JP2014109284A - Gasket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve seal robust performance by high surface pressure, and to obtain a low reaction force, in a gasket composed of a rubber elastic material.SOLUTION: A gasket 1 comprises: a base part 11 held to an attachment groove formed at a second member which opposes a first member, and tightly contacting with a bottom face of the attachment groove; and an overhanging part 12 which hangs out to internal/external peripheries from a tip of the base part 11 protruding from the attachment groove, and is sandwiched between the first member and the second member. In the gasket, a main lip 13 is formed at an opposing face opposing the first member of the base part 11, and a first sub-lip 15 is formed at an opposing face opposing the first member of the hanging part 12. A second sub-lip 16 is formed at an opposing face opposing the second member of the hanging part 12, and the second sub-lip 16 is displaced in the width direction with respect to the first sub-lip 15.

Description

  The present invention relates to a gasket that is interposed between two members such as a cylinder head and a cylinder head cover in an internal combustion engine and seals between the two members.

  For example, in an internal combustion engine, a head cover gasket that is interposed between a cylinder head and a cylinder head cover and seals engine oil is mainly made of rubber-like elastic material (rubber material or synthetic resin material having rubber-like elasticity). The gasket is used. As shown in FIG. 10, a rigid type gasket 100A in which the cylinder head 2 and the cylinder head cover 3 that are coupled to each other by the bolt 4 are in contact with each other and no gap is set between them, as shown in FIG. As shown in FIG. 11, there is a float type gasket 100 in which the cylinder head 2 and the cylinder head cover 3 do not contact each other and a gap is set therebetween.

  The float type gasket 100 typically has a substantially T-shaped cross section as shown in FIG. That is, the base portion 101 held in the mounting groove 32 formed in the housing portion 31 of the cylinder head cover 3 and the one end projecting from the one end to the inner peripheral side and the outer peripheral side are sandwiched in the gap between the cylinder head 2 and the cylinder head cover 3. The base lip 103 is formed in one end of the base 101 and is in close contact with the cylinder head 2 in a compressed state, and the other end is in close contact with the bottom surface of the mounting groove 32 in the compressed state. A back lip 104 is formed, and a sub lip 105 is formed on the protruding portions 102 on both sides so as to be in close contact with the cylinder head 2 in a compressed state.

  The gasket 100 has not only a sealing function but also a function of enhancing a soundproofing effect and a vibrationproofing effect by interposing an overhanging portion 102 between the cylinder head 2 and the cylinder head cover 3 (the following patents). Reference 1).

JP 2003-240122 A

  In recent years, there has been a tendency to reduce the weight of vehicles in order to control carbon dioxide emissions and to reduce environmental burdens as a countermeasure against global warming. For this reason, there is a tendency that the housing part 31 of the cylinder head cover 3 is thinned and the number of bolts 4 is reduced. However, when the housing portion 31 is thinned or the number of bolts 4 is reduced, the cylinder head cover 3 may be deformed by the compression reaction force of the gasket 100, and the sealability of the gasket 100 is reduced by such deformation. It will be damaged.

  Therefore, in order to prevent the deformation of the cylinder head cover 3 due to the compression reaction force of the gasket 100, a reduction in the reaction force of the gasket 100 is required, and in addition, in order to cope with a long life of the vehicle, a high surface pressure and a high durability. There is also a request. In the conventional gasket 100 shown in FIG. 12, the auxiliary lips 105 and 105 formed on the overhanging portion 102 are for meeting such a demand.

  However, although high surface pressure and low reaction force are achieved by the secondary lips 105 and 105 for the cylinder head 2, the overhanging portion 102 is not in close contact with the cylinder head cover 3 by high surface pressure, and the surface pressure is increased. When trying to increase it, it was inevitable that it would become a high reaction force.

  The present invention has been made in view of the above points, and its technical problem is to improve seal robustness due to high surface pressure and reduce reaction force in a gasket made of a rubber-like elastic material. Is to plan.

  As a means for effectively solving the technical problem described above, the gasket according to the present invention is held in a mounting groove formed in a second member facing the first member, and A base portion that is in close contact with the bottom surface, and a projecting portion that projects from the distal end portion of the base portion protruding from the mounting groove to the inner and outer circumferences and is sandwiched between the first member and the second member, and the first portion of the base portion In a gasket in which a main lip is formed on a surface facing one member and a first sub lip is formed on a surface facing the first member of the projecting portion, the second member of the projecting portion and A second sub lip is formed on the opposing surface of the first sub lip, and the second sub lip is shifted in the width direction from the first sub lip.

  According to the gasket of the present invention, the second sub lip that is in close contact with the second member in the compressed state is formed in the overhang portion in addition to the first sub lip that is in close contact with the first member in the compressed state. As a result, the surface pressure on the first and second members is ensured and the seal robustness is improved, and the first sub lip and the second sub lip are shifted from each other in the width direction. Compression reaction force can be suppressed.

It is sectional drawing of the mounting state which shows preferable embodiment of the gasket which concerns on this invention. It is sectional drawing which shows preferable embodiment of the gasket which concerns on this invention alone. It is sectional drawing which compares and shows the mounting state of the gasket which concerns on this invention, and the conventional gasket. It is a diagram which shows the surface pressure distribution of the width direction of the gasket which concerns on this invention with respect to the bottom face of a mounting groove, and the conventional gasket. It is a diagram which shows the result of having measured the compression reaction force by the side of the cylinder head cover of the gasket which concerns on this invention, and the conventional gasket. It is a diagram which shows the surface pressure distribution of the width direction of the gasket which concerns on this invention with respect to a cylinder head, and the conventional gasket. It is a diagram which shows the result of having measured the compression reaction force by the side of the cylinder head of the gasket which concerns on this invention, and the conventional gasket. It is a diagram which shows the surface pressure distribution of the gasket which concerns on this invention with respect to R surface of the groove shoulder part of a mounting groove, and the conventional gasket. It is explanatory drawing which shows the target part of the surface pressure distribution of FIG. It is sectional drawing of the mounting state which shows an example of the gasket interposed by a rigid type between a cylinder head and a cylinder head cover. It is sectional drawing of the mounting state which shows an example of the gasket interposed by a float type between a cylinder head and a cylinder head cover. It is sectional drawing which shows an example of the conventional gasket used as a float type.

  Hereinafter, preferred embodiments of a gasket according to the present invention will be described in detail with reference to the drawings.

  First, in the mounted state shown in FIG. 1, reference numeral 2 is a cylinder head of an automobile internal combustion engine, reference numeral 3 is a cylinder head cover, and reference numeral 4 is a bolt that couples the cylinder head 2 and the cylinder head cover 3 to each other. The cylinder head 2 corresponds to a first member described in claim 1, and the cylinder head cover 3 corresponds to a second member described in claim 1.

  A gasket 1 according to the present invention is interposed between a cylinder head 2 and a cylinder head cover 3 and used as a head cover gasket for sealing engine oil, and is a rubber-like elastic material (rubber material or rubber-like material). The base 11 held in the mounting groove 32 formed in the housing portion 31 of the cylinder head cover 3, and the cylinder head protruding from one end thereof to the inner peripheral side and the outer peripheral side. 2 and the cylinder head cover 3 have a flat plate-like projecting portion 12 sandwiched in the gap between the cylinder head cover 3, that is, the cross-sectional shape is substantially T-shaped.

  As shown in FIG. 2, a main lip 13 having a mountain-shaped cross section is formed on the surface of the base portion 11 facing the cylinder head 2, and a cross section is formed on the surface facing the bottom surface of the mounting groove 32 on the opposite side. A chevron back lip 14 is formed.

  A pair of first sub lips 15 and 15 having a height and a cross-sectional area smaller than that of the main lip 13 are formed on the surface of the projecting portion 12 on both the inner and outer peripheral sides facing the cylinder head 2. A pair of second sub lips 16, 16 having the same height and cross-sectional area as the first sub lip 15 are formed on the surface of the head cover 3 facing the housing portion 31. The first sub lip 15 and the second sub lip 16 are in a positional relationship shifted from each other by δ in the width direction. Specifically, the first sub lip 15 is located near the inner peripheral end portion and the outer peripheral end of the projecting portion 12. The second sub lips 16, 16 are located closer to the base 11 than the first sub lips 15, 15, while being near the portion. δ is 0.3 mm or more in actual size.

Further, the sum of the height h of the thickness t ₁ and the second sub-lip 16 of the projecting portion 12, the thickness t ₂ of the projecting portion 102 of the gasket 100 shown in FIG. 12 described above below, i.e.,
t ₁ + h ≦ t ₂
H is an actual size and is 0.2 mm or less.

The reason why h is 0.2 mm or less in actual size is that, in the case of a head cover gasket, it is mainly formed by injection molding, but the thickness t ₁ of the overhanging portion 12 = the injection gate thickness is often obtained. if reduced as compared to the thickness t ₂ of the projecting portion 102 of the gasket 100 thickness t ₁ of the projecting portion 12 of 0.2mm or less, impact on the quality and productivity of the molded article to be minimal It is possible.

  In the mounted state shown in FIGS. 3A and 1, the gasket 1 having the above configuration is held in a state where the base portion 11 is appropriately compressed in the mounting groove 32 of the housing portion 31 of the cylinder head cover 3. In addition, the rear lip 14 is brought into close contact with the bottom surface of the mounting groove 32 so that the overhanging portion 12 is sandwiched in the gap between the cylinder head 2 and the housing portion 31 of the cylinder head cover 3, and the main lip 13 and the first sub lip 15 are in close contact with the cylinder head 2 in a completely collapsed state, and the second sub lip 16 is in close contact with the housing portion 31 (the groove shoulder of the mounting groove 32). Is done.

By mounting in this manner, leakage of engine oil from between the cylinder head 2 and the cylinder head cover 3 is prevented, and soundproofing is achieved by the rubber elasticity of the gasket 1 interposed between the cylinder head 2 and the cylinder head cover 3. It has a function to enhance the effect and the vibration proof effect. In addition, as described above, t ₁ + h ≦ t ₂ and the first sub lip 15 and the second sub lip 16 are in a positional relationship shifted from each other by δ in the width direction. When the main lip 13, the first sub lip 15, and the second sub lip 16 are completely crushed by being clamped between the head 2 and the housing portion 31 of the cylinder head cover 3, the cylinder head 2 and The gap G between the cylinder head cover 3 and the housing portion 31 is smaller than that in the prior art shown in FIG.

  Conventionally, the main lip 103 and the sub lip 105 are provided only on the surface of the overhanging portion 102 facing the cylinder head 2, whereas in the present invention, the main lip provided on the surface of the overhanging portion 12 facing the cylinder head 2 is provided. In addition to the lip 13 and the first sub lip 15, since the second sub lip 16 provided on the surface of the overhanging portion 12 facing the cylinder head cover 3 is provided, the surface pressure required for sealing at each of these lips 15, 16 is increased. As a result, the robustness of the seal is increased and the compression reaction force is reduced.

  As a result, the cylinder head cover 3 is reduced in thickness and the deformation of the cylinder head cover 3 due to the reduction in the number of bolts 4 is suppressed. As a result, the deterioration of the sealing performance of the gasket 1 due to the deformation of the cylinder head cover 3 is prevented.

  FIG. 4 is a diagram showing the surface pressure distribution in the width direction of the gasket 1 according to the present invention and the conventional gasket 100 with respect to the bottom surface of the mounting groove 32 of the cylinder head cover 3. As shown in this diagram, it can be seen that the surface pressure distribution of the gasket of the present invention at the groove bottom surface is equivalent to that of the conventional gasket.

  FIG. 5 is a diagram showing the results of measuring the compression reaction force on the cylinder head cover 3 side of the gasket 1 according to the present invention and the conventional gasket 100. As shown in this diagram, it can be seen that the compression reaction force of the gasket of the present invention against the cylinder head cover is reduced by about 40% at the maximum compared to the conventional gasket.

  FIG. 6 is a diagram showing the surface pressure distribution in the width direction of the gasket 1 according to the present invention and the conventional gasket 100 with respect to the cylinder head 2. As shown in this diagram, the surface pressure of the gasket of the present invention against the cylinder head is the same as that of the conventional gasket at the intermediate portion corresponding to the main lip, but the surface pressure is low at both side portions corresponding to the sub lip. I understand that.

  FIG. 7 is a diagram showing the results of measuring the compression reaction force on the cylinder head 2 side of the gasket 1 according to the present invention and the conventional gasket 100. As shown in this diagram, it can be seen that the compression reaction force of the gasket of the present invention against the cylinder head is reduced by about 40% at the maximum compared to the conventional gasket.

  FIG. 8 is a diagram showing the surface pressure distribution of the gasket 1 according to the present invention and the conventional gasket 100 against the R surface 32a of the shoulder portion of the mounting groove 32 shown in FIG. Note that a to e on the horizontal axis in FIG. 8 correspond to a to e positions on the R surface 32 a shown in FIG. 9. As shown in this diagram, the surface pressure of the conventional gasket is slightly higher in the vicinity of the point a on the flat portion side, but the surface pressure of the gasket according to the present invention is in the vicinity of the points b to d on the R surface of the groove shoulder. However, it is higher due to the presence of the second sub lip, and since the maximum surface pressure portion exists at this position, an improvement in sealing performance can be expected.

1 Gasket 11 Base 12 Overhang 13 Main lip 15 First sub lip 16 Second sub lip 2 Cylinder head (first member)
3 Cylinder head cover (second member)
32 Mounting groove

Claims (1)

  A base portion that is held in the mounting groove formed in the second member facing the first member and is in close contact with the bottom surface of the mounting groove, and an inner and outer periphery from the tip of the base portion that protrudes from the mounting groove A projecting portion that projects between the first member and the second member, a main lip is formed on a surface of the base facing the first member, and the first portion of the projecting portion is In the gasket in which the first sub lip is formed on the surface facing the member, the second sub lip is formed on the surface of the projecting portion facing the second member, and the second sub lip is A gasket characterized by being displaced in the width direction from the first sub lip.

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