JP2720087B2 - Acceleration sensor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acceleration sensor for detecting the acceleration of a vehicle body during skid control of an automobile or the like.

[Conventional technology]

Conventionally, as such an acceleration sensor, an acceleration sensor using a mercury switch is often used, and is configured as shown in, for example, FIGS. 4 (A) and 4 (B).

That is, the acceleration sensor 1 has a case 2 whose lower surface is fixed to the body of an automobile, and an upper surface inside the case 2 which are opposite to each other with respect to the direction in which acceleration is to be detected (for example, the longitudinal direction of the automobile). The mounting bases 2a and 2b are provided so as to be inclined, and the mercury switches 3 and 4 provided on the mounting bases 2a and 2b, respectively.

The lead wires 3a, 4a of the mercury switches 3, 4 are connected by soldering to the terminal portions 5, 6 provided on the mounting bases 2a, 2b, and signals from the mercury switches 3, 4 are externally provided. A lead wire of a harness (not shown) for taking out is also connected to the terminal portions 5 and 6 by soldering.

Finally, the acceleration sensor 1 is completed by filling the inside of the case 2 with a resin and performing resin molding.

The acceleration sensor 1 configured as described above is mounted on a vehicle body or the like so that the mercury switch is normally closed. When acceleration occurs in the direction indicated by the arrow, the acceleration causes the inside of the mercury switches 3 and 4 to change. Mercury enclosed in moves
When the acceleration reaches a certain level, the mercury separates from the contact portion.

As a result, since the two electrodes of the contact portion become non-conductive, the off of the contact portion is taken out through the lead wires 3a and 4a, and is processed by an appropriate electric circuit or the like. Of the vehicle in the forward or reverse direction is detected.

[Problems to be solved by the invention]

However, the acceleration sensor 1 thus configured
In the above case, since the case 2 is formed of resin, the mounting surface thereof may be deformed such as a warp during molding, and may not be formed as an accurate flat surface.

In such a case, the mounting surface does not sufficiently adhere to the mounting reference surface of the body of the automobile or the like, and rattling occurs.

Therefore, there is a problem that the mounting surface of the acceleration sensor is easily fixed with an undesired inclination with respect to the mounting reference surface, so that accurate acceleration cannot be detected.

In view of the above, it is an object of the present invention to mount and fix a case accommodating a mercury switch on a mounting reference surface of a vehicle body or the like with necessary and sufficient accuracy, and to perform accurate acceleration detection. It is an object of the present invention to provide an acceleration sensor capable of performing the following.

[Means for Solving the Problems] According to the present invention, the object is to provide a resin case having a mounting surface to be fixed to a vehicle body or the like of an automobile, and a heat welding or the like to a bottom surface inside the inner case. A resin mounting plate to be mounted, at least one mounting base formed on the surface of the mounting plate so as to be inclined with respect to a direction in which acceleration is to be detected, and a terminal unit integrally provided on the mounting plate, A mercury switch mounted on the inclined surface of the mounting base and having its lead wire soldered to the terminal portion, wherein the case is formed on the surface of the mounting surface when forming the case. At a location that is difficult to deform, it is provided with at least three projections of uniform height protruding downward, first after mounting a mercury switch on a mounting base of the mounting plate, mounting the mounting plate in a case. ,this This is achieved by filling the inside of the case with resin and performing resin molding.

Furthermore, according to the present invention, a resin case having a mounting surface to be fixed to a vehicle body or the like of an automobile, and at least one mounting base formed inside the case so as to be inclined with respect to a direction in which acceleration is to be detected. And a terminal unit provided integrally with the mounting plate, and a mercury switch mounted on the inclined surface of the mounting base and having its lead wire soldered to the terminal unit, On the surface of the mounting surface of the case, at a place where it is difficult to deform during molding of this case, there are provided at least three projections of uniform height protruding downward, and the mercury switch was first mounted on the mounting base. This is achieved later by filling the case with resin and performing resin molding.

(Operation)

According to the above configuration, at least three projections having a uniform height are provided at locations where the mounting surface of the case is not easily deformed during molding. The mounting surface of the case is brought into contact with the mounting reference surface of the vehicle body or the like, and a proper weight is applied to the case with respect to the mounting reference surface, so that the projection provided on the surface of the mounting surface is mounted on the mounting reference surface. When the case is contacted, even if the case is slightly deformed at the time of molding, since each projection provided on the mounting surface comes into contact with the mounting reference surface, the case can be mounted without rattling. The plane may be aligned with the mounting reference plane. In addition,
For example, the protrusion may be formed as a double protrusion provided with a smaller diameter protrusion at the tip of the protrusion.

By fixing the case to the vehicle body or the like by screwing or the like in this state, the case is accurately mounted at a desired mounting position, and accurate acceleration can be detected.

Furthermore, if the mercury switch is mounted on a mounting plate fixed to the bottom inside the case, before mounting the mounting plate on the bottom inside the case, place it on the mounting base formed on this mounting plate. The mercury switch is placed, and the lead wires of this mercury switch are soldered to the terminals of the mounting plate, and then the mounting plate is mounted in the case. In addition, it is possible to solder the lead wire of the mercury switch to the terminal portion in a wide place, and it is also possible to solder a harness for taking out the signal of the mercury switch to the outside to the terminal portion.

Moreover, with the mounting plate removed from the case,
Since it is possible to perform an operation test of an electrical connection state, assembly work can be performed easily and quickly,
Furthermore, even if a connection failure is found, the re-soldering operation can be performed relatively easily, so that the workability of assembly can be improved.

〔Example〕

Hereinafter, an embodiment of the acceleration sensor according to the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, the resin case 11 of the acceleration sensor 10 of the present invention is formed of a rectangular box with an open top.

On both sides of the case 11, overhang mounting portions 11e extending in the longitudinal direction are integrally formed. This overhang mounting part 1
1e is provided with a mounting hole 11a for fixing it to a vehicle body or the like by screwing or the like.

The screwing into the mounting hole 11a is performed by the mounting surface 11b of the case 11.
Is performed on the basis of

A resin mounting plate 12 formed in a flat plate shape is mounted on a bottom surface inside the case 11.

The mounting plate 12 has at least one, and in the illustrated case, three mounting bases 13a, 13b,
13c is formed. The mounts 13a, 13b, 13c are formed to be inclined at an appropriate angle with respect to the direction in which the acceleration indicated by the arrow in the drawing is to be detected. Each mounting base 13a, 13b, 13c
Mercury switches 15a, 15b, and 15c are mounted on the top, respectively.

The mounting plate 12 is integrally provided with a terminal portion 14 by, for example, insert molding. The lead wires of the mercury switches 15a, 15b, 15c are connected to the terminal portions 14 by soldering.

Further, the terminal unit 14 has the mercury switches 15a, 15b,
A harness (not shown) for taking out the signal of 15c to the outside is soldered.

Thus, the mounting base 13a formed on the mounting plate 12,
Mercury switches 15a, 15b, 15c are mounted on 13b, 13c, respectively, and the lead wires of the mercury switches 15a, 15b, 15c are soldered to the terminal portions 14 of the mounting plate.
Attach 12 to the bottom inside the case 11.

Then, a cover 16 is attached to the open upper edge of the case, and the interior space of the case 11 is filled with a resin and molded with a resin.

The mounting of the mounting plate 12 to the bottom inside the case 11 is as follows.
Two bosses 11c protruding from the bottom of the case 11 (third
(See FIG. 2), a mounting hole 12a (see FIG. 2A) provided in the mounting plate 12 is fitted, and the lower surface of the mounting plate 12 is brought into contact with the bottom surface of the case 11; The upper end of the boss 11c is thermally caulked by heat welding or the like.

Further, the lower surface of the mounting plate 12 is provided with at least three projections 12b having four uniform heights in the drawing, projecting downward. By the projections 12b, the mounting plate 12 is fixed and held while slightly rising from the bottom surface inside the case 11, so that vibrations and the like from the case 11 are not directly transmitted to the mercury switches 15a, 15b, 15c. It has become.

The mounting plate 12 has a plurality of through holes for venting air.
An opening 12c is provided so that when the inside of the case 11 is resin-molded, air is not trapped below the mounting plate 12.

Also, mercury switches 15a, 15b, formed on the mounting plate 12
As shown in FIG. 2 (B), the mounts 13a, 13b, 13c for mounting the 15c are each divided in the acceleration detection direction and have extended portions extending upward from both sides. I have. The mercury switches 15a, 15b, 15c are loosely held by the extended portions, so that their movement is prevented. Thereby, as shown in FIG.
The mercury switches 15a, 15b, 15c mounted on the b, 13c are surrounded by the resin mold over the entire circumference in the area of the slit portion between the divided mounts 13a, 13b, 13c. Will be done. Therefore, the mercury switch is 15
Since most of the surfaces of the a, 15b, and 15c are surrounded by the resin mold, the stress acting on the surfaces of the mercury switches 15a, 15b, and 15c from the resin mold is substantially uniform over the entire surface. And this mercury switch 15a, 15b, 15
There is no crack in c.

Further, as shown in FIG. 2 (C), the terminal portion 14 integrally provided on the mounting plate 12 by insert molding is
Each of the mercury switches 15a, 15b, and 15c has a slit 14a that is deeply cut downward at a portion where the lead wire is soldered.

This slit 14a is provided on each of the mounting bases 13a, 13b, 13c of the mounting plate 12.
The lead wires of the mercury switches 15a, 15b, and 15c placed on the upper surfaces are respectively received and temporarily fixed at the time of soldering. As a result of the operation test in the temporarily fixed state, if it is necessary to adjust the inclination angles of the mercury switches 15a, 15b, and 15c, the lead wires are shifted up and down in the direction of the arrows in the slits 14a, thereby adjusting Mercury switch
The inclination angles of 15a, 15b and 15c can be adjusted (see FIG. 2 (C)).

Furthermore, as best shown in FIG. 3 (C), at least three projecting parts are provided on the surface of the mounting surface 11b of the case 11 at locations where the case 11 is not easily deformed during molding. It has three protrusions 11d. By forming these projections 11d, the case 1
Even if 1 is slightly deformed, the entire case 11 is relatively accurately positioned and fixed to the mounting reference plane 17 such as the body of the automobile.

The acceleration sensor 10 according to the present invention is configured as described above. When assembling, first, each of the mounting bases 13a, 13a of the mounting plate 12 is used.
Mercury switches 15a, 15b, and 15c are mounted on b and 13c, respectively.

Next, the lead wires of the mercury switches 15a, 15b, 15c are inserted into the corresponding slits 14a of the terminal portion 14 and temporarily fixed.

Also, the lead wires of a harness (not shown) for taking out the signals of the mercury switches 15a, 15b, 15c to the outside are inserted into the corresponding slits 14a of the terminal portion 14, and each lead wire is soldered. I do.

In this state, an operation test of each of the mercury switches 15a, 15b, and 15c is performed. If there is an error in the detection result, soldering of the terminal portion 14 of each of the mercury switches 15a, 15b, and 15c to the slit 14a is performed. Is removed, the lead wire is moved up and down in the slit 14a, soldering is performed again at a desired inclination angle, and the inclination angle of the mercury switch is adjusted.

Thereafter, the mounting plate 12 is brought into contact with the bottom surface inside the case 11 by fitting the mounting hole 12a into the boss 11c, and the boss 11c is thermally caulked by heat welding or the like, whereby the mounting is performed. The plate 12 is fixed to the bottom of the case 11.

Finally, a cover 16 is attached to the open upper edge of the case 11, and the interior space of the case 11 is filled with resin. At this time, since the plurality of through-holes 12c are opened in the mounting plate 12, the resin surely flows into a small space below the mounting plate 12, so that air pockets are not generated. Absent. Thus, the acceleration sensor 10
Is completed.

As shown in FIG. 2 (D), the acceleration sensor 10 manufactured as described above places an appropriate weight on the case 11 with its mounting surface 11b facing a mounting reference surface 17 such as an automobile body. Three uniform height projections 1 provided on the mounting surface 11b
By ensuring that 1d abuts against the mounting reference plane, accurate positioning can be achieved. Where the protrusion
When 11d is a double projection, even if pressure is applied too much, the first-stage projection is simply crushed, and accurate and strong positioning with respect to the mounting reference plane can be performed.

The mounting hole 11 of the case 11 is
By screwing “a”, it becomes possible to mount the “a” on a vehicle body or the like.

External force such as vibration applied to the acceleration sensor 10 from the outside of the vehicle body or the like is directly applied when the mounting plate 12 is lifted from the bottom surface inside the case 11 by the protrusion 12b provided on the lower surface thereof. Mercury switches 15a, 15b, 15c
, The acceleration can be detected more accurately.

Further, the above-described embodiment includes the mounting bases 13a, 13b, and 13c.
Is a mounting plate to be mounted on the bottom inside the case 11.
Although formed on the surface of 12, the present invention is not limited to this, and it is apparent that the present invention is also applicable to the case where the mounting bases 13a, 13b, and 13c are formed directly on the bottom surface of the conventional case, for example. .

〔The invention's effect〕

As described above, according to the acceleration sensor of the present invention,
By simple means of providing several projections on the mounting surface and the mounting plate, the case accommodating the mercury switch can be accurately aligned without undesired inclination with respect to the mounting reference surface of the car body etc. At the same time, transmission of external force such as vibration is reduced, and an excellent effect that accurate acceleration can be detected is exhibited.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an embodiment of the acceleration sensor according to the present invention, FIG. 2 shows a mounting plate in the embodiment of FIG. 1, (A) is a bottom view, and (B) is a side view. , (C)
3 is a perspective view showing a mounted state of a mercury switch, (D) is a schematic side view showing a mounted state of a case, FIG. 3 shows a case in the embodiment of FIG. 1, (A) is a plan view thereof.
(B) is a side view, and (C) is a bottom view. FIG. 4 shows an example of a conventional acceleration sensor.
(A) is an exploded perspective view, and (B) is a sectional view. 10 …… Acceleration sensor; 11 …… Case; 11d …… Protrusion; 12 ……
Mounting plate; 12b Projection; 13a, 13b, 13c Mounting base; 14 Terminal section; 15a, 15b, 15c Mercury switch; 16 Cover.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Mitsuhisa Tamaki 33, Ginkgo, Imajuku, Kawasaki-cho, Shibata-gun, Miyagi Japan Inside the Aleph Sendai Plant in Japan (56) References Real Opening 57-77953 (JP, U) Japanese Utility Model 1-120666 (JP, U) Japanese Utility Model 1-180772 (JP, U) Japanese public utility model 38-19024 (JP, Y1)

Claims (3)

(57) [Claims] 1. A case having a mounting surface fixed to a mounting reference surface of a vehicle or the like, and at least one mounting base formed inside the case so as to be inclined with respect to a direction in which acceleration is to be detected. An accelerometer having a terminal unit integrally provided on the mounting base and a mercury switch mounted on an inclined surface of the mounting base and having a lead wire soldered to the terminal unit; An acceleration sensor, characterized in that at least three projections having a uniform height protruding toward the mounting reference surface are formed at locations on the mounting surface that are not easily deformed during molding. 2. A case having a mounting surface fixed to a mounting reference surface of a vehicle or the like, and at least one mounting base formed inside the case so as to be inclined with respect to a direction in which acceleration is to be detected. An accelerometer having a terminal unit integrally provided on the mounting base and a mercury switch mounted on an inclined surface of the mounting base and having a lead wire soldered to the terminal unit; At the bottom of the inside, a mounting plate is attached separately from this, and the mounting base and the terminal portion are provided on the mounting plate, and at a location on the mounting surface of the case that is not easily deformed during molding, An acceleration sensor, wherein at least three protrusions having a uniform height protruding toward the mounting reference surface are formed. 3. The acceleration sensor according to claim 1, wherein at least three protrusions having a uniform height protruding toward the mounting reference surface are double protrusions.