JPH03209172A - Acceleration detector - Google Patents

Abstract

PURPOSE:To make a detector low-cost and small-sized and to improve the resistance to shock by arranging stopper parts of a bypass member on both sides of a weight, which has a part made of a magnetic body or a magnet of a flat spring mobile part, with a prescribed gap between them. CONSTITUTION:When the acceleration in the direction of an arrow A is applied to a detector 10, a weight 32 of a flat spring mobile part 30 is kept in the position by the inertia and a flat spring 31 is bent. Therefore, the weight 32 is moved in the direction of an arrow B relatively to magneto-resistance elements 42 and 43 from the position indicated by a continuous line to the position indicated by a dotted line. When the weight 32 is moved in this manner, the intensity of the magnetic field acting upon the magneto resistance element 42 from which the weight 32 goes away is weakened but that acting upon the magnetic resistance element 43 which the weight 32 approaches is increased. The change of resistance values of respective magneto resistance elements 42 and 43 due to the change of intensities of magnetic fields appears as a voltage signal between terminals F and G in a bridge circuit, and the acceleration generated in the weight 32 is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an acceleration detector for detecting the acceleration of a moving object such as an automobile, and in particular aims to reduce the size and improve impact resistance.

BACKGROUND OF THE INVENTION Conventionally, an acceleration detector as shown in FIG. 7 has been provided.

In this acceleration detector 1, a weight 4 is attached to the free end of a leaf spring 3 whose one end is fixed to the inner wall of a case 2, and a strain gauge 5 is attached to one side of the weight 4, and the signal generated by the strain gauge 5 is , are outputted to an amplifier 7 via an output cord 6.

In the above acceleration detector 1, for example, the ? When acceleration is applied in the direction of mark The signal generated by the strain gauge 5 in response to the deflection of the leaf spring 3 is sent via the output coat 6 to the amplifier 7, where it is amplified in the amplifier 7; J″12( has been converted to the color of acceleration.

1j}i Rikiki・￥lMy husband is trying to solve the problem, but l-. In the 2K acceleration detection system, when a 1:11 velocity is applied, the first signal output from the strain cage is weak, so a high-sensitivity amplifier is required.

Therefore, the overall size of the acceleration detector has to be increased. There is a problem with the cost of Yoto and J (with high filfi).

In addition, in the above acceleration detector, iUl' is used exclusively for mechanical shock.
J++ of l: When subjected to + deceleration, the leaf spring's 1■4
[．． The weight fixed on the end of the 111 may vibrate with excessive amplitude and cause scratches, which poses a problem in terms of shock resistance.

[The present invention] has advantages over the conventional acceleration detector described above:
1) to solve the problem and improve the impact resistance of the small size. Another object of the present invention is to provide an acceleration detector with a low CdIi rating.

Means for Solving the Problems In the present invention, a magnetoresistive element is arranged in the magnet part -L, and a detecting part, a plate spring fixed at one end, A plate spring movable part, etc., which is fixed to the free end of the plate spring and has a weight having a portion made of a magnetic body or a magnet, which is arranged to face the magnetoresistive element L at a predetermined distance. A stopper part is located on both sides of the base in which the detection part is installed and the weight of the plate spring movable part with a gap between them to tightly couple the magnet part and the weight and to restrict the t2 movement of the weight. A bypass member made of a magnetic material having the following features.

Two of the magnetic resistance elements provided in the detection part are arranged in parallel in the moving direction of the magnetic material or magnet part of the weight,
These two magnetoresistive elements and two electrical 71< resistors form a bridging path, and the resistance f of the magnetoresistive element
Alternatively, the detection section may include four magnetoresistive elements, and the magnetic material or magnet I of the weight may be detected differentially. 2-way tr”
h and four magnetoresistive elements arranged in parallel in the direction perpendicular to said direction,
//A circuit is constructed.

In the acceleration detector according to the present invention, the jl-
Magnetic k+ changed in response to acceleration due to the circular motion of i
The strength of is converted into a change in resistance using a magnetoresistive element (..., the acceleration applied to the movable part of the leaf spring is detected from this electrical resistance.

Jt-, top, ;12 acceleration detector; top, from magnetic material/
．． A detection unit is installed in the extension department where the part of the plate spring is fully located, and the stop collar part of the side rod is placed on both sides of the weight that hits the magnetic material or magnet part of the leaf spring movable member. Since the anchors are placed across an air gap, the magnetic flux circulates through the magnet part of the detection unit, the weight, and the bypass member, reducing leakage of magnetic flux, improving the magnetic sensitivity of the magnetoresistive element, and increasing the output sensitivity by 1. Great. In addition, when the leaf spring is subjected to excessive acceleration or deceleration due to mechanical shock, etc., the weight of the leaf spring movable part hits the stopper part, so it does not vibrate with excessive amplitude and prevents damage. .

Embodiments Next, the present invention will be explained in detail based on embodiments shown in the drawings.

In the first embodiment shown in FIGS. 1 and 2, accelerated epidemic detection 2
310 is a plate spring movable part 30 and a detection part 4 inside the case 20.
0 and side route material 50.

The leaf spring movable part 30 includes a leaf spring 31 fixed at one end to the upper inner surface 20a of the case 20 and extending downward, and a weight 32 made of a magnetic material fixed to the lower end (free end) of the leaf spring 31. We are prepared. That is, in the case 20 i.e., in the case 20 i. JI and relatively move in the direction of arrow B.

The bypass member 50 is made of a magnetic material and has a substantially inverted U-shaped cross section, and its base 50a is fixed to the inner support 20b of the case 20.The upper surface of the base 50a has a detection section 12. 10 is Qing 1
has been established. Side portions 50b extending -4 degrees above both sides of the base portion 50a are provided with inwardly protruding support portions 50c adjacent to each other. The tip of the stopper portion 50c is placed on both sides of the side 32 of the leaf spring i+J QJ portion 30 with a gap W obstructing it. The air gap is excessively large.
In this case, when the weight 32 hits and completes the stonova throw, it is set to a predetermined amount that can collect the magnetic field from the weight 32 within a single nod.

Detection 1 (, 10f, side passage {A50 weir 5 [) aJ
= nit! 1i] Set the magnet part 41 with a constant value of 0;j1 to the -L plane of the magnetic τi part 41. , 43 are arranged.

The magnetoresistive elements 42 and 43 are arranged parallel to the moving direction of the weight 32 of the leaf spring driving part 30 shown by the arrow A or arrow I3 of the leaf spring movable part 30, and on both sides of the weight 32. The weights 20 are arranged side by side in such a manner that the weights 20 and 20 are placed in parallel, and are opposed to the weight 20 at a predetermined distance.

As mentioned above, the side passage part +4'50 made of a magnetic material is provided, and the magnet ring 41 is provided on the body of the side passage member 50. On the other hand, the stopper parts are placed oppositely on both sides of the weight 32. Therefore, the magnetic flux emitted from the magnet part 41 is . Most of the magnetic flux returns from the magnet part 41 to the magnet part 41 via the magnetoresistive elements 42, 43, the weight 32, and the side path 50, as schematically shown by the dotted line C in FIG. There is almost no leakage. Therefore, magnetic field 1. detects the change in the strength of the magnetic field due to the movement of the weight 32. The magnetic sensitivity of the k anti-element is increased.

Further, in order to dampen the auburn coat caused by the vibration of the weight 32, the inside of the case 20 is filled with Noricon Ab, etc., and a filled damper I1 is installed.

FIG. 3 shows the electricity of the magnetoresistive elements 42 and 43 [:::
il line connection is shown, forming a Brino circuit with magnetoresistive elements 42, 43; and electric resistors 61, 62.

In this Brino circuit, by applying a voltage between terminals D and E, the magnetic resistance changes 42 and 43. 31 and 2 sea urchins were detected.

Next, the operation when measuring acceleration with the acceleration detector 10 having the above configuration will be explained.

For example, when an acceleration in the direction of the missing mark A is applied to the acceleration detecting point 10, the tilt 32 of the leaf spring movable part 30 becomes L due to inertia as described above. Taimu. Therefore, as shown in FIG. 4, the weight is relative to the magnetoresistive elements 42, .
Move in the direction of 3 and move 1° from the position indicated by the dotted line to the position indicated by the dotted line.

As the weight 32 moves as described above, the strength of the magnetic field acting on the magnetoresistive element 42 as the weight 32 moves away decreases, while the strength of the magnetic field acting on the magnetoresistive element 13 as the weight 32 approaches decreases. becomes stronger. Then, the change in the resistance value of each magnetoresistive element 12, 43 due to the change in the strength of the magnetic field is the third
In the bridge concave path shown in the figure, the acceleration generated in the weight 32 is detected as a voltage signal between the terminals F and G.

At this time, as described above, in the acceleration detector 10 of this embodiment, the weight 32 of the leaf spring movable part 30 and the magnet part 4l of the detection part 40 are magnetically closely connected, so the magnetoresistive element 42 , 43's magnetic sensation ``l? t'7I, therefore, this A
The signals detected by the magnetoresistive elements 42 and 13 have a relatively uniform amplitude deviation f using an amplifier with a relatively high multiplier.

In addition, if there is a mechanical t4 impact on the acceleration detector 10 mentioned above,
+ In the case of a stiffening, the weight 32 of the leaf spring movable portion 30 hits the stop collar portion 5()c of the side path member 50, and the leaf spring 3I does not vibrate with excessive amplitude.

In the present embodiment, although the entire weight 32 is made of a magnetic material, a magnet (1) may be used instead of the magnetic material.When a weight made of a magnet is used, (i , the strength of the magnetic field becomes stronger, and the sensitivity of the magnetoresistive element can be further improved.Furthermore, the body does not need to be made of a magnetic material or a magnet, and the part made of a magnetic material or a magnet can be used. A portion made of other materials may also be used.

In addition, it is not necessary that the entire side track material 50 is made of magnetic material,
Similar to the weight described above, a portion made of a magnetic material and a portion made of another material may be used together.

Next, a second embodiment shown in FIG. 5 will be described. Note that the same members as those in the I-th tip embodiment indicated by L are given the same numbers and their explanations are omitted.

In the second example, the fixed plate of the detecting unit 30 is magnetically {1 (anti-element) .12, 43
are arranged in 41 rows, and magnetism 1j (antibodies r-44, l
5 ry' same < ill2 column L - (1'lL!
The tail is placed.

child! 1, magnetoresistive cables 42, 43, 44, and 45 form a blank circuit as shown in FIG.
, terminal I], the acceleration is detected by a change in the voltage signal between the two terminals.

In the second embodiment, since the Britno circuit is constructed from four magnetoresistive elements, the output sensitivity between terminals F and G can be doubled compared to the first embodiment using two magnetoresistive elements. Therefore, it is possible to detect acceleration with higher accuracy.

As is clear from the above description, in the acceleration detector according to the present invention, when the track member made of a magnetic material is provided and the magnet part of the detection part is attached to the side track member, Since the stopper part of the path member is arranged with a certain gap on both sides of the magnetic t.tx body of the leaf spring movable part or the weight having a part made of a magnet, the magnetic flux from the magnet part overlaps, and the side path The leakage of magnetic flux is reduced because it returns to the magnet part through the member, and the magnet part of the detection part and the weight of the movable part are closely magnetically coupled.Therefore, the magnetic sensitivity of the magnetoresistive element is high. , detects the strength of the magnetic field acting on the magnetoresistive element with high sensitivity. Therefore,
The output sensitivity of the signal that is rejected first by Ia is good, and the amplification factor of the amplifier can be suppressed. Therefore, the overall acceleration detection device can be made smaller and the cost can be kept low.

Additionally, if the leaf spring is subjected to excessive acceleration or deceleration due to mechanical shock, etc., the weight of the movable part of the leaf spring will come into contact with the suspension part of the above-mentioned sideway member, causing the leaf spring to vibrate with an excessive amplitude. It has excellent impact resistance.

[Brief explanation of drawings]

FIG. 1 shows a first embodiment of an acceleration detector according to the present invention.
1. A schematic sectional view, FIG. 2 is an acceleration sensor shown in FIG. I. j
Figure 3 is a schematic perspective view of the accelerometer shown in Figure 1; Figure 4 is a schematic diagram showing the relationship between the magnetoresistive element and the weight; is related to the present invention)I
6 is a schematic cross-sectional view showing a second embodiment of the l+ speed detector, and FIG. 6 is a schematic sectional view of the acceleration detector shown in FIG.
The figure is a 4-81 perspective view showing a conventional acceleration detector. DESCRIPTION OF SYMBOLS 10... Acceleration detector, 20... Case, 30... Leaf spring movable part, 3l... Leaf spring, 32... Weight, . 10...
Detection section, 11... Magnet section, 42, 43, 44, 45... Magnetoresistive element, 50...
・Side channel {o, 50a... base, 50b... side part, 50c...
・Stosopa club. Patent applicant Sumitomo Electric Industries, Ltd.

Claims (1)

[Scope of Claims] 1. A detection unit having a magnetic resistance element arranged on a magnet part, a plate spring having one end fixed, and a plate spring fixed to the free end of the plate spring at a predetermined distance from the magnetic resistance element. a leaf spring movable part comprising a weight having a portion made of a magnetic material or magnet and arranged to face each other across the body, a base on which the detection part is installed, and both sides of the weight of the leaf spring movable part. an acceleration detection device comprising: a side path member made of a magnetic material and having a stopper portion positioned across an air gap to magnetically tightly couple the magnet portion and the weight and restrict movement of the weight; vessel. 2. The detector according to claim 1, wherein the detection unit includes a pair of magnetoresistive elements, and the magnetoresistive elements are arranged in parallel in a moving direction of a portion of the weight made of a magnetic material or a magnet. Acceleration detector. 3. The detection unit has four magnetoresistive elements, and two magnetoresistive elements are arranged in parallel in the direction of movement of the magnetic material or magnet portion of the weight and in the direction perpendicular to the direction of movement. 2. The acceleration detecting device according to claim 1, wherein a bridge circuit is formed by these four magnetoresistive elements.