invention, as another method for lowering the hardness of the part located on the distal end side or the proximal end side in the specific direction in at least one of the valve body and the valve seat, the elastic member is disposed in the part. A method is conceivable.

  In this case, the deformation of the elastic member enables the valve body and the valve seat to be in close contact with each other, and the deviation of the portion located on the distal end side or the proximal end side in the specific direction in at least one of the valve body and the valve seat. It is also possible to suppress the occurrence of wear and hitting sound.

  In addition, you may make it provide the clearance gap which accept | permits a deformation | transformation of an elastic member when a valve body seats to a valve seat around the site | part in which an elastic member is arrange | positioned. In this case, the elastic member is not sandwiched between the valve body and the valve seat (or cylinder head). As a result, the elastic member can be prevented from being damaged.

  When an elastic member is disposed at a position of the valve seat on the distal end side or the proximal end side in the specific direction, a holding member that urges the elastic member in the radial direction is provided on the valve seat to prevent the elastic member from falling off. You may make it do.

  The elastic member and the holding member may be provided over the entire circumference of the valve seat. When the elastic member is provided over the entire circumference of the valve seat, the elastic member is deformed so as to be in close contact with the valve body, so that a decrease in airtightness is suppressed. Furthermore, the impact applied to the part where the valve body and the valve seat first or last contact is buffered by the elastic member, so that uneven wear and sound generation at the part where the valve body and the valve seat contact first or last are suppressed. can do.

  According to the present invention, in the valve operating mechanism of an internal combustion engine provided with a valve body that opens while tilting in a specific direction with respect to the valve seat, the parallelism and coaxiality of the valve body and the valve seat are low. However, it is possible to suppress a decrease in airtightness.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

  First, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing a schematic configuration of a valve mechanism for an internal combustion engine according to the present invention.

FIG. 1 is a longitudinal sectional view of the valve mechanism, and FIG. 2 is a transverse sectional view of the valve mechanism. 1 and 2, an intake port 2 is formed in the cylinder head 1 of the internal combustion engine. A spindle housing hole 100 is provided in the cylinder head 1 near the intake port 2. The intake port 2 and the support shaft housing hole 100 communicate with each other via a communication hole 110.

  The support shaft 3 is fixed to the support shaft storage hole 100. A rocker arm 4 is rotatably attached to the support shaft 3. The rocker arm 4 includes a cylindrical rocker body 40 having an inner diameter substantially the same as the outer diameter of the support shaft 3, and an arm 41 protruding from the rocker body 40.

  The arm 41 extends into the intake port 2 through the communication hole 110. An intake valve body 5 (hereinafter referred to as a valve body 5) for opening and closing the intake port 2 is formed at the tip of the arm 41.

  A cylindrical guide 7 is embedded in the cylinder head 1, and one end of the guide 7 is exposed in the intake port 2. A push rod 6 is slidably held on the guide 7.

  The tip of the push rod 6 is connected to the valve body 5 (or the arm 41) so as to be movable. Specifically, the tip of the push rod 6 and the valve body 5 are connected to each other via a shaft 8 parallel to the support shaft 3 so as to be rotatable. At that time, the bearing 60 on the push rod 6 side is formed into a long hole in a direction orthogonal to the axis of the push rod 6.

  A valve lifter 9 is attached to the proximal end of the push rod 6, and the valve lifter 9 is in contact with the cam 11 of the camshaft 10. The push rod 6 is biased by the valve spring 12 in the valve closing direction (upward in FIG. 1).

  The valve lifter 9, the cam shaft 10, the cam 11, and the valve spring 12 described above can use parts of a conventional poppet valve type valve operating mechanism.

  In the valve mechanism configured as described above, when the base circle portion of the cam 11 is in contact with the valve lifter 9, the valve body 5 is attached to the valve seat (valve seat) 13 provided at the opening end of the intake port 2. Sit down.

  When the camshaft 10 rotates and the nose portion of the cam 11 presses the valve lifter 9, the push rod 6 is lowered accordingly. When the push rod 6 descends, the rocker arm 4 rotates downward about the support shaft 3.

  Here, since the tip of the push rod 6 moves linearly while the valve body 5 moves circularly, a shift occurs between the track drawn by the tip of the push rod 6 and the track drawn by the valve body 5. Since the six bearings 60 are machined into a long hole, it is possible to suppress the bending and partial wear of the push rod 6 and the rocker arm 4.

  When the rocker arm 4 rotates about the support shaft 3, the valve body 5 moves on a circular orbit drawn by the tip of the arm 41. As a result, as shown in FIG. 3, the valve body 5 opens the valve while being inclined in the specific direction S with respect to the valve seat surface.

  When the valve body 5 opens while inclining, most of the intake air flowing out from the intake port 2 flows in the specific direction S along the surface of the valve body 5. As a result, it is possible to generate an intake flow with high directivity.

By the way, in the valve operating mechanism in which the valve body 5 opens while tilting as described above, the valve body 5 and the valve seat when the valve is closed due to manufacturing tolerances or assembly tolerances of the arm 41, the shaft 8, the bearing 60, etc. The parallelism of 13 may decrease. In this case, the valve body 5 cannot be in close contact with the entire circumference of the valve seat 13.

  For example, as shown in FIG. 4, the valve body 5 may be seated on the valve seat 13 before the surface M of the valve body 5 becomes parallel to the seat surface L of the valve seat 13. In this case, the part located on the proximal end side in the specific direction S in the valve body 5 is in close contact with the valve seat 13, but the part located on the distal end side in the specific direction S is not in close contact with the valve seat 13. As a result, the airtightness of the valve body 5 and the valve seat 13 on the tip side in the specific direction S decreases.

  If the airtightness of the valve body 5 and the valve seat 13 is reduced on the tip side in the specific direction S, there is a possibility that a reduction in the compression ratio during the compression stroke, a reduction in the combustion pressure during the expansion stroke, or the like may be induced.

  On the other hand, the method of forming the whole region of the part which contacts the valve body 5 in the valve seat 13 with a low-hardness member capable of plastic deformation can be considered. In this case, when the valve body 5 is repeatedly seated on the valve seat 13, the valve seat 13 is plastically deformed so as to be parallel to the valve body 5. As a result, the entire circumference of the valve seat 13 can be brought into close contact with the valve body 5.

  However, even after the shape of the valve seat 13 becomes parallel to the valve body 5, the plastic deformation of the low-hardness member proceeds, and the valve body 5 at the time of seating may sink inward of the cylinder head 1. When the valve body 5 at the time of seating is depressed inward of the cylinder head 1, unnecessary irregularities are generated on the wall surface of the combustion chamber, so that the airflow in the combustion chamber (swirl flow, tumble flow, squish flow, etc.) Unnecessary turbulence may occur and the combustion state may deteriorate.

  Therefore, in the valve operating mechanism of the present embodiment, as shown in FIG. 5, the base end side in the specific direction S (the portion on the support shaft 3 side in FIG. 1) in the portion that contacts the valve body 5 of the valve seat 13. The low-hardness member 131 is disposed only in the case.

  The range in which the low-hardness member 131 is disposed is preferably determined so as to conform to manufacturing tolerances, assembly tolerances, and the like. For example, when manufacturing tolerance or assembly tolerance is relatively high, it may be provided at a part of the base end side of the specific direction S. When manufacturing tolerance or assembly tolerance is relatively low, the base in the specific direction S may be provided. You may make it provide in the semicircle of an end side.

  The low hardness member 131 is made of a metal having a lower hardness than the valve body 5 and capable of plastic deformation. The other part of the valve seat 13 is formed of a high hardness member 130 having a higher hardness than the low hardness member 131. The high hardness member 130 is a metal having the same hardness as the valve body 5 and excellent in heat resistance and wear resistance.

  When the valve seat 13 is configured in this manner, the low hardness member 131 is plastically deformed by repeating the seating of the valve seat 13 on the low hardness member 131 at the base end side in the specific direction S of the valve body 5. .

  As the plastic deformation of the low hardness member 131 proceeds, the distal end side portion of the valve body 5 in the specific direction S is seated (adhered) to the high hardness member 130 of the valve seat 13. When the portion of the valve body 5 on the tip side in the specific direction S comes into close contact with the high hardness member 130 of the valve seat 13, the plastic deformation of the low hardness member 131 does not proceed any further.

Therefore, even when the parallelism between the valve body 5 and the valve seat 13 is low, the valve body 5 comes into close contact with the entire circumference of the valve seat 13 due to the plastic deformation of the low hardness member 131. Further, when the valve body 5 comes into close contact with the entire circumference of the valve seat 13, plastic deformation of the valve seat 13 is suppressed, so that the seated valve body 5 sinks inward of the cylinder head 1. Nor.

  In this embodiment, the example in which the valve body 5 is seated before the surface M of the valve body 5 becomes parallel to the seat surface L of the valve seat 13 has been described. When the parallelism of the seat 13 is lowered, the surface M of the valve body 5 exceeds the state parallel to the seat surface L of the valve seat 13 as shown in FIG. It is also conceivable to sit on the valve seat 13 in an inclined state in the direction S and the reverse direction T.

  When seated on the valve seat 13 with the surface M of the valve body 5 tilted in the direction T opposite to the specific direction S, the valve body 5 is positioned on the base end side in the reverse direction T (tip side in the specific direction S). The part to be in close contact with the valve seat 13, but the part located on the distal end side in the reverse direction T (the base end side in the specific direction S) does not adhere to the valve seat 13. As a result, the airtightness of the valve body 5 and the valve seat 13 is deteriorated on the distal end side in the reverse direction T (base end side in the specific direction S).

  Therefore, when the valve body 5 is seated on the valve seat 13 in a state where the surface M is inclined in the direction T opposite to the specific direction S, the base end side of the valve seat 13 in the reverse direction T as shown in FIG. The low hardness member 132 may be arranged only (at the tip side in the specific direction S).

  When the valve seat 13 is configured in this manner, the low hardness member 132 is plastically deformed by repeating the seating of the valve seat 13 on the low hardness member 132 at the tip side in the specific direction S of the valve body 5.

  When the plastic deformation of the low hardness member 132 proceeds, the base end side portion of the valve body 5 in the specific direction S is seated (adhered) to the high hardness member 130 of the valve seat 13. When the proximal end portion of the valve body 5 in the specific direction S comes into close contact with the high hardness member 130 of the valve seat 13, the plastic deformation of the low hardness member 132 does not proceed any further.

  Therefore, even when the parallelism between the valve body 5 and the valve seat 13 is low, the valve body 5 comes into close contact with the entire circumference of the valve seat 13 due to the plastic deformation of the low hardness member 132. Further, when the valve body 5 comes into close contact with the entire circumference of the valve seat 13, plastic deformation of the valve seat 13 is suppressed, so that the seated valve body 5 sinks inward of the cylinder head 1. Nor.

  In the present embodiment, the example in which the low-hardness member is arranged on the distal end side or the proximal end side in the specific direction S in the valve seat 13 has been described. However, the portion of the valve body 5 in the specific direction S is in contact with the valve seat 13. Even if the low hardness member is arranged on the distal end side or the proximal end side, the same action and effect can be obtained.

  Next, a second embodiment of the present invention will be described with reference to FIGS. Here, a configuration different from that of the first embodiment will be described, and description of the same configuration will be omitted.

  In the first embodiment described above, an example in which a plastically deformable low-hardness member is disposed on the base end side in the specific direction S of the valve seat 13 has been described, but in this embodiment, the base of the specific direction S in the valve seat 13 is described. An example in which a laminated body of a low hardness member and a high hardness member is arranged on the end side will be described.

  FIG. 8 is a diagram showing a configuration of the valve seat 13 in the present embodiment. As shown in FIG. 8, a laminated body 133 is disposed in a portion on the proximal end side in the specific direction S in the valve seat 13.

  The base layer of the laminated body 133 is formed of a low hardness member 134 made of a metal having a hardness lower than that of the valve body 5. A high hardness member 135 made of a metal having a hardness equivalent to that of the valve body 5 is sprayed or welded to a portion of the low hardness member 134 that contacts the valve body 5.

  According to the valve seat 13 configured as described above, when the valve body 5 is seated on the valve seat 13 before the surface M of the valve body 5 becomes parallel to the seat surface L of the valve seat 13, By repeating the seating of the valve seat 13 on the laminate 133 at the base end side in the specific direction S, the low hardness member 134 of the laminate 133 is plastically deformed.

  When plastic deformation of the low-hardness member 134 of the laminated body 133 proceeds, a portion on the tip side in the specific direction S in the valve body 5 comes to be seated (adhered) to the high-hardness member 130 of the valve seat 13. When the portion of the valve body 5 on the tip side in the specific direction S comes into close contact with the high hardness member 130 of the valve seat 13, the plastic deformation of the low hardness member 134 does not proceed any further.

  Therefore, even when the parallelism between the valve body 5 and the valve seat 13 is low, the valve body 5 comes into close contact with the entire circumference of the valve seat 13 due to plastic deformation of the low hardness member 134. Further, when the valve body 5 comes into close contact with the entire circumference of the valve seat 13, plastic deformation of the valve seat 13 is suppressed, so that the seated valve body 5 sinks inward of the cylinder head 1. Nor.

  By the way, when the valve body 5 repeatedly sits on the valve seat 13, the surface of the valve seat 13 may be worn. In particular, if a part of the valve seat 13 is made of a low hardness member, the low hardness member is more easily worn than other parts (high hardness member 130). That is, the part where the low hardness member is arranged in the valve seat 13 may be unevenly worn.

  On the other hand, in the present embodiment, since the high hardness member 135 having excellent wear resistance and lubricity is disposed on the surface of the low hardness member 134, uneven wear of the valve seat 13 can be suppressed.

  In addition, when the valve body 5 is seated on the valve seat 13 after the surface M of the valve body 5 exceeds the state parallel to the seat surface L of the valve seat 13, the above-described laminated body is placed in a specific direction S in the valve seat 13. You may make it arrange | position in the site | part of the front-end | tip side.

  Of course, the laminated body described above may be disposed on the proximal end side or the distal end side of the valve body 5 in the specific direction S.

  The laminated body described above may be provided on the entire circumference of the valve seat. That is, you may make it a valve seat be comprised with an above described laminated body. However, since the low hardness member is easily deformed by the heat in the combustion chamber, if the base layer of the laminate is composed of the low hardness member, the residual stress when the valve seat is pressed into the cylinder head is low. May become excessively small due to thermal deformation. In such a case, the valve seat may fall off from the cylinder head.

  Therefore, as shown in FIG. 9, the valve seat 14 is composed of a high-strength member 140 whose base layer is made of a high-strength metal, and whose surface layer is made of a metal having substantially the same hardness as the valve body 5. The intermediate layer between the high-strength member 140 and the high-hardness member 142 may have a three-layer structure including a low-hardness member 141 made of a metal whose hardness is lower than that of the valve body 5.

According to such a configuration, the residual stress when the valve seat 14 is press-fitted into the cylinder head 1 remains large even when the valve seat 14 is used for a long time. The valve seat 14 will not fall off.

  Further, when the low-hardness member 141 is disposed on the entire circumference of the valve seat 14, not only when the parallelism between the valve body 5 and the valve seat 14 is low, but also when the coaxiality (concentricity) is low, Since the low-hardness member 141 is deformed so that the body 5 is in close contact with the entire circumference of the valve seat 14, it is possible to suppress a decrease in sealing performance.

  On the other hand, when the low-hardness member 141 is arranged on the entire circumference of the valve seat 14, the plastic deformation of the low-hardness member 141 may proceed even after the valve body 5 and the valve seat 14 come into close contact with each other. There is a concern that excessive plastic deformation of the low-hardness member 141 is regulated between the high-strength member 140 and the high-hardness member 142, so that the seat surface is excessively depressed inward of the cylinder head 1. There is no.

  Next, a third embodiment of the present invention will be described with reference to FIGS. Here, a configuration different from that of the first embodiment will be described, and description of the same configuration will be omitted.

  In the first embodiment described above, an example in which a plastically deformable low-hardness member is disposed on the base end side in the specific direction S of the valve seat 13 has been described, but in this embodiment, the base of the specific direction S in the valve seat 13 is described. An example in which an elastically deformable low-hardness member is disposed on the end side will be described.

  FIG. 10 is a diagram showing a configuration of the valve seat 13 in the present embodiment. As shown in FIG. 10, a heat resistant elastic body 136 is embedded in a portion of the valve seat 13 that is in contact with the valve body 5 and located on the base end side in the specific direction S.

  The heat-resistant elastic body 136 is positioned in the axial direction by fitting a convex portion provided on the inner peripheral surface of the heat-resistant elastic body 136 into a groove provided on the outer peripheral surface of the high-hardness member 130 and has a diameter. The positioning in the direction is performed by being sandwiched between the high hardness member 130 and the cylinder head 1.

  When the valve seat 13 is configured in this manner, when the proximal end portion of the valve body 5 in the specific direction S is seated on the heat resistant elastic body 136 of the valve seat 13, the heat resistant elastic body 136 is in the specific direction S of the valve body 5. The tip side portion of the valve seat 13 is elastically deformed until it is seated (contacted) on the high hardness member 130 of the valve seat 13.

  Therefore, even if the valve body 5 is seated on the valve seat 13 before the surface M of the valve body 5 becomes parallel to the seat surface L of the valve seat 13, the elastic deformation of the heat-resistant elastic body 136 causes the valve The body 5 comes into close contact with the entire circumference of the valve seat 13.

  Furthermore, according to the valve seat 13 of the present embodiment, since the impact when the valve body 5 is seated on the valve seat 13 is attenuated by the heat-resistant elastic body 136, the bounce of the valve body 5 and the generation of a hitting sound are suppressed. It is also possible.

  In addition, after the surface M of the valve body 5 exceeds the state parallel to the seat surface L of the valve seat 13, that is, in a state where the surface M of the valve body 5 is inclined in the direction T opposite to the specific direction S, When seated, the heat-resistant elastic body 136 described above may be disposed at the tip side of the valve seat 13 in the specific direction S.

  Moreover, you may make it the whole valve seat be comprised with a heat-resistant elastic body. In that case, as shown in FIG. 11, the entire circumference of the portion of the valve seat 15 that contacts the valve body 5 is constituted by a heat-resistant elastic body 150.

  The heat-resistant elastic body 150 is positioned by an annular holding metal fitting 151 that is press-fitted into the cylinder head 1. That is, the annular protrusion provided on the inner peripheral surface of the heat-resistant elastic body 150 is fitted into the annular groove provided on the outer peripheral surface of the holding metal fitting 151 so that the heat-resistant elastic body 150 is positioned in the axial direction and held. Residual stress when the metal fitting 151 is press-fitted into the cylinder head 1 biases the heat-resistant elastic body 150 in the radial direction (that is, presses the cylinder head 1), thereby positioning the heat-resistant elastic body 150 in the radial direction.

  When the heat-resistant elastic body 150 is provided on the entire circumference of the valve seat 15 as described above, the valve body 5 and the valve seat 15 have a low degree of parallelism, and even when the coaxiality (concentricity) is low, Since the heat-resistant elastic body 150 is elastically deformed so that the body 5 is in close contact with the entire circumference of the valve seat 15, it is possible to suppress a decrease in sealing performance.

  Next, a fourth embodiment of the present invention will be described with reference to FIGS. Here, a configuration different from that of the first embodiment will be described, and description of the same configuration will be omitted.

  In the first embodiment described above, an example in which a plastically deformable low-hardness member is disposed on the base end side in the specific direction S of the valve seat has been described. In this embodiment, the valve seat 5 contacts the valve seat 13. An example in which a heat-resistant elastic body and a high-hardness member are provided along the entire circumference of the part will be described.

  FIG. 12 is a diagram showing the configuration of the valve body 5 and the valve seat 16 in the present embodiment. As shown in FIG. 12, the peripheral edge portion on the surface of the valve body 5 is formed into a flat surface. On the other hand, the cylinder head 1 is provided with a valve seat 16 at a portion that contacts the flat portion of the surface of the valve body 5 when the valve body 5 is seated.

  The valve seat 16 includes an annular high hardness member 160. An annular heat-resistant elastic body 161 is disposed on the outer periphery of the high hardness member 160. The heat resistant elastic body 161 protrudes from the high hardness member 160 toward the combustion chamber. The lower end (end portion on the combustion chamber side) of the high hardness member 160 is formed in a weight shape that gradually decreases in thickness toward the combustion chamber side, and a gap is formed between the high hardness member 160 and the heat resistant elastic body 161. 162 is generated.

  When attaching such a valve seat 16 to the cylinder head 1, first, the heat resistant elastic body is formed such that the annular protrusion provided on the outer peripheral surface of the heat resistant elastic body 161 is fitted in the annular groove provided in the cylinder head 1. 161 is attached to the cylinder head 1. Subsequently, the high hardness member 160 is press-fitted into the cylinder head 1.

  When the valve seat 16 is attached to the cylinder head 1 as described above, the annular protrusion of the heat resistant elastic body 161 is fitted into the annular groove of the cylinder head 1 so that the heat resistant elastic body 161 is positioned in the axial direction. Residual stress at the time of press-fitting the high hardness member 160 acts to urge the heat resistant elastic body 161 in the radial direction, whereby the heat resistant elastic body 161 is positioned in the radial direction.

  According to the valve body 5 and the valve seat 16 configured as described above, when the valve body 5 is seated on the valve seat 16, the flat portion of the valve body 5 first comes into contact with the heat-resistant elastic body 161 and then the valve body 5. The flat portion is seated on the lower end of the high hardness member 160.

  At that time, if the parallelism or concentricity (concentricity) between the valve body 5 and the valve seat 16 is low, the valve body 5 may not be in close contact with the high-hardness member 160 and the sealing performance may be lowered. On the other hand, in the valve seat 16 of this embodiment, since the lower end of the heat resistant elastic body 161 protrudes from the high hardness member 160, the valve body 5 is brought into close contact with the heat resistant elastic body 161, so that a decrease in sealing performance is suppressed. The

  Further, when the valve body 5 is seated on the high hardness member 160, the heat resistant elastic body 161 is crushed by the valve body 5, and between the cylinder head 1 and the valve body 5 or between the valve body 5 and the high hardness member 160. However, in the valve seat 16 of the present embodiment, the heat-resistant elastic body 161 enters the gap 162 as shown in FIG. 13, and therefore, between the cylinder head 1 and the valve body 5 and the valve. It is not sandwiched between the body 5 and the high hardness member 160.

  Furthermore, since the lower end of the high-hardness member 160 is formed in a thin weight, the lower end of the high-hardness member 160 comes into close contact with the valve body 5 when the valve body 5 is repeatedly seated on the high-hardness member 160. Plastically deformed. Therefore, the sealing performance between the valve body 5 and the valve seat 16 is further enhanced.

  In the first to fourth embodiments described above, the mechanism shown in FIG. 1 is given as an example of the mechanism that opens the valve while inclining in a specific direction. However, the mechanism is not limited to this mechanism. For example, as shown in FIG. 14, the arm 41 may be a mechanism configured by connecting two links 41a and 41b with a pair of pairs 41c with one degree of freedom.

  As another mechanism for opening the valve while inclining in a specific direction, as shown in FIG. 15, the tip of the valve stem 60 and the valve body 61 are rotatable with respect to each other via a shaft 62 orthogonal to the valve stem 60. And a mechanism in which the connection position of the valve stem 60 (the position of the shaft 62) in the valve body 61 is offset from the center of gravity 63 of the valve body 61.

  In the mechanism as shown in FIG. 15, when the valve body 61 is seated, the valve body 61 may sit before returning to the state parallel to the valve seat 17. That is, the entire valve body 61 may be seated on the valve seat 17 after a part of the valve body 61 contacts the valve seat 17.

  In such a case, a relatively large force is applied to the first contact portion of the valve body 61 and the valve seat 17, and a relatively large acceleration is applied to the portion of the valve body 61 and the valve seat 17 that is finally contacted. Works.

  Therefore, the heat-resistant elastic body 150 as shown in FIGS. 10 and 11 described above or the above-described FIG. By disposing the heat-resistant elastic body 162 as shown in the figure, the valve body 61 and the valve seat 17 are first or last contacted with each other, bounce of the valve body 61, or the valve body 61 and the valve seat 17. Generation of a hitting sound at the time of contact can be suppressed.

  As another mechanism for opening the valve while inclining in a specific direction, as shown in FIG. 16, the tip of the valve stem 60 and the valve body 61 are rotatable with respect to each other via a shaft 62 orthogonal to the valve stem 60. And a mechanism in which a winding spring 64 for urging the valve body 61 in a specific direction around the shaft 62 is fixed to the shaft 62.

In the mechanism as shown in FIG. 16, when the valve body 61 is seated, the valve body 61 is in contact with the valve seat 17 while being inclined in a specific direction. A large load acts on the valve body 61, and a large acceleration acts on a portion of the valve body 61 and the valve seat 17 that finally contact each other.

  Accordingly, in the same manner as the mechanism of FIG. 15 described above, the portion of the valve seat 17 that contacts the valve body 61 first or last, or the entire circumference of the valve seat 17 is heat resistant as shown in FIGS. By disposing the elastic body 150 and the heat-resistant elastic body 162 as shown in FIG. 12 described above, uneven wear at a portion of the valve body 61 and the valve seat 17 that contact each other first or last, bounce of the valve body 61 Alternatively, it is possible to suppress the generation of hitting sound when the valve body 61 and the valve seat 17 are in contact with each other.

It is a longitudinal cross-sectional view of the valve operating mechanism to which this invention is applied. It is a cross-sectional view of a valve operating mechanism to which the present invention is applied. It is a figure which shows the valve opening operation | movement of the valve operating mechanism to which this invention is applied. It is a figure which shows the seating example of a valve body in case the parallelism of a valve body and a valve seat is low. FIG. 3 is a diagram illustrating a configuration of a valve seat in Example 1. It is a figure which shows the other seating example of a valve body in case the parallelism of a valve body and a valve seat is low. 6 is a view showing another configuration of the valve seat in Example 1. FIG. FIG. 6 is a diagram showing a configuration of a valve seat in Example 2. 6 is a view showing another configuration of the valve seat in Example 2. FIG. FIG. 6 is a diagram showing a configuration of a valve seat in Example 3. 6 is a view showing another configuration of the valve seat in Example 3. FIG. It is a figure which shows the structure of the valve seat in Example 4. FIG. It is a figure which shows the state of a valve seat when a valve body seats in Example 4. FIG. It is a 1st figure which shows the other structure of the valve mechanism to which this invention is applied. It is a 2nd figure which shows the other structure of the valve mechanism to which this invention is applied. It is a 3rd figure which shows the other structure of the valve mechanism to which this invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Cylinder head 2 ... Intake port 3 ... Support shaft 4 ... Rocker arm 5 ... Valve body 6 ... Push rod 13. ... Valve seat 14 ... Valve seat 15 ... Valve seat 16 ... Valve seat 130 ... High hardness member 131 ... Low hardness member 132 ... Low hardness member 136 ...・ Heat resistant elastic body (low hardness member)
140 ... high strength member 141 ... low hardness member 142 ... high hardness member 150 ... heat resistant elastic body (low hardness member)
151... Holding bracket (holding member)
160 ... high hardness member 161 ... heat resistant elastic body (low hardness member)

Claims (7)

A valve operating mechanism of an internal combustion engine including a valve body that opens while tilting in a specific direction with respect to a valve seat;
A valve operating mechanism for an internal combustion engine, characterized in that at least one of the valve body and the valve seat is formed with a portion located on the base end side in the specific direction with lower hardness than other portions. A valve operating mechanism of an internal combustion engine including a valve body that opens while tilting in a specific direction with respect to a valve seat;
A valve operating mechanism for an internal combustion engine, characterized in that at least one of the valve body and the valve seat is formed with a portion located on the distal end side in the specific direction with a lower hardness than other portions. 3. The operation of an internal combustion engine according to claim 1, wherein a laminate in which a member having a high hardness, a member having a low hardness, and a member having a high hardness are sequentially laminated is press-fitted into the portion where the hardness is reduced. Valve mechanism. 3. The valve operating mechanism for an internal combustion engine according to claim 1, wherein an elastic member is disposed at a portion where the hardness is lowered. 5. The internal combustion engine according to claim 4, wherein a gap that allows deformation of the elastic member when the valve body is seated on the valve seat is provided around a portion where the elastic member is disposed. Valve mechanism. 6. The valve operating mechanism for an internal combustion engine according to claim 4, wherein a portion whose hardness is lowered is formed in the valve seat, and the valve seat includes a holding member that urges the elastic member in a radial direction. The internal combustion engine operation according to any one of claims 3 to 6, wherein the portion whose hardness is lowered is formed on the entire circumference of a portion that contacts the other of at least one of the valve body and the valve seat. Valve mechanism.

Images