JPH0453530Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a tilt sensor that detects the tilted state of an object when it is tilted.

(Prior art) Conventionally, this type of inclination measuring device has ranged from simple devices such as those installed in kerosene stoves, etc., by suspending a weight from a chain to measure levelness, or a spirit level, to devices such as a gyro horizon. There are various types, up to advanced ones.

However, although a simple device such as the above-mentioned spirit level is inexpensive, it is only used to visually determine the state of inclination, and is not used in connection with a control system for returning a tilted object to the horizontal level. In addition, advanced instruments such as a gyrohorizontal scope are used only in expensive and limited equipment such as aircraft.

Therefore, the inventors of the present invention first housed a permanent magnet whose surface was covered with magnetic fluid in a hollow case, and placed a magnetic sensing element on the outside of the case, so that when the case was tilted, the internal permanent magnet would be activated. Since the magnetism detected by the magnetic sensing element changes as the case moves to the lowest position due to its own weight, we proposed a tilt sensor that detects when the case is tilted (see Japanese Patent Application No. 169930/1982). According to this, the state of inclination can be detected with high accuracy with a simple configuration, and the detection signal can also be used in a control system such as attitude control.

(Purpose of the invention) The present invention is a further application and development of the basic structure, and like the tilt sensor of the above application,
As the case is tilted, the permanent magnet moves in a continuous and gradual manner, i.e., in a linear motion, so that the magnetic strength around the magnetically sensitive element does not change continuously, gradually, i.e., in a linear motion. When the inclination angle of the case is below a certain predetermined angle, the magnetism sensed by the magnetically sensitive element hardly changes, and when the angle exceeds the certain angle, the permanent magnet inside the case is largely displaced, causing the magnetically sensitive element to The sense of magnetism suddenly increases,
That is, the present invention provides an inclination sensor that changes with non-linear operation, thereby clearly detecting that the case is tilted beyond a certain predetermined angle.

(Structure of the invention) The inclination sensor of the invention includes a first bottom surface in the center,
a non-magnetic material case including a hollow portion having a bottom portion including a second bottom surface that intersects the first bottom surface at a predetermined angle with the first bottom surface surrounding the non-magnetic material case;
It consists of a permanent magnet whose surface is coated with magnetic fluid, and a magnetic sensing element that is placed and fixed on the outside of the bottom of the case and senses the magnetism of the permanent magnet.

According to the above configuration, the magnetic attraction force of the permanent magnet housed in the hollow portion overcomes the weight of the permanent magnet itself and attracts the magnetic fluid between the permanent magnet and the bottom surface, thereby causing the permanent magnet itself to become hollow. The magnet is levitated from the bottom surface, so that the friction between the magnet and the bottom surface during movement of the magnet is extremely small. By configuring the hollow bottom surface with a first bottom surface and a second bottom surface that intersects with the first bottom surface at a predetermined angle, when the inclination of the case exceeds a certain angle, The permanent magnet instantly undergoes a large displacement, which makes it possible to clearly detect that the case is tilted at a certain angle.

(Example) Hereinafter, an example will be described in detail with reference to the drawings. FIG. 1 shows an embodiment of the present invention. Reference numeral 1 is a case made of a non-magnetic material, for example, aluminum, and the hollow part is located at the center of the case, as shown in FIG. An annular inverted truncated conical surface 2 whose bottom surface is a circular plane 2a, and whose periphery is a second bottom surface having a predetermined angle θ with respect to the plane 2a.
It has a bottom part 2 consisting of b. Note that Figure 2a is the second
A cross section taken along line A-A in Figure b is shown. Reference numeral 3 denotes a substantially disk-shaped permanent magnet, and a magnetic fluid 4 is adhered to the surface of the permanent magnet. The magnetic fluid 4 is made by dispersing 50 to 150 particles of metal magnetic powder (cobalt, iron, nickel, etc.) in a relatively low viscosity liquid (eg kerosene, water), and generally contains a surfactant. 5 is a cover placed at a predetermined height from the bottom 2 to prevent the top and bottom of the permanent magnet 3 from being reversed, 6 is a mounting base, and 7 is a non-linear magnet placed outside the bottom of the case 1. With a reed switch as a sensing element,
The end of one lead 7a is located close to the center of the bottom 2, and the end of the other lead 7b is located far from the bottom.

Next, the operation of this embodiment will be explained. The state shown in Figure 2 is the state when case 1 is not tilted.
The plane 2a at the center of the bottom is horizontal. At this time, since the permanent magnet 3 is on the plane 2a, the end of one lead 7a of the reed switch 7 is close to the permanent magnet 3, so that the lead 7a
The end of the reed switch is affected by the magnetism of the permanent magnet, and is magnetized to the north pole in the figure, while the other end (center of the reed switch) is magnetized to the south pole.
Become the pole. Furthermore, since the end of the other lead 7b that is close to the S pole is magnetized to the N pole, both leads are attracted to each other and connected. In other words, if there is a circuit connected to leads 7a and 7b, that circuit will be closed.

Next, suppose that the case is tilted to one side as shown in FIG. However, when the slope is small, the conical surface 2
b is still an upward plane at a certain angle with respect to the horizontal plane maintains the connection state.

As shown in FIGS. 4a and 4b, the case 1 is further tilted and the angle θ (actually, due to the viscosity of the magnetic fluid) formed between the plane 2a and the conical surface 2b at the approximate center
When the permanent magnet 3 is tilted (at an angle slightly larger than θ) and the conical surface 2b becomes a downward surface as shown in FIG. That is, the position of the permanent magnet 3 with respect to the central plane 2a changes in a non-linear motion. When the permanent magnet is moved, the magnetic fluid 4 acts as a lubricating oil, so the resistance to movement is very small, and the permanent magnet can be easily moved to the lowest part of the bottom. At this time, the end of one lead 7a of the reed switch 7 rapidly moves out of the effective range of magnetic influence of the permanent magnet 3, that is, in a non-linear motion, and the magnetization substantially disappears. As a result, the magnetic attraction between the leads 7a and 7b is substantially eliminated, and the switch opens.

As is clear from the above description, in this embodiment, when the case is tilted at a predetermined angle or more, the reed switch opens rapidly, that is, in a non-linear operation, and thereby the case is tilted at a predetermined angle. It is possible to clearly detect that the device is tilted by more than an angle. Furthermore, when the case returns to its original tilt, the permanent magnet also quickly returns to the central plane, and the reed switch closes rapidly, ie, in a non-linear motion.

In this embodiment, the first bottom surface is a flat surface, and the second bottom surface is an inverted truncated conical surface, but a slightly concave surface may also be used. In short, it is sufficient that the first bottom surface and the second bottom surface intersect non-linearly at a certain angle.

FIG. 5 shows a modified embodiment of FIG. In the case shown in FIG. 1, the reed switch 7 is in the closed state when the case 1 is in the state shown in FIG. 2, but in the embodiment shown in FIG. By arranging the auxiliary magnet 8 at the position, the switch is kept in an open state. That is, if the polarities of the two magnets and the arrangement of the reed switch are set as shown in FIG. 5, the polarities of both lead ends in the center of the reed switch 7 will be the same, and they will repel each other and will not be connected. However, when the case is tilted and the end of one lead 7a is substantially no longer affected by the magnetism of the permanent magnet 3, only the auxiliary magnet 8 will affect the polarity of both lead ends at the center of the reed switch 7. They will be connected to each other as opposite poles.

FIG. 6 shows another embodiment of the present invention, in which the reed switch 7 is laid down and mounted substantially parallel to the first bottom surface of the case 1. In this case, when the case is not tilted, both leads 7a and 7b of the reed switch 7 are equally affected by the permanent magnet 3 and have the same polarity at the center of the switch, as shown in Figure 7. repel each other,
Therefore, the switch is in an open state.

When the case is tilted and the permanent magnet 3 moves to the position shown in Figure 8, that is, when the second bottom surface is slightly downward from horizontal, only the lead 7b on one side is affected by the permanent magnet, so the switch cannot be activated. The polarities of both leads at the center become different and a connected state is established. Furthermore, if the case is tilted so that the permanent magnet moves in the P direction, the switch will not close because both leads are not affected by the permanent magnet or are affected equally. Therefore, in this embodiment, the directionality of the inclination can also be detected.

In this embodiment as well, the angle of inclination of the case and the movement of the permanent magnet are the same as in the embodiment shown in FIG.

In order to optimize the magnetic influence of the permanent magnet on the reed switch, it is preferable to adjust the mounting position of the reed switch.
Further, a ring-shaped permanent magnet can also be used. In short, any shape is sufficient as long as the permanent magnet does not change its top and bottom in relation to the cover 5 even if it vibrates or falls over. Furthermore, although the embodiment has been described using a reed switch as the magnetically sensitive element, it goes without saying that other elements, such as a Hall element, may be used. Regarding the magnetic fluid, the same effect can be obtained by using not only a metal magnetic fluid but also a so-called oxide magnetic fluid in which ferrite magnetic powder is dispersed.

(Effects of the invention) As explained above, the invention provides the following effects.

(1) Since the first bottom surface and the second bottom surface intersect in a non-linear manner, when the case is tilted, the switch is activated rapidly, that is, non-linearly, after a certain tilt angle is reached. Since the case is opened and closed, it is possible to clearly detect whether the case, or in other words, the tilt sensor, is tilted by a certain angle, and it is possible to prevent the tilt sensor from malfunctioning due to small vibrations, etc. .

(2) In the embodiments shown in Figures 1 and 5, the reed switch is installed vertically, so
It is particularly suitable when small lateral dimensions are required.

(3) Since the embodiment shown in FIG. 5 is provided with an auxiliary magnet, the magnetic force around the reed switch is strong, the operation of the reed switch is stable, and there is no possibility of malfunction due to small vibrations.

(4) In the embodiment shown in Fig. 6, the reed switch is installed in the horizontal direction, so it is particularly suitable when a small vertical dimension is required. Can be detected.

(5) The reed switches used in the embodiments shown in Figures 1, 5, and 6 have a simple structure, are therefore inexpensive, and can easily provide nonlinear opening/closing operations. .

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the present invention, FIGS. 2 to 4 are explanatory diagrams of the operation of the same embodiment, FIG. 5 is a configuration diagram of a modified embodiment of FIG. 1, and FIG. The figure is a sectional view of another embodiment of the present invention, and FIGS. 7 and 8 are explanatory diagrams of the operation of the same embodiment. DESCRIPTION OF SYMBOLS 1... Case, 2... Bottom surface, 2a... Central plane, 2b... Conical surface, 3... Permanent magnet, 4... Magnetic fluid, 7... Reed switch, 7a, 7b...
Lead, 8...auxiliary magnet.

Claims (1)

[Claims for Utility Model Registration] (1) A bottom portion consisting of a first bottom surface in the center, a second bottom surface surrounding the first bottom surface that intersects with the first bottom surface at a predetermined angle, and a peripheral wall around the bottom portion. a non-magnetic case having an enclosed hollow part, a permanent magnet housed in the hollow part and having a magnetic fluid coated on its surface, and disposed outside the bottom of the case;
A tilt sensor comprising: a fixed magnetic sensing element that senses the magnetism of the permanent magnet; (2) The inclination sensor according to claim (1) of the utility model registration, characterized in that the magnetic sensing element is attached to the first bottom area so that its distance from the permanent magnet can be adjusted. (3) Utility model registration claim No. 1 characterized in that the magnetically sensitive element is a nonlinear magnetically sensitive element.
The tilt sensor described in (1). (4) The tilt sensor according to claim (3), wherein the nonlinear magnetic sensing element is a reed switch. (5) The tilt sensor according to claim (4) of the utility model registration, wherein the reed switch is installed perpendicularly or substantially perpendicularly to the first bottom surface. (6) The reed switch has one reed end close to the permanent magnet in the first bottom area,
The tilt sensor according to claim (5) of the utility model registration, characterized in that the end of the other lead is arranged far away, and an auxiliary magnet is arranged close to the end of the other lead. . (7) The inclination sensor according to claim (4) of the utility model registration, characterized in that the reed switch is attached in a direction parallel or substantially parallel to the first bottom surface.