JP3304351B2 - Voltage indicating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Industrial applications]

The present invention relates to a voltage indicating device for indicating a voltage, and more particularly to a voltage indicating device using a cross coil and a permanent magnet for zero return.

[0002]

[Prior art]

Conventionally, as this kind of voltage indicating device, there is one having a configuration as shown in FIG. In the figure, L ₁ and L ₂ are the pointer axes R
The first and second coils, which are wound around the outer periphery of a coil bobbin B accommodating a rotating magnet (not shown) so as to rotate in such a manner as to rotate, and Mg are fixed return zeros. The permanent magnet 1 is an insulating seat for positioning and fixing the permanent magnet for return magnet Mg. Further, Figure 5 shows the electric circuit of the voltage indicating device of FIG. 4, the first and second coil L ₁ and L ₂ are connected in series, a fixed resistor R ₁ is further the second coil L _{2 connected, L 1, L 2, R} 1
Form a series circuit. The two terminals a and b of the series circuit are connected to the + electrode and the-electrode of a DC voltage source V, such as an on-vehicle battery, to be indicated.

In the above configuration, the first and second coils L ₁ and L ₂
Assuming that the combined pure resistance component of the copper wire forming is _RL , a DC current I ₁ represented by the following equation (1) flows through the series circuit. I ₁ = V ₁ / (R ₁ + _RL ) …… (1)

The DC current I ₁ flows through the _first and _second coils L ₁ and L ₂ , and a magnetic field Φ obtained by combining the magnetic fields Φ _L1 and Φ _L2 as shown in FIG.
_L is a vector composition of the magnetic fields Φ _L1 and Φ _L2 .
On the other hand, the permanent magnet Mg for zeroing has a magnetic field [Phi _M of the first 180 to the magnetic field [Phi _L1 of the coil L ₁ occurs DEG inverse direction as shown in FIG. 6 occurs.

The [0005] above, the final combined magnetic field [Phi is the direction of the resultant magnetic field [Phi _L and the magnetic field [Phi _M and vector combination of the voltage indicating device. Field [Phi _L1 and [Phi _L2 as described above here is proportional to the current I _1, since the current I ₁ is proportional to the voltage of the DC voltage source V, the direction of the combined magnetic field [Phi _L is the voltage of the DC voltage source V size Corresponding to the magnetic field Φ _L and the combined magnetic field Φ _M
Also corresponds to the voltage of the DC voltage source V.

Therefore, as shown in FIG. 7, if a rotating magnet Mgr rotatable about the pointer axis R is installed in the magnetic field of the synthetic magnetic field Φ,
Since the rotating magnet Mgr rotates to a position where its NS magnetic pole coincides with the direction of the magnetic field of the synthetic magnetic field Φ, the rotating magnet Mgr is rotated by the pointer A and the scale plate B attached to the pointer axis R which is the rotating axis of the rotating magnet Mgr. By reading the angle, the voltage of the DC voltage source V can be recognized. When no voltage is applied from the DC voltage source V, the synthesized magnetic field Φ is
As consisting of Mg of the magnetic field [Phi _M, the voltage of the DC voltage source V is when it is 0V, the rotating magnet Mgr is to be zero indication rotated position to match the direction of the combined magnetic field [Phi.

[0007]

[Problems to be solved by the invention]

In the above-described voltage indicating device, when the ambient temperature changes, the magnitude of the magnetic field Φ _M changes due to the temperature characteristics of the permanent magnet for return zero Mg, and at the same time, the magnetic field Φ _M changes due to the temperature characteristics of the first and second coils L ₁ and L _2. the magnitude of the resultant vector [Phi _{L L1} and [Phi _L2 also changes. Incidentally, when the temperature change rate of the combined magnetic field [Phi experimenting with discussed with reference to FIG. 8, the magnetic field [Phi _M first by the permanent magnet Mg for zero-reset, because depending on the specific temperature coefficient of the permanent magnet Mg, its The temperature change rate is constant. While the temperature change rate of the combined magnetic field [Phi _L of the coil L _1, L ₂ is as follows. That is, the first and second coils L ₁ and L ₂
The pure resistance component R _{L of, R L = R L '+} R L (t) ...... (2) R L': resistivity, R _L (t): from being represented by a resistance component dependent on the temperature, The current I ₁ flowing in the series circuit is (1)
And the equation (2) from _{I 1 = V 1 / (R} 1 + R L '+ R L (t)) ...... (3). (3) direct current I ₁ is changed by a temperature change from the equation. Such a DC current I ₁ is applied to the first and second coils L ₁
And by flowing to L _2, the magnetic field [Phi _L1 and [Phi _L2 is varied by temperature. Therefore, the resultant magnetic field Φ _L also changes with temperature.

FIG. 8 shows the change of each magnetic field depending on the temperature. The solid line in FIG. 8 shows the magnetic field at room temperature, the dashed line shows the magnetic field at room temperature lower than room temperature, and the dotted line shows the magnetic field at room temperature higher than room temperature. Temperature change rate of the magnetic field [Phi _M of the permanent magnet Mg for zeroing the figure is greater than the temperature change rate of the first and second combined magnetic field [Phi _L of the coil L ₁ and L _2,
If the rates of temperature change are different from each other, the direction of the synthetic magnetic field Φ varies in the range of θ in the drawing, and the indication of the voltage of the DC voltage source V changes depending on the temperature. Accordingly, in view of the above-described problems, it is an object of the present invention to provide a voltage indicating device that reduces the change in the indicated value of the DC voltage with respect to the temperature change and improves the temperature characteristics.

[0009]

[Means for Solving the Problems]

In order to solve the above-mentioned problems, a voltage indicating device according to the present invention comprises a first and a second coil arranged crossing each other and a combined pure resistance component of the first and second coils. The first and second coils are connected in series with a fixed resistor having a predetermined resistance value that determines the value of a direct current flowing through the first and second coils to form a series circuit. And generating a first synthesized magnetic field obtained by synthesizing a magnetic field generated by the second coil and disposing a fixed magnet in the synthesized magnetic field, and synthesizing the magnetic field generated by the fixed magnet and the first synthesized magnetic field. A voltage indicating device that generates a combined magnetic field, rotates the rotating magnet so that the magnetic poles coincide with the direction of the second combined magnetic field, and indicates the voltage value of the DC voltage by the rotational position of the rotating magnet. The first and A third coil superposed on at least one coil of the second coil and wound in the opposite direction, and having the same inductance as the third coil, and superposed on the coil wound with the third coil. A fourth coil wound in the same direction is connected in series with the series circuit,
And the combined pure resistance component of the fourth coil is set to a value required to make the temperature change rate of the first combined magnetic field equal to the temperature change rate of the fixed magnet, or when the third and fourth coils are not provided. In comparison, the temperature change rate of the first combined magnetic field is not a value necessary for approaching the temperature change rate of the fixed magnet, and the resistance value of the fixed resistor is determined from the predetermined resistance value by the third and fourth coils. Reduced by the combined pure resistance component, and maintained a DC current flowing in a series circuit of the first to fourth coils and the fixed resistor at a value determined by a predetermined resistance value of the fixed resistor before reducing the resistance value. It is characterized by doing.

[0010]

[Action]

In the above configuration, since the third and fourth coils are wound in opposite directions, the magnetic fields of the coils are canceled out because they have the same magnitude and are shifted by 180 °. Accordingly, a first combined magnetic field is generated by combining the magnetic fields of the first and second coils. On the other hand, the resistance of the series circuit having a predetermined resistance value that determines the value of the DC current flowing through the first and second coils together with the combined pure resistance components of the first and second coils is determined by subtracting the third resistance value from the predetermined resistance value.
And the resistance value obtained by subtracting the combined pure resistance component of the fourth coil, the series resistance of the series circuit including the third and fourth coils is the same as before connecting the third and fourth coils. , And the sum of the predetermined resistance value and the combined pure resistance components of the first and second coils. Therefore, a current flows through the series circuit due to the DC resistance, and the magnitude of each magnetic field generated by the first and second coils is determined. Therefore, the direction of the first combined magnetic field is set, and combined with the magnetic field of the fixed magnet. Second by
Is generated. Since the direction of the second combined magnetic field corresponds to the magnitude of the DC voltage, the DC voltage can be indicated by this.

On the other hand, since the pure resistance components of the first and second coils have temperature characteristics, the current flowing in the series circuit changes depending on the temperature, and the magnitude of the magnetic field of the first and second coils decreases. Change. For this reason, the direction of the first combined magnetic field also changes depending on the temperature. If the temperature change rate of the first combined magnetic field is different from that of the fixed magnet, the second combined magnetic field changes with the temperature.

However, the pure resistance components of the third and fourth coils also have temperature characteristics, and the series resistance can be determined by appropriately setting the value of the combined pure resistance component of the third and fourth coils. By changing the temperature change rate of the current flowing through the circuit and changing the temperature change rate of each magnetic field of the first and second coils, the temperature change rate of the first combined magnetic field can also be changed. Accordingly, the temperature change rate of the first combined magnetic field can be made to match the temperature change rate of the fixed magnet, or can be made closer to the case where the third and fourth coils are not provided. Can be reduced.

[0013]

【Example】

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an electric circuit diagram showing an embodiment of a voltage indicating device according to the present invention. In FIG. 1, the same parts as those in FIG. In FIG. 1, −L ₃ and L ₃ are third and fourth coils, and the third coil −L ₃ is in the opposite direction to the second coil,
Fourth coil is wound respectively overlapped with the second coil L ₂ around the second coil L ₂ and the same direction. The third and fourth coil -L ₃ and L ₃ have the same inductance.

Further, the fixed resistor R ₃ has a resistance value of a third value from the resistance value R ₁ .
And it is set to the fourth value obtained by subtracting the synthesized pure resistance component R ₂ coils -L ₃ and L _3. The resistor R ₃ , the first to fourth coils L ₁ , L ₂ , −L ₃ and L ₃ are connected in series to form a series circuit, and a series voltage source V connected to both terminals a and b thereof A voltage is applied. In addition, each coil and permanent magnet for zero return Mg
Are arranged as shown in FIG. In the above configuration, when a pure resistance component and R _2, the combined resistance R of the series circuit _{R = R 3 + R 2 +} R L = R 1 -R 2 + R 2 + R L = R 1 + R L ...... (4) next Therefore, the current I ₁ becomes I ₁ = V ₁ / (R ₁ + R _L ),
This is consistent with the equation (1). Therefore, the same current I ₁ in the case of FIG. 4 flows first through fourth coil by the current I ₁ is generated a magnetic field.

FIG. 2 shows each magnetic field, and the second coil L ₂
Because it is wound in the same direction and the fourth coil L ₃ when,
The magnetic fields Φ _L2 and Φ _L3 are in the same direction. Since the third coil -L ₃ are wound in the second and fourth coil direction opposite, as shown, opposite direction magnetic fields - [Phi] _L3 was 180 ° out of the magnetic field [Phi _L2 and [Phi _L3 It has become. And the third
And since the fourth inductance coils -L ₃ and L ₃ are equal, the magnitude of the magnetic field - [Phi] _L3 and [Phi _L3 are equal, after all fields - [Phi] _L3 and [Phi _L3 are mutually canceled. Therefore, the combined magnetic field Φ _L of each coil is a composite of the magnetic fields Φ _L1 and Φ _L2 of the first and second coils L ₁ and L ₂ , and the combined magnetic field Φ is the combined magnetic field of Φ _M and Φ _L. Become. Thus, the voltage value of the DC voltage source V is indicated in the direction of Φ in the same manner as in the case of FIG.

Next, the operation of the apparatus having the configuration shown in FIG. 1 in consideration of a temperature change will be described. Third combined pure resistance component of and the fourth coil -L ₃ and L ₃ R ₂
Also have temperature characteristics like the first and second coils, and R ₂ = R ₂ ′ + R ₂ (t)... (5) R ₂ ′: specific resistance, R ₂ (t): temperature-dependent It is expressed as a resistance component. On the other hand since the fixed resistor R ₃ has no little temperature characteristics and the resistance value _{R 3 = R 1 -R 2 '} . Accordingly, the combined resistance R is (4), (5) the _{formula, R = R 3 + R 2} + R L = R 1 -R 2 '+ R 2' + R 2 (t) + R L '+ R L (t) = R 1 _{+ R L '+ R L (} t) + R 2 (t) ...... (6) , and the current I ₁ is _{I 1 = V 1 / R =} V 1 / (R 1 + R L' + R L (t) + R 2 (t )) ... (7) (7) it is possible to vary the temperature change rate of the current I ₁ according to R _L (t) and R ₂ (t). The temperature-dependent component R ₂ (t) can be varied by varying the pure resistance component R _{2 according} to the number of turns of the third and fourth coils L ₃ and L ₃ and the wire diameter of the coil.

For example, when a copper wire is used for the third and fourth coils, R ₂ (t) has a temperature dependency of 0.4% / ° C., while resistance R ₃ is a fixed resistance, The dependence is 0% / ° C. Accordingly, the temperature coefficient of the combined resistance R, changing the ratio between the pure resistance component R ₂ fixed resistors R ₃ and the third and fourth coil -L ₃ and L _3, the temperature coefficient of the combined resistance Ra 0 ~ 0.4% / ℃
Can be varied by varying the range. In other words, all of the combined resistors Ra are fixed resistors, and the pure resistance component R ₂
Is 0, the temperature coefficient of the combined resistance Ra is 0% / ° C.
And all of the combined resistances Ra are equal to the third and fourth coils −L ₃
And the pure resistance component of L ₃ , the temperature coefficient of the combined resistance Ra is 0.4% / ° C. When the temperature coefficient of the combined resistance Ra is 0% / ° C., the combined resistance R
Temperature coefficient but remains source maintained at a temperature coefficient of the first and second coil, the third and fourth coil -L ₃ and
As the ratio of the pure resistance component of L ₃ increases and the temperature coefficient of the combined resistance Ra increases, the proportion of the temperature-dependent resistance component constituting the combined resistance R increases, and the combined resistance R increases.
Looks like the temperature coefficient of is changed, the temperature change rate of the combined magnetic field [Phi _M can be varied accordingly.

FIG. 3 shows the temperature change characteristics of the magnetic field generated in FIG. 1, and the magnetic fields Φ _L1 and Φ _L1 generated by the _first and _second coils L ₁ and L ₂ are different from those of the prior art shown in FIG. The rate of change in temperature of Φ _L2 increases, and the rate of change in temperature of the resultant magnetic field Φ _L also increases, and is substantially equal to the rate of change in temperature of the permanent magnet for zero return. Therefore, the variation angle θ due to the temperature change rate of the composite magnetic field is smaller than that in FIG. In the above embodiment, the third and fourth coils are superimposed on the second coil and wound in the opposite direction and in the same direction. However, the third and fourth coils may be superimposed on the first coil and wound. Each of the first and second coils may be wound.

[0019]

【The invention's effect】

As described above, according to the present invention, a third coil overlapped with at least one of the first and second coils and wound in the opposite direction has the same inductance as the third coil, A fourth coil superposed and wound in the same direction with the one coil is connected in series to a series circuit of the first and second coils and the fixed resistor, and the resistance value of the fixed resistor is changed from a predetermined resistance value. Since the DC current flowing through the series circuit of the first to fourth coils and the fixed resistor is maintained at the original value by reducing only the combined pure resistance component of the third and fourth coils, the first and second coils are reduced. By setting the pure resistance components of the third and fourth coils connected in series to the first coil to an appropriate value, the temperature change rate of the current flowing through the series circuit is varied, and each of the first and second coils is changed. By varying the temperature change rate of the magnetic field, The temperature change rate of the first composite magnetic field can also be made to be equal to or close to the temperature change rate of the fixed magnet by changing the temperature change rate of the first composite magnetic field, and the variation of the second composite magnetic field due to the temperature can be reduced. It is possible to improve the temperature characteristics by reducing the fluctuations in the voltage value indicating characteristics due to the temperature without changing the voltage indicating characteristics and adding almost no components.

[Brief description of the drawings]

FIG. 1 is an electric circuit diagram showing an embodiment of a voltage indicating device according to the present invention.

FIG. 2 is a view showing a magnetic field characteristic of the apparatus shown in FIG. 1;

FIG. 3 is a view showing a magnetic field characteristic when the temperature characteristic of the apparatus shown in FIG. 1 is considered.

FIG. 4 is a plan view showing a general appearance of a main part of the voltage indicating device.

FIG. 5 is an electric circuit diagram of a conventional device.

FIG. 6 is a view showing a magnetic field characteristic of the apparatus shown in FIG. 5;

FIG. 7 is a diagram showing a specific example of a device for performing the voltage instruction shown in FIG. 4;

8 is a diagram showing magnetic field characteristics when the temperature characteristics of the device of FIG. 5 are considered.

[Explanation of symbols]

L ₁ … First coil L ₂ … Second coil −L ₃ … Third coil L ₃ … Fourth coil R ₃ …… Fixed resistance Mg …… Return-to-zero permanent magnet Mgr …… Rotation Magnet V: DC voltage source

Claims (1)

(57) [Claims] 1. A value of a direct current flowing through said first and second coils together with a first and second coil disposed crossing each other and a combined pure resistance component of said first and second coils. A fixed resistor having a predetermined resistance value that determines a series circuit is connected in series to form a series circuit, and a DC voltage is applied to both ends of the series circuit to combine the first and second coils to produce a first magnetic field. And a fixed magnet is arranged in the combined magnetic field, and a second combined magnetic field is generated by combining the magnetic field generated by the fixed magnet and the first combined magnetic field. In the voltage indicating device, the rotating magnet is rotated so that the magnetic poles coincide with the direction, and the voltage value of the DC voltage is indicated by the rotating position of the rotating magnet. At least one of the first and second coils Overlap with coil A third coil wound in the same direction, and a fourth coil wound in the same direction with the same inductance as the third coil and superposed on the coil wound with the third coil. While being connected in series to the series circuit, the combined pure resistance components of the third and fourth coils are set to a value required to make the temperature change rate of the first combined magnetic field match the temperature change rate of the fixed magnet, or Compared to the case where the third and fourth coils are not provided, the temperature change rate of the first combined magnetic field is not a value required to approach the temperature change rate of the fixed magnet, and the resistance value of the fixed resistor is set to the predetermined value. The resistance value is reduced by the combined pure resistance component of the third and fourth coils, and the DC current flowing through the series circuit of the first to fourth coils and the fixed resistance is reduced by the fixed resistance before the resistance value is reduced. To the value determined by the specified resistance value of And a voltage indicating device.