JPH089864Y2 - Acceleration sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an acceleration sensor, and more particularly 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, for example, an acceleration sensor using a mercury switch is often used. This type of acceleration sensor is configured, for example, as shown in FIGS. 4 (A) and 4 (B).

That is, the acceleration sensor 1 includes a case 2 whose lower surface is fixed to a vehicle body of an automobile, and an inside of the case 2 so as to be inclined in directions opposite to each other with respect to a direction in which acceleration is to be detected (for example, a front-back direction of the automobile). And two mercury switches 3 and 4 disposed on the mounting bases 2a and 2b provided on the upper surface of the.

The lead wires 3a and 4a of this mercury switch 3 and 4 are
It is connected by soldering to terminal portions 5 and 6 integrally provided in 2a and 2b.

In addition, lead wires of a harness (not shown) for extracting signals from the mercury switches 3 and 4 to the outside are also connected to the terminal portions 5 and 6 by soldering.

Finally, the acceleration sensor 1 is completed by resin-filling the case 2 with resin.

Such an acceleration sensor 1 is attached to a vehicle body or the like so that the mercury switch is normally closed. When acceleration occurs in the direction shown by the arrow in FIG. The mercury enclosed in 3, 4 moves, and when the acceleration reaches a certain level, the mercury separates from the contact part. Then, since the two electrodes of the contact portion become non-conductive, the off state is taken out to the outside through the lead wires 3a and 4a and processed by an appropriate electric circuit or the like, or the forward direction of the automobile or the like. The acceleration in the reverse direction is detected.

[Problems to be solved by the device]

However, in the acceleration sensor 1 as described above, as shown in FIG. 5, the mercury switches 3 and 4 are closely attached to the inclined mounts 2a and 2b, respectively. The lower side of 4 is surrounded by the mounts 2a and 2b, and the parts other than the mounts 2a and 2b are surrounded by the resin mold.

Therefore, at low temperature, for example, at −35 ° C. or lower (−50 ° C. in environmental test), there is a difference between the stress from the resin applied to the mercury switches 3 and 4 and the stress from the mounting bases 2a and 2b that are molded products. Therefore, stress strain occurs, and the mercury switch
There was a problem that cracks C were likely to occur in 3 and 4.

After assembling, the case 2 is filled with resin. For that purpose, it is desirable to form a side wall as a weir around the case 2.

However, the lead wires of the mercury switches 3 and 4 and the harness are
Terminals provided near the bottom inside the case 2
Since they are connected to 5 and 6 by soldering, there is a problem that if the side wall is formed, its assembling is complicated, the workability is poor, and the assembling takes time.

Furthermore, if a defect is found in the operation test after assembly, the soldering has to be removed again, and the workability is also poor.

Further, since the mercury switches 3 and 4 are directly attached to the case 2 fixed to the body of the automobile, etc., the mercury switches 3 and 4 are susceptible to vibrations from the outside, and accurate acceleration cannot be detected. was there.

In view of the above points, the present invention provides an acceleration sensor that prevents cracks from occurring in a mercury switch particularly at low temperatures, and that enables easy and quick assembly and can detect accurate acceleration. It is intended to be provided.

[Means for solving the problem]

According to the acceleration sensor of the present invention, the above object is to provide an acceleration sensor that accurately fixes a case housing a mercury switch at a predetermined location such as a vehicle to detect acceleration. The formed mounting plate is attached, and at least one mounting base having an inclined surface inclined with respect to the direction in which acceleration is to be detected is integrally formed on the surface of the mounting plate. , Dividedly formed via a gap so as to be separated in the inclination direction, and the mercury switch is loosely clamped by a columnar extended portion extending upward from the side portion of the divided inclined surface, and further, the mounting plate This is accomplished by providing a terminal portion integrally with the mounting base, mounting the mercury switch on the inclined surface of the mounting base, and soldering the lead wire to the terminal portion.

Further, in an acceleration sensor that accurately fixes a case containing a mercury switch to a predetermined location such as a vehicle to detect acceleration, a bottom surface inside the case has an inclined surface inclined with respect to a direction in which acceleration should be detected. The at least one mounting base having the mounting base is integrally formed, and the inclined surface of the mounting base is divided and formed via a space so as to be separated in the inclination direction, and upward from the side of the divided inclined surface. The mercury switch is loosely held by the extended columnar extension, and a terminal portion is provided on the inner bottom surface of the case, and the mercury switch is placed on the inclined surface of the mounting base and the lead wire is attached to the terminal. This is accomplished by soldering the part to the structure.

[Action]

According to the above configuration, since the inclined surface of the mount on which the mercury switch is to be mounted is divided by the void so as to be separated in the tilt direction, the entire area of the mercury switch is covered by the void. The mercury switch is surrounded by the resin mold, and most of the surface of the mercury switch is surrounded by the resin mold.

Therefore, even when stress acts on the surface of the mercury switch due to contraction of the resin mold, especially at low temperature, the stress is substantially uniform over the entire surface of the mercury switch.

Therefore, the mercury switch is not cracked at all.

If the mercury switch is mounted on the mounting plate that should be fixed inside the case, mount the mercury switch on the mounting base formed on the mounting plate before mounting the mounting plate inside the case. Then, after the lead wire of the mercury switch is soldered to the terminal portion of the mounting plate, the mounting plate is mounted in the case. Therefore, the lead wire of the mercury switch can be soldered to the terminal portion not in the narrow space inside the case but in a wide space. Further, under the same condition, a harness for taking out the signal of the mercury switch to the outside can be soldered to the terminal portion.

Moreover, since the operation test such as the electrical connection state can be performed with the mounting plate removed from the case, the assembling work can be performed easily and quickly.

Furthermore, even if a poor connection is found, the re-soldering work can be performed relatively easily.
The workability of assembly can be improved.

〔Example〕

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

As shown in FIG. 1, the acceleration sensor 10 of the present invention has a case 11 made of resin, and both sides of the case 11 in the longitudinal direction are integrally formed with protruding portions 11e. Debu 1
A mounting hole 11a is opened in 1e.

The case 11 is formed of a rectangular box and its mounting surface
11b is fixed by screwing the mounting hole 11a of the overhanging portion 11e to the vehicle body of an automobile or the like. Inside the case 11, a resin-made mounting plate 12 formed into a flat plate on the bottom surface is mounted.

At least one mounting plate 12 is formed to support the mercury switch at an appropriate angle with respect to the direction in which acceleration is to be detected, which is indicated by the arrow in the drawing, and three mounting members are provided in the illustrated case. The bases 13a, 13b, 13c are integrally formed.

Further, the mounting plate 12 is integrally provided with a metal terminal portion 14 such as nickel-plated by insert molding, and the mercury switch 15a is provided on each of the mounting bases 13a, 13b and 13c. , 15b, 15c are mounted respectively.
The lead wires of this mercury switch 15a, 15b, 15c are
Soldered to 4 respectively.

Further, lead wires of a harness (not shown) for taking out signals of the mercury switches 15a to 15c to the outside are also soldered and connected to the terminal portion 14.

In this assembled state, the mounting plate 12 formed separately from the case 11 is attached to an appropriate position in the case 11, for example, the bottom surface, and the cover 16 is attached to the opening edge of the case. Then, the remaining space inside the case 11 is filled with resin and resin-molded.

When mounting the mounting plate 12 to the bottom of the case 11,
Mounting holes provided in the mounting plate 12 as shown in FIG. 2 (A)
12a is fitted to two bosses 11c projecting upward from the bottom surface of the case 11 shown in FIGS. 3 (A) and 3 (B), and the lower surface of the mounting plate 12 is brought into contact with the bottom surface of the case 11. In this state, the upper end of the boss 11c is heat crimped by heat welding or the like.

Further, as shown in FIGS. 2 (A) and 2 (B), on the lower surface of the mounting plate 12, at least three parts projecting downward are provided.
One, in the illustrated case, four protrusions 12b are provided. As a result, the mounting plate 12 is fixedly held in a state of slightly floating with respect to the inner bottom surface of the case 11, so that vibrations and the like from the case 11 are not directly transmitted to the mercury switches 15a to 15c.

Furthermore, the mounting plate 12 has a plurality of through holes 12c for venting air. Therefore, no air pocket is formed below the mounting plate 12 during resin molding.

Further, the mounting bases 13a, 13b, 13c of the mounting plate 12 are formed separately in the inclination direction as shown in FIGS. 1 and 2 (B), and the mounting bases 13a, 13b, 13c are It has a columnar extended portion extending upward from both sides of the inclined surface, and these extended portions loosely clamp the mercury switches 15a, 15b, 15c and prevent their movement.

Thus, as shown in FIG.
Mercury switches 15a, 15b, 15c mounted on a, 13b, 13c are
In the region of the void S between them, the resin mold 17 surrounds the entire circumference. Therefore, most of the surfaces of these mercury switches 15a, 15b, 15c are surrounded by the resin mold 17. Therefore, the stress acting on the surface of the mercury switch 15a,
Since the entire surface of 15b, 15c is substantially uniform, the mercury switch does not crack.

Further, the terminal portion 14 integrally provided on the mounting plate 12
Has a slit 14a deeply cut downward at a portion to which the lead wire of each mercury switch is soldered. These slits 14a are attached to each mounting base 13a, 1 of the mounting plate 11.
It is formed in order to fix the lead wires of the mercury switches 15a, 15b, 15c mounted on the 3b, 13c at an optimum angle.For example, when soldering the mercury switch, the lead wires are slit 14a. First, the lead wire is temporarily fixed by receiving the lead wire at an appropriate depth. Then, as a result of the operation test, when it is necessary to adjust the tilt angle of the mercury switches 15a, 15b, 15c, the lead wires are vertically displaced in the slit 14a to move the mercury switches 15a, 15b, 15c. The tilt angle is adjusted to maintain the optimum height.

The acceleration sensor 10 of the present invention is constructed as described above. At the time of assembly, first, the mounting bases 13a, 13b, 13 of the mounting plate 12 are first assembled.
Mercury switches 15a, 15b and 15c are mounted on c respectively.

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

Further, lead wires of a harness (not shown) for taking out signals from the mercury switches 15a, 15b, 15c to the outside are also inserted into the slits 14a of the corresponding terminal portions 14 to solder the respective lead wires.

In this state, perform an operation test of each mercury switch 15a, 15b, 15c, and if there is an error in the detection result, solder to the slit 14a of the terminal portion 14 of each mercury switch 15a, 15b, 15c. Once removed, the lead wire is moved up and down in the slit 14a, and soldering is performed again at a desired tilt angle to adjust the tilt angle of the mercury switch.

After that, by fitting the mounting hole 12a of the mounting plate 12 into the boss 11c formed on the bottom surface inside the case 11, the mounting plate 12 is brought into contact with the bottom surface inside the case 11, and the boss 11c is heated. This mounting plate 12 by heat caulking by welding etc.
Is fixed to the bottom surface of the case 11.

Finally, the cover 16 is attached to the opening edge of the case 11, and the internal 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 will surely flow into a slight space below the mounting plate 12, and air will remain and an air pool will be generated. There is no such thing. Thus, the acceleration sensor 10 of the present invention is completed.

In the acceleration sensor 10 manufactured in this manner, the mounting surface 11b is brought into contact with the mounting reference surface, and the mounting hole 11a is mounted in the vehicle body or the like of the automobile by screwing or the like in the aligned state.

Incidentally, since the projection 12b is provided on the lower surface of the mounting plate 12, the mounting plate 12 is held in a state of being lifted from the case 11.
External force such as vibration applied to the mercury switch 15a, 15
It is not transmitted directly to b, 15c. Therefore, more accurate acceleration can be detected.

In the embodiment described above, the mounting base is formed on the surface of the mounting plate 12 formed separately from the case 11, but not limited to this, the mounting base is directly formed on the bottom surface inside the case. However, it is clear that it can also be applied.

[Effect of device]

As described above, according to the acceleration sensor of the present invention,
In particular, the mercury switch is prevented from cracking at a low temperature, and further, the assembly can be easily and quickly performed, and an accurate acceleration can be detected.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of the acceleration sensor of the present invention, and FIG. 2 shows a mounting plate in the embodiment of FIG.
(A) is a bottom view, (B) is a side view, (C) is a partial cross-sectional view of a mounting base formed on a mounting plate, and FIG. 3 shows the case in the embodiment of FIG. ) Is its plan view,
(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 thereof, (B) is a sectional view, and FIG. 5 is a partial sectional view of a mounting base of the conventional acceleration sensor. 10 …… Accelerometer; 11 …… Case; 12 …… Mounting plate; 13a, 1
3b, 13c …… Mounting base; 14 …… Terminal part; 15a, 15b, 15c …… Mercury switch; 16 …… Cover.

Claims (2)

[Scope of utility model registration request] 1. An acceleration sensor for accurately fixing a case containing a mercury switch to a predetermined location of a vehicle or the like to detect acceleration, wherein a mounting plate formed separately from the case is attached inside the case, On the surface of the mounting plate, at least one mounting base having an inclined surface inclined with respect to the direction in which acceleration is to be detected is integrally formed, and the inclined surfaces of the mounting base are separated in the inclination direction. An acceleration sensor, characterized in that the mercury switch is dividedly formed through a gap, and the mercury switch is loosely held by a columnar extension extending upward from the side of the divided inclined surface. 2. An acceleration sensor for detecting an acceleration by accurately fixing a case containing a mercury switch to a predetermined position of a vehicle or the like, wherein the bottom surface inside the case is inclined with respect to the direction in which the acceleration should be detected. At least one mounting base having an inclined surface is integrally formed, and the inclined surface of the mounting base is divided and formed via a space so as to be separated in the inclination direction, and side portions of the divided inclined surface. An acceleration sensor, wherein the mercury switch is loosely clamped by a columnar extension extending upward from the.