JPH0413944B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic neutral position detection device used to detect the magnetic neutral position of a rotor of a flywheel magnet generator driven by an internal combustion engine or the like.

Prior Art A flywheel magnet generator, which is generally attached to an internal combustion engine, is equipped with a generating coil that supplies power to the ignition system for the internal combustion engine. Unless the output is induced according to the relationship, the ignition operation cannot be performed at the proper position.
The flywheel magnet rotor is usually installed by fitting the engine's rotating shaft into the boss part of the flywheel, and the rotor is positioned in the circumferential direction by fitting a keyway provided in the boss part on the rotating shaft side. This is done by fitting the key. In such a magnet rotor, the magnetic pole position of the magnet on the inner circumference of the flywheel is set so that the ignition operation is performed at the optimal timing when the flywheel is attached to the rotating shaft. If the keyway is misaligned or the magnet is attached to the inner surface of the flywheel, the ignition timing of the internal combustion engine ignition system will deviate from the specified timing, which may have a negative impact on the engine. Become.

A method for determining whether the magnetic pole position of this type of magnet rotor attached to a rotating shaft is normal is to detect the magnetic neutral position of the magnet rotor and check whether the position is normal or not. There is a way to determine. The magnetic neutral position of the magnet rotor is
It is the boundary position between each adjacent N pole and S pole of the rotor,
When the center of the magnetic poles of the stator core is located at this neutral position, the magnetic flux is balanced within the stator core, and the magnetic poles of the stator core become both the N and S poles of the rotor. It also becomes a state where it is not attracted.
Conventionally, when detecting the magnetic neutral position of a flywheel magnet rotor, the flywheel is fitted onto a rotating shaft with sufficiently weakened braking force, and the magnets on the inner circumference of the flywheel are connected to the stator core. By arranging the magnetic poles of the flywheel to face each other and slowly rotating the flywheel by hand, the flywheel is placed at a position where no rotational torque is generated between the flywheel magnet rotor and the stator core (the magnetic flux is balanced within the stator core). The method used was to find the position at which the condition occurred and read that position on a scale plate.

However, with this method, it is difficult to avoid a certain amount of braking force acting on the flywheel, making it difficult to determine the critical state in which rotational torque no longer acts on the flywheel, making it difficult to accurately determine the magnetic neutral position. Ta. In addition, detection requires considerable skill and detection takes a long time.

OBJECTS OF THE INVENTION An object of the present invention is to provide a magnetic neutral position detection device for a magnet rotor that can easily and accurately detect the magnetic neutral position of a magnet rotor.

Structure of the Invention The present invention is a magnetic neutral position detection device for detecting the magnetic neutral position of a flywheel magnet rotor in which a plurality of magnetic poles are formed at predetermined intervals on the inner periphery of a flywheel. , such that the center is located at a position corresponding to a fixed shaft that positions and supports the flywheel, and a regular magnetic neutral position of a magnet rotor disposed inside the flywheel magnet rotor and supported by the fixed shaft. A fixed iron core having a pair of magnetic poles provided therein; and a magnetic flux detector disposed between the poles of the fixed iron core to detect the magnitude and direction of the magnetic flux flowing through the stator iron core, The magnetic neutral position of the flywheel magnet rotor supported by the fixed shaft is detected based on the magnitude and direction of the magnetic flux detected by the detector.

The fixed shaft is adapted to fixedly support the flywheel magnet rotor whose magnetic neutral position is to be detected in a fixed positional relationship at all times. Since the center of the pair of magnetic poles of the fixed iron core is located at a position corresponding to the normal (theoretical) magnetic neutral position of the magnet rotor supported on the fixed shaft, the magnetism of the magnet rotor supported on the fixed shaft is When the neutral position is at the normal position, substantially no magnetic flux flows through the fixed iron core. A magnetic flux detector that detects the direction and magnitude of the magnetic flux (magnetic flux density) flowing through the fixed iron core is placed between the poles of the fixed iron core, so that the magnetic neutral position of the magnet rotor is of)
If the fixed iron core is out of position and magnetic flux is flowing through it, the magnetic flux detector detects the magnetic flux in either direction. Since the amount of magnetic flux is proportional to the amount of deviation of the magnetic neutral position from the normal position, it is possible to know how far the magnetic neutral position has deviated in which direction based on the direction of the magnetic flux and the amount of magnetic flux. .

The magnetic flux detector may be inserted, for example, into a gap provided between the poles of the fixed core. This magnetic flux detector can be constituted by a Hall element, for example. Since a Hall element can only detect magnetic flux density in one direction, when a magnetic flux detector is configured using Hall elements, the first and second Hall elements are provided with opposite polarities. In this case, the first and second Hall elements do not necessarily need to be provided separately, but two Hall elements may be housed in a package with their polarities reversed so that magnetic flux density in two directions can be detected. Of course, it can also be used.

The output signal obtained from the magnetic flux detector may be processed in any manner, and the output signal may be displayed in analog form and the neutral position may be determined from its scale. The neutral position may be directly read by converting it into a quantity corresponding to , and displaying the converted quantity in analog or digital form.

Effects of the Invention As described above, according to the present invention, the magnetic flux flowing through the fixed iron core is provided so that the magnetic flux does not substantially flow when the magnetic neutral position of the magnet rotor is at the normal position. Since a magnetic flux detector is provided to detect the direction and magnitude of the magnetic flux, there is an advantage that the magnetic neutral position of the flywheel magnet rotor can be detected statically, simply and accurately.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

1 and 2 are a top view and a front view, respectively, showing an embodiment of the present invention for detecting the magnetic neutral position of a four-pole flywheel magnet rotor, and in these figures, 1 is a board of the detection device. ,
Reference numerals 2 and 2 denote I-shaped fixed iron cores fixed to the substrate 1 by screws 3 arranged symmetrically on the substrate 1 at angular intervals of 180 degrees. A pair of magnetic pole parts 2a and 2a' are provided at both ends of each fixed iron core 2 with a pole pitch equal to the pole pitch of the rotor's magnetic poles (the angular interval between the center positions of adjacent magnetic poles). Outer surface 2a
1 and 2a1' are formed into a cylindrical surface having a slightly smaller radius of curvature than the magnetic pole surface of the flywheel magnet rotor to be detected so as to be able to face the magnetic pole surface of the flywheel magnet rotor through a predetermined gap. There is. Each fixed core 2 is formed by laminating steel plates punched into a predetermined shape, and a gap G is provided in the center between the poles of the fixed core 2.

In the gap G, first and second Hall elements 5 and 6 constituting the magnetic flux detector 4 are inserted. The first and second Hall elements 5 and 6 are arranged with their respective polarities reversed, and both Hall elements 5 and 6 are arranged with their polarities reversed.
and 6 flow in the fixed iron core 2 in one direction (from one magnetic pole part 2a side to the other magnetic pole part 2a' side) and in the other direction (from the other magnetic pole part 2a' side to one magnetic pole part 2a side). ) is designed to detect the flowing magnetic flux. Reference numerals 7 and 8 denote a group of lead wires connected to the terminals of the Hall elements 5 and 6 and led out.

A fixed shaft 9 fixed to the substrate 1 is disposed between the fixed iron cores 2, 2, and the fixed shaft is tapered to match the tapered hole of the boss of the flywheel magnet rotor. The fixed shaft 9 is provided with a key 10 that fits into the keyway of the boss of the flywheel magnet rotor, and the magnet rotor to be detected is aligned with the fixed cores 2 by the engagement of the key and the keyway. They are positioned in a predetermined positional relationship in the circumferential direction. With the flywheel magnet rotor positioned in this manner, the centers of the magnetic pole portions 2a, 2a' of each fixed iron core 2, 2 are located at a position corresponding to the regular magnetic neutral position of the magnetic pole of the magnet rotor, When the magnetic neutral position of the magnetic poles of the magnet rotor supported by the fixed shaft 9 is at a normal position, substantially no magnetic flux flows through each fixed iron core 2.

3 and 4 show a state in which the magnetic neutral position of the flywheel magnet rotor 11 is detected by the above-mentioned detection device, together with an example of the configuration of a circuit used for detection. Flywheel 12 formed into a cup shape
It consists of four arc-shaped permanent magnets 13a to 13d fixed to the inner periphery of the rotor by appropriate means such as adhesive, and the magnets 13a to 13d are arranged alternately in the circumferential direction of the rotor so that different magnetic poles are arranged alternately. They are magnetized in different radial directions. flywheel 1
A boss 14 is provided at the center of the bottom wall of the boss 14, and the fixed shaft 9 is fitted into the tapered hole 14a of the boss.
The magnet rotor is positioned in the circumferential direction by being fitted into the keyway 4a. In this state, each fixed core 2
The centers of the magnetic pole portions 2a, 2a' are located at positions corresponding to the normal magnetic neutral position of the magnet rotor 11, respectively.

In order to cause a predetermined DC current to flow through the first and second Hall elements 5 and 6, a DC voltage of about 1 [V] is applied from a DC power supply 15 to the current input terminals of both Hall elements. The Hall element 5 detects the magnetic flux when it flows from the magnetic pole portion 2a at one end of each fixed iron core 2 to the magnetic pole 2a' side at the other end, and generates an output voltage proportional to the detected magnetic flux. Further, the second Hall element 6 detects the magnetic flux when it flows from the magnetic pole 2a' side at the other end of each fixed iron core 2 to the magnetic pole 2a side at one end, and generates an output voltage. The output voltages of the first and second Hall elements 5 and 6 are input to the first and second amplifiers 16 and 17, respectively, and in this example, the output voltages of the amplifiers 16 and 17 are input to the voltage angle conversion circuit 1.
8 is entered. The output of the voltage angle conversion circuit 18 is input to a display 19, and the magnetic neutral position is displayed on the display. A power supply 15, first and second amplifiers, a voltage angle conversion circuit 18, and a display 19 are provided for each fixed core, and the four locations of the magnet rotor 11 are controlled by the output of the Hall elements provided in both fixed cores. The position of the magnetic neutral is detected.

In the above embodiment, if the magnetic neutral position of any of the magnetic poles of the magnet rotor 11 attached to the fixed shaft 9 is not at the normal (theoretical) position, the magnetic flux will flow to one of the fixed iron cores 2. This magnetic flux is detected by the first or second Hall element 5 or 6. At this time, depending on which of the first and second Hall elements detects the magnetic flux, it is possible to know whether the actual magnetic neutral position deviates from the normal position to the lag side or the leading side. be able to. Furthermore, since the magnitude of the magnetic flux density detected by the Hall element is proportional to the deviation of the actual magnetic neutral position from the normal position, it is not possible to know the actual magnetic neutral position from the magnitude of the detected magnetic flux. can. In the above example, the magnetic flux detection voltage output by the Hall element is converted into an angle by the voltage angle conversion circuit 18, so
The actual magnetic neutral position can be easily determined. The angular voltage conversion circuit 18 determines which of the two amplifiers 16 and 17 is generating the output, and converts the output of the amplifier into a signal corresponding to the angle. In this case, the polarity of the signal is made to differ depending on the direction of deviation of the magnetic neutral position.

By inputting this signal to the display 19 and displaying it, the position of the magnetic neutral can be easily known.

In the above embodiment, two fixed iron cores are provided, but depending on the purpose and usage conditions of the magnet generator, it may not be necessary to measure all magnetic neutral positions of the flywheel magnet rotor. , the number of fixed cores is arbitrary. When only one fixed core is provided, it goes without saying that the position of the key on the fixed shaft 9 is set so that the magnetic pole portion of the fixed core is located at a position corresponding to a predetermined magnetic neutral position to be detected.

[Brief explanation of drawings]

Figures 1 and 2 are a top view and a front view showing an embodiment of the present invention, respectively, and Figure 3 shows the detection device of the same embodiment used to detect the magnetic neutral position of the flywheel magnet rotor. FIG. 4 is a top view showing a cross-sectional view of the flywheel together with a configuration example of a circuit used for detecting the state, and FIG. 4 is a front view of FIG. 3 showing a cross-sectional view of the flywheel magnet rotor. 1... Device board, 2... Fixed iron core, 2a...
Magnetic pole part, 4... Magnetic flux detector, 5... First Hall element, 6... Second Hall element, 9... Fixed axis,
11... Flywheel magnet rotor, 13a to 13d... Magnet.

Claims (1)

[Scope of Claims] 1. In a magnetic neutral position detection device for detecting the magnetic neutral position of a flywheel magnet rotor in which a plurality of magnetic poles are formed at predetermined intervals on the inner periphery of a flywheel, a fixing member that positions and supports the flywheel; a shaft, and a pair of magnetic poles disposed inside the flywheel magnet rotor and provided with a center located at a position corresponding to a regular magnetic neutral position of the flywheel magnet rotor supported by the fixed shaft. and a magnetic flux detector disposed between the poles of the fixed core to detect the magnitude and direction of the magnetic flux flowing through the stator core, A magnetic neutral position detection device for a magnet rotor, characterized in that the magnetic neutral position of a flywheel magnet rotor supported by the fixed shaft is detected based on size and direction. 2. The magnetic neutral position detection device for a magnet rotor according to claim 1, wherein the magnetic flux detector is comprised of first and second Hall elements provided with different polarities. .