JPH02212709A - Horizontal sensor - Google Patents

Abstract

PURPOSE:To obtain a highly accurate sensor by setting a permanent magnet at the center of a hollow part when a bottom surface of the hollow part is horizontal to detect that the permanent magnet is displaced to any one way from the center thereof with a magnetosensitive element when the bottom surface is inclined. CONSTITUTION:When a horizontal sensor is horizontal, a bottom surface 2a of a hollow part 2 is horizontal and hence, a permanent magnet 3 is located at the center of the hollow part. At this point, Hall ICs 7a and 7b are both under the influence of N and S polarities of the permanent magnet 3, so that the Hall ICs 7a and 7b are both turned ON to let LEDs 9a and 9b come ON. Then, for example, when the horizontal sensor is tilted being lowered on the S side thereof, the permanent magnet 3 floating with a magnetic fluid 5 is displaced easily to the S side. In this case, the Hall IC 7b is kept ON with the N polarity thereof right thereabove to leave the LED 9a ON. On the other hand, the Hall IC 7b comes under the influence of the N polarity from under the influence of the S polarity and turned OFF and the LE 9b goes out. By the contrary, when the sensor is tilted to the N side, the Hall IC 7a is turned OFF while the Hall IC 7b is turned On and the LED goes out.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a horizontal sensor, that is, a spirit level for detecting the horizontal level.

(Prior Art) As a spirit level, a bubble tube type is generally well known. With this method, you can visually see the position of the bubble and know whether it is horizontal or not.

The inventors of the present invention previously proposed a tilt sensor that detects the tilted state of an object when it is tilted (Japanese Patent Laid-Open No. 6
3-26520). This device has a structure in which a permanent magnet whose surface is coated with magnetic fluid is displaceably housed in a hollow part of a non-magnetic case, and a magnetic sensing element is placed on the outside of the case. As the magnet is displaced, the magnetism sensed by the magnetic sensing element changes, thereby detecting the tilted state of the case.

(Problems to be Solved by the Invention) Therefore, the present invention aims to develop the above-mentioned inclination sensor and provide a horizontal sensor with a simple structure and high accuracy. The horizontal sensor according to the present invention can magnetically detect horizontality and electrically display it.

(Means for Solving the Problems) The horizontal sensor of the present invention includes a non-magnetic case having a cylindrical hollow part whose axis is oriented in the horizontal direction, and a non-magnetic case that is housed in the hollow part and is freely displaceable in the axial direction of the hollow part. A permanent magnet, a magnetic fluid that is attracted to the magnetized part of the permanent magnet and causes the permanent magnet to levitate from the bottom surface of the hollow part, and a magnetic fluid that is arranged in the axial center of the hollow part outside the non-magnetic case. or a plurality of magnetically sensitive elements.

(Function) When the bottom of the hollow part is horizontal, it means that the permanent magnet is located at the center of the hollow part, and when the bottom is tilted, it means that the permanent magnet has been displaced from the center in one direction. A magnetic sensing element detects this and extracts it as electrical output.

(Example) Hereinafter, embodiments will be described in detail with reference to the drawings.

1 and 2 show a horizontal sensor according to a first embodiment of the present invention, and FIG. 2 is a cross section taken along line XX in FIG. 1. Reference numeral 1 denotes a non-magnetic case having a cylindrical hollow part 2 whose axis is oriented in the horizontal direction, and a lid 1 that seals both ends of the hollow part.
a, lb and a board storage section cover 1c. Reference numeral 3 is a cylindrical permanent magnet housed in the hollow part 2, the shaft of which is oriented in the same direction as the axis of the hollow part, both sides of the shaft are magnetized, and is freely displaceable in the axial direction. A tapered non-magnetic member 4 is attached to both end faces, and this member 4 will be described later. 5 is a magnetic fluid that is attracted to the magnetized portion of the permanent magnet 3 and causes the permanent magnet to float from the bottom surface 2a of the hollow portion.

Reference numerals 7a and 7b are two switch-type Hall ICs mounted on the board 8 and placed outside the non-magnetic case 1 in the axial center of the hollow part, one of which is the Hall IC? For example, the surface of a that turns on in response to N polarity faces the permanent magnet, and the surface of the other Hall IC 7b that turns on in response to S polarity faces the permanent magnet side. In addition, Hall IC7
As shown in FIG. 3, a and 7b are slightly offset in the axial direction of the hollow portion. In FIG. 3, N displayed on the Hall IC 7a indicates that the surface that turns on in response to N polarity faces the permanent magnet side. The same applies to S displayed on the Hall IC 7b. As shown in FIG. 4, the Hall IC 7a (7b) forms a circuit with LE I', ) 9a (9b), a DC power supply 10, and a resistor 11. Therefore, when the Hall IC is turned on, L J>D lights up, and when it is turned off, L E D goes out.

Next, the operation of this embodiment will be explained with reference to FIG. First, when the horizontal sensor is horizontal, the bottom surface 2a of the hollow part 2 is also horizontal, and the permanent magnet 3 is located at the center of the hollow part. At this time, both Hall ICs 7a and 7b are under the influence of the N polarity and S polarity of the permanent magnet 3, respectively, so both Hall ICs 7a and 7b are turned on and L E
D 9 a and 9b are both lit. That is, two L
When ED and D are lit at the same time, it means that the horizontal sensor is horizontal.

Next, when the horizontal sensor is tilted, for example, so that the S side is lowered, the permanent magnet 3 levitated by the magnetic fluid 5 is easily displaced to the S side. In this case, the Hall IC 7a is placed directly above the N
Since the pole comes, it is of course under the influence of the N polarity, so it remains on and the LED 9a is lit. On the other hand, the Hall IC 7b is no longer under the influence of the S polarity and is now under the influence of the N polarity, so it is turned off, and therefore the LED 9 b goes out. On the other hand, if it tilts to the N side, Hall IC7
a is turned off, the Hall IC 7b is turned on, the LED 9a goes out, and the LED 9b lights up.

Here, a tapered member 4 attached to both end surfaces of the permanent magnet 3
This is to prevent the permanent magnet 3 from adhering to the inner wall of the lid due to the viscosity or surface tension of the magnetic fluid 5 when the horizontal sensor is tilted and the permanent magnet 3 moves toward the seal lid 1a or 1b. When the permanent magnet 3 moves, since the magnetic fluid 5 is present, friction is extremely small, and the permanent magnet 3 starts moving when the inclination angle of the horizontal sensor is 1/60 degree.

Also, as shown in FIG. 3, the hole IC7a.

The reason why 7b is slightly shifted is that both Hall ICs 7a and 7b are lit. This is because the displacement area of the permanent magnet 3 can have a width.

In this embodiment configured as described above, it is possible to detect whether the horizontal sensor is horizontal or tilted depending on whether both of the two LEDs are lit or only one of them is lit, and the direction of the tilt is also detected. can also be detected at the same time. Furthermore, the level can be easily detected by lighting the LED even in a dark place where it is difficult to see visually like a conventional bubble level.

Note that the shape of the hollow portion is not limited to a cylindrical shape, and may be, for example, a polygonal cylindrical shape. However, it is necessary to have a horizontal bottom surface as a reference. Further, the permanent magnet is not limited to a cylindrical shape, but a cylindrical shape having a through hole in the axial direction, a polygonal column shape, a polygonal cylinder shape, etc. can also be used.

Further, in the embodiment, the LED is lit by a signal from the Hall IC, but the signal can also be used as a horizontal control signal.

In the first embodiment, the direction of inclination can also be detected at the same time, but simply detecting whether the object is horizontal requires only one detection element. Figure 5 ((b) is 'Y- of (a)
(Y sectional view) shows the second embodiment of the present invention,
21 is a cylindrical hollow part whose axis is oriented in the horizontal direction, and 22 is a permanent magnet housed in the hollow part and movable in the axial direction of the hollow part. It has a disc shape with .

23 is a magnetic fluid that is attracted to the magnetized part of the permanent magnet 22 and makes the permanent magnet levitate from the bottom surface of the hollow part; 24 is a magnetic fluid that is arranged in the axial center of the hollow part at the lower part of the outside of the non-magnetic case;
This is a linear type Hall IC. Note that an MR element may be used instead of this Hall IC.

In such a configuration, when the bottom surface of the hollow part 21 is horizontal, the permanent magnet 22 is located at the center of the hollow part, and therefore the strength of the magnetic field sensed by the Hall IC 22 is the largest.
As shown in FIG. 6, the level of the signal output by the Hall IC 22 is also the highest, and when the bottom surface of the hollow part 21 is tilted, the permanent magnet is displaced from the center, and the Hall IC
The output level of 22 also becomes smaller. In other words, leveling involves finding the position where the output is maximum.

In addition, the shape of the magnet in this case may be other than a disk, such as a donut shape with a through hole in the center of the disk, or a prismatic shape with the axis facing the same direction as the hollow part, but in either case. It is necessary that the magnetized surfaces are up and down.

It goes without saying that the relative size of the hollow part and the permanent magnet should be such that the permanent magnet does not turn upside down or roll over.

(Effects of the Invention) As described above, according to the present invention, it is possible to provide a horizontal sensor that has a simple configuration, is inexpensive, and has high accuracy.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of one embodiment of the present invention, and FIG. 2 is a cross-sectional view of one embodiment of the present invention.
FIG. 3 is an explanatory diagram of the same operation, and FIG. 4 is an electric circuit diagram for horizontal detection. FIG. 5 is a block diagram of another embodiment of the present invention, and FIG. 6 is an output characteristic diagram of the same embodiment. ■...Non-magnetic case, 2.21...Hollow part, 3
．． 22... Permanent magnet, 5, 23... Magnetic fluid, 7
a, 7b...Switch type Hall IC 19a. 9b L E I), linear type Hall IC.

Claims (3)

[Claims] (1) A non-magnetic case having a cylindrical hollow part whose axis is oriented in the horizontal direction, a permanent magnet housed in the hollow part and movable in the axial direction of the hollow part, and a magnetized part of the permanent magnet. a magnetic fluid that is attracted to the magnetic fluid that causes the permanent magnet to levitate from the bottom surface of the hollow portion, and one or more magnetic sensing elements disposed outside the non-magnetic case and in the axial center of the hollow portion. , when the bottom surface of the hollow section is horizontal, the permanent magnet is located at the center of the hollow section, and when the bottom surface is tilted, the magnetic sensor detects that the permanent magnet is displaced from the center in one direction. A horizontal sensor characterized by detection using an element. (2) The horizontal sensor according to claim (1), wherein the permanent magnet has a magnetized surface in the vertical direction, and the magnetically sensitive element is an MR element or a linear type Hall IC. (3) A non-magnetic case having a cylindrical hollow part with an axis oriented in the horizontal direction, and a non-magnetic case housed in the hollow part, with the axis oriented in the same direction as the axis of the hollow part, and both sides of the axis magnetized. A columnar or cylindrical permanent magnet that can be freely displaced in the axial direction,
A magnetic fluid that is attracted to the magnetized portion of the permanent magnet and causes the permanent magnet to levitate from the bottom surface of the hollow portion, and a magnetic fluid that is attracted to the magnetized portion of the permanent magnet and floats the permanent magnet from the bottom surface of the hollow portion, and a magnetic fluid that is attached to the axially central portion of the hollow portion outside the non-magnetic case, one of which is sensitive to N polarity. It consists of two switch-type Hall ICs arranged such that one side that turns on and the other side that turns on in response to S polarity faces the permanent magnet side, and the bottom surface of the hollow part is horizontal. When the permanent magnet is located in the center of the hollow part, both of the two Hall ICs are turned on, and when it is tilted to one side, one Hall IC is turned off and the other Hall IC is turned on, and vice versa. A horizontal sensor characterized in that when tilted to the other side, the other Hall IC is turned off and one Hall IC is turned on.