JPH0711539B2 - Drive device for cross-coil type instrument - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention has a cross coil composed of first and second coils that generate magnetic fields intersecting with each other, and a magnet within a synthetic magnetic field generated by the cross coil. The present invention relates to a drive device for a cross-coil type instrument in which a rotor is provided and a predetermined measurement amount is displayed according to the rotation angle of the magnet rotor.

[Conventional technology]

Generally, a conventional cross-coil type instrument has a first coil L ₁ and a second coil L ₁ arranged so as to intersect with each other so as to generate magnetic fields intersecting with each other, as shown in FIGS. 7 (a) and 7 (b).
And a cross coil L composed of L ₂ and a magnet rotor Mg is rotatably arranged in a magnetic field generated by the cross coil L. A pointer A is attached to one end of the rotating shaft at the center of the magnet rotor Mg. In addition, B is a scale plate that displays the measured amount in cooperation with the pointer A, and is provided with a scale for displaying the speed of the vehicle as shown in the drawing, for example.

In the above-described structure, when a current is passed through the first and second coils L ₁ and L ₂ , magnetic fields are generated by the coils. The magnet rotor Mg is rotated so that the composite magnetic field direction of these magnetic fields and the magnetic pole direction of the magnet rotor Mg match.

Since the first and second coil L ₁ and L ₂ are the magnitude of the magnetic field generated respectively in proportion to the magnitude of the current supplied to the coils L _1, L _2, each of the current corresponding to a predetermined measured quantity Coil L ₁ ,
Flowing to L _2, the coils L _1, L ₂ rotates and the magnet rotor Mg in the direction of the combined magnetic field obtained by combining the magnetic field generated pointer A
Rotates to a predetermined rotation angle, whereby the pointer A displays the predetermined measurement amount.

As a drive device for supplying a current according to a predetermined measurement amount to the first and second coils L ₁ and L ₂ , the rotation angle of the magnet rotor is divided into 8 minutes circles, and the quadrant is 0 °. ~
Tangent corresponding to the measured amount within the range of 45 °, that is, tan θ
The duty data consisting of (θ = 0 ° to 45 °) is stored in advance in a storage means such as a ROM, and the duty data according to the measured amount is read from the storage means to convert the rectangular wave current of the duty into a cross coil. There is one that supplies one coil to the other coil and supplies a current of 100% duty to the other coil.

As another device, the rotation angle of the magnet rotor is divided into quadrants, and the duty corresponding to the measured amount within the range of 0 ° to 90 °, which is one quadrant, is stored in a storage means such as a ROM. A predetermined measurement by reading the duty data according to the measured amount from the storage means, supplying a current having a duty corresponding to the data to one coil and supplying a current having a duty complementary to the duty to the other cross coil It is an indicator of quantity.

[Problems to be Solved by the Invention]

In the former drive device described above, since the duty data for 0 ° to 45 ° may be stored in the storage means, the storage capacity of the storage means may be small, but on the other hand, pointers are provided in each of the eight circles. There is a problem in that the logic circuit for switching and selecting the direction of the current flowing in each coil for rotating is complicated.

On the other hand, in the latter driving device, since the direction switching of the current flowing through each coil may be a quadrant, the problem of the former device is somewhat alleviated, but on the other hand, within the range of 0 ° to 90 °. Since it is necessary to store the duty data, there is a problem that the capacity of the storage means becomes larger than that of the former one.

Therefore, according to the present invention, the logic circuit for switching and selecting the direction of the current flowing in each coil for rotating the pointer can be simplified, and the storage capacity of the storage means for storing the duty data can be reduced. An object of the present invention is to provide a drive device for such a cross coil type instrument.

[Means for Solving the Problems]

In order to solve the above problems, a drive device for a cross-coil type instrument according to the present invention has a cross-coil including first and second coils that generate magnetic fields intersecting each other,
In a drive device of a cross-coil type instrument in which a magnet rotor is arranged in a synthetic magnetic field generated by the cross coil and a predetermined measurement amount is displayed by the rotation angle θ of the magnet rotor, 0 ° with respect to the rotation angle θ. A storage means for storing tan θ in the range of ≦ θ ≦ 45 ° and a rotation angle according to the measurement amount are (90 × X ° −90 °) ≦ θ ≦ (90 × X ° −45 °)
(However, when X = 1,3), {θ−
Tan θ corresponding to (90 × X ° −90 °)} is read and the duty _ay % is _ay = tan {θ− (90 × X ° −90 °)} / [1 + tan {θ−
(90 × X ° −90 °)}], and the rotation angle θ corresponding to the measured amount is (90 × X ° −90 °)
° -45 °) <θ ≦ (90 × X °) (where X = 1,3), ta corresponding to (90 × X ° -θ) from the storage means
duty a _x% reads nθ data _{a x = tan (90 × X} ° -θ) / {1 + tan (90 × X ° -
θ)} and the rotation angle corresponding to the measured amount is (90 × X °
−90 °) ≦ θ ≦ (900 × X ° −45 °) (where X = 2,
In the case of 4), the storage means {θ− (90 × X ° −90
°) the duty a _x% reads the corresponding tanθ _{to} a x = tan {θ- (} 90 × X ° -90 °)} / [1 + tan {θ-
(90 × X ° −90 °)}], and the rotation angle θ corresponding to the measured amount is (90 × X ° −90 °)
° -45 °) <θ ≦ (90 × X °) (where X = 2,4), ta corresponding to (90 × X ° -θ) from the storage means
nθ Data is read out and the duty a _y % is a _y = tan (90 × X ° -θ) / {1 + tan (90 × X °-
θ)}, a first supply means for supplying a rectangular wave current having a duty a _y % or a _x % from the calculation means to the first or second coil, and the duty. Complementary duty (100−a _y )% or (100−a _x )%
Second supply means for supplying the rectangular wave current to the second or first coil, and the first and second coils from the first and second supply means according to the magnitude of the measurement amount. And a polarity setting means for setting the polarity of the rectangular wave current supplied to.

[Action]

In the above configuration, the rotation angle according to the measurement amount is (90 × X
° -90 °) ≤ θ ≤ (90 x X ° -45 °) (where X = 1,
At the time of 3), from the storage means {θ− (90 × X ° −90 °)}
The tan θ corresponding to is read and the duty a _y % is a _y = tan {θ− (90 × X ° −90 °)} / [1 + tan {θ−
(90 × X ° −90 °)}] and the rotation angle according to the measured amount is (90 × X ° −45 °)
°) ≤ θ ≤ (90 x X °) (where X = 1,3),
Duty a _x% reads tanθ data corresponding to 90 × X ° -θ) from the storage means _{a x = tan {θ- (90} × X ° -θ) / {1 + tan (90 × X °
-Θ)} and the rotation angle according to the measured amount is (90 × X ° -90
°) ≦ θ ≦ (90 × X ° −45 °) (where X = 2,4), tanθ corresponding to {θ− (90 × X ° −90 °)} is read from the storage means and the duty is read. a _x% of _{a x = tan {θ- (90} × X ° -90 °)} / [1 + tan {θ-
(90 × X ° −90 °)}] and the rotation angle θ corresponding to the measured amount is (90 × X ° −90 °)
45 °) <θ ≦ (90 × X °) (where X = 2,4), the tan θ data corresponding to 90 × X ° −θ from the storage means is read and the duty a _y % is a _y = tan (90 × X ° −θ) / {1 + tan (90 × X ° −
θ)} and calculate the duty a _y % or a _x %
To the first or second coil of the rectangular wave current of (100- _ay )% or (100-
a _x )% rectangular wave current is supplied to the second or first coil, respectively, and the polarities of the rectangular wave current supplied to the first and second coils are set according to the magnitude of the measurement amount. Therefore, the magnet rotor can be driven to the position at the rotation angle corresponding to the measured amount, and the measured amount can be displayed.

Now, when X = 1, that is, when 0 ° ≦ θ ≦ 45 °, tan θ corresponding to θ is read from the storage means and the duty a _y % is calculated by a _y = tan θ / (1 + tan θ) and measured. Rotation angle θ according to quantity is 45 ° <θ ≦ 90
At the time of °, the tan θ data corresponding to (90−θ) is read from the storage unit and the duty duty a _x % is calculated by a _x = tan (90 ° −θ) / {1 + tan (90 ° −θ)} .

When X = 2, that is, 90 ° ≦ θ ≦ 135 °
At this time, tan θ corresponding to (θ−90 °) is read from the storage means, and the duty a _x % is calculated by a _x = tan (θ−90 °) / {{1 + tan (θ−90 °)}, Rotation angle θ according to the measured amount is 135 ° <θ ≦ 1
Tanθ corresponding to (180 ° -θ) from the storage means when 80 °
Data is read out and the duty a _y % is calculated by a _y = tan (θ−180 °) / {1 + tan (180 ° −θ)}.

Further, when X = 3, that is, 180 ° ≦ θ ≦ 225 °
At this time, tan θ corresponding to θ−180 ° is read out from the storage means and the duty a _y % is calculated by a _y = tan (180 ° −θ) / {1 + tan (θ−180 °)} to obtain the measured amount. Rotation angle θ is 225 ° <θ ≦ 2
Tan θ corresponding to (270 ° -θ) from storage means when 70 °
Duty a _x% reads data calculated by _{a x = tan (270 ° -θ} ) / {1 + tan (270 ° -θ)}.

Furthermore, when X = 4, that is, 270 ° ≦ θ ≦ 3
At 15 °, tan θ corresponding to θ-270 ° is read from the storage means, and duty a _x % is calculated by a _x = tan (θ-270 °) / {1 + tan (θ-270 °)} and measured. Rotation angle θ depending on the amount is 315 ° <θ ≦ 3
Tanθ corresponding to (360 ° −θ) from the storage means at 60 °
The data is read and the duty a _y is calculated by a _y = tan (360 ° −θ) / {1 + tan (360 ° −θ)}.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit configuration diagram showing an embodiment of a driving device for a cross-coil type instrument according to the present invention. Before explaining the driving device, referring to FIGS. 2 to 5, the principle of the present invention will be described. Will be explained.

In the drive device according to the present invention, rectangular wave currents having complementary duty are supplied to the respective coils of the cross coil. That is, the duty a _y = (0 <a _y <depending on a predetermined measurement amount
The rectangular wave current of 100 %% is supplied to the first coil L ₁ , and the duty of the first rectangular wave current is complementary to the duty a _x = (= (100−a _y ))% of the rectangular wave current. Is supplied to the second coil L ₂ , or the duty a _X % (0 <a _x <
The square wave current of 100) was supplied second to the coil L _2, which is complementary duty _{a y (= (100-a} x)) the% of the square wave current to be supplied to the first coil L ₁ ing.

Next, the duty of the rectangular wave current supplied to the _first and _second coils L ₁ and L ₂ by the driving device according to the present invention will be described.

Now, as shown in FIGS. 2 and 3, the duty a _y (0 <a _y <1) of the rectangular wave current flowing through the first coil L ₁ is flown through the second coil L ₂ in the Y direction. Square wave current duty a
_{When x} (0 <a _x <1) is set in the X direction, a rectangular wave flowing in each coil along a quadrangle connecting a circle centered on the origin O with a radius of 1 and a fulcrum of the X axis and the Y axis. By changing the value of the duty of the current, a synthetic magnetic field can be formed in an arbitrary direction θ and the pointer A can be swung in that direction.

Then, considering the combined magnetic field direction (rotation angle θ) which is the touch angle of the pointer A in the quadrant, in the range of 0 ° ≦ θ ≦ 45 °, From a _x = 1- _{ay y} (2), θ is And solving equation (3) for a _y , Becomes That is, a _x = 1- _ay Becomes Here, a _y and a _x are the duty of the rectangular wave current supplied to the _first and _second coils L ₁ and L ₂ , respectively, as described above.

That is, the duty a _y given to the first coil L ₁ is calculated from the rotation angle θ based on the above equation (5), and the second coil
The duty a _x given to L ₂ may be a duty complementary to the duty a _y .

In the range of 45 ° <θ ≦ 90 °, a _y = 1-a _x Becomes Here, within the above range, 0 ° ≦ (90−θ) ≦ 45 °
Therefore, depending on the rotation angle θ of 0 ° ≦ θ ≦ 45 °, 0 ° ≦
First and second coils L ₁ at a rotation angle θ of θ ≦ 90 °
And the duty a _y , a _{x of the} rectangular wave current flowing in L ₂ is determined.

Therefore, the measured amount and the rotation angle θ are associated with each other, and the value of tan θ data corresponding to the rotation angle θ corresponding to the measured amount is 0 ° ≦ θ.
Preliminarily stored in the storage means within a range of ≦ 45 °. Then, the corresponding rotation angle θ is detected from the measured amount, and if the detected rotation angle θ is within the range of 0 ° ≦ θ ≦ 45 °, the tan θ data corresponding to the rotation angle θ is read from the storage unit, and the reading is performed. Duty based on the above equation (5) based on tan θ data
a _x, to calculate the a _y. Also. The detected rotation angle θ is 45 ° <
If within the range of θ ≦ 90 °, tan θ data corresponding to (90−θ) is read from the storage means, and a _x , a _{y is} calculated from the above equation (6).
To calculate. Furthermore, the rotation angle θ is 90 ° in other quadrants.
In the range of <θ ≦ 360 °, the quadrant and the sign of the duty are different, and the values are the same as in (5) and the above equation (6). Therefore, it is determined which quadrant the rotation angle θ is from the measured amount, and the duty is determined. a _x, a value of _{a y (5), (6} ) to calculate from the equation, to set the direction of the square wave current to flow from the code first, the second coil L _1, L _2.

The calculation formula in the range of 90 ° to 360 ° is as follows.

90 ° <θ ≦ 135 ° a x = tan (θ-90 °) / {1 + tan (θ-90 °)} a y = 1-a x 135 ° <θ ≦ 180 ° a x = 1-a y a y = tan (180 ° -θ) / {1 + tan (180 ° -θ)} 180 ° <θ ≦ 225 ° a x = 1-a y a y = tan (θ-180 °) / {1 + tan (θ-180 ° )} 225 ° <θ ≦ 270 ° a x = tan (270 ° -θ) / {1 + tan (270 ° -θ)} a y = 1-a x 270 <θ ≦ 315 ° a x = tan (θ-270 °) / {1 + tan ( θ-270 °)} a y = 1-a x 315 ° <θ <360 ° a x = 1-a y a y = tan (360 ° -θ) / {1 + tan (360 ° - θ)} The above can be summarized and expressed by a general formula as follows.

The rotation angle according to the measurement amount is (90 × X ° −90 °) ≦ θ ≦
(90 × X ° -45 °) (where X = 1,3), {θ
Tan θ corresponding to − (90 × X ° −90 °)} is read and the duty _ay % is _ay = tan {θ− (90 × X ° −90 °)} / [1 + tan {θ−
(90 × X ° −90 °)}], the rotation angle θ according to the measured amount is (90 × X ° −45 °) <θ ≦
(90 × X °) (where X = 1,3) (90 × X ° −
tanθ data corresponding to θ) read duty a _x %
A _x = tan (90 × X ° −θ) / {1 + tan (90 × X ° −
θ)}, the rotation angle corresponding to the measured amount is (90 ° of 90 × X °) ≦ θ ≦
(90 × X ° −45 °) (where X = 2,4), {θ
- (90 × X ° -90 ° ) the duty a _x% reads the corresponding tanθ _{to} a x = tan {θ- (} 90 × X ° -90 °} / [1 + tan {θ-
(90 × X ° −90 °)}], the rotation angle θ according to the measured amount is (90 × X ° −45 °) <θ ≦
(90 × X °) (However, X = 2,4) (90 × X °-
tan θ data corresponding to θ) is read duty a _y %
A _y = tan (90 × X ° −θ) / {1 + tan (90 × X ° −
θ)} and calculate the calculated duty a _y % or a _x
Duty (100− _ay )% or (100−
a _x ) may be further calculated.

Next, the polarity setting of the rectangular wave current with respect to the rotation angle θ of the magnet rotor Mg will be described. In the quadrant shown in FIG. 4, first, in the range (quadrant) in which the magnet rotor Mg rotates from 0 ° to 90 °, in order to rotate the magnet rotor Mg from 0 ° to 90 °, FIG. Of the cross coil L shown in (a), the first rectangular wave current is caused to flow in the direction in which the duty a _y % increases with respect to the direction from the terminal of the first coil L ₁ , and the second coil L ₂ with respect to the direction from the terminal, the duty _{(100-a y) (=} a x)% may be to flow a second square wave current in a direction to decrease. Since the duty of each of the first and second rectangular wave currents changes complementarily as described above, there is a relationship that if the duty of one rectangular wave current increases, the duty of the other rectangular wave current decreases. is there.

In the range of 90 ° to 180 ° quadrant, 90 ° to 180 °
To rotate the magnet rotor Mg in the direction of
The first rectangular wave current in the direction in which the duty decreases with respect to the direction from the terminal of the coil L ₁ , and the direction in which the duty increases in the direction from the terminal of the second coil L ₂ in the direction in which the duty increases. A rectangular wave current of 2 may be passed.

In the following quadrants of 180 ° to 270 ° and quadrants of 270 ° to 360 °, in order to rotate the magnet rotor Mg in the direction in which the rotation angle increases, the direction from the terminal of the first coil L ₁ The duty increases (decreases)
So that the first rectangular wave current is caused to flow, and the second rectangular wave current is caused to flow in the direction in which the duty decreases (increases) with respect to the direction () from the terminal () of the second coil L _2. do it. The above operations are summarized in Table I below.

Here, in each of the four quadrants, the deflection angle θ of the pointer A
Is obtained by θ = tan ¹ (I ₁ / I ₂ ), where I ₁ and I ₂ are the currents flowing through the first and second coils L ₁ and L ₂ , respectively. Therefore, in the present invention, in the range of each quadrant (range of rotation angle 90 °), this angle θ is 0 ° ≦ θ45 °
It is judged whether it is in the range of 45 or in the range of 45 <θ ≤ 90 ° (whether it is larger or smaller than 135 °, 225 °, 315 ° in quadrant ~) and corresponds to the measured amount from the storage means. to read the tanθ data corresponding to theta or (90-theta), by determining the duty a _x and a _y performs calculation of the above equation (5) or ^{(6), θ = tan -} (a y / a _x ) is satisfied.

Further, by setting the polarities of the rectangular wave currents flowing through the first and second coils L ₁ and L ₂ in accordance with the magnitude of the predetermined measurement amount to be displayed, the magnet rotor Mg is set to the above-mentioned 4
It is set which quadrant or which quadrant is to be positioned, and the first and second rectangular wave currents having complementary duties according to a predetermined measurement amount are made to flow through each coil, so that the magnets are set in the set quadrant. The rotor Mg rotates to the rotation angle position according to the duty. Through the above operation, the magnet rotor Mg rotates in the range of 0 to 360 ° according to the predetermined measurement amount, and this measurement amount is displayed.

In summary, the duty a _x and a _y of the first and second coil L ₁ and respectively supplying the square wave current to the L ₂ relative to the rotational angle θ is as shown in Figure 5.

Referring again to FIG. 1, an embodiment of the driving device according to the present invention will be described. In FIG. 1, reference numeral 1 denotes an input terminal to which a signal representing a measured amount to be displayed such as vehicle speed is input, and a signal having a cycle corresponding to the measured amount generated by, for example, a speed sensor is input to the input terminal 1. Is entered. Reference numeral 2 is a waveform conversion circuit for converting the periodic signal input to the input terminal 1 into a pulse signal, and 3 is a cycle for measuring the period of the pulse signal waveform-converted by the waveform conversion circuit 2 and outputting the measured value as a digital signal. A measuring circuit 4, a microcomputer (hereinafter abbreviated as CPU) to which the digital signal output from the cycle measuring circuit 3 is input, and 5 is tan θ data for a rotation angle θ corresponding to the digital signal, 0 ° ≦ θ ≦ 45 °
The ROM stored in the range, 6 is a drive circuit, 7 is a duty generation circuit, and 8 is a logic circuit for setting the direction, that is, the polarity, of the rectangular wave current supplied to the coils L ₁ and L ₂ .

In the drive circuit 6, one end of the first coil L ₁ is connected in series between the power source Vcc and ground, and the other end is similarly connected in series to the interconnection point of the PNP and NPN switching transistors Q ₁ and Q ₂ . PNP and NPN switching transistors Q ₃ and Q ₄ are connected to the interconnection points respectively, and the switching transistor Q ₅ is also connected to both ends of the second coil L _2.
And Q ₆ and Q ₇ and Q ₈ respectively.

On the other hand, the CPU 4 receives an input digital signal representing a predetermined measurement amount, outputs duty data from its output port O ₁ , and inputs this to the duty pulse generator 7. The CPU 4 also outputs the polarity identification signal S ₁ from its output ports O ₂ and O _3.
And S ₂ are output and these are input to the logic circuit 8.

The logic circuit 8 outputs the first and second rectangular wave currents based on the pulse of the predetermined duty output from the duty pulse generator 7 to the first and second coils L ₁ according to the polarity identification signals S ₁ and S _2. And for supplying L ₂ with a predetermined polarity,
It is composed of NAND circuits 8 _{1 to} 8 ₄ and inverter circuits 8 _{5 to} 8 ₇ . The outputs of the NAND circuits 8 _{1 to} 8 ₄ are directly connected to each other and the switching transistor Q ₁ and
It is connected to the bases of Q ₂ , switching transistors Q ₃ and Q ₄ , switching transistors Q ₅ and Q ₆ , and switching transistors Q ₇ and Q ₈ , respectively.

Further, in the ROM 5, duty data read according to the input digital signal and output to the duty pulse generator 7, and polarity identification data S ₁ for setting one of the four quadrants according to the input digital signal. And S ₂ are stored. Then, the duty pulse generator 7 is configured to output a rectangular wave signal having a duty corresponding to the duty data from the CPU 4.

If, for example, the amount of change "1" of the measured amount to be displayed corresponds to a rotation angle of 1 ° of the magnet rotor Mg in the ROM 5, the input digital signal 0 is output as shown in Table II (1) below. ~ 89,90 ~ 179,180 ~ 269,270 ~ 360 range,
The polarity identification data S ₁ and S ₂ are (1,1), (0,1),
Tables (0,0) and (1,0) are prepared. Further, as shown in the following Table II (2), the input digital signal is 0 to 45, that is, the rotation angle θ of the pointer A is composed of tan θ data for the corresponding rotation angle θ in the range of 0 ° to 45 °. a
_{0 to} s ₄₅ are available.

If the data stored in the ROM5 is tan θ data, the CPU 4 performs the operation of the above formula (5) or (6) based on the data read from the ROM5 according to the input digital signal, and directly generates the duty pulse. The duty pulse generator 7 to the first coil L ₁
It outputs a square wave signal to supply a _y % square wave current.

With the above configuration, the operation of the apparatus will be described with reference to the flowchart of FIG. 6 showing the work executed by the CPU 4 according to a predetermined program.

First, the CPU 4 reads the input digital signal data from the cycle measuring circuit 3 in step S1, and then in step S2
In the step S3, the read data is compared with the data read before, and when there is a change (when the data is updated), the process proceeds to step S3, and based on the rotation angle θ corresponding to the input digital data. To access ROM5.

That is, when the tan θ data for the rotation angle θ is stored in the ROM 5, for example, when 0 ° ≦ θ ≦ 45 °, the input digital signal data is used as the direct access data,
When 45 ≦ θ ≦ 90 °, the data corresponding to (90−θ) is used as the access data. Then the process proceeds to step S4, where reading data and polarity identification S ₁ and S ₂ corresponding to the input digital signal data from within the ROM 5. At this time, ROM5 tan
If the θ data is stored, the duty data is calculated by performing the calculation of tan θ / (1 + tan θ) of the above equation (5) from tan θ read from the ROM 5. Also, the calculated duty data is output to the duty pulse generator 7 as duty data. And 45 ° <θ ≤
When it is 90 °, duty data of complementary value is read from ROM5. That is, _assuming that the data when 0 ° <θ ≦ 45 ° is a _n , the data of (1-a _n ) is read. This is (6) As shown in equation, 45 ° <a range of theta ≦ 90 °, the second coil L ₂ to tan (θ-90) / { 1 + tan (90-
This is for supplying a rectangular wave current with a duty a _x of θ)} and a complementary rectangular wave current with a duty a _y (= 1−a _x ) to the first coil L ₁ .

Next, in step S5, the access data read in step S4 is input to the duty pulse generator 7,
The duty pulse generator 7 generates a rectangular wave signal with a duty a _y % according to the input digital signal data, and inputs this to the logic circuit 8. Further, the polarity identification data S ₁ and S ₂ read in step S are input to the logic circuit 8.
The logic circuit 8 sets one input of each of the NAND circuits 8 _{1 to} 8 ₄ based on the input polarity identification data S ₁ and S ₂ , and
The ND circuit generates a logic output as shown in Table III below.

The logic output of each of the switching transistors Q ₁ through Q ₈ of the drive circuit 6 by turning off one of the transistors connected in series, from the power supply V _cc from the coil L ₁ of the first and second first and second Sets the direction (polarity) of the rectangular wave current supplied to the coils L ₁ and L ₂ . On the other hand, the duty pulse generator 7 outputs a rectangular wave signal having a duty a _y % according to the magnitude of the input digital signal based on the duty data from the CPU 4. This rectangular wave signal is output from the NAND circuit 8 ₁ or 8 ₂ and the switching transistor Q ₁ or Q ₂ ,
The switching operation of Q ₃ or Q ₄ supplies the first coil L ₁ with the first rectangular wave current of the duty a _y % from the power supply V _cc . The square wave signal from the duty pulse generator 7 is inverted by the inverter 8 _6,
Rectangular wave signal (100-a _y)% duty a _x is output. This rectangular wave signal is output through the NAND circuit 8 ₃ or 8 ₄ and the switching transistor Q ₅ or Q ₆ and Q ₇ or Q _{8 is} output.
The supplying a second coil L ₂ to the duty from the power supply _{V cc (100-a x)} (= a x)% of the second square wave current by switching operation.

According to the above drive device, the duty data and the polarity identification data S ₁ and S ₂ corresponding to the input digital signal are stored in the data set in the ROM 5 (for example, Table II), and the drive control is performed by the quadrant structure. As shown in Tables I and III, it is easy to set the polarity of the rectangular wave current supplied to the cross coil L and the drive current value. Further, since the octet data of 0 ° to 45 ° may be stored in the ROM 5, the memory capacity can be reduced.

Considering the case where the present invention is applied to, for example, a speed indicator of a vehicle, recently, in a certain type of vehicle, various signal data generated in the vehicle are digital data stored in a vehicle-mounted computer (CPU). As a result, most of them are digitally displayed.

However, even in a vehicle in which the signal data has been digitally processed in this way, there are many users who desire the display to be performed by an analog instrument according to a pointer.

Therefore, by using this digital data as input data to the CPU 4, the vehicle speed can be displayed on the capacity by an analog meter (cross-coil meter). Moreover, the CPU 4 can also be used as a CPU already provided in the vehicle.

For example, if the vehicle speed is 27 km / h, the CPU 4 receives digital data corresponding to the vehicle speed. At this time, the pointer of the vehicle speed meter is set to 0 km / h at the 0 ° position in FIG. 4, and the display of 27 km / h is performed at the position rotated 27 ° clockwise from the 0 ° position. Then, the CPU 4 refers to the table in the ROM 5 and sets the polarity identification data S ₁ and S ₂ to 1, respectively. Also based on the data read from ROM5
The duty data corresponding to 27 km / h is obtained, and the duty pulse generator 7 outputs a rectangular wave signal having a duty corresponding to this duty data.

From the above, based on the polarity identification data S ₁ and S ₂ and the rectangular wave signal, the cross coil L is driven to move the magnet rotor Mg to 27
Rotate ° and display 27 km / h with pointer A. Note that CP
The U4 periodically inputs the vehicle speed data every predetermined time.

〔effect〕

As described above, according to the present invention, the magnet rotor can be rotated to a rotation angle position corresponding to a predetermined measurement amount and the measurement amount can be displayed with a relatively simple configuration.

Further, the storage capacity of the storage means for storing the data for determining the duty can be reduced.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a drive device for a cross coil type instrument according to the present invention, FIG. 2 is a diagram showing a synthetic magnetic field of a cross coil for explaining the operation of the present invention, FIG. 3 and FIG. FIG. 4 is a diagram showing rotation ranges of the cross coil and the magnet rotor according to the present invention, FIG. 5 is a diagram showing duty characteristics with respect to a rotation angle according to the present invention, and FIG. 6 is a process of FIG. 1 CPU. The flowchart and FIGS. 7A and 7B are a top view and a perspective view showing the configuration of a general cross-coil type instrument. L: cross coil, L _1: first coil, L _2: second
Coil, Mg …… Magnet rotor, A …… Indicator, 4 ...
... CPU, 5 ... ROM, 6 ... driver circuit, 7 ... duty generator, 8 ... logic circuit.

Claims (1)

[Claims] 1. A cross coil comprising first and second coils that generate magnetic fields intersecting each other, and a magnet rotor is disposed in a composite magnetic field generated by the cross coils.
In a drive device for a cross coil type instrument that displays a predetermined measurement amount according to the rotation angle θ of the magnet rotor, tan θ within a range of 0 ° ≦ θ ≦ 45 ° with respect to the rotation angle θ.
And a rotation angle corresponding to the measured amount is (90 × X ° −90 °) ≦ θ
When ≦ (90 × X ° −45 °) (where X = 1,3), it corresponds to {θ− (90 × X ° −90 °)} from the storage means.
tanθ is read and the duty _ay % is calculated as _ay = tan {θ− (90 × X ° −90 °)} / [1 + tan {θ−
(90 × X ° −90 °)}], and the rotation angle θ corresponding to the measured amount is (90 × X ° −90 °)
° -45 °) <θ ≦ (90 × X °) (where X = 1,3), ta corresponding to (90 × X ° -θ) from the storage means
duty a _x% reads nθ data _{a x = tan (90 × X} ° -θ) / {1 + tan (90 × X ° -
θ)} and the rotation angle corresponding to the measured amount is (90 × X °
−90 °) ≦ θ ≦ (90 × X ° −45 °) (where X = 2,
In the case of 4), the storage means {θ− (90 × X ° −90
°) the duty a _x% reads the corresponding tanθ _{to} a x = tan {θ- (} 90 × X ° -90 °)} / [1 + tan {θ-
(90 × X ° −90 °)}], and the rotation angle θ corresponding to the measured amount is (90 × X ° −90 °)
° -45 °) <θ ≦ (90 × X °) (where X = 2,4), ta corresponding to (90 × X ° -θ) from the storage means
nθ Data is read out and the duty a _y % is a _y = tan (90 × X ° -θ) / {1 + tan (90 × X °-
θ)}, a first supplying means for supplying a rectangular wave current having a duty a _y % or a _x % from the calculating means to the first or second coil, and the duty, complementary duty (100-a _y)% or (100-a _x)% of the square wave current second or first
Second supply means for supplying the first coil to the second coil, and the polarity of the rectangular wave current supplied from the first and second supply means to the first and second coils according to the magnitude of the measurement amount. A drive device for a cross-coil type instrument, comprising: polarity setting means.