JP4745155B2 - Sensor mounting boss structure - Google Patents

Description

  The present invention relates to a sensor mounting boss structure for sensor mounting used to detect the state of exhaust gas in an exhaust system member of an automobile.

  Conventionally, various sensors for detecting the state of exhaust gas in an exhaust system member of an automobile, for example, a branch pipe of an exhaust manifold, a collective portion of an exhaust manifold, a downstream side of a catalytic converter, etc. are mounted (patents). Reference 1).

Such a sensor is fixed by inserting the sensing portion side into a sensor mounting boss portion that is fixed in a state of facing the mounting hole of the exhaust system member.
In addition, a plurality of types of sensor mounting bosses having different heights are manufactured so that the sensing part of the sensor is at the optimum position (center position of exhaust gas). Alternatively, the height around the mounting hole of the exhaust system member is changed.
JP 2003-83061 A

However, in the conventional invention, a plurality of types of sensor mounting bosses having different heights must be manufactured, leading to an increase in cost.
In addition, changing the height around the exhaust system member mounting hole tends to adversely affect the flow of exhaust gas. As a result, the height of the sensor mounting boss must be changed. It was.
In addition, if the length of the sensing part of the sensor is changed, the cost is most increased.

  Furthermore, in the conventional invention, the sensor mounting boss cannot be adjusted and fixed to the exhaust system member at a desired angle, and consequently, the sensing unit insertion angle is adjusted as desired. There was a problem that it was not possible.

  The present invention has been made to solve the above-described problems, and the object of the present invention is to change the height of the sensor mounting boss with respect to the exhaust system member without incurring costs, and at the same time, for sensor mounting. It is an object of the present invention to provide a sensor mounting boss structure that can be adjusted and fixed to a desired angle with respect to an exhaust system member.

In the substantially cylindrical sensor mounting boss structure that is fixed to the exhaust system member in a state of facing the mounting hole of the exhaust system member, and the sensing unit side of the sensor is inserted and fixed,
A taper portion having a linear taper is formed on the outer periphery of the sensor mounting boss portion so as to decrease in diameter toward the exhaust system member side, and this taper portion is inserted into and contacted with the exhaust system member mounting hole. As a state, the outer periphery of the sensor mounting boss and the corner of the exhaust system member are fixed by welding.

  In the first aspect of the present invention, the substantially cylindrical sensor is fixed to the exhaust system member in a state of facing the mounting hole of the exhaust system member, and the sensing portion side of the sensor is inserted and fixed. In the mounting boss structure, a reduced diameter portion is formed on the outer periphery of the sensor mounting boss portion so that the diameter decreases toward the exhaust system member, and the reduced diameter portion is inserted into the exhaust system member mounting hole. Since the outer periphery of the sensor mounting boss and the corner of the exhaust system member are fixed by welding as being in contact with each other, the height of the sensor mounting boss with respect to the exhaust system member can be changed at the same time without incurring costs. The sensor mounting boss can be adjusted and fixed to a desired angle with respect to the exhaust system member.

  Embodiments of the present invention will be described below with reference to the drawings.

Example 1 will be described below.
In the first embodiment, a case where the exhaust system member is applied to an exhaust manifold assembly and the sensor is applied to an oxygen sensor will be described.
FIG. 1 is a plan view showing an exhaust manifold adopting the sensor mounting boss structure according to the first embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line S2-S2 of FIG. 1, and FIG. FIG. 3 is an exploded view (partially sectional view) for explaining the part, the sensor mounting boss part, and the oxygen sensor.

  4 is a top view of the sensor mounting boss portion according to the first embodiment, FIG. 5 is a bottom view thereof, FIG. 6 is a cross-sectional view taken along the line S6-S6 of FIG. 4, and FIG. FIG. 8 is a diagram for explaining the fixing of the mounting boss, FIG. 8 is a diagram for explaining the fixing of the sensor mounting boss and the oxygen sensor of the first embodiment, and FIG. 9 is a gathering of the sensor mounting boss of the first embodiment. It is a figure explaining the case where it provided in the state inclined with respect to.

First, the overall configuration will be described.
As shown in FIG. 1, in the sensor mounting boss structure of the first embodiment, a head flange 1 fixed to an engine (not shown) and four connected to each cylinder of the engine via the head flange 1 are shown. Branch pipes 2 to 5, a cylindrical gathering portion 6, a catalytic converter 8 containing a catalyst carrier 7 therein, a sensor mounting boss portion 9, and an oxygen sensor 10.

  As shown in FIG. 2, the exhaust gas downstream ends 2a to 5a of the branch pipes 2 to 5 are processed into a substantially quarter circular cross section, and the side walls 2b to 5b of the branch pipes 2 to 5 are overlapped with each other. In addition, they are housed in the exhaust gas upstream end 6a of the gathering portion 6 in a state of being gathered in a circular shape.

An oxygen sensor 10 is attached to the assembly portion 6 via a sensor mounting boss portion 9 described later.
As shown in FIG. 3, the oxygen sensor 10 is used for feedback control of the air-fuel ratio of the engine by detecting the oxygen concentration contained in the exhaust gas. In addition to the electrically connected wiring 10a, a hexagonal columnar flange portion 10b is provided in the middle portion, and a sensing portion 10d in which a plurality of pores 10c are formed is formed in the lower portion.
Further, a male screw groove 10e is formed at a position close to the flange portion 10b of the sensing portion 10d.

As shown in FIGS. 3 to 6, the sensor mounting boss portion 9 is formed in a substantially cylindrical shape, and a female screw groove 9 a that can be screwed into the male screw groove 15 of the oxygen sensor is formed on the inner periphery thereof. In the outer periphery, a reduced diameter portion 9b having a diameter reduced in a taper shape toward the lower end is formed.
In the first embodiment, the reduced diameter portion 9b is formed on a part of the outer periphery of the sensor mounting boss portion 9, but the reduced diameter portion may be formed by reducing the diameter of the entire outer periphery toward the lower end. good.

  A circular mounting hole 6c is formed in the seating surface 6b of the collective portion 6 to which the sensor mounting boss portion 9 is fixed. The size is larger than the minimum diameter D2 (see FIG. 6) of the portion 9b and smaller than the maximum diameter D3 (see FIG. 6).

  In addition, all the structural members described above are made of metal. The catalyst carrier 7 may be a ceramic catalyst carrier.

Next, the operation will be described.
When the thus configured oxygen sensor 10 is attached to the assembly portion 6 via the sensor attachment boss portion 9, first, as shown in FIG. 7, the reduced diameter portion 9b of the sensor attachment boss portion 9 is provided. As a state of being inserted into the mounting hole 6c of the seat surface 6b and brought into contact therewith, the outer periphery of the sensor mounting boss portion 9 (a part of the reduced diameter portion 9b) and the corner portion of the seat surface 6b extend over the entire periphery. Fix with welding X1.

  At this time, since the height of the sensor mounting boss portion 9 with respect to the assembly portion 6 is determined by the diameter D1 of the mounting hole 6c, one type of sensor mounting boss portion 9 is manufactured, and the mounting hole 6c of each product is manufactured. By forming the diameter D1 in the range of the minimum diameter D1 to the maximum diameter D2 of the reduced diameter portion 9b, the height of the sensor mounting boss portion 9 with respect to the seat surface 6b can be easily changed without cost.

  Next, as shown in FIG. 8, after the seal member S (see FIG. 3) is installed on the upper surface 9 c of the sensor mounting boss 9, or when the seal member S is temporarily assembled to the oxygen sensor 10. In this state, the sensor 10d of the oxygen sensor 10 is inserted into the assembly 6 through the female thread 9a and the mounting hole 6c of the assembly 6, and the male screw 10e of the oxygen sensor 10 is inserted into the sensor mounting boss. The oxygen sensor 10 is mounted in a state where the tip of the sensing unit 10d is disposed at the center position O of the collecting unit 6 by screwing into the female screw groove 9a of the unit 9.

  Therefore, as described above, since the height of the sensor mounting boss 9 with respect to the seating surface 6b can be easily changed without incurring costs, the sensing unit 10d of the oxygen sensor 10 can be easily positioned at the optimum position (of the collecting unit 6). The oxygen sensor 10 can be placed at the center position O), thereby enabling highly accurate sensing of the oxygen sensor 10.

  Further, as shown in FIG. 9, the diameter-reduced portion 9 b is tapered in a tapered shape toward the lower end, so that the sensor mounting boss portion 9 can be easily adjusted to a desired angle α with respect to the assembly portion 6. Thus, the sensing unit 10d can be arranged at a desired position.

Next, the effect will be described.
As described above, in the sensor mounting boss structure according to the first embodiment, the sensor is fixed to the assembly portion 6 while facing the mounting hole 6c of the assembly portion 6, and the sensing of the oxygen sensor 10 is performed. In the substantially cylindrical sensor mounting boss structure in which the portion 10d side is inserted and fixed, a reduced diameter portion 9b whose diameter decreases toward the assembly portion 6 side is formed on the outer periphery of the sensor mounting boss portion 9, and Since the diameter portion 9b is inserted into the mounting hole 6c of the collecting portion 6 and brought into contact with the mounting portion 6, the outer periphery of the sensor mounting boss portion 9 and the corner portion of the collecting portion 6 are fixed by welding X1, which increases costs. In addition, the height of the sensor mounting boss 9 relative to the collective portion 6 can be changed, and at the same time, the sensor mounting boss 9 can be adjusted and fixed to the collective portion 6 at a desired angle α.

Although the present embodiment has been described above, the present invention is not limited to the above-described embodiment, and design changes and the like within a scope not departing from the gist of the present invention are included in the present invention.
For example, the type of sensor and the exhaust system member can be set as appropriate.
In the present embodiment, the oxygen sensor 10 is screwed to the sensor mounting boss portion 9, but the fixing method can be set as appropriate.

Furthermore, as shown in FIGS. 10 to 12, a sensor mounting boss portion 21 in which the diameter reducing portion 20 is reduced in an arc shape may be employed.
In this case, the sensor mounting boss portion 21 (oxygen sensor 10) can be fixed to the assembly portion 6 at a wider range of angles than in the first embodiment.

It is a top view which shows the exhaust manifold by which the boss | hub part structure for sensor attachment of Example 1 of this invention was employ | adopted. It is sectional drawing in the S2-S2 line | wire of FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded view (partially cross-sectional view) for explaining an assembly portion, a sensor mounting boss portion, and an oxygen sensor according to Embodiment 1; It is a top view of the boss | hub part for sensor attachment of the present Example 1. FIG. It is a bottom view of the boss part for sensor attachment of Example 1. It is sectional drawing in the S6-S6 line of FIG. It is a figure explaining fixation of the gathering part of this Example 1, and the boss | hub part for sensor attachment. It is a figure explaining fixation of the boss | hub part for sensor attachment of this Example 1, and an oxygen sensor. It is a figure explaining the case where the sensor attachment boss | hub part of the present Example 1 is provided in the state inclined with respect to the gathering part. It is a top view of the boss part for sensor attachment of other examples. It is a bottom view of the boss part for sensor attachment of other examples. It is sectional drawing in the S12-S12 line | wire of FIG.

Explanation of symbols

S Seal member X1 Welding 1 Head flange 2, 3, 4, 5 Branch pipes 2a, 3a, 4a, 5a Exhaust gas downstream end 6 Collecting portion 6a Exhaust gas upstream end 6b Seat surface 6c Mounting hole 7 Catalyst carrier 8 Catalytic converter 9 Sensor mounting boss 9a Female screw groove 9b Reduced diameter portion 9c Upper surface 10 Oxygen sensor 10
10a Wiring 10b Flange part 10c Small hole 10d Sensing part 10e Male screw groove

Claims (1)

In the substantially cylindrical sensor mounting boss structure that is fixed to the exhaust system member in a state of facing the mounting hole of the exhaust system member, and the sensing unit side of the sensor is inserted and fixed,
A taper portion having a linear taper is formed on the outer periphery of the sensor mounting boss portion so as to decrease in diameter toward the exhaust system member side, and this taper portion is inserted into and contacted with the exhaust system member mounting hole. A sensor mounting boss structure characterized in that, as a state, the outer periphery of the sensor mounting boss and the corner of the exhaust system member are fixed by welding.

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