JPH04109374U - Cross coil ammeter - Google Patents

Abstract

(57) [Summary] [Purpose] By simply passing current in one direction through the coil, the pointer can be adjusted.
Plus and minus from the zero point at the center of the instrument's indication range
Proposal of a cross-coil type ammeter that can be swung to both sides.
For the purpose of providing. [Structure] A disk-shaped magnet is inside the coil bobbin (not shown).
A rotor 2 is arranged rotatably. center of the rotor
A pointer 4 is attached to the tip of a pointer shaft 3 fixed to the pointer.
Coil L on the coil bobbin₁and L₂Winding perpendicularly to
and further the coil L ₁Coil L parallel to₃roll. Koi
The Lubobin is stored in a case (not shown), and the case body is attached to a magnet.
Attach the Mg stone piece. The arrangement position of the magnet piece Mg is
Le L₂Same as the direction of the magnetic field generated when a current flows through
Position it so that the magnetic field is directed in the same direction. Variable resistor VR, coil
L₁, coil L₂are connected in series and connected to power supply E. Ko
Il L ₃connects one end to the power supply E and the other end to the sensor circuit (not shown).
).

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention relates to a cross-coil type ammeter, and in detail, the zero point is located at the center of the display range. The pointer is either positive or negative depending on the direction of current flow in the part being measured. This paper relates to a cross-coil type ammeter that can swing in both directions.

0002

[Conventional technology]

Conventionally, ammeters used in automobiles have a zero point in the center of the display range. For example, there is a cross-coil type ammeter. The ammeter is connected to the case as shown in FIG. There is a coil bobbin (not shown) around which a coil L is wound in a space body (not shown), A disc-shaped magnet rotor 2 is rotatably disposed inside the coil bobbin. Ru. A pointer shaft 3 is fixed to the center of the magnet rotor 2. protrudes from the coil bobbin, and a pointer 4 is attached to its tip. Furthermore , a magnet piece Mg is attached to the case body, and its attachment position is The direction of the magnetic field generated by the stone piece Mg is orthogonal to the direction of the magnetic field generated by the coil L. It's the location.

0003 Further, a sensor R is attached to the coil L in parallel, and the sensor R is connected to the coil L in parallel. The load 7 and the generator 6 are connected to a power source E via the power source E. The above code based on sensor R The magnetic field generated in the coil by energizing the coil L and the magnetic field generated by the magnet piece Mg. The pointer is rotated in the direction of the composite magnetic field. Note that the resistance of sensor R The resistance value of the coil L is much smaller.

0004 In this state, when switch 8 is turned off, the magnet rotor is exposed only to the magnetic field of the magnet pieces. The magnetic rotor 2 rotates and stands still, so it is attached to the tip of the pointer shaft 3 of the magnet rotor 2. If the attached pointer 4 is attached to the position indicating the zero point on the scale plate 5 of the meter, , when the switch 8 is off, the pointer 4 always indicates the zero point.

[0005] When switch 8 is turned on, current flows through coil L based on sensor R. A magnetic field is generated, and the magnet rotor 2 absorbs this magnetic field and the magnet piece perpendicular to this magnetic field. It rotates in the direction of the composite magnetic field created with the Mg magnetic field and comes to rest.

[0006] That is, the switch 9 to the load 7 is turned on and the current i is supplied from the power source E. Then, a current flows in the sensor R in the direction of arrow A, and a current I flows in the coil L in the direction of arrow A. Flowing, the pointer 4 swings to the minus side of the scale plate 5. Also, the voltage of power supply E decreases. When the power source E is charged by the generator 6, the current i flows in the opposite direction and the pointer 4 becomes Swings to the positive side. In this way, the direction of the current flowing through the coil L by the sensor R Since the circuit is configured so that the current flows in either the forward or reverse direction, the pointer will move from the zero point. It can swing in either the positive or negative direction.

[0007]

[Problem that the idea aims to solve]

However, in order to allow current to flow in both directions through the coil L, This is because it is necessary to flow the load current or charging current directly to the sensor R as described above. Therefore, the resistance value of sensor R should be determined by a comma of several ohms considering heat generation, voltage drop, etc. A sensor that has a small precision resistance value and can flow a large current, but must be ordered. is expensive, and its use will result in high costs. Also, like this These sensors consume a lot of power, and heat dissipation must also be taken into consideration. There is a problem.

[0008] This invention allows you to move the pointer to the center of the meter's indicated range by simply passing current through the coil in one direction. A cross-coil type electric current that can be swung from the zero point to both positive and negative sides. The purpose is to provide a flow meter.

[0009]

[Means to solve the problem]

This invention uses a magnetic rotor that has a pointer shaft with a pointer attached to the tip. It is rotatably arranged inside the coil bobbin, and when the coil is wound around the coil bobbin. The coil bobbin is stored inside the case body, and a magnet piece is attached to the case body. When there is no voltage, the pointer points to the zero point at the center of the display range, and the coil When energized, the composite magnetic field of the magnetic field generated in the coil and the magnetic field generated by the magnet piece In a cross-coil type indicator that rotates the pointer in the direction of It consists of a first coil, a second coil, and a third coil, and the first coil and the second coil The second coil is wound perpendicularly to the coil and connected in series, and the second coil is The direction of the magnetic field is the same as that of the magnet piece, and the third coil is the same as the first coil. The coils are wound in parallel, and the direction of the generated magnetic field is opposite to that of the first coil, and the coils are connected in series. One of the first and second coils or the third coil has a constant power in a certain direction. One current flows through one, and the other flows a current based on the sensor signal in a fixed direction. It is characterized by

0010

[Effect]

Based on the above configuration, when the start switch is off, no current flows through each coil. Since no magnetic field is generated, the magnet rotor rotates only by the magnetic field of the magnet pieces. The pointer then points to the zero point at the center of the display range. Also, the switch is on. For example, when a constant current is passed through the first and second coils, the second coil The magnetic field generated by the magnetic field is simply added because it is in the same direction as the magnetic field of the magnet piece. Also, the first The magnetic field generated by the magnetic field differs in direction from the above magnetic field by 90 degrees, so this magnetic field and the second The composite magnetic field with the magnetic field due to the coil and magnet piece is the vectorially added magnitude and It will have a name and direction.

[0011] On the other hand, when a current based on the sensor signal is applied to the third coil, the generated The magnetic field is in a direction opposite to the direction of the magnetic field generated by the first coil. Therefore, this magnetic If the current in the third coil is small, the direction of the magnetic field combined with the field and the composite magnetic field will change depending on the direction of the magnetic field. is close to the direction of the composite magnetic field, and as the current increases, the direction of the magnetic field changes to the third direction. It approaches in the direction of the magnetic field generated by the illumination. The magnet rotor follows this direction As the pointer rotates, the pointer rotates from the minus side through the zero point to the plus side, and the sensor receives a signal. Indicate the value according to the number.

0012

【Example】

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows an on-vehicle ammeter as an embodiment of the cross-coil type indicating instrument of the present invention. The ammeter has a disc-shaped magnet rotor 2 rotatably disposed in a coil bobbin (not shown), and a pointer shaft 3 is fixed to the center of the magnet rotor. It protrudes from the coil bobbin, and a pointer 4 is attached to its tip. Further, coils L ₁ and L ₂ are wound orthogonally around the coil bobbin, and a coil L ₃ is further wound in parallel to the coil L ₁ .

[0014]The coil bobbin is housed in a case (not shown), and a magnet piece Mg is attached to the case body. The magnet piece Mg is arranged at a position where the magnetic field is directed in the same direction as the direction of the magnetic field generated when current flows through the coil _L2 . Further, the position of the scale plate 5 attached to the case body is such that when no current flows through any of the coils L ₁ , L ₂ , L ₃ and the magnet rotor 2 is operated only by the magnet piece Mg, the pointer 4 The scale plate 5 is arranged so that its position corresponds to the zero point at the center of the scale plate 5.

Further, as shown in the figure, the circuit 1 connecting these coils L ₁ , L ₂ , L _{3 ,} etc. is as follows: the variable resistor VR, the coil L ₁ , and the coil L ₂ are connected in series and connected to the power source E. One end of the coil _L3 is connected to a power source E, and the other end is connected to a sensor circuit (not shown). As the sensor of the sensor circuit, it is appropriate to use a Hall element. The Hall element is placed close to the electric wire of the part to be measured, detects the magnetic field generated in proportion to the electric current i flowing through the electric wire, converts it into a voltage, and connects the voltage to the coil _L3 via a buffer circuit. Connect in series.

Therefore, the characteristics of the sensor circuit are as shown in FIG. The current I flowing through the coil L ₃ increases linearly, and the current I flowing through the coil L ₃ remains in a constant direction regardless of whether the current i flows in the forward or reverse direction.

For example, when the current i of the part to be measured is -i _A , a current I _A flows through the coil _L3 , when the current i is i _B , a current I _B flows, and when the current i is zero, a current I ₀ flows. flows. In this way, even if the signal output of the sensor circuit changes based on a change in the current in the part to be measured, the circuit is configured such that a current always flows in a fixed direction through the coil _L3 . Note that the measurement range of the current i of the part to be measured is from -i _A to i _B.

With the above configuration, when the switch 8 of the vehicle is turned off, no current flows through the coils L ₁ , L ₂ , L ₃ , and as shown in FIG. Activated solely by a magnetic field, the pointer 4 points to the zero point in the center of the scale plate 5.

When the switch 8 is turned on, the power supply E is applied to the coils L ₁ and L ₂ via the variable resistor VR, and a constant current I _C flows therethrough. As shown in FIG. 3, this current I _C generates a constant magnetic field Φ _L2 in the coil L ₂ and a constant magnetic field Φ _L1 in the coil L ₁ as well. Then, a composite magnetic field Φ _L of these magnetic fields and the magnetic field Φ _Mg of the magnet piece Mg is generated.

On the other hand, the magnetic field Φ _L3 generated in the coil L ₃ is such that when the current i in the part to be measured is zero, a current I _O flows through the coil L ₃ and the magnitude of the magnetic field Φ _L3 becomes Φ _I0 . The total magnetic field obtained by combining the magnetic field Φ _I0 and the composite magnetic field Φ _L is Φ ₀ . To adjust the direction of the magnetic field Φ ₀ , adjust the variable resistor VR to change the current I _C so that it is the same as the direction of the magnetic field Φ _Mg of the magnet piece Mg, and the pointer 4 indicates the zero point of the scale plate 5. Let's do it like this.

[0021] The current i of the part to be measured is -i_AWhen , coil L₃has a current I_Aflows and its magnetic field Φ_L3The size of is Φ_IASo, the magnetic field Φ_IAand the composite magnetic field Φ_LComprehensive magnet that synthesizes The field becomes -Φ, and the pointer 4 swings from the zero point of the scale plate 5 to the minus side by an angle θ. Also , the current i of the part to be measured is i_BWhen , coil L₃has a current I_Bflows and its magnetic field Φ _L3 The size of is Φ_IBSo, the magnetic field Φ_IBand the composite magnetic field Φ_LThe total magnetic field that combines becomes +Φ, and the pointer 4 swings by an angle θ from the zero point of the scale plate 5 to the positive side. .

As described above, according to this embodiment, even in a sensor circuit in which the current I flowing through the coil L ₃ is always in the same direction even if the direction of the current i flowing through the part to be measured changes in the forward or reverse direction, the switch 8 When the pointer 4 is off, the pointer 4 can indicate the zero point at the center of the scale plate 5, and even when the switch 8 is on, when the current i in the part to be measured changes between -i _A and i _B , the coil changes according to this change. The magnetic field generated by L ₃ changes between Φ _IA and Φ _IB , and the pointer 4 can be swung between the minus side and the plus side. Therefore, by displaying a value corresponding to the current i on the scale plate 5, the value of the current flowing through the part to be measured can be read. Note that FIG. 4 shows the relationship between the current I flowing through the coil L ₃ and the deflection angle of the pointer 4.

FIGS. 5A to 5D show a partially modified version of the electric circuit 1 in the cross-coil ammeter of the previous embodiment. As shown in FIG. 5(A), a variable resistor VR may be inserted into the coil _L3 side for adjustment. Furthermore, as shown in Fig. 5(B), a resistor R may be added for use with a high power supply voltage, and as shown in Fig. 5(C), a constant voltage circuit may be inserted to improve the voltage characteristics. Alternatively, as shown in FIG. 5(D), the coil L ₃ connected to the sensor circuit and the other coils L ₁ and L ₂ can be reversed from those in the previous embodiment.

[0024]

[Effect of the idea]

As explained above, according to the present invention, the cross-coil type ammeter coil has a constant direction. Even if current flows in the opposite direction, when the switch is off or when the current flowing through the measured part is zero, Point the pointer to the zero point in the center of the display range, and when the current in the part being measured changes in the forward and reverse directions, The pointer can be moved to the left or right of the display range to indicate plus or minus. child Therefore, a precision and expensive sensor is required to flow current in both forward and reverse directions through the coil. First, manufacturing costs can be reduced.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a cross-coil type ammeter according to an embodiment of the present invention.

FIG. 2 is a diagram showing sensor characteristics.

FIG. 3 is a vector diagram of the magnetic field generated by each coil and magnet piece and the composite magnetic field.

FIG. 4 is a diagram showing the relationship between the current flowing through the coil and the deflection angle of the pointer.

FIGS. 5A to 5D are diagrams showing electric circuits of other embodiments.

FIG. 6 is a diagram showing a conventional cross-coil type ammeter.

[Explanation of symbols]

1 Electric circuit 2 Magnet rotor 3 Pointer shaft 4 Pointer 5 Scale plate L ₁ First coil L ₂ Second coil L ₃ Third coil Mg Magnet piece

Claims (1)

[Scope of utility model registration request] Claim 1: A magnet rotor having a pointer shaft with a pointer attached to its tip is rotatably disposed inside a coil bobbin, a coil is wound around the coil bobbin, and the coil bobbin is housed in a case body; A magnet piece is attached to the case body, and when there is no voltage, the pointer indicates the zero point at the center of the display range, and when the coil is energized, the magnetic field generated in the coil and the magnetic field generated by the magnet piece are combined. In a cross-coil type ammeter in which the pointer is rotated in the direction of the magnetic field, the coil is connected to a first coil and a second coil.
a coil, a third coil, the first coil and the second coil are wound orthogonally and connected in series,
and the second coil has its generated magnetic field direction in the same direction as the magnet piece, and the third coil is wound in parallel with the first coil, and its generated magnetic field direction is opposite to the first coil. The present invention is characterized in that a constant current is passed in a fixed direction in one of the first and second coils or the third coil connected in series, and a current is passed in a fixed direction in the other based on the sensor signal. Cross-coil type ammeter.