JPH07113819A - Servo acceleration sensor - Google Patents

Abstract

PURPOSE:To provide a servo acceleration sensor which can improve an acceleration sensitivity, a stability and the like performance by reducing a distance between confronting permanent magnets thereby to decrease a distance between the permanent magnet and, a metallic plate and a moving coil. CONSTITUTION:Metallic plates 30 are suspended between a first permanent magnet 22 and a second permanent magnet 24, and between a third permanent magnet 26 and a fourth permanent magnet 28. The permanent magnets 22, 24, 26, 28 are arranged at a gatepost 12 of a servo acceleration sensor 10. A moving coil 32 is held between the metallic plates 30. A flexure 36 is hung down at a top part 14 of the gatepost 12, which suspends the metallic plates 30 and movable coil 32. A light emitting diode is set between the first and second permanent magnets 22 and 24. A light-receiving position sensor 42 is placed between the third and fourth permanent magnets 26 and 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile navigator, an anti-lock brake system, an earthquake prediction sensor,
The present invention relates to a servo type acceleration sensor which is used for a high precision inclinometer and can accurately detect a change in speed, centrifugal force, gravity and the like.

[0002]

2. Description of the Related Art As shown in FIG. 4, in a conventional servo type acceleration sensor (50), a first permanent magnet (54) and a second permanent magnet (56) are arranged inside a gate pillar (52). , A third permanent magnet (58) spaced below the first permanent magnet (54), and a fourth permanent magnet (60) spaced below the second permanent magnet (56). It is arranged. The first permanent magnet (54), the second permanent magnet (56), the third permanent magnet (58), and the fourth permanent magnet (6).
0) is provided with a plate-shaped metal plate (62), and one surface (62A) of the metal plate (62) has the first permanent magnet (5).
4), facing the second permanent magnet (56), the metal plate (62)
The other surface (62B) faces the third permanent magnet (58) and the fourth permanent magnet (60). A movable coil (64) is fixed to the other surface (62B) of the metal plate (62), and a slit (65) is formed through the metal plate (62) and the movable coil (64). .
A flexure (68) is suspended from a top plate (66) of the gate post (52), and the flexure (68) suspends the metal plate (62) and the movable coil (64) in a swingable manner. A light emitting diode (70) is arranged above the metal plate (62), and a light receiving position sensor (72) is arranged below the movable coil (64). Therefore, when acceleration in the direction of the acceleration input axis shown by the arrow A in FIGS. 4 and 5 acts, the metal plate (62) and the movable coil (64) are fulcrumed at the upper portion of the flexure (68) as shown in FIG. Since it swings like a swing, it is necessary to secure the vertical dimension H when the metal plate (62) and the movable coil (64) swing. For this reason, the intervals between the first permanent magnets (54), the second permanent magnets (56) and the third permanent magnets (58), the fourth permanent magnets (60) cannot be narrowed, and various performances of acceleration sensitivity and stability are obtained. Is one of the reasons why it cannot be improved.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above facts, and the permanent magnets, the metal plate, and the movable coil can be formed by narrowing the gap between the permanent magnets facing each other. It is an object of the present invention to provide a servo type acceleration sensor capable of improving various performances such as acceleration sensitivity and stability by narrowing the interval of the.

[0004]

According to a first aspect of the present invention, there is provided a first permanent magnet and a second permanent magnet arranged on a gate pole, and a first permanent magnet and a second permanent magnet arranged on the gate pole with a space provided therebetween. A third permanent magnet that is provided, a fourth permanent magnet that is disposed on the gate pole and is spaced apart from the second permanent magnet, and the first permanent magnet.
Permanent magnet and second permanent magnet and the first permanent magnet and second
A plate-shaped metal plate that is swingably suspended between a permanent magnet, a coil that is fixed to the metal plate, and the metal that hangs on the gate pole along one surface and the other surface of the metal plate. And a flexure for suspending the plate and the coil.

[0005]

According to the first aspect of the present invention, when acceleration acts in the direction of the acceleration input axis, it is suspended from the first permanent magnet and the second permanent magnet and the third permanent magnet and the fourth permanent magnet on the gate pole via a flexure. Although the metal plate and the coil are oscillated, one surface and the other surface of the metal plate are arranged so as to extend in the hanging direction of the flexure, so that the metal plate and the coil become the first permanent magnet to the fourth permanent magnet. Do not rock to approach. Therefore, the distance between the first permanent magnet, the second permanent magnet and the third permanent magnet, and the fourth permanent magnet can be narrowed, so that the distance between the coil and the first permanent magnet to the fourth permanent magnet becomes large. It becomes narrower and the performance can be further improved.

[0006]

1 and 2 show one embodiment of a servo type acceleration sensor according to the present invention. The arrow A in the figure indicates the acceleration input shaft. As shown in FIG. 1, the gate plate (12) of the servo type acceleration sensor (10) has a top plate (1
4), vertical part (16), bottom plate part (18), folded part (2)
0) is formed. The bottom plate (1 of this gatepost (12)
The block-shaped first permanent magnets (2
2), second permanent magnet (24), third permanent magnet (26),
A fourth permanent magnet (28) is provided upright. As shown in FIG. 2, between the first permanent magnet (22), the second permanent magnet (24) and the third permanent magnet (26), the fourth permanent magnet (28), metal plates (30), ( 30) is arranged in a suspended state. These metal plate (30) and metal plate (30)
A movable coil (32) is sandwiched between them. Further, slits (34) are formed through the metal plates (30) and (30) and the movable coil (32), respectively. As shown in FIG. 1, the top plate portion (14) of the gate post (12) has a leaf spring-shaped flexure (36).
Is hung down and the upper end (36) of the flexure (36) is
A) is fixed to the top plate (14), and the flexure (3
The lower end (36B) of 6) has the metal plates (30), (3).
0) and the moving coil (32). Therefore, the flexure (36) is
6) One surface (30A) of the metal plate (30) in the hanging direction
And the metal plate (30) with the other surface (30B) along
(30) and the movable coil (32) are suspended. Therefore, when acceleration is applied, the flexure (36) has an arrow A with the upper end (36A) as a fulcrum.
Since it swings in the direction, the metal plates (30), (30) and the movable coil (32) also swing in the direction of arrow A. As shown in FIG. 2, the first permanent magnet (22) and the second permanent magnet (2)
4) is provided with a light emitting diode (40), and a light receiving position is provided between the third permanent magnet (26) and the fourth permanent magnet (28) at a position corresponding to the light emitting diode (40). A sensor (42) is provided. 3 shows a circuit diagram. In FIG. 3, (44) is an amplifier and (46) is an output resistance.

Next, the operation of the embodiment will be described. When acceleration acts in the direction of arrow A, the light emitting diode (4
The light emitted from 0) passes through the slits (34) of the metal plate (30) and the movable coil (32) and strikes the light receiving position sensor (42). The light receiving position sensor (42) outputs a signal voltage corresponding to the position where the light is applied. The signal voltage is amplified by the amplifier (44), and the moving coil (3
Power is applied to 2) to generate magnetic force. In this case, the amplifier (44) and the moving coil (32) are connected so as to generate a magnetic force in a reaction direction with respect to the acting direction of the moving coil (32). Therefore, the movable coil (32) is always in the reaction direction with respect to the action (acceleration) direction from the outside, that is, the negative feedback (servo function) that the movable coil (32) always returns to the original position. . An electric current that generates a magnetic force in the opposite direction proportional to the acceleration force flows through the movable coil (32), so that the current value can be read as acceleration. Moreover, since the flexure (36) of the servo type acceleration sensor (10) according to the present invention swings in the direction of arrow A (vertical direction in FIG. 2) with the upper part as a fulcrum,
The metal plates (30), (30) and the movable coil (32) also swing in the direction of arrow A (vertical direction in FIG. 2). Therefore, the first permanent magnet (22), the second permanent magnet (24), the third permanent magnet (26), and the fourth permanent magnet (28) do not swing toward the first permanent magnet (22) and the second permanent magnet (22). Permanent magnet (24) and third
The intervals between the permanent magnets (26) and the fourth permanent magnets (28) are determined by the thicknesses of the metal plates (30), (30) and the movable coil (32) such that the first permanent magnets (22) and the second permanent magnets ( 24) and the tolerance of the metal plate (30) and the third permanent magnet (26),
Since it is sufficient that there is a minimum gap including the tolerance dimension of the fourth permanent magnet (28) and the metal plate (30), the gap can be minimized. Therefore, the magnetic field generated by the first permanent magnet (22), the second permanent magnet (24), the third permanent magnet (26), and the fourth permanent magnet (28) becomes strong, and the sensitivity to the movement of the movable coil (32) is increased. And temperature characteristics and stability are improved. Further, since the eddy current flows through the metal plates (30) and (30) when the movable coil (32) swings, the braking effect generated by the eddy current becomes stronger, so that the transient characteristic is improved.
Furthermore, the first permanent magnet (22), the second permanent magnet (24), and the third permanent magnet (2) against the swing of the movable coil (32).
6), since the distance to the fourth permanent magnet (28) is equal, the linearity is improved. Therefore, the servo type acceleration sensor (1
The acceleration sensitivity and stability performance of 0) can be improved.

[0008]

As described above, in the servo type acceleration sensor according to the present invention, the interval between the permanent magnets facing each other can be narrowed, so that various performances of acceleration sensitivity and stability can be further improved. It has an excellent effect.

[Brief description of drawings]

FIG. 1 is an overall perspective view of a servo type acceleration sensor according to the present invention.

FIG. 2 is a position of a first permanent magnet, a second permanent magnet, a third permanent magnet, a fourth permanent magnet, a metal plate, a movable coil, a light emitting diode, and a light receiving position sensor of the servo type acceleration sensor according to the present invention. It is a top view which shows a relationship.

FIG. 3 is a circuit diagram of a servo type acceleration sensor according to the present invention.

FIG. 4 is an overall perspective view of a conventional servo type acceleration sensor.

FIG. 5 is a schematic diagram showing a swing of a metal plate of a conventional servo-type acceleration sensor.

[Explanation of symbols]

 (10) ... Servo type acceleration sensor (12) ... Gate post (22) ... First permanent magnet (24) ... Second permanent magnet (26) ... Third permanent magnet (28)・ ・ ・ 4th permanent magnet (30) ・ ・ ・ Metal plate (30A) ・ ・ One side (30B) ・ ・ Other side (32) ・ ・ ・ Movable coil (36) ・ ・ ・ Flexure

Claims (1)

[Claims] 1. A first permanent magnet and a second permanent magnet arranged on a gate pillar.
A permanent magnet, a third permanent magnet disposed on the gate pole and spaced from the first permanent magnet, and a third permanent magnet disposed on the gate pole and spaced from the second permanent magnet. A fourth permanent magnet, a plate-shaped metal plate oscillatably suspended between the first permanent magnet and the second permanent magnet, and the first permanent magnet and the second permanent magnet, and fixed to the metal plate And a flexure that hangs the metal plate and the coil so as to hang down from the gate pillar along one surface and the other surface of the metal plate.