JPS5920746Y2 - position detection device - Google Patents

Description

[Detailed description of the invention] The present invention relates to a device for detecting the position of a moving object using a reed switch and a permanent magnet. It is an object of the present invention to provide a position detection device that can freely select the generation position or generation time of an electric signal.

FIG. 1 shows a conventional example.

In the figure, 1 is a DC power supply, 2 is a resistor, and 3 is a reed switch, which are connected in series.

4 indicates a permanent magnet, and 5 indicates the moving direction of the moving object.

Either a reed switch 3 or a permanent magnet 4 is attached to the moving object, and the remaining one remains stationary to detect the moving object.

The same applies even if the direction of movement is reversed.

Further, the moving direction is not limited to a linear direction, but the same can be considered when moving in an arc shape.

Furthermore, although the magnetic poles of the permanent magnet 4 are shown as N and S, the same applies even if they are reversed.

Note that the electrical signal is obtained between the terminals 6 and 7.

FIGS. 2a and 2b schematically show the positional relationship between the reed switch 3 and the permanent magnet 4 and their operating range in the conventional example.

In those drawings, a reed switch 3 and a permanent magnet 4
are in the same plane, and the case where the reed switch 3 and the permanent magnet 4 are moved 4 mm apart is shown by a straight line M, and the case where the reed switch 3 and the permanent magnet 4 are moved 6 mm apart is shown by a straight line N.

Note that the shaded area in FIG. 2 indicates the reed switch ON region.

Since the straight line M passes through three ON regions of the node switch 3, the distance between the reed switch 3 and the permanent magnet 4 is 4 mm.
When moving away, turn on reed switch 3 three times.
take action.

In addition, the reed switch 3 and the permanent magnet 4 in a straight line N are 6 m long.
It can be seen that when moving a distance of m, the reed switch 3 operates only once.

However, such a position detection device has the following problems.

(1) Depending on the distance between the reed switch and the permanent magnet, the reed switch may be turned on 9 or 3 times instead of once.

As a result, the detection position of the moving object is shifted and the operation becomes unstable.

(2) The width of the ON region of a reed switch varies somewhat depending on the strength of the magnetic pole of the permanent magnet and the magnetization characteristics of the reed switch, but most of it depends on the lengthwise dimension of the reed switch and can be freely selected. Can not.

For this reason, a computer-based logic circuit is used to process the detected electrical signals, and the operation becomes unstable if the moving object moves at a high speed.

The present invention solves such conventional problems.

Hereinafter, the present invention will be explained based on the illustrated embodiments.

FIG. 3 is a top view of an embodiment of the present invention, FIG. 4 is a front view thereof, and FIG. 5 is a side view thereof.

In those drawings, 8 represents a reed switch and 9 represents a permanent magnet.

Although the magnetic poles of the permanent magnet 9 are shown as N and S, the same applies even if the relationship between the N and S poles is reversed.

Reference numeral 10 indicates the moving direction of a moving object (not shown) whose position is to be detected, and in the case of FIG. 5, it indicates the direction penetrating the paper.

Note that the same holds true even if the moving direction of the moving object is reversed.

Furthermore, either the reed switch 8 or the permanent magnet 9 is attached to the moving object, and the remaining one is used fixedly.

Note that the DC power supply 1 and resistor 2 as shown in FIG. 1 are omitted from illustration.

Next, the operation of this embodiment will be explained.

First, when examining the operating range of the reed switch 8 in the side view of FIG. 5, it becomes as shown in FIG. 6.

That is, it can be seen that the reed switch performs an OFF operation at the center of the node switch 8, and an ON operation exists at both ends several mm away from the center of the reed switch.

From this, it can be seen that if the position of the permanent magnet is selected as point A of Y-Q, ZP, the reed switch will turn on because it is within the ON region of the reed switch.

Next, let's examine the operation of the reed switch in this Z-P cross section.

In this case, the cross-sectional view taken along line Z-P in FIG. 4 can be considered, and the operating region is as shown in FIG. 7.

A straight line R in FIG. 7 shows the operation when Z=P and Y=Q.

From this, if the object to be detected moves while maintaining Z=P and Y=Q, the reed switch is turned ON over a distance of 40 mm or more.

Note that the length indicated by S in FIG. 7 indicates the length of the permanent magnet 9 used.

From this, Z=P and Y=Q can be selected as in the present invention, the reed switch always operates at the same position, and the ON operation distance or ON operation time of the reed switch in the moving direction of the moving object to be detected is could be made longer than the length of the permanent magnet in the moving direction of the moving object to be detected.

As is clear from the above description, according to the present invention, the position of the moving object to be detected can be detected accurately, so that the control of the apparatus can be realized with high precision.

Further, since the reed switch ON operation time can be obtained as long as necessary, a low-cost position detection device that does not cause malfunction can be realized.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a conventional example, Fig. 2 a, l) is a diagram of component arrangement and characteristic diagrams for explaining the operation of Fig. 1, Fig. 3 is a top view of an embodiment of the present invention, and Fig. 4 5 is a front view thereof, FIG. 5 is a side view thereof, and FIGS. 6 and 7 are operational characteristic diagrams of the same embodiment. 8...Reed switch, 9...Permanent magnet, 10...Movement direction of moving object.

Claims (1)

[Scope of utility model registration request] A node switch is arranged perpendicularly or substantially perpendicularly to the moving direction of the moving object to be detected, and a permanent magnet is arranged only on one side away from the center of the reed switch, and one of the permanent magnets is arranged at a distance from the center of the reed switch. The reed switch and the permanent magnet are arranged so that their magnetic pole faces face each other, one of the reed switch and the permanent magnet is provided on a fixed part, and the other is provided on a moving object to be detected, so that the position of the moving object to be detected is detected. position detection device.