JPS623382B2 - - Google Patents

Description

Detailed Description of the Invention The present invention generates eddy current torque in a good electrical conductor placed in a rotating magnetic field formed by a coil, and controls this torque with a hairspring to generate a rotating magnetic field that can be instructed by a pointer. The present invention relates to a rotating magnetic field instrument and a method for driving the same, which is related to instruments and particularly aims to simplify the drive circuit thereof.

The present inventor has already proposed a rotating magnetic field instrument as shown in FIGS. 1 to 3.

That is, in FIGS. 1 to 3, a copper cup 4 fixed to a pointer shaft 3 is disposed within the magnetic field of two mutually intersecting first and second coils 1 and 2, and a hairspring 5 is used. Then, a control torque is applied to the pointer shaft 3. Note that 6 and 7 are a core and a yoke for efficiently forming a magnetic circuit.

The third coil is connected to the first coil 1 in an instrument with this structure.
If we input the sine wave AC signal shown in Figure A, and the AC signal whose phase is delayed by 90 degrees with respect to the signal in Figure 3 A (Figure 3 B) to the second coil 2, we get
This generates a rotating magnetic field passing through the circumferential surface of the copper cup 4, and since the copper cup generates a torque in the direction of rotation, an indication proportional to the frequency of the input signal can be obtained.

However, although this method generates an almost perfect rotating magnetic field, when an AC signal is used as the input to be measured, an AC signal with a phase delay of 90 degrees relative to the AC signal is generated for the second coil. There is a need,
In addition, since it is necessary to convert pulse input into a sine wave or an approximate triangular wave, the circuit becomes complicated and expensive.

The inventor of the present invention, as a result of various studies to see if it was possible to drive the above-mentioned instrument with a fairly simple circuit, decided to use a pulse instead of an alternating current signal, and to apply a pulse to the first coil to another adjacent coil. He invented that by delaying the phase of the pulse applied to the pulse, an instrument reading approximately proportional to the pulse frequency can be obtained.

According to the present invention, since the rotating magnetic field instrument can be driven by pulses, the signal transmitter can be a simple one using contacts, reed switches, etc., and phase-shifted pulses can also be generated with a simple processing circuit. An inexpensive rotating magnetic field meter that is less affected by ambient temperature and power supply voltage can be provided, and is also suitable as a vehicle engine tachometer or speed meter.

FIGS. 1 and 2 for the first embodiment of the present invention,
To explain based on FIGS. 4 and 5, 1 is a first coil, 2 is a second coil, which are wound so as to be perpendicular to each other, and have a rotor of copper in the inner space.
A cup 4 made of a good electrical conductor such as aluminum is arranged. 3 is a pointer shaft with a pointer 8 fixed to its upper end;
The cup 4 is fixed to the middle part. A hairspring 5 is press-fitted into the pointer shaft 3 and controls the rotation of the pointer shaft 3.

Reference numeral 6 denotes a core disposed within the cup 4, and 7 a cup-shaped yoke fitted around the outer peripheries of the first and second coils. It is provided so as to penetrate the circumferential surface.

To explain the circuit of this embodiment using FIG. 4, 9
is an input terminal to which, for example, a pulse signal (FIG. 5A) from a reed switch that repeatedly opens and closes in proportion to the vehicle speed is input. Reference numeral 10 denotes a first flip-flop circuit, which is driven at the rising edge of the input pulse signal and produces an output with a duty ratio of 50% as shown in FIG. 5B. Reference numeral 11 denotes a second flip-flop circuit, which is driven at the falling edge of the input signal and produces the output shown in FIG. 5C. Therefore, with respect to the output of the first flip-flop circuit 10 (FIG. 5b), the output of the second flip-flop circuit 11 (FIG. 5c) has a phase lag of, for example, 90 degrees. Reference numeral 12 denotes a first polar drive circuit, which converts the output of the first flip-flop circuit 10, which is a non-polar pulse, into a polar pulse to drive the first coil. i.e. NPN transistor Q ₁
and the base of the PNP transistor Q ₂ are the first
The collector of the transistor Q ₁ is connected to the power supply, and the emitter of the transistor Q ₁ and the emitter of the transistor Q ₂ are both connected to one end of the first coil 1. The bases of the NPN transistor _Q3 and the PNP transistor _Q4 are connected to the first transistor through an inverter.
The collector of the transistor Q ₃ is connected to the power supply, and the emitters of the transistor Q ₃ and the transistor Q ₄ are both connected to the other end of the first coil 1 . Note that the collectors of transistors Q ₂ and Q ₄ are grounded.

To explain the operation of the polar drive circuit 12, when the output terminal of the first flip-flop circuit 10 becomes H level, the transistor _Q1 is turned on, the transistor _Q2 is turned off, the transistor _Q3 is turned off, and the transistor _Q4 is turned on. Therefore, the first coil 1 has the fourth
Current flows toward the right in the figure. Next, when the output terminal of the first flip-flop circuit 10 becomes L level, the transistor Q ₁ is turned off, the transistor Q ₂ is turned on, the transistor Q ₃ is turned on, and the transistor Q ₄ is turned off, so that the first coil A current flows through the coil 1 toward the left, and the first coil 1 is polarized.

The second polar drive circuit 13 connected to the second flip-flop circuit 11 also connects to the first polar drive circuit 1.
The second coil 2 has the same configuration and operation as the second coil 2, and the second coil 2 is polarized.

Therefore, the drive signal for the first coil 1 is as shown in FIG. 5D, and that for the second coil 2 is as shown in FIG. 5E.

Therefore, as shown in FIG.
When the second coil 2 is excited in the positive direction, a magnetic field F ₁ is generated, and when the second coil 2 is excited in the negative direction, a magnetic field F ₂ is generated, and the resultant magnetic field F _R is oblique in plan view. However, when the second flip-flop circuit 11 outputs the output as shown in _FIG . It is formed by
In the following order, the direction of the composite magnetic field rotates clockwise in steps of 90 degrees, and the rapid change in direction of the composite magnetic field during these step rotations produces eddy current torque in cup 4, and the average value of this torque is the hairspring. 5
In balance with the winding torque, the pointer 8 is rotationally displaced approximately in proportion to the frequency of the input pulse (FIG. 5A), and can indicate the number of input pulses.

In other embodiments shown in FIGS. 6 to 8, the first and second coils 1 and 2 are bifilar-wound, and a pulse transmitter 16 using reed switches 14 and 15 is combined to form a circuit. This is a simplified version.

In FIG. 6, the transmitter 16 includes a permanent magnet 17 driven by the rotational speed of the vehicle's transmission output shaft, and first and second transfer reed switches 14 and 15 arranged in parallel with the permanent magnet. The two reed switches 14 and 15 are set at a central angle.
Crossed at 45°. First reed switch 14
has a normally open terminal a and a normally closed terminal b, and the second reed switch 15 has a normally open terminal c and a normally closed terminal d. , b, c, d are the first
and both ends of the second coils 1 and 2, and the intermediate points of the first and second coils are grounded.

In the above embodiment, when the permanent magnet 17 is within the area shown in FIG. (Fig. 8), the terminals a and c output as shown in Fig. 8 a, c, and the first and second coils 1 and 2 produce magnetic fields as shown in Fig. 8 e.
F ₁ and F ₂ are generated, and their combined magnetic field F _R is formed diagonally upward and to the left. Thereafter, when the permanent magnet 17 moves from the area shown in Fig. 7, the composite magnetic field rotates clockwise in steps of 90 degrees as shown in Fig. 8e.
and FIG. 2).

According to this embodiment, the circuit is simplified and can be implemented relatively inexpensively.

9 is an example in which a rotating magnetic field instrument having bifilar-wound first and second coils 1 and 2 is driven by a non-polar pulse input, similar to the embodiment shown in FIG.
The pulse applied to the input terminal 9 is inputted to the first flip-flop circuit 10, and both ends of the first bifilar-wound coil are connected between the Q terminal and the terminal, and the second flip-flop circuit 11 is connected to the first flip-flop circuit 11.
The input pulse is inputted through an inverter, and a second bifilar-wound coil is connected to the Q terminal and the terminal. Note that 19 to 20 are width increasing drive circuits. This circuit also drives a meter in the same way as the one shown in FIG. 6 above.

FIG. 10 shows the structure of a rotating magnetic field instrument suitable for being driven by pulse input as described above, in which a copper cup 4 serving as a rotor is housed within a frame 23 made of a non-magnetic material, preferably synthetic resin. and a core 6 made of a high magnetic permeability material are arranged concentrically,
The first and second coils 1 and 2 are wound around the outer periphery of the frame 23 so as to cross each other. Reference numeral 7 denotes a yoke made of a high magnetic permeability material that also serves as a case, and is sized to surround the outer periphery of the first and second coils 1 and 2, and is sized to surround the outer periphery of the first and second coils, and has a yoke that extends from the adjacent side surfaces of the first and second coils. Inwardly recessed magnetically induced portions 7a are formed corresponding to the four concave portions formed in this way. This has the effect of strengthening the composite magnetic field formed by the first and second coils 1 and 2.

FIG. 11 also shows the structure of a rotating magnetic field instrument suitable for being driven by pulse input as described above, in which the first and second coils 1 and 2 are connected to cores 6 and 6' which are orthogonal to each other in a cross shape. Each is wound and placed inside a copper cup 4, and an annular yoke 7 made of a high magnetic permeability material is placed outside the copper cup 4.

Although each of the above embodiments has been described as having the first and second coils 1 and 2, it goes without saying that the number of coils may be three or more and they may be arranged at equal angles to each other.

As described above, the present invention includes a pointer shaft 3, a rotor 4 made of a good electrical conductor and fixed to the pointer shaft,
A plurality of coils 1 and 2 are arranged close to the rotor to apply a rotating magnetic field to the rotor and generate eddy current torque in the rotor, and a hairspring 5 fixed to the pointer shaft. In a rotating magnetic field instrument, one of the plurality of coils is energized by inputting a pulse, and during the duration of the pulse, another pulse is input to another adjacent coil to activate the other coil. A method for driving a rotating magnetic field instrument, characterized in that a combined rotating magnetic field F _R is excited and rotated stepwise by the excited coil, and an indicated torque is generated in the rotor 4, the method comprising: According to the present invention, since the rotating magnetic field instrument can be driven by pulses, the circuit becomes extremely simple, unlike the conventional drive using sine waves or triangular waves.

In particular, the signal input from one coil to another requires a signal with a phase lag, but if it is a pulse signal, a phase lag signal can be easily generated using a flip-flop circuit, etc., and the circuit can be easily constructed. Become.

Furthermore, in the present invention, while the pulse input to one coil continues, pulses are input to the other adjacent coils to obtain a composite rotating magnetic field that rotates stepwise, so that the direction of the composite rotating magnetic field can be changed. It is possible to produce an effective command torque on the rotor 4 by changing rapidly.

Furthermore, according to the present invention, since the rotating magnetic field meter is driven by pulses, this pulse signal can also be used to drive other step motors, so when this is implemented for automobiles, the speedometer and totalizer can be driven by the same input signal, which has the effect of simplifying the structure and reducing cost.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the main parts of a rotating magnetic field instrument, Fig. 2 is a sectional view of the rotating magnetic field instrument, Fig. 3 is a signal waveform diagram input to the rotating magnetic field instrument, and Fig. 4 is a first embodiment of the present invention. FIG. 5 is a signal waveform diagram and magnetic field direction diagram in the first embodiment, FIG. 6 is a circuit partial diagram in the second embodiment of the present invention, and FIG.
The plan view of the pulse generation section in the figure, Figure 8 is the second
FIG. 9 is a partial circuit diagram of the third embodiment of the present invention; FIG. 10 is a cross-sectional plan view of the fourth embodiment of the present invention; FIG. 11 FIG. 5 is a perspective view of a main part of a fifth embodiment of the present invention. 1, 2...Coil, 3...Pointer shaft, 4...Rotor (cup), 5...Hairspring, 6...Core, 7...Yoke, 7a...Inductive part, 8...Pointer, 9...Input terminal, 10, 11...Flip-flop circuit, 12, 13...Polar drive circuit, 1
4, 15...Transfer read switch, 16
... Transmission section, 17 ... Permanent magnet, 18 ... Power supply,
19, 20, 21, 22... Width increase drive circuit, 23
……flame.

Claims (1)

[Scope of Claims] 1. A pointer shaft, a rotor made of a good electrical conductor and fixed to the pointer shaft, and a rotating magnetic field applied to the rotor to produce eddy current torque in the rotor. In a rotating magnetic field instrument consisting of a plurality of coils placed close to each other and a hairspring fixed to the pointer shaft, one of the plurality of coils is energized by inputting a pulse, and the pulse is While this continues, other pulses are input to other adjacent coils to excite the other coils, and these excited coils form a composite rotating magnetic field that rotates stepwise, causing the rotor to A method for driving a rotating magnetic field instrument characterized by generating an indicated torque. 2. The rotor is cup-shaped, and the coil is a first coil wound perpendicularly to the upper and lower surfaces of the rotor so that the magnetic field penetrates the circumferential surface of the rotor.
and a second coil to form a composite rotating magnetic field that rotates in a stepwise manner to produce a directed torque on the rotor.
A method for driving a rotating magnetic field instrument as described in Section 1. 3. The rotor is cup-shaped, and the coils are rotated stepwise by mutually orthogonal first and second coils that are disposed within the rotor and wound around a cross-shaped orthogonal core. 2. The method of driving a rotating magnetic field instrument according to claim 1, further comprising forming a composite rotating magnetic field and producing an indicated torque on the rotor. 4. A pointer shaft, a rotor made of a good electrical conductor and fixed to the pointer shaft, and a plurality of rotors arranged close to the rotor so as to apply a rotating magnetic field to the rotor and generate eddy current torque in the rotor. In a rotating magnetic field instrument comprising a hairspring fixed to the pointer shaft and a plurality of coils, a polarized pulse is supplied to one of the plurality of coils in response to an input pulse, and a polarized pulse is supplied to one of the plurality of coils in response to an input pulse. A drive circuit is provided in the coil for supplying a polarized pulse whose phase is delayed with respect to the polarized pulse during the duration of the polarized pulse, and a composite rotating magnetic field rotated in a stepwise manner by the plurality of coils is generated. 1. A method of driving a rotating magnetic field instrument, characterized in that the rotor is formed with an instruction torque. 5. The drive circuit includes a first flip-flop circuit driven by the rising edge of the input pulse, a second flip-flop circuit driven by the falling edge of the input pulse, and first and second flip-flop circuits connected to the two flip-flop circuits, respectively. The coil is connected to the first and second polar drive circuits and wound at right angles to each other.
5. The method of driving a rotating magnetic field instrument according to claim 4, wherein a composite rotating magnetic field that rotates stepwise is formed by the coils of the rotor, and an instruction torque is generated in the rotor. 6. A pointer shaft, a rotor made of a good electrical conductor and fixed to the pointer shaft, and a plurality of rotors arranged close to the rotor so as to apply a rotating magnetic field to the rotor and generate eddy current torque in the rotor. In a rotating magnetic field instrument consisting of a coil and a hairspring fixed to the pointer shaft, each of the plurality of coils is a bifilar wound coil, and both ends of each of the plurality of coils are connected to a non-polar pulse generating section. connection,
The non-polar pulse generator supplies a positive pulse to one end of one of the plurality of coils, a pulse inverted to the positive pulse to the other end, and a pulse opposite to the positive pulse to one end of the adjacent other coil. A positive pulse with a delayed phase is supplied to the other end, and a pulse inverted to the positive pulse with a delayed phase is supplied to the other end, and a composite rotating magnetic field that rotates in a stepwise manner by the plurality of coils is formed to generate a composite rotating magnetic field that rotates the rotor. A method for driving a rotating magnetic field instrument, characterized in that it produces an indicated torque. 7 The non-polar pulse generator is placed under the magnetic flux of a permanent magnet that rotates in proportion to the rotational speed to be measured, and pulses are supplied to the coil by a plurality of transfer lead switches driven with a phase difference between them. A method for driving a rotating magnetic field instrument according to claim 6, characterized in that: 8. The non-polar pulse generator includes a first flip-flop circuit that is driven by the rising edge of the input pulse and has a positive output and an inverted output terminal, and a first flip-flop circuit that is driven by the falling edge of the input pulse and has a positive output and an inverted output terminal. The plurality of coils are composed of two bifilar-wound coils that are orthogonal to each other, and the plurality of coils form a composite rotating magnetic field that rotates in a stepwise manner, and the rotor 7. A method for driving a rotating magnetic field instrument according to claim 6, characterized in that an instruction torque is generated at a rotational magnetic field meter. 9 A pointer shaft, a cup-shaped rotor made of a good electrical conductor and fixed to the pointer shaft, and a top and bottom surface of the rotor so as to apply a rotating magnetic field to the rotor and generate eddy current torque in the rotor. A plurality of coils are wound around each other in a crosswise manner, and one of the coils is energized by inputting a pulse, and during the duration of the pulse, another pulse is applied to the other coil. a pulse generating means for exciting the other coil by inputting a pulse; A rotating magnetic field instrument characterized by comprising an induction part through which a synthetic magnetic field passes. 10. Claim 9, characterized in that the magnetic induction part is a yoke that also serves as a case and is made of a highly permeable material surrounding the outer periphery of the plurality of coils, and is partially formed into a concave shape. The rotating magnetic field instrument described.