JPH011966A - 4-direction acceleration detection device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] This invention aims to simplify the structure, reduce size and weight, and
The present invention relates to a four-directional acceleration detection device that can be used in various industrial fields such as in-vehicle use and robot use.

[Conventional technology]

Conventional acceleration detection devices generally use a swinging dog or a ball type.

[Problem that the invention seeks to solve]

For these acceleration detection devices.

(1) The goal or pendulum as an acceleration acting body is considerably heavy and large; (It) There is a mechanically worn part, which becomes more noticeable as the amount of the acting body increases; ( iiD There were problems such as the structure being complicated, making it difficult to make it smaller and lighter, and making it expensive.

This invention was made to solve these problems, and has a simple structure, can be made small and lightweight, has high reliability, and is capable of detecting acceleration in four directions (left, right, up and down). The purpose is to obtain equipment.

[Means for solving problems]

The four-direction acceleration detection device according to the present invention includes a closed pipe line made of a non-magnetic material having a large diameter part and a narrow pipe part with a small diameter extending from the large diameter part in the horizontal and vertical directions; The magnetic fluid is held in the large diameter part by magnetic force at all times, and the magnetic fluid is held at predetermined positions in the thin tube part in the vertical and horizontal directions by a pair of magnets placed close to the large diameter part. A magnetic detector including a bias magnet and a magnetoresistive element is provided.

[Effect]

In this invention, under the action of acceleration, the magnetic fluid is displaced in a direction opposite to the direction of acceleration, and the magnetic resistance of the magnetoresistive element changes in the magnetic detector on the side of this displacement, but in the magnetic detector on the opposite side. The magnetic resistance of the magnetoresistive element does not change, but its detection output changes in proportion to the magnitude of acceleration according to the amount of displacement of the magnetic fluid, and the detection output reverses in the direction of acceleration, and its sign and magnitude change. This makes it possible to detect the magnitude and direction of acceleration, and detects acceleration in four directions.

〔Example〕

Embodiments of the four-direction acceleration detection device of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 are cross-sectional views showing the configuration of one embodiment of the present invention. FIG. 1 shows a state where acceleration is zero, and FIG. 2 shows a state where acceleration is applied to the right.

In both FIGS. 1 and 2, reference numeral 1 denotes a closed conduit made of non-magnetic material, in which a large-diameter portion 1a at the center is filled with magnetic fluid 3, and a thin tube extending from the large-diameter portion 1a. Part 1b
, lc, ld, and le at predetermined locations.
a, 5b, 6a, 6b.

7a and 7b are arranged, and the magnetic fluid 3 is normally held in the large-diameter portion 1a of the closed conduit under the action of the magnetic force of these magnet pairs.

The magnetic detector is composed of bias magnets 8a to 11a and magnetoresistive elements 8b to Ilb.
1a, i-resistance elements 8b-11b are symmetrically arranged at predetermined locations in the thin tube portion 1b=1e of the closed conduit 1.

The magnetic resistance elements of the magnetic detectors 8a, 8b=11a, llb constitute a grit detection circuit (not shown),
In the state shown in Figure 1 where no acceleration is applied, the output of the 1 Litz detection circuit is configured to be zero, and when acceleration is applied as shown in Figure 2, the balance of the glitch detection circuit is lost and an output is generated. It has become.

Next, the operation will be explained. As already mentioned, FIG. 1 shows a state in which the applied acceleration is zero, and since the magnetic fluid 3 is held in the central large-diameter portion 1a, the magnetic fluid 3 is -Yb) The output of the magnetic detector in the direction becomes zero.

In addition, in Fig. 2, acceleration acts on the right side (Xa direction) in the figure, so when the acting force due to this acceleration overcomes the holding force by the magnet pair, the magnetic fluid 3 moves to the left side (Xb direction) opposite to the direction of acceleration. ), and a part of it flows out into the thin tube portion 1d on the left (Xb direction).

Therefore, the resistance changes occur in the magnetoresistive elements of the left magnetic detectors 10a and 10b, but the right magnetic detector 8
Since no resistance change occurs in the magnetoresistive elements a and 8b, an output voltage proportional to the applied acceleration is generated in the grit detection circuit constituted by both of these magnetoresistive elements.

Further, in this case, it goes without saying that the magnetic fluid is not displaced in the vertical direction (Ya-Yb).

Since the above phenomenon occurs completely symmetrically in the four directions of left and right and up and down, the present invention enables acceleration detection in four directions.

It goes without saying that when the applied acceleration disappears, the magnetic fluid 3 that has flowed out into the thin tube section 1d is restored to the central large diameter section 1a due to the magnetic force of the magnet pair.

Furthermore, in the above, by changing the position where the magnetic detector is set, it is possible to make the magnitude of the detectable acceleration variable.

〔Effect of the invention〕

As explained above, in this invention, a magnetic fluid is sealed in a large diameter part in the center of a closed pipe line, a magnetic detector is arranged in a thin tube part extending from the large diameter part in the horizontal and vertical directions, and The system was configured to use a magnetic detector to detect the displacement of the magnetic fluid in the direction opposite to the direction of acceleration, so it is similar to the conventional method? - Without using a pendulum or a pendulum structure, the structure is simple, small and lightweight, and the reliability is excellent. It is possible to detect acceleration in four directions (left, right, up and down), and its effects are extremely large.

In addition, by changing the set position of the magnetic detector, the magnitude of the detectable acceleration can be freely selected.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a four-direction acceleration detection device according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the same embodiment when acceleration acts on the magnetic fluid in the right direction. l...Closed pipe line, la...Large diameter part, 1b=le...
・Thin tube part, 3...Magnetic fluid, 4a, 4b, 5a, 5b
. 6a, 6b, 7a, 7b---Magnet pair, 8a, 8b. 9a, 9b, 10a, 10b, lla, 1lb-=magnetic detector. In addition, the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] A closed conduit made of a non-magnetic material formed by a large-diameter portion forming a magnetic fluid reservoir and small-diameter thin tube portions extending from the large-diameter portion in four directions (left, right, up and down), and a magnetic fluid sealed within the large-diameter portion. a pair of magnets for holding the magnetic fluid disposed close to the large diameter section; a bias magnet disposed at a predetermined location in the narrow tube section to always hold the magnetic fluid in the large diameter section; A four-directional acceleration detection device equipped with a magnetic detector composed of a magnetoresistive element that detects displacement.