JPH04215410A - Generating magnetic field detecting switch - Google Patents

Abstract

PURPOSE:To be able to detect a magnetic field strength and set a corresponding magnetic field by detecting the magnetic field strength as an analog voltage outputted from a Hall element and comparing the voltage with a reference voltage so as to actuate a magnetic field detecting switch for obtaining a preset strength of the magnetic field. CONSTITUTION:When a magnetic flux a generated by a magnetic field generating circuit is higher than a set value, an output voltage from a Hall element 9 becomes higher than a voltage to be supplied from reference voltage setting circuits 21, 22. A comparator 23 for comparing these 2 voltage does not output. If the magnetic flux is lower than the set value, the output voltage from the Hall element 9 becomes lower than the voltage to be supplied from the reference setting circuit and is compared by a comparator circuit. As a result, the comparator 23 outputs a comparator data to a deciding output part 24, which produces output signals for instructing an increase in the output towards an external magnetic field generating circuit or the like. Thus, mechanical operations are made unnecessary and a magnetic field detecting power is not limited.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is applied to magnetic field forming presses, magnetizing devices, magnetic induction heating devices, etc. that use magnetic field generating circuits, and is applicable to magnetic field forming presses, magnetizing devices, magnetic induction heating devices, etc. that use magnetic field generation circuits. The present invention relates to a magnetic field detection switch that detects by conduction of electrodes configured by the following.

0002

2. Description of the Related Art As shown in the cross-sectional view of FIG. 2, a switch conventionally used for detecting a magnetic field generating device uses a force arrow b generated by magnetization of an electrode 13 formed by a magnetic lead by a magnetic field. in contact with the other electrode 14;
As a result, electrical continuity was obtained, and the electrical continuity was used as a detection signal.

0003

[Problem to be solved by the invention] In conventional magnetic field detection switches, changes in magnetic field strength act on lead electrodes made of magnetic material, and are detected as mechanical displacement, so There were problems such as errors in detection power depending on mechanical accuracy, malfunctions due to external forces such as vibrations, and detection of open and closed states only, including non-detection in weak magnetic field regions. Furthermore, since the detection force is determined depending on the mechanical strength of the electrode, it is necessary to replace or change the arrangement position of the detection switch itself if the magnetic field strength to be detected changes.

0004

[Means for Solving the Problems] In order to solve the conventional problems, the present invention uses a Hall element that outputs an analog voltage change according to the magnetic field strength instead of a detection switch, and obtains a result from this Hall element. The generated voltage is compared with the voltage from a reference voltage generation circuit that is created in advance to generate a voltage corresponding to the required magnetic field strength, and if the difference is greater than a certain value, the magnetic field is detected and output. A generated magnetic field detection switch was constructed by the circuit.

[0005]

[Function] Since the Hall element does not require mechanical action,
There is no restriction on the magnetic field detection ability due to this. Further, even if there is a slight change in the magnetic field strength to be detected, stable detection can be achieved by performing arbitrary processing on the subsequent electric circuit. Furthermore, by making it possible to set the reference voltage to any value, it is possible to use it as a detection switch in a wide range of magnetic field strengths.

[0006]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings. An example of the detection section of the present invention is shown in the front view of FIG. In the figure, the magnetic field generated by passing current through the magnetic field coils 5 and 8 is generated by the upper pole piece 3, the upper yoke 1, the side yokes 7 and 8, the lower yoke 2, and the lower pole piece 4.
A magnetic circuit is formed by the pole pieces 3 and 4, and magnetic flux lines a as shown by the arrows are generated between the pole pieces 3 and 4. The Hall element 9 is arranged so that the Hall effect can be obtained by this magnetic flux line a, and a predetermined current is supplied to the Hall element by a power line 10 of the Hall element 9 diagram. Further, the output line 11 of the Hall element 9 applies a voltage generated by the Hall effect to the input of a judgment circuit to be described later. FIG. 3 is an example of a block diagram of a circuit forming part of the present invention. In the same figure, 19 is a power supply section that supplies an appropriate current to the Hall element 9 and also provides operating current to other blocks, and a buffer section 20 that does not affect the output of the Hall element in subsequent stages. , the purpose is to remove noise contained in the output from the Hall element 9. 2
The reference voltage generating section 1 always generates a constant voltage and supplies it to the reference setting section 22 . The reference setting section 22 divides the supplied reference voltage to obtain a predetermined voltage corresponding to the magnetic field strength, and adds this to one input of the comparator 23 . The output from the Hall element is added to the other input of the comparator 23 through the buffer section. Comparator 23 compares these two inputs, and the output of Hall element 9 is lower than the reference. Or if it is high, the comparator output is output to the judgment output section 24. The judgment output section receives the comparator output and outputs a signal that can be driven to an external circuit as a judgment output.

Next, the operation will be explained. Now, when the magnetic flux a generated by the magnetic field generation circuit is higher than the set value, the output voltage from the Hall element 9 becomes higher than the voltage supplied from the reference voltage setting circuit. Comparator 23, which compares these two voltages, does not provide its output. If the magnetic flux a is lower than the set value, the output voltage from the Hall element will be lower than the voltage supplied from the reference setting circuit,
Compare using a comparator circuit. As a result, the comparator 23 outputs the comparator output to the judgment output section 24, and the judgment output section generates an output signal instructing an external magnetic field generation circuit or the like to increase its output.

[0008]

As described above, the present invention detects the strength of the magnetic field by detecting the output voltage from the Hall element as an analog quantity, compares the voltage with a reference voltage, and uses it as a magnetic field detection switch. It is possible to set a suitable magnetic field, and by electrically processing the detection signal, a highly accurate and reliable magnetic field detection switch can be obtained at low cost.

[Brief explanation of the drawing]

FIG. 1 is a front view of main parts of a device showing an embodiment of a detection section of the present invention.

FIG. 2 is a sectional view showing the structure of a switch used as a conventional magnetic field detection switch.

FIG. 3 is a block diagram showing an embodiment of a magnetic field detection/judgment circuit according to the present invention.

[Explanation of symbols]

1 Upper yoke 2 Lower yoke 3 Upper pole piece 4 Lower pole piece 5 Upper magnetic field generating coil 6 Lower magnetic field generating coil 7 Side yoke 1 8 Side yoke 2 9 Hall element 10 Hall element power supply line 11 Hall element output line 12 Case 13 Magnetic material 1 14 Magnetic material 2 15 Electrode contact 1 16 Electrode contact 2 17 Sealant 1 18 Sealant 2 19 Power supply section 20 Buffer section 21 Reference voltage generation section 22 Standard setting section 23 Comparator section 24 Judgment output section

Claims (1)

[Claims] [Claim 1] A Hall element that detects magnetic flux generated within or near the magnetic circuit in a magnetic field generating circuit configured by passing a current through a coil of a magnetic circuit consisting of a coil, a yoke, and a pole piece. and an electric circuit configured to compare and calculate the voltage corresponding to the magnetic flux density obtained by this Hall element with an arbitrary reference voltage and output an arbitrary signal when a certain difference occurs. Generated magnetic field detection switch.