JP4851101B2 - gasket - Google Patents

Description

  The present invention relates to a gasket.

  Conventionally, as a gasket for sealing between two members, the shaft is fitted in the outer periphery of the small diameter portion formed at the tip of the shaft member, and the small diameter portion is inserted into the hole formed in the attached member. It is known that when a member is attached to the attached portion, the member is sandwiched between the shaft member and the attached member to seal between them.

  As such a gasket, for example, a gasket that is attached to an exhaust system of an automobile engine and seals a gap between the injector that adds fuel to the exhaust and the engine can be used. A small-diameter portion having an injection hole is formed at the tip of the injector, and a hole for inserting the small-diameter portion of the injector is formed on the engine side. Moreover, the said gasket is formed in an annular | circular shape, and is fitted by the small diameter part outer periphery of an injector. In this state, when the small diameter portion is inserted into the hole and the injector is attached to the engine with a bolt, the injector is pressed against the engine and a gasket is sandwiched between the two.

  Thus, when the gasket is sandwiched between the injector and the engine, the contact surface between the injector side wall surface and the gasket axial side surface, and the contact surface between the gasket axial side surface and the engine side wall surface are sealed. The The sealability of these contact surfaces varies depending on the surface pressure of the contact surfaces and the radial width of the contact surfaces. In order to make the surface pressure of the contact surface necessary to ensure the sealing performance, the bolt tightening torque when the injector is attached to the engine, that is, the force (axial force) for pressing the injector against the engine side is adjusted. Is called. Furthermore, in order to make the radial width of the contact surface a value necessary for ensuring the sealing property, the radial width of the gasket is set to a value equal to or slightly larger than the above value.

Since the gasket performs sealing on a high-temperature and high-pressure fluid such as engine exhaust, as disclosed in Patent Document 1, the necessary sealing performance can be ensured even under such high-temperature and high-pressure conditions. It is formed of a metal such as copper.
JP-A-10-141181 (paragraph number [0024])

  By the way, since the small-diameter portion of the injector and the hole on the engine side have dimensional variations, when the small-diameter portion is inserted into the hole, a clearance is generated between them. When the small-diameter portion is inserted into the hole, the small-diameter portion is shifted to one side within the hole by the amount of the clearance, and the injector may be attached to the engine in that state. As an example of such a situation, there is a situation in which the small diameter portion is displaced downward by the dead weight of the injector and is positioned below the hole, and in this state, the injector is attached to the engine.

  In this case, the gasket fitted in the small diameter portion is also displaced downward together with the injector, and the clearance between the small diameter portion and the hole is maximized on the upper side of the small diameter portion. For this reason, in the upper portion of the small diameter portion of the gasket, the gasket protrudes to the hole side by the amount displaced downward together with the injector, and the radial width of the contact surface between the axial side surface of the gasket and the engine side wall surface becomes small. . If the radial width of the contact surface is reduced, the necessary sealability cannot be ensured at that portion, which may cause exhaust leakage.

  When the gasket is sandwiched between the injector and the engine with the gasket displaced downward as described above, the radial width of the contact surface between the axial side surface of the gasket and the engine wall surface is the small diameter portion. It becomes a non-uniform state around the small-diameter portion that becomes the minimum in the upper portion and becomes larger toward the lower side of the small-diameter portion. When the injector is pressed against the engine in such a state, the surface pressure tends to increase above the small diameter portion on the contact surface, and conversely, the surface pressure tends to decrease below the small diameter portion. As a result, at the lower portion of the small diameter portion on the contact surface, the necessary sealing performance cannot be ensured as the surface pressure decreases, and there is a risk of exhaust leakage.

  The small-diameter portion may be displaced in a direction other than the downward direction in the hole. Even when the small-diameter portion is shifted to one side in the hole due to such displacement, the same problem as described above occurs. Such a problem is generally common even when a shaft member other than the injector and the engine and the attached member are sealed with a gasket.

  The present invention has been made in view of such circumstances, and the object thereof is to prevent the required sealability from being ensured when the small diameter portion of the shaft member approaches one side within the hole of the attached member. It is to provide a gasket that can be used.

In the following, means for achieving the above object and its effects are described.
In order to achieve the above object, according to the first aspect of the present invention, the shaft member is inserted into the outer periphery of the small diameter portion formed at the tip of the shaft member and the small diameter portion is inserted into the hole of the attached member. When attached to the attached member, in the gasket that is sandwiched between the shaft member and the attached member and seals between them, the metal member is made of a metal ring having a larger diameter than the small diameter portion, A seal surface having an area necessary for sealing between the shaft member and the mounted member when the entire axial side surfaces become a seal surface for sealing between the shaft member and the mounted member. A seal part having a radial width set so as to be obtained; and a seal part formed so as to protrude with a constant radial width inside the seal part and fitted into an outer periphery of the small diameter part. Support part having a smaller axial width than the part The provided, the radial width of the support portion is set to a value larger than the maximum value of the clearance between the said small diameter portion bore.

  When the shaft member is attached to the mounted member and the gasket is sandwiched between the shaft member and the mounted member, the wall surface of the shaft member and the axial side surface of the seal portion of the gasket, and the seal portion The contact surface between the axial side surface and the wall surface of the attached member is sealed. When the shaft member is attached to the attached member, the small diameter portion of the shaft member inserted into the hole of the attached member may be shifted to one side within the hole by the amount of clearance between the shaft member and the attached member. . At this time, the gasket fitted in the small diameter portion is also displaced in the same manner as the small diameter portion. The clearance between the small-diameter portion and the hole is maximized on the side opposite to the side where the small-diameter portion approaches in the hole, and the seal portion tends to protrude to the hole side due to the displacement of the gasket in this portion. Here, if the seal portion protrudes to the hole side at the portion where the clearance is maximized, the radial width of the contact surface between the axial side surface of the seal portion and the wall surface of the mounted member is reduced at this portion. As a result, there is a possibility that a necessary sealing property cannot be secured between the shaft member and the mounted member. However, according to the said structure, a support part is formed in the radial inside of a seal part, and this support part is engage | inserted by the small diameter part of a shaft member. For this reason, even if the gasket is displaced to one side of the hole together with the small diameter portion, and the seal portion tries to protrude into the hole side as described above, the seal portion is positioned on the side away from the hole by the amount of the support portion. The seal portion can be prevented from protruding to the hole side at the portion where the clearance between the small diameter portion and the hole is maximized. Therefore, the radial width of the contact surface between the axial side surface of the seal portion and the wall surface of the mounted member is reduced at the portion where the clearance is maximized, and accordingly, it is necessary between the shaft member and the mounted member. It is possible to suppress the inability to ensure proper sealing performance.

Incidentally, in the invention according to claim 1, for the radial width of the front Symbol support portion, that is set to a value larger than the maximum value of the clearance between said small diameter portion and the bore.

Therefore, even if the gasket is displaced to one side of the hole together with the small diameter portion, and the seal portion tries to protrude to the hole side at the portion where the clearance between the small diameter portion and the hole is maximum, the seal portion is larger than the maximum value of the clearance. It is located on the side away from the hole by the support portion having the radial width. For this reason, it can be avoided that the seal portion protrudes to the hole side at the portion where the clearance between the small diameter portion and the hole is maximum, and as a result, the axial side surface of the seal portion and the wall surface of the attached member at that portion. It can be avoided that the radial width of the contact surface becomes small and the necessary sealing performance cannot be secured between the shaft member and the mounted member.

According to a second aspect of the present invention, in the first aspect of the present invention, when the clearance between the support portion and the small-diameter portion is maximized, the outer edge of the seal portion is the radial width of the support portion. The gist is that the shaft member and the attached member are set to values that do not protrude from the radial width.

  The gasket fitted on the outer periphery of the small-diameter portion of the shaft member may be in a state of being shifted to one side with respect to the small-diameter portion by the clearance between the small-diameter portion and the support portion. At this time, the clearance between the small-diameter portion and the support portion is maximized on the side opposite to the side where the gasket is offset with respect to the small-diameter portion, and the seal portion is located on the side away from the small-diameter portion by the amount of the clearance. The outer edge of the portion corresponding to the portion having the maximum clearance in the portion tends to protrude from the radial width of the shaft member or the attached member. Here, if the outer edge of the seal portion protrudes from the radial width of the shaft member or attached member, the radial width of the contact surface between the wall surface of the shaft member or attached member and the axial side surface of the seal portion in this portion. As a result, the required sealing performance may not be ensured between the shaft member and the mounted member. However, according to the above configuration, the radial width of the support portion is set so that the outer edge of the seal portion does not protrude from the radial width of the shaft member or the attached member at this time. For this reason, the radial width of the contact surface between the wall surface of the shaft member or the attached member and the axial side surface of the seal portion is reduced at a portion corresponding to the portion where the clearance is maximized in the seal portion, and As a result, it is possible to avoid that the necessary sealing performance cannot be ensured between the shaft member and the mounted member.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the axial side surface of the support portion is in a state of being immersed with respect to the axial side surface of the seal portion. The level difference between both side surfaces in the axial direction is set to be larger than the collapse amount in the axial direction of the seal portion when the shaft member is attached to the attached member.

  When the shaft member is attached to the attached member and the gasket is sandwiched between the shaft member and the attached member, the wall surface of the shaft member and the attached member is pressed against the axial side surface of the seal portion, The seal portion is crushed. Here, if the wall surface of the shaft member and the attached member reaches the axial side surface of the support portion when the seal portion is crushed, the diameter of the contact surface between the wall surface of the shaft member and the axial side surface of the gasket The direction width and the radial width of the contact surface between the axial side surface of the gasket and the wall surface of the mounted member are increased. Due to such an increase in the radial width, there is a possibility that the surface pressure of the contact surface is lowered and the sealing performance is lowered. However, according to the above configuration, since the step on the side surface in the axial direction between the support portion and the seal portion is larger than the collapse amount of the seal portion, the shaft member and the attached member when the seal portion is crushed The wall surface of the support member does not reach the axial side surface of the support portion, the radial width of the contact surface between the wall surface of the shaft member and the axial side surface of the gasket, and the axial side surface of the gasket and the wall surface of the mounted member An increase in the radial width of the contact surface can be avoided. Therefore, it is possible to avoid a decrease in the sealing performance due to a decrease in the surface pressure of the contact surface due to an increase in the radial width of the contact surface.

  Hereinafter, an embodiment in which the present invention is embodied in a gasket that seals between an injector attached to an exhaust system of an automobile engine and the engine will be described with reference to FIGS.

  FIG. 1 is a cross-sectional view showing a structure for attaching an injector 2 to an engine 1. The injector 2 is for adding fuel to the exhaust passage 1 a of the engine 1, and is clamped to the engine 1 side by the clamp 3, and tightens a bolt 4 that passes through the clamp 3 and is screwed into the engine 1. Is attached to the engine 1.

  The injector 2 includes a main body 5 that receives a pressing force from the clamp 3 when the bolt 4 is tightened, and a small-diameter portion 6 formed at the tip of the main body 5. The small diameter portion 6 is formed with a fuel injection hole 6a. An annular gasket 8 made of a metal such as copper is fitted on the outer periphery of the small diameter portion 6. As shown in FIGS. 2 (a) and 2 (b), the gasket 8 has a seal portion 8a having a diameter larger than that of the small diameter portion 6, and is formed on the radially inner side of the seal portion 8a. And a support portion 8b having a small axial width. On the other hand, as shown in FIG. 1, a hole 7 is formed near the exhaust port in the cylinder head of the engine 1 so as to be connected to the exhaust passage 1a and into which the small diameter portion 6 of the injector 2 can be inserted. When the gasket 2 (support portion 8b) is fitted on the outer periphery of the small diameter portion 6 of the injector 2 and the small diameter portion 6 is inserted into the hole 7, the injector 2 is attached to the engine 1 as described above. The gasket 8 is sandwiched between the two by being pressed to the side.

  When the gasket 8 is sandwiched between the injector 2 and the engine 1 in this way, both side surfaces in the axial direction of the seal portion 8a come into contact with the wall surface 9 on the injector 2 side and the wall surface 10 on the engine 1 side, respectively. The contact surface with the wall surfaces 9 and 10 is sealed. The sealing performance of these contact surfaces (hereinafter referred to as seal surfaces) varies depending on the surface pressure of the seal surfaces and the radial width of the seal surfaces. Here, the surface pressure of the seal surface is determined by the area of the seal surface and a force pressing the injector 2 against the engine 1 (hereinafter referred to as an axial force), and the area of the seal surface is determined by the radial width of the seal surface. The relationship between the surface pressure of these seal surfaces, the axial force, and the area of the seal surface is shown in the graph of FIG.

  In the figure, solid lines L1 and L2 indicate changes in the surface pressure of the seal surface with respect to changes in the magnitude of the axial force. The change when the seal surface area is minimized due to the dimensional tolerance of the gasket 8 is represented by a solid line L1, and the change when the seal surface area is maximized due to the dimensional tolerance is represented by a solid line L2. Has been. As can be seen from the figure, as the area of the seal surface becomes smaller and the axial force becomes larger, the surface pressure of the seal surface tends to increase and the sealing performance tends to increase.

  Then, the minimum surface pressure of the seal surface for obtaining the required sealing performance is set to the minimum surface pressure P, and the axial force for obtaining the minimum surface pressure P is the minimum value when the area of the seal surface is maximum (solid line L2). In the case of X1, the radial width of the seal surface (the axial side surface of the seal portion 8a) and the tightening torque of the bolt 4 are set as follows to ensure the necessary sealing performance. That is, the minimum value X1 at the time when the seal surface area is maximum (solid line L2) is made somewhat smaller than the allowable maximum value X2 which is the upper limit value of the axial force corresponding to the strength of the bolt 4 and the engine 1 side. In addition, the radial width of the seal portion 8a is set to a small value. However, since the sealing performance deteriorates even if the radial width of the seal surface becomes too small, the radial width of the seal portion 8a is set to a value of “C”, for example, in consideration of this point. Then, the tightening torque of the bolt 4 when the injector 2 is attached to the engine 1 is adjusted so that the axial force becomes a value between the minimum value X1 and the allowable maximum value X2.

  By the way, since the small diameter portion 6 of the injector 2 and the hole 7 of the engine 1 have dimensional variations, when the small diameter portion 6 is inserted into the hole 7, a clearance is generated between them. For this reason, the injector 2 may be attached to the engine 1 side in a state where the small diameter portion 6 is biased to one side in the hole 7. For example, as shown in FIG. 4, when the small diameter portion 6 is inserted into the hole 7, the small diameter portion 6 is displaced downward by its own weight such as the injector 2, and is positioned below the hole 7. Is attached to the engine 1. In this case, the gasket 8 fitted into the small diameter portion 6 is displaced downward similarly to the small diameter portion 6. Further, the clearance between the small diameter portion 6 and the hole 7 becomes the maximum value b on the side opposite to the side where the small diameter portion 6 approaches in the hole 7 (upper side).

  If a conventional gasket is used at this time, the state shown in FIG. 7 is obtained. In the figure, the conventional gasket 81 is displaced downward along with the small diameter portion 6 which is close to the lower side in the hole 7, and the hole 7 is formed at the portion where the clearance above the small diameter portion 6 becomes the maximum value b. It will stick out to the side. However, when the gasket 81 protrudes to the hole 7 side as described above, even if the radial width of the gasket 81 is set to the above-described value “C”, the wall portion 10 on the engine 1 side and the shaft of the gasket 81 are in the protruding portion. The radial width of the contact surface (seal surface) with the directional side surface becomes smaller than the value “C”, and the sealing performance required for the seal surface cannot be ensured.

  Further, the seal surface at this time is in a range indicated by hatching in FIG. The radial width of the seal surface in the figure is an unequal state around the small-diameter portion 6, which is minimum at the upper portion of the small-diameter portion 6 and becomes larger toward the lower side of the small-diameter portion 6. When the injector 2 is pressed against the engine 1 in such a state, the surface pressure tends to increase above the small-diameter portion 6 on the seal surface, and conversely, the surface pressure tends to decrease below the small-diameter portion 6. . As a result, in the portion below the small-diameter portion 6 on the sealing surface, the surface pressure decreases below the minimum surface pressure P, and the required sealing performance cannot be ensured.

  Furthermore, as described above, the required sealing performance at the sealing surface cannot be ensured, and if the exhaust gas in the exhaust passage 1a leaks outside through the hole 7, the high-temperature exhaust gas passes around the nozzle hole 6a of the injector 2. It will be. As a result, the fuel adhering to the periphery of the injection hole 6a is burned by the exhaust gas, and the injection hole 6a is clogged.

In this regard, in the gasket 8 of the present embodiment, as shown in FIG. 4, a support portion 8b is formed on the radially inner side of the seal portion 8a, and the support portion 8b is fitted into the small diameter portion 6 of the shaft member.
For this reason, even if the gasket 8 is displaced downward together with the small-diameter portion 6, the seal portion 8 a is located above the small-diameter portion 6 and in the portion where the clearance between the small-diameter portion 6 and the hole 7 is maximum. It is located on the side away from the hole 7 by 8b. Accordingly, the seal portion 8a is prevented from protruding into the hole 7 at the portion where the clearance is maximized, and the diameter of the contact surface (seal surface) between the axial side surface of the seal portion 8a and the wall surface 10 on the engine 1 side at that portion. It can be prevented that the direction width becomes smaller than the value “C” and the sealing performance required in the portion cannot be secured.

  In addition, since the radial width of the seal surface is suppressed to be reduced in the portion, unevenness of the surface pressure around the small diameter portion 6 in the seal surface is suppressed, and the injector 2 is pressed against the engine 1 side. At this time, it is possible to suppress the reduction of the surface pressure of the sealing surface below the minimum surface pressure P below the small-diameter portion 6 and the required sealing performance cannot be ensured.

  Furthermore, by suppressing that the required sealing performance cannot be ensured by the sealing surface, it is possible to prevent the exhaust gas in the exhaust passage 1a from leaking outside through the hole 7, and a high temperature accompanying the leak. It is also possible to suppress clogging of the nozzle hole 6a due to the passage of the exhaust gas around the nozzle hole 6a of the injector 2.

Next, the gasket 8 of this embodiment will be described in more detail.
About the support part 8b of this gasket 8, the radial direction width a is set to the larger value than the maximum value b of the said clearance above the small diameter part 6. FIG. For this reason, when the small-diameter portion 6 is displaced downward in the hole 7 and the clearance between the small-diameter portion 6 and the hole 7 reaches the maximum value b above the small-diameter portion 6, the gasket 8 moves downward together with the small-diameter portion 6. Even if it is displaced, it is avoided that the seal portion 8a protrudes to the hole 7 side at the portion where the clearance is maximized. Accordingly, the radial width of the contact surface (seal surface) between the axial side surface of the seal portion 8a and the wall surface 10 on the engine 1 side at that portion is smaller than the value “C”, which is necessary for the seal surface. It is also avoided that the sealing performance cannot be ensured.

  Further, the gasket 8 is displaced downward relative to the small diameter portion 6 by its own weight by the clearance between the support portion 8 b and the small diameter portion 6. At this time, the clearance between the small diameter portion 6 and the support portion 8b becomes the maximum value e on the opposite side (lower side) to the side where the gasket 8 is offset with respect to the small diameter portion 6, and the seal portion 8a becomes the support portion 8b and the clearance described above. Therefore, the lower outer edge of the seal portion 8a tends to protrude downward from the radial width of the main body 5 of the injector 2 by being located on the side away from the small diameter portion.

  Here, if the lower outer edge of the seal portion 8a protrudes downward from the radial width of the main body 5, the positional relationship of the gasket 8 with respect to the injector 2 side and the engine 1 side is as shown in FIG. Thus, the lower outer edge of the seal portion 8a protrudes downward from the radial width of the main body 5, so that the contact surface (seal surface) between the axial side surface of the seal portion 8a and the wall surface 9 on the injector 2 side at that portion. The radial width becomes smaller than the value “C”, and the sealing performance necessary for the sealing surface cannot be ensured.

  Note that the range of the seal surface at this time is a range indicated by hatching in FIG. The radial width of the seal surface in the figure is the smallest at the lower part of the small diameter part 6 and becomes larger toward the upper side of the small diameter part 6, which is an uneven state around the small diameter part 6. When the injector 2 is pressed against the engine 1 in such a state, the surface pressure tends to increase below the small-diameter portion 6 on the seal surface, and conversely, the surface pressure tends to decrease above the small-diameter portion 6. . As a result, in the portion above the small-diameter portion 6 on the sealing surface, the surface pressure decreases below the minimum surface pressure P, and the necessary sealing performance cannot be secured.

  In consideration of the above points, as shown in FIG. 4, the radial width of the support portion 8b of the gasket 8 is determined when the clearance between the support portion 8b and the small diameter portion 6 reaches the maximum value e. The outer edge of the portion 8a is also set to a value that does not protrude from the radial width of the main body 5. For this reason, when the gasket 8 is displaced downward by its own weight, the axial direction of the wall surface 9 on the injector 2 side and the seal portion 8a at the portion where the clearance in the seal portion 8a becomes the maximum value e, that is, the lower portion of the seal portion 8a. It can be avoided that the radial width of the contact surface (seal surface) with the side surface becomes smaller than the value “C”. Therefore, it is possible to avoid the above-described problem that the necessary sealing performance cannot be ensured.

  As for the gasket 8, the axial side surface of the support portion 8b on the main body 5 side is immersed in the axial side surface of the seal portion 8a on the main body 5 side, and the axial side surface of the support portion 8b on the engine 1 side is sealed. The part 8a is formed so as to be immersed in the axial side surface of the engine 1 side. The step d of the axial speed surface on the main body 52 side of the support portion 8b and the seal portion 8a is the axial direction of the main body 52 side portion in the seal portion 8a when the injector 2 is attached to the engine 1 side (left-right direction in the figure). It is formed to be larger than the amount of crushing. Further, the step d on the axial side surface on the engine 1 side of the support portion 8b and the seal portion 8a is the axial direction of the engine 1 side portion of the seal portion 8a when the injector 2 is attached to the engine 1 side (left and right direction in the figure). ) To be larger than the crushing amount.

  Here, assuming that the step d is smaller than the collapse amount, when the injector 2 is attached to the engine 1 side and the gasket 8 is sandwiched between the two and the seal portion 8a is collapsed, the following problem is caused. Occurs. That is, when the seal portion 8a is crushed, the wall surface 9 on the injector 2 side and the wall surface 10 on the engine 1 side reach the side surface in the axial direction of the support portion 8b, and the contact surface between the wall surface 9 and the axial side surface of the gasket 8 (seal Surface) and the radial width of the contact surface (seal surface) between the axial side surface of the gasket 8 and the wall surface 10 on the engine 1 side are increased. Due to such an increase in the radial width of the sealing surface, the surface pressure of the sealing surface may be lower than the minimum surface pressure P and the sealing performance may be deteriorated.

  However, since the level difference d is larger than the collapse amount, the wall surfaces 9 and 10 do not reach the axial side surface of the support portion 8b when the seal portion 8a is collapsed. An increase in the direction width is avoided. Therefore, it is possible to avoid a decrease in sealing performance due to a decrease in the surface pressure of the sealing surface below the minimum surface pressure P as the radial width of the sealing surface increases.

According to the embodiment described in detail above, the following effects can be obtained.
(1) In the gasket 8, a support portion 8 b having a smaller axial width than the seal portion 8 a is formed on the radially inner side of the seal portion 8 a that seals between the injector 2 side and the engine 1 side. And the small diameter part 6 is inserted in the hole 7 by the side of the engine 1 in the state which fitted the gasket 8 (support part 8b) in the outer periphery of the small diameter part 6 of the injector 2, and the injector 2 is attached to the engine 1 side. At this time, even if the small diameter portion 6 is shifted to one side with respect to the hole 7 and the gasket 8 is displaced in the same direction as the small diameter portion 6, the portion of the hole 7 opposite to the side where the small diameter portion 6 is offset Then, the seal portion 8a is positioned on the side away from the hole 7 by the amount of the support portion 8b. Therefore, when the seal portion 8a protrudes to the hole 7 side in the above portion, the radial width of the contact surface (seal surface) between the axial side surface of the seal portion 8a and the wall surface 10 on the engine 1 side is referred to as “C”. It becomes smaller than a value and it can suppress that it becomes impossible to ensure the sealing performance required by the said sealing surface.

  (2) Further, regarding the radial width of the support portion 8b, the small diameter portion 6 is close to one side of the hole 7, and the clearance between the opposite side and the opposite side reaches the maximum value b. Is set to a value larger than the maximum value b. For this reason, when the gasket 8 is displaced in the same direction as the small-diameter portion 6, it is possible to avoid the seal portion 8a from protruding to the hole 7 side at the portion where the clearance is maximized. It is possible to accurately avoid that the radial width is smaller than the value “C” and the sealing performance required for the sealing surface cannot be ensured.

  (3) Further, regarding the radial width of the support portion 8b, when the clearance between the support portion 8b and the small diameter portion 6 reaches the maximum value e, the portion corresponding to the portion where the clearance in the seal portion 8a is maximized. The outer edge is set to a value that does not protrude from the radial width of the main body 5 in the injector 2. For this reason, when the clearance becomes the maximum value e, the radial width of the contact surface (seal surface) between the wall surface 9 on the injector 2 side and the axial side surface of the seal portion 8a in the above portion is a value of “C”. It is possible to avoid that the sealing performance required by the sealing surface cannot be ensured.

  (4) Steps d on both side surfaces in the axial direction of the support portion 8b and the seal portion 8a in the gasket 8 are larger than the amount of axial collapse in the seal portion 8a when the injector 2 is attached to the engine 1 side. Is formed. For this reason, even if the seal portion 8a is crushed during the attachment, the wall surface 9 on the injector 2 side and the wall surface 10 on the engine 1 side do not reach the axial side surface of the support portion 8b. Therefore, it can be avoided that the radial width of the seal surface is expanded due to the collapse of the seal portion 8a, whereby the surface pressure of the seal surface is reduced below the minimum surface pressure P and the sealing performance is deteriorated.

In addition, the said embodiment can also be changed as follows, for example.
Although the present invention is applied to the gasket 8 that seals between the injector 2 that adds fuel to the exhaust passage 1a of the engine 1 and the engine 1, the same engine as the injector that injects fuel into the intake system and combustion chamber of the engine You may apply this invention to the gasket which seals between.

  A path for flowing fluids such as fuel, water, and lubricating oil, such as the fuel supply system, cooling water circulation system, and lubricating oil circulation system of the engine 1 as well as the gasket 8 that seals between the injector 2 and the engine 1 You may apply this invention to the gasket which seals regarding the same fluid above.

  In the above embodiment, the present invention is applied to members having a relatively large difference in size, such as the injector 2 and the engine 1, but the present invention is applied to a shaft member and a mounted member that are not so different in size. You can also In this case, when the clearance between the support portion 8b and the small diameter portion of the shaft member is maximized, the outer edge of the seal portion 8a of the gasket 8 is the radial width of the attached member. It is preferable to set the value so that it does not protrude. Thus, if the radial width of the support portion 8b is set, the radial width of the contact surface (seal surface) between the axial side surface of the seal portion 8a and the wall surface of the attached member becomes smaller than the value “C”. Thus, it is possible to avoid that the sealing performance required by the sealing surface cannot be secured.

  In the above embodiment, the radial width of the support portion 8b in the gasket 8 is set as described in (3) above. However, it is not always necessary to set in this way, and it is set to a value larger than the value at the time of setting. May be. Even in this case, the effects (1) and (2) can be obtained.

  In the above embodiment, the radial width of the support portion 8b in the gasket 8 is set as described in (2) above, but it is not always necessary to set in this way. Even if the radial width of the support portion 8b is equal to or less than the maximum value b, the effect (1) can be obtained.

  The step d on the injector 2 side of the gasket 8 may be “0”. In this case, the axial side surface of the support portion 8b on the injector 2 side does not dip into the axial side surface of the seal portion 8a on the injector 2 side, and these axial side surfaces are positioned on the same plane.

Sectional drawing which shows the attachment structure to the engine of the injector to which the gasket of this embodiment is applied. (A) is the perspective view of a gasket, (b) is sectional drawing which looked at the gasket of (a) from the AA direction. The graph which shows the relationship between the surface pressure of a sealing surface, axial force, and the area of a sealing surface. The expanded sectional view which shows the state by which the said gasket was pinched | interposed into the wall surface by the side of an injector, and the wall surface by the side of an engine. The expanded sectional view which shows the state by which the said gasket was pinched | interposed into the wall surface by the side of an injector, and the wall surface by the side of an engine. Schematic which shows the contact surface (seal surface) of the wall surface by the side of an injector, and the seal part of a gasket. The expanded sectional view which shows the state by which the conventional gasket was pinched | interposed into the wall surface by the side of an injector, and the wall surface by the side of an engine. Schematic which shows the contact surface (seal surface) of the engine-side wall surface and the said gasket.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Engine (member to be attached), 1a ... Exhaust passage, 2 ... Injector (shaft member), 3 ... Clamp, 4 ... Bolt, 5 ... Main body, 6 ... Small diameter part, 6a ... Injection hole, 7 ... Hole, 8 ... Gasket, 8a ... seal part, 8b ... support part, 9 ... wall surface, 10 ... wall surface, 81 ... gasket.

Claims (3)

When the shaft member is attached to the mounted member with the small diameter portion being inserted into the hole of the mounted member while being fitted into the outer periphery of the small diameter portion formed at the tip of the shaft member, the shaft member and the mounted In the gasket that is sandwiched between the members and seals between the two,
It is made of a metal ring formed with a diameter larger than that of the small diameter portion, and when the entire axial side surfaces become seal surfaces that seal between the shaft member and the mounted member, the shaft member and the A seal portion having a radial width set so as to obtain a seal surface having an area necessary for sealing between the mounted members;
A support part having an axial width smaller than the seal part, formed so as to protrude with a constant radial width inside the seal part and fitted into the outer periphery of the small diameter part; The radial width of the support portion is set to a value larger than the maximum clearance between the small diameter portion and the hole.
A gasket characterized by that. About the radial width of the support portion, when the clearance between the support portion and the small diameter portion is maximized, the outer edge of the seal portion does not protrude from the radial width of the shaft member and the attached member. The gasket according to claim 1 , wherein the gasket is set. The axial side surface of the support portion is in a state of being immersed in the axial side surface of the seal portion, and the steps on both axial side surfaces of the support portion and the seal portion attach the shaft member to the attached member. the sealing portion gasket according to claim 1 or 2 are larger than crushing amount in the axial direction of the case.

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