JP2002257240A - Gasket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gasket capable of effectively preventing heat deterioration of one member by suppressing heat conduction between members to be used under high temperatures. SOLUTION: This gasket 1 is constituted mainly of mica which is a heat- insulating inorganic material. Therefore, heat transmitted to a main body metal fitting 102 from a boss 111 and heat (a thick solid line arrows in Fig.) transmitted from a pipe wall of a pipe 110 or a detecting part 104 of a gas sensor 101 via the boss 111 can be interrupted or suppressed at a position of the gasket 1 (thin dotted-line arrows in Fig.). As a result, heat transmitted to an upper side of the main body metal fitting 102 can be reduced as a whole, and heat deterioration of a filter and a rubber grommet within a gas sensor 101 is prevented to prolong their service lives.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a gasket for maintaining airtightness between members, and more particularly to a gasket suitable for suppressing heat conduction between members used at high temperatures.

[0002]

2. Description of the Related Art Conventionally, in order to maintain airtightness between a plurality of members, a ring-shaped gasket is interposed between the members. For example, as shown in FIG. 6, when mounting the gas sensor 101 to the pipe 110, to a predetermined measurement position in the pipe 110, and fixing thereof is exposed detector section 104. Specifically, a cylindrical boss 111 is provided in a circular hole 110 a provided at a measurement position of the pipe 110.
Are screwed on the inner peripheral surface of the boss 111.
11a is formed. Then, the gas sensor 101 is fixed to the boss 111 (that is, to the pipe 110) by screwing a screw portion 103 provided below the metal shell 102 of the gas sensor 101 with the screw portion 111a. At this time, the upper surface of the boss 111 and the metal shell 102 are fixed.
A gasket 105 is interposed between the mounting surface (lower surface) 102a of the gasket. Figure 7 is, C section detailed sectional view of FIG. 6 is shown.

The gasket 105 is formed by folding a thin plate of stainless steel in a predetermined pattern so as to have elasticity in the thickness direction, and the entire body thereof is formed in a ring shape. For this reason, when the gas sensor 101 is screwed into the boss 111 during fixing to the pipe 110, the gasket 1
Due to the elasticity of 05, the sealing property between the gas sensor 101 and the pipe 110 is enhanced, and the exhaust gas flowing through the pipe 110 is effectively prevented from flowing out.

[0004]

However, such a gas sensor 101 is often used at a high temperature, and as shown by an arrow in FIG. 7, heat in the pipe 110 is connected to the metal shell 102 or the metal shell 102. The gas is transmitted to the upper layer of the gas sensor 101 via the outer cylinder and the like.

At this time, heat is naturally transmitted to the metal shell 102 via the detecting section 104 (dotted arrow in the figure), but from the pipe wall of the pipe 110 via the boss 111 and the gasket 105. The transmitted heat and the detecting unit 104
Heat also transmitted through the boss 111 and the gasket 105 (FIG arrow of solid line). Conventionally, since the gasket 105 is mainly composed of a metal material such as stainless steel, the heat transmitted to the boss 111 is transmitted to the metallic shell 102 almost as it is, causing a rise in the temperature of the gas sensor 101. When the heat transmitted at this time exceeds the heat resistant temperature of various components such as a filter and a rubber grommet in the gas sensor 101, there is a problem that the components are thermally deteriorated.

The present invention has been made in view of such a problem, and suppresses heat conduction between members used at a high temperature while maintaining a predetermined sealing property, thereby preventing thermal deterioration of one member. It is an object to provide a gasket that can be effectively prevented.

[0007]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, a gasket according to the present invention has a ring-shaped main body, and is interposed between these members in order to maintain airtightness between at least two members. The main body is mainly composed of a heat-insulating inorganic material.

As the "heat insulating material" here, as is well known, a material made of a porous material having a low thermal conductivity and having an air layer or a vacuum layer inside can be considered. Also,
The reason why the term “inorganic material” is used here is that an inorganic material is generally used as a heat insulating material at high temperatures.

More specifically, powder or particulate heat insulating material such as alumina powder, fibrous heat insulating material such as asbestos (asbestos), solid heat insulating material such as mica (mica), foam glass, glass fiber, alumina fiber, etc. A cotton-like heat insulating material or the like can be used, and it is conceivable to add a binder (adhesive) to these materials to form the main body.

As described above, by constituting the gasket mainly from a heat-insulating inorganic material, it is possible to effectively suppress the heat conduction through the gasket from one high-temperature member to the other member. For this reason, when the heat resistance of the other member is low, or when a member having low heat resistance is connected to the other member, thermal deterioration of these members having low heat resistance can be effectively prevented. . In the example of the gas sensor described above, it is possible to prevent thermal deterioration of the filter, the rubber grommet, and the like in the gas sensor, thereby extending their life.

The entire body of the gasket may be made of the above-mentioned heat-insulating inorganic material, but some of the inorganic material is easily peeled off due to frictional force due to its structure. For example,
When two members are screwed and fixed as in the case where a gasket is interposed between the gas sensor and the pipe, there is a possibility that the surface of the gasket may be peeled off due to frictional force at the time of screwing. When such peeling occurs, the sealing property due to the gasket decreases, it can not be fixed to the gas sensor collapsed shape of the gasket in a stable position (angle).

Therefore, it is preferable that at least a part of the contact surface of the gasket main body with the above members is covered with a metal material. According to this configuration, the contact surface of the gasket with the member is protected, and the gasket can sufficiently withstand the frictional force described above.

In this case, the metal coating may be performed by plating, but from the viewpoint of abrasion resistance, it is preferable to bond a metal member. Specifically, as described in claim 3, the main body is composed of a heat insulating ring made of the inorganic material and having a predetermined thickness, and two metal rings made of the metal material having a smaller thickness. ,
It is conceivable that the heat insulating ring is sandwiched between two metal rings.

[0014] Even if a metal ring is employed, a heat insulating ring is interposed between the two metal rings, so that heat conduction between the two metal rings can be suppressed. Further, the reason why the thickness of the heat insulating ring is set to be larger than the thickness of the metal ring is to make the above-described heat insulating effect (heat shielding effect) excellent. However, specific dimensions and the like of the thickness can be appropriately set depending on the use environment, use conditions, and the like of the gasket.

Further, when the above members are connected, the work and can be locked is facilitated gasket on one of the members. Therefore, as described in claim 4, at least one peripheral edge of the metal ring is formed with one or a plurality of protrusions that protrude more radially than the heat-insulating ring, and this protrusion is formed by each member. preferably lockably configured on at least one portion.

According to such a configuration, the operator can hold one member holding the gasket in one hand and support the other member with the other hand. Or you can do another task with the other hand. Therefore, workability is extremely improved.

[0017]

Preferred embodiments of the present invention will be described below with reference to the drawings. In this embodiment, the gasket of the present invention is configured as a seal member of a gas sensor for detecting a gas concentration at a high temperature. 1 (a) is a plan view of the gasket, Fig. (B) is a A-A cross-sectional view.

As shown in FIG. 1B, the gasket 1
Is composed of a heat insulating ring 11 and metal rings 12 and 13 bonded to the upper and lower surfaces thereof with an adhesive, respectively. Thermal insulation ring 11, the mica is a high heat-insulating inorganic material is obtained by forming the circular ring by the addition of binder, the internal diameter Di is 18 mm, an outer diameter Do 26m
m, the thickness t is formed in 1.5 mm.

The metal ring 12 is obtained by forming the thin plate-shaped stainless steel circular ring, an inner diameter and similarly outer diameter and insulation ring 11 respectively 18 mm, are formed in 26 mm, thickness t1 is 0.25mm Is formed. Also, on the inner peripheral edge of the metal ring 12, three projecting portions 12a projecting inward are arranged at equal intervals (that is, every θ = 120 °).
Is provided. This projection 12a has a radius of curvature of 5 m.
m from the inner peripheral edge.
It is formed so as to protrude 5 mm.

The metal ring 13 has substantially the same shape as the metal ring 12, are not provided corresponds to the protrusion 12a. The outer surfaces of the metal rings 12 and 13 are provided with molybdenum disulfide (MoS) for lubrication.
2) The coat is applied.

FIG. 2A shows a state where the gasket 1 is attached to the gas sensor 101. As shown in the figure, the gasket 1 is engaged with a screw portion 103 provided at a lower portion of the metal shell 102 and is locked near a mounting surface (lower surface) 102 a of the metal shell 102. In this figure, the upper and lower portions of the gasket 1 are reversed from those shown in FIG.

That is, as shown in FIG. 2 (b), which is a detailed sectional view of a portion B in FIG. 2 (a), the radius of the gasket 1 (that is, the radius of the heat insulating ring 11, the metal rings 12, 13) is , The radius rP of the screw thread position
It is larger than 1. On the other hand, the radius R of the position of the protruding portion 12a of the metal ring 12 (that is, the distance R from the center to the vertex of the protruding portion 12a: see FIG. 1A) is larger than the radius rP1 of the thread position of the screw portion 103. Although it is small, it is larger than the radius rP2 of the thread root position. Specifically, the dimension is R = (rP1 + rP2) / 2.

The thickness of the entire gasket (t + t1 +
t1: see Fig. 1 (b)) is smaller than the distance between the mounting surface 102a and the apex of the screw thread portion 103a which is closest thereto. Therefore, the protruding portion 12a is threaded section 10
3a, the gasket 1 is fixed to the metal shell 10
2 can be locked near its mounting surface 102a. Then, in this state, the gas sensor 101
When the gasket 1 is screwed into the boss 111, the gasket 1 elastically seals the space between the gas sensor 101 and the pipe 110 in an airtight manner.

As described above, since the gasket 1 is mainly composed of mica which is a heat-insulating inorganic material, as shown in FIG.
Heat transmitted from 1, pipe wall of pipe 110 or gas sensor 10
The heat (thick solid line arrow in the figure) transmitted from the first detection unit 104 via the boss 111 can be cut off or suppressed at the position of the gasket 1 (thin dotted arrow in the figure). For this reason, the heat transmitted upward through the metal shell 102 can be reduced as a whole, and the filter and the rubber grommet in the gas sensor 101 can be prevented from being thermally degraded, and their life can be extended.

Next, experimental results showing the heat shielding effect of the gasket 1 of the present invention will be described. The applicant of the present application has conducted a test for confirming the heat shielding effect of the gasket 1 of the present embodiment by comparison with a conventional stainless steel gasket 105. Specifically, as shown in FIG. 6, when the gasket 1 of the present embodiment or the conventional gasket 105 is installed in a separately prepared test pipe 110, and a predetermined exhaust gas flows through the pipe 110, It was performed by measuring the temperature rise of the gas sensor 101 units.

As shown in FIG. 6, the measurement location is the position Ti of the protector that covers the detection unit 104 of the gas sensor 101.
p, a position Hex near the upper surface of the mounting surface 102a of the metal shell 102, a filter position above the filter, and a rubber grommet position Grommet above the four positions.

The shape and the like of the gasket 1 are as described above, and the shape of the conventional gasket 105 used is similar to this. Also, the gas sensor 101
The heater voltage inside is fixed at 12 V, and the piping 110
The temperature of the exhaust gas in the furnace was adjusted with a target of 600 ° C.
The measurement was performed for 00 seconds.

FIG. 4 is a graph showing the temperature rise of each part of the gas sensor 101 at that time. The horizontal axis is the time from the start of the test represents the (s), the vertical axis represents the temperature (° C.). In the figure, a thick line indicates a gasket (mica gasket) of the present invention, and a thin line indicates a conventional gasket (metal gasket). Incidentally, the second stage from the top in the drawing indicates the ambient temperature inside the pipe 110.

Firstly, the uppermost curve in the figure shows a measurement result at the position Tip protector, the position pipe 11
The temperature is highest because it is directly exposed to zero.
In this case, since the position is below the gaskets 1 and 105, the gasket 1 or 10
5 rather than the thermal barrier effect due to the difference between the case of using the case with conventional gasket 105 using a gasket 1 of the present embodiment is not observed. The measurement at this protector position Tip
Dare was performed for comparison with other positions.

The second curve from the top in the drawing, which shows the measurement result at the position Hex the upper vicinity of the mounting face of the metal shell, it is the measured temperature is lower in the case of using the gasket 1 of the present embodiment, The temperature difference from the case where the conventional gasket 105 is used gradually increases after the start of measurement, and finally a temperature difference of about 20 ° C. occurs.

The third curve from the top in the figure shows the measurement results at the filter position Filter. In this case as well, the measurement temperature is lower when the gasket 1 of the present embodiment is used, and the conventional gasket is used. Between 10 and 105
There is a temperature difference of about 15 ° C. to 15 ° C.

The fourth curve from the top in the figure shows the measurement results at the position of the rubber grommet Grommet,
Also in this case, the measurement temperature is lower when the gasket 1 of the present embodiment is used, and a temperature difference of about 10 ° C. to 15 ° C. occurs with the case where the conventional gasket 105 is used.

From the above experimental results, it was found that according to the gasket 1 of this embodiment, a heat shielding effect of 10 ° C. to 20 ° C. was obtained as compared with the case where the conventional gasket 105 was used. It should be noted that this temperature difference, it can be said that quite large for the gas sensors precise measuring accuracy is requiring. In Modified Example described above, although the embodiment of the configuration of the gasket of the present invention, There are various configurations other than this.

For example, as shown in FIG. 5A, the protruding portion 12a of the metal ring 12 is also provided on the lower metal ring 213.
May be provided. With this configuration, the gasket 201 is
Can be stably screwed onto the screw portion 103 of the above.
However, in this case, the interval between the upper protruding portion 12a and the lower protruding portion 213a needs to be adapted to the shape of the screw portion 103. If the gap does not conform to the shape of the screw portion 103, when the gasket 201 is screwed, a force for separating the metal ring 12 or the metal ring 213 from the heat insulating ring 11 is applied, and the gasket 201 may be damaged. Because.

In this case, the positions of the protruding portions 12a and 213a do not need to be at positions facing each other in the vertical direction, and may be shifted in the circumferential direction. Further, as shown in FIG. (B), to form a metal ring 312 of gasket 301 to U-shaped cross section, it may be configured to accommodate the insulation ring 11 therein.

This configuration is not preferable from the viewpoint of heat conduction because it corresponds to the above-described mode in which the metal ring 12 and the metal ring 13 are connected. However, since the heat insulating ring 11 is provided at the center, the configuration is smaller than the conventional configuration. It is considered that a heat shielding effect can be obtained. Moreover, if treatment such a thickness of the metal thin to reduce the thermal conductivity, it is considered possible to improve the thermal barrier effect.

Further, as shown in FIG. 3C, the metal ring of the gasket 401 is connected to the inner ring 4 having a U-shaped cross section.
12 and an outer ring 413 also having a U-shaped cross section, and the heat insulating ring 11 may be sandwiched from inside and outside by these. In this case, since it is possible to block or suppress heat that is going to pass through at least the center of the heat insulating ring 11, it is considered that a certain heat blocking effect is obtained.

[0038] Having described embodiments of the present invention, the embodiment of the present invention is not to be limited to the above embodiments, but may be embodied in various forms within the technical scope of the present invention it is needless to say. For example, in the above-described embodiment, the configuration in which the protruding portion 12a is protruded horizontally with respect to the metal ring 12 has been described. May be.

With this configuration, the gasket 1
Insertion of threaded portion 103 is improved to. Conversely, it is possible to prevent the time of screwing the gasket 1 to the threaded portion 103, a working peeling force between the metal ring 12 or the metal ring 13 and the heat insulating ring 11.

Further, in the above embodiment, the gasket 1 of the present invention has been described as an example in which the gasket 101 is configured as a seal member when the gas sensor 101 is mounted on the pipe 110. It goes without saying that the present invention can be similarly applied as long as it aims at sealing between members used in the above.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a configuration of a gasket according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a state in which the gasket of the embodiment is mounted on a gas sensor.

FIG. 3 is an explanatory diagram illustrating a heat shielding effect of the gasket of the example.

FIG. 4 is a graph showing the results of an experiment performed to confirm the heat shielding effect of the gasket of the example.

FIG. 5 is an explanatory diagram illustrating a configuration of a gasket according to a modification.

FIG. 6 is an explanatory diagram showing a usage state of a conventional gasket.

7 is an explanatory view showing a problem of the conventional gasket.

[Explanation of symbols]

1, 201, 301, 401 ... gasket, 11
... Insulation rings, 12, 13, 213, 312 ...
Metal ring, 12a Projection, 101 Gas sensor, 102 Metal shell, 103 Screw, 110 Pipe, 111 Boss, 412
... the inner ring, 413 ... outer ring

Claims (4)

[The claims] 1. A has a ring-shaped body, to hold the airtightness between at least two members, a gasket is interposed between the member, the body, mainly the heat-insulating inorganic material A gasket comprising: 2. The gasket according to claim 1, wherein at least a part of a contact surface of said main body with said members is coated with a metal material. 3. The main body is formed by sandwiching a heat insulating ring made of the inorganic material and having a predetermined thickness by two metal rings made of the metal material having a smaller thickness. Item 2. The gasket according to Item 2. 4. At least one peripheral edge of the metal ring is provided with one or a plurality of protruding portions that protrude radially from the heat insulating ring, and the protruding portion is related to at least one portion of each of the members. The gasket according to claim 3, wherein the gasket is configured to be stoppable.