JP2603492B2 - Tilt sensor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an inclination sensor for detecting a state of an object when the object is inclined.

(Prior art) A permanent magnet with a magnetic fluid adhered to the surface is housed in a hollow case, and a magnetically sensitive element is arranged outside the case. When the case is tilted, the permanent magnet inside is low due to its own weight. There has been proposed an inclination sensor that detects that the case is tilted because the magnet sensed by the magnetically sensitive element changes because of movement to a position.

FIG. 6 shows a tilt sensor of this type, in which 1 is a case made of non-magnetic aluminum, and a cup-shaped case 1a and a lid 1b are formed. It has a hollow portion 2 which is adhered with an adhesive at an overlapping portion and is sealed. The hollow portion 2 accommodates a substantially disk-shaped permanent magnet 4 having a surface on which a magnetic fluid 3 is adhered. Reference numeral 1c denotes a small-hole lid for inserting the permanent magnet 1 therein, fixing the cup-shaped case 1a and the lid 1b with an adhesive, injecting the magnetic fluid 3 from the small hole, and thereafter closing the small hole. . Reference numeral 5 denotes a sensor mounting base made of a plastic molded product. The case 1 is inserted into an upper portion of the mounting base, and is fixed with a resin 6. Reference numeral 7 denotes a reed switch as a magnetically sensitive element having a lead terminal soldered to the printed circuit board 8, from which a lead wire 9 is drawn. Reference numeral 10 denotes a back cover, which is fixed by engaging a claw 10a rising from a pair of opposing sides with a recess formed inside the mounting base 5. Reference numeral 11 denotes an amorphous magnetic piece adhered to the top of the mounting table 5, and the response angle of the inclination sensor is adjusted at the position where the amorphous magnetic piece is adhered. Reference numeral 12 denotes a label on which a name, a model number, a manufacturer name, and the like are displayed.

In such a configuration, when the case 1 is not tilted, the permanent magnet 4 is located at the center of the case. The switches have the same polarity at the center of the switch and repel each other, so that the switch is open. Next, when the case 4 is tilted and the permanent magnet 4 moves to the lower side, only the lead on one side is affected by the permanent magnet 4, so that the polarities of both leads at the center of the switch are different. The connection state is established. The magnetic fluid 3 acts as a lubricating oil when the permanent magnet 4 moves. As described above, it is possible to detect that the case 1 is tilted by the opening / closing operation of the reed switch 7.

(Problems to be Solved by the Invention) However, the conventional example of the above configuration has the following problems.

(1) The non-magnetic case 1 is, as described above, a cup-shaped 1a
Then, the cup-shaped case 1a having an adhesive applied in advance to the overlapping portion and the lid 1b are fitted and bonded together. Next, after injecting the magnetic fluid 3 from the small hole opened in the lid 1b, the small hole is closed with the small hole lid 1c. At this time, an adhesive is used. Further, the case 1 thus sealed is inserted through the opening at the bottom of the mounting table 5, and the case 1 is turned upside down, and the resin 6 is poured, solidified and fixed. Each time these adhesives and resins need to be heat-cured, and since the adhesives used are two-part types that are not affected by the solvent used for the magnetic fluid 3, the time required for setting up the adhesives and resins is also taken into account. It required a great deal of man-hours and was very poor in mass productivity.

(2) After the case 1 is fixed to the upper part in the mounting table 5, the printed circuit board 8 on which the reed switch 7 is mounted is inserted, positioned by a stopper (not shown), and the back cover 10 is fitted and fixed. At this time, the distance between the permanent magnet 4 and the reed switch 7 greatly affects the response angle as a tilt sensor. In the configuration of FIG. 6, the cup-shaped case 1a
Depending on the adhesion state between the lid 1b and the lid 1b, the adhesion state of the small hole lid 1c, or the fixed state of the case 1 with the resin 6, furthermore, the protrusion of the adhesive causes protrusions to be formed between the lid 1b and the ceiling of the mounting base 5. For example, there is a gap in the mounting position of the case 1 such as a gap, and therefore, the response angle is likely to vary.

(3) In order to finally fine-tune the response angle, an amorphous piece 11 is attached to the top of the mounting base 5. Furthermore, a label with adhesive 12 on which the name, model number, manufacturer name, etc. are displayed
However, the surface was uneven because the base was not flat, and the appearance was unsightly.

The present invention solves the above-described problems, and in particular, an inclination sensor that eliminates a sealing method of a non-magnetic case using an adhesive, achieves a significant reduction in man-hours, and eliminates manufacturing variations. Is provided.

(Means for Solving the Problems) As a sealing method for the non-magnetic case according to the present invention, a cold pressure welding method is adopted. That is, a non-magnetic metal that can be cold-pressed is used as the non-magnetic case, and the cup-shaped case is
The opening edge portion has a flange portion that protrudes outward, and the lid has a bent protruding portion having a substantially U-shaped cross section formed in a ring shape along the inner wall surface of the opening portion of the cup-shaped case, and a lid on the outside of the protruding portion. It has a formed flange portion, and the two flange portions are fused to each other by a cold welding method.

(Operation) In the cold pressure welding method, metal-to-metal fusion can be achieved only by pressure without heating, and a highly reliable sealed state of the case can be obtained. The productivity can be greatly improved as compared with the step of heat curing. Further, by using the case having the above-mentioned shape, it becomes possible to mount the case from the upper part of the mounting base having the mounting portion vertically penetrated, and the mounting position of the case is always stable, and therefore, the permanent magnet and the lead Since the distance between the switch and the switch is constant, the response angle of the tilt sensor does not vary.

(Example) Hereinafter, an Example is described in detail with reference to drawings. First
FIG. 1 shows an embodiment of the present invention, and FIG.
1 is a sectional view taken along line XX of FIG. 1A, or FIG. 2 is an exploded perspective view of FIG. The magnetic fluid 3, permanent magnet 4, reed switch 7, printed circuit board 8, lead wire 9, and amorphous piece 11 are the same as those in the conventional example.

Reference numeral 21 denotes a non-magnetic case in which the permanent magnet 4 to which the magnetic fluid 3 is attached is housed in the hollow portion 2, and is composed of a cup-shaped case 22 and a lid 23, both made of aluminum. twenty four
Is a mounting base made of a plastic molded article having a mounting part vertically penetrated, 25 is a mounting screw hole as an inclination sensor formed on the mounting base 24, and 26 has an engaging claw 27 rising from the opposite side. A back cover made of a plastic molded product, 28 is an inner cover made of aluminum to which the amorphous piece 11 is adhered, and 29 is a nameplate with an alumite-treated adhesive displaying a name, a model number, a manufacturer name, and the like.

The present invention uses a non-magnetic metal that can be cold-welded as its material in the non-magnetic case 21, and the cup-shaped case 22 and the lid 23 are fused and sealed at their flanges by a cold-welding method. However, it has the biggest feature. In this embodiment, aluminum is used. FIG. 3 shows the shape of the case 21, and FIG. 4 shows the cold welding method. In addition, as the material of the nonmagnetic case, besides aluminum, copper, copper alloy, nonmagnetic stainless copper, or the like can be used.

As shown in FIG. 3, the cup-shaped case 22 has a flange portion 22a projecting outward at an opening edge thereof, and a lid 23.
Has a bent protruding portion 23a having a substantially U-shaped cross section formed along the inner wall surface of the opening of the cup-shaped case 22 and a flange portion 23b formed outside the protruding portion. When the lid 23 is fitted to the cup-shaped case 22, the outer peripheral surface of the protruding portion 23a is loosely inserted along the inner wall surface of the opening of the cup-shaped case 22, and the case 22 and the lid 23 are positioned and both flange portions 22a and 23b overlaps.

FIG. 4 explains the principle of the cold pressure welding method. The cold pressure welding method is a known technique which has been mainly used as a method for enclosing a quartz oscillator. However, in this case,
As the fusion metal, there are many cases in which oxygen-free copper is nickel-plated on the surface, or a cold-rolled material of iron is nickel-plated with gold underlayer plating. In the present embodiment, after the cup-shaped case 22 and the lid 23 are preliminarily annealed and degreased using pure aluminum, a permanent magnet and a magnetic fluid are put therein and fitted together, as shown in FIG. Then, the flange portion is sandwiched between the upper mold 31 and the lower mold 32. The lower mold 32 is provided with a projection 32 having a trapezoidal cross section at a position corresponding to the fusion portion. Next, as the mold is pressed against a hydraulic palace or the like, as shown in FIG. 4 (b), the projection 32a bites into the flange portion 22a, and the metal of the flange portion flows as shown by the arrow. At the same time, the flanges fuse. In this case, as shown in FIG. 4 (c), the metal flowing on the lid 23 side
It is absorbed by the deformation of 23a and does not affect the deformation of the entire lid. The non-magnetic case 21 thus fused is heated at 125 ° C. for 30 minutes and then immersed in a 120 ° C. Fluorinert solution for 5 minutes to check for air bubble generation and a sealing test by a vacuum heating test or the like. As a result, it was confirmed that the sealing was complete.

The sealing process by the cold pressure welding method does not use any heat, and can be fused in an extremely short time of 20 to 30 seconds / piece, and can be further shortened by using an automatic machine. Including the shortening, the number of steps is remarkably reduced as compared with the conventional curing time of 1 hour × 2 times = 2 hours or more using the adhesive. Moreover, the reliability has been significantly improved, and
There is no variation in the work, and the effect is incalculable.

Since the nonmagnetic case 21 has a flanged shape, it is improved so that it can be mounted on the mounting stand 24 from above. FIG. 5 shows the mounting base 24, which has a mounting part 35 penetrating vertically. A step 36 is formed near the upper edge of the mounting portion 35, and the flange 22a of the case is placed on the step 36, and the case is perfectly positioned. The flange portion 22a and the step portion 36 are bonded and fixed with a heat-curable adhesive,
Since this adhesive has nothing to do with the sealing of the case, an adhesive which is dried at room temperature may be used. A concave portion 37 is formed at an unnecessary portion on the inner wall of the mounting portion 35, and a hollow portion 38 is formed on the back surface of the mounting base.
And thinning meat to save material. In addition,
A portion where the lead terminal of the reed switch 7 extends is also formed with a recess so as to escape.

Reference numeral 39 denotes a notch provided on the lower side wall of the mounting portion 35. The notch 39 covers the heat-shrinkable tube 40 (refer to FIG. 2) at an appropriate position of the lead wire drawn out of the printed circuit board 8, and pushes into the notch 39 for fixing. . In addition, the heat-shrinkable tube 40 at this time also serves as a guide for determining the length of the lead wire to be drawn out, thereby improving workability. The side wall provided with the notch and the side wall opposed thereto have a bottom surface slightly higher than the portion provided with the mounting screw hole 25, and therefore, the mounting bottom surface as the inclination sensor has the same shape as the portion provided with the mounting screw hole 25. It will be the bottom. As described above, it is more stable to take a horizontal state at the two ends in the longitudinal direction than to make the whole plane in the same plane.

The printed circuit board 8 is inserted from below the mounting part 35 and is positioned by the step part 41. As a result, the relative position with respect to the case 21 positioned by the step portion 36 becomes constant, and there is no variation between products. The printed circuit board 8 is fixed at the tip of the engaging claw 27 of the back cover 26 fitted from below the mounting portion 35.

The mounting screw holes 25 are formed in two stages. With this configuration, when the mounting screw is inserted when mounting the tilt sensor on the object, the mounting screw head is located at the large diameter portion of the screw hole, and the tip of the driver is engaged with the mounting screw head. It becomes very easy to combine.

After the non-magnetic case 21 is mounted on the mounting portion 35 of the mounting base 24, as shown in FIG. 1 or FIG.
Is attached, and the amorphous piece 11 is attached to this.
The final response angle as a tilt sensor is adjusted by the attaching position of the amorphous piece 11. After the adjustment is completed, the nameplate 29 is attached to the surface. The nameplate 29 is provided with projections 29a at two locations on the outer periphery, while a concave portion 42 (see FIG. 5 (a)) is provided at a corresponding location on the mounting base 24. The workability was greatly improved as compared with the conventional method of sticking a circular label while visually positioning the label. In addition, when a label is used, the surface is uneven and the appearance is not preferable. However, by using a nameplate as in this embodiment, the surface becomes flat and the commercial value is increased.

In the embodiment, the reed switch is used as the magnetically sensitive element, but another element may be used. In addition, although amorphous pieces are used for adjusting the response angle,
The present invention is not limited to this, and any material having a large saturation magnetization, such as permalloy or silicon steel, may be used.

(Effects of the Invention) As described above, according to the present invention, a nonmagnetic metal that can be cold-welded to a material is used as the nonmagnetic case,
By fusing and sealing the cup-shaped case and lid at their flanges by the cold welding method, the number of manufacturing steps can be significantly reduced, and the sealing reliability is significantly improved. The greater the variation in, the greater the effect.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG.
FIG. 3 is a cross-sectional view showing the shape of the non-magnetic case, FIG. 4 is a view showing the fusion of the cup-shaped case and the lid by the cold welding method, and FIG. Configuration diagram of the table, 6th
FIG. 1 is a configuration diagram of a conventional example. 2 ... hollow part, 3 ... magnetic fluid, 4 ... permanent magnet, 7 ...
... reed switch, 8 ... printed circuit board, 11 ... amorphous piece, 21 ... non-magnetic case, 22 ... cup-shaped case, 22a ... flange part, 23 ... lid, 23a ... protruding part, 23
b …… Flange part, 24 …… Mounting stand, 26 …… Back cover, 28
…… Inner lid, 29 …… Nameplate.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kei Imaizumi 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDK Corporation (72) Inventor Ryoki Odagawa 1-13-1 Nihonbashi, Chuo-ku, Tokyo Inside the corporation

Claims (1)

(57) [Claims] 1. A non-magnetic case having a hollow portion sealed by a cup-shaped case and a lid, a permanent magnet housed in the hollow portion and having a surface covered with a magnetic fluid, In a tilt sensor provided with a magnetically sensitive element that senses the magnetism of the permanent magnet, a nonmagnetic metal that can be cold-pressed is used as the nonmagnetic case, and the cup-shaped case has an opening edge. The lid has a flange portion that protrudes outward, and the lid is formed on the outside of the projection with a bent projection having a substantially U-shaped cross section formed in a ring shape along the inner wall surface of the opening of the cup-shaped case. A tilt sensor having a flange portion, wherein the two flange portions are fused to each other by a cold pressure welding method.