JPS6213012Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a meter drive device for rotating the pointer of a moving coil type, moving magnet type, rotating magnetic field type, etc. meter to an appropriate position on a scale plate.

Conventionally, in an electric speedometer using a moving coil ammeter, as shown in FIG. For example, it is not equal to that between the scale "10" and the scale "20" in FIG. For this reason, there is a drawback that the speed cannot be displayed in the low speed range or the accuracy is not achieved. This is due to the structure of the moving coil ammeter that is the display section.
As shown in FIG. 2, the moving coil ammeter consists of a permanent magnet 101 and two yokes 102 and 103.
An air gap is provided between the two yokes 102, 103 to create an equal magnetic field, and the two yokes 102, 103
A moving coil 104 is disposed between the moving coil 104 and a certain current flowing through the moving coil 104, and the force acting on the moving coil 104 at that time is controlled by a spring 105, and the moving coil 104 is rotated to an angle proportional to the current flowing through the moving coil 104. is rotated, and the pointer 107 is rotated by the rotation angle via a shaft 106 fixed to a movable coil 104. Then, the deflection angle θ of the pointer 107 and the movable coil 104
The relationship between the current value flowing in and the deflection angle θ, the proportionality constant
K ₁ and current i, it is expressed as θ=K ₁ i, and the third
It is straight as the solid line in the figure. However, guideline 10
The deflection angle of 7 is the moving coil 10 near θ=0°.
Even if the current flowing into the moving coil 104 is 0 due to the unbalance of the pointer 4 and the pointer 107, as well as the friction of the bearing, the pointer 107 does not necessarily point to θ=0°.
It will stop near there. For this reason, the pointer 10 is moved by the stopper 108 in advance to the point θ=0°.
7 is raised (this is called zero raising) to eliminate the failure of the pointer 107 to return to zero due to the above-mentioned friction or the like. Then, the drive circuit changes the input signal frequency to
If the circuit output current is i and the proportionality constant is _K2 , then the formula i
= _K2 , and has a linear characteristic as shown by the solid line in FIG. Therefore, θ=0°~θ=θ ₀
The pointer 107 always points to the "0" scale for coil input currents up to 100 degrees, and has the disadvantage that it does not indicate the speed in the low speed range.

Therefore, the present invention was devised to provide a meter drive device that eliminates the above-mentioned drawbacks, and the meter (ammeter) is configured to change the fixed position of the spring 105 by θ=θ ₀ in the decreasing direction (minus). Shift it so that the characteristics are as shown by the broken line in Figure 3,
The drive circuit has an output circuit that is linearly proportional to the input signal frequency, and a compensation circuit that causes a certain input current i ₀ corresponding to θ=θ ₀ to flow through the meter, completely independent of the input signal frequency. If the output characteristics of the circuit are represented by a formula, i = K ₂ + i ₀ , that is, as shown by the dashed-dotted line in Fig. 4, and if the combined characteristics of the ammeter and the drive circuit are represented by a formula, the proportionality constant is K ₃ Let θ=K ₃ , make it a straight line as shown in the solid line in Figure 6, and set the pointer 10 on the ammeter.
Even if the deflection angle of No. 7 is near 0, by making it equal to the scale intervals of the other deflection angles as shown in Fig. 5,
The purpose is to eliminate the drawbacks of conventional meters.

A first embodiment of the present invention will be described in detail below with reference to the electrical wiring diagram shown in FIG. In FIG. 7, 1 is a battery, 2 is a key switch, 3 is a vehicle speed sensor that generates a vehicle speed signal, 4 is an ammeter with characteristics as shown in the broken line in FIG. waveform shaping circuit section for removing the component, 6
is a differential capacitor for triggering, 7 is a trigger circuit for triggering monostable multivibrator 8, and 9 is a trigger circuit for triggering monostable multivibrator 8.
10 is a constant voltage power supply unit for stabilizing the operation of each circuit from voltage fluctuations of the battery 1; 10 is a constant current circuit as a compensation circuit that supplies a constant current to the ammeter 4;
Reference numeral 11 denotes a constant current circuit that supplies a constant current to the ammeter 4 in response to a signal from the monostable multivibrator 8. And the above components 3, 5, 6, 7, 8,
10 constitutes an output circuit.

Now, when key switch 2 is turned on and the vehicle is not running, no signal is generated from vehicle speed sensor 3.
The monostable multivibrator 8 does not operate, the constant current circuit 10 driven by the monostable multivibrator 8 also does not operate, and no current from the signal system of the vehicle speed sensor 3 flows through the ammeter 4. However, since the constant current circuit 11 supplies a constant current i ₀ to the ammeter 4 regardless of the signal from the vehicle speed sensor 3, the ammeter 4 has no current.
A driving force corresponding to i ₀ acts and changes by θ ₀ . However, the ammeter 4 has the characteristic shown by the broken line in FIG.
Since it has a deflection angle characteristic expressed as =K ₁ i - θ ₀ , even though the pointer 107 actually moves by θ ₀ , it remains at the stopper 108 on the scale plate 100 and points to "0". Since the output _i0 of the constant current circuit 11 is unrelated to the signal of the vehicle speed sensor 3, the fourth
It looks like the two-dot chain line in the figure. Then, when the vehicle starts running from this state and a vehicle speed signal is issued from the vehicle speed sensor 3, each pulse of the vehicle speed signal passes through the waveform shaping circuit 5, the trigger differential capacitor 6, and the trigger circuit 7 to the monostable multivibrator 8.
is triggered, a pulse with a constant time width is generated, and a constant current pulse with a constant time width is further generated by the constant current circuit 10 and supplied to the ammeter 4. Therefore, a current linearly proportional to the signal frequency of the vehicle speed sensor 3 where i=K ₂ (K ₂ is a proportionality constant) is supplied to the ammeter 4 through the constant current circuit 10 as shown by the solid line in FIG. . Since the characteristics of the ammeter 4 itself are as shown by the broken line in Fig. 3, the combined characteristics are the deflection angle θ = K ₃ , which indicates completely linearly from the low speed range to the high speed range as shown in Fig. 6. It becomes a speedometer with the characteristics of

Next, a second embodiment shown in FIG. 8 will be described. In the first embodiment described above, a constant current circuit 11 was used to always supply a constant current value i ₀ to the ammeter 4 regardless of the input signal frequency, whereas in this embodiment, a constant voltage power supply is used. are different. Now, in FIG. 8, 9a and 9b are constant voltage power supply circuits, respectively. When the vehicle is not running, the monostable multivibrator 8 is activated as in the first embodiment described above.
is not activated, and no current flows through the ammeter 4 due to the signal system of the vehicle speed sensor 3. However, from the constant voltage power supply circuit 9a, the voltage V ₀ of the constant voltage circuit section 9a, the resistance value R ₀ of the resistor 12, and the inside of the ammeter 4 are transmitted to the ammeter 4 through the current limiting resistor 12 and the reverse current prevention diode 13. Current determined by resistor R _M and forward voltage drop V _Z of diode 13 (current value i ₀ =
V ₀ −V _Z /R ₀ + _RM ) flows, and a driving force corresponding to the current value i ₀ acts on the movable part of the ammeter 4, causing it to fluctuate by θ ₀ . However, since the ammeter 4 has the characteristics shown by the broken line in FIG. 3, it points to "0" on the scale plate 100 as in the first embodiment. And constant voltage circuit 9a
The output characteristic of the current supply circuit consisting of the resistor 12 and the diode 13 is as shown by the two-dot chain line in FIG. When the vehicle starts running from this state, the monostable multivibrator 8 is triggered by the signal from the vehicle speed sensor 3, and a pulse with a constant time width and constant voltage is generated for each pulse of the vehicle speed signal, and the pulse is supplied to the ammeter 4. be done. The output current characteristic of the monostable multivibrator 8 is expressed by i=K ₂ . Therefore, the characteristic in combination with the ammeter 4 becomes the linear characteristic shown in FIG. 6, and the scale plate 10
As shown in FIG. 5, 0 is a scale with equal intervals over the entire range from low speed range to high speed range.

In the above embodiment, a moving coil type meter was described, but the present invention is not limited to the moving coil type, and can be applied to meters that control torque with a spring, such as a moving magnet type, a rotating magnetic field type, etc. Good too.

Also, instead of a stopper that holds the key switch at the minimum scale position, the pointer is positioned below the "0" scale when the key switch is OFF, and the key switch is
It is also possible to turn it on and indicate the "0" scale when the vehicle speed is 0 km/h.

In addition, we have installed a dial dial plate in which the dial area of the meter is cut out and the pointer rotates through the window area, and when the key switch is turned off, the pointer moves out of the window area of the dial dial plate and enters the back side of the dial plate. It is also possible to construct a structure in which the pointer is located within the window range and becomes visible only when the key switch is turned on.

As described above, the present invention includes an output circuit that electrically detects the state of the display target item and generates an output signal for driving the meter based on the detected signal;
The output signal from this output circuit indicates the state of the display target item at the position of the pointer on the scale plate, and the rotation range of the pointer is changed by a predetermined rotation range from the rotation range on the scale plate in response to the output signal. A meter having a characteristic of being translated in a decreasing direction by a range, and a constant signal being supplied to the meter regardless of a change in the output signal, and rotating the pointer in an increasing direction by the predetermined rotation range; Since it is equipped with a compensation circuit that compensates for the rotational characteristics of the pointer, it is possible to rotate the pointer to the appropriate position even near the minimum scale position, and therefore the scale on the scale plate can be adjusted over the entire rotational range of the pointer. This has the excellent effect of making it possible to space them at equal intervals.

[Brief explanation of the drawing]

Figure 1 is a front view of the display section of a conventional speedometer, Figure 2 is a structural diagram of a moving coil type meter, and Figure 3 is a characteristic diagram showing the relationship between the current value for driving the meter and the deflection angle of the pointer. , Fig. 4 is a characteristic diagram showing the relationship between the frequency of the output signal according to the vehicle speed and the current value for driving the meter, Fig. 5 is a front view of the display section of the speedometer according to the present invention, and Fig. 6 is the output signal according to the vehicle speed. 7 is an electrical wiring diagram showing the first embodiment of the meter drive circuit according to the present invention, and FIG. 8 is a second embodiment of the meter drive circuit according to the present invention. FIG. 3 is an electrical wiring diagram showing an example. 3, 5, 6, 7, 8, 10...Vehicle speed sensor, waveform shaping circuit, capacitor, trigger circuit, monostable multivibrator, constant current circuit forming the output circuit, 4...Ammeter forming the meter, 11 ... Constant current circuit, 100 ... Scale plate, 107 ... Pointer,
108...stoppa.

Claims (1)

[Claims for Utility Model Registration] An output circuit that electrically detects the state of the display target item and uses the detected signal to generate an output signal for driving a meter; The state of the pointer is indicated by the position of the pointer on the scale plate, and the pointer has a characteristic in which the rotation range of the pointer is shifted parallel to the rotation range on the scale plate by a predetermined rotation range in a decreasing direction with respect to the output signal. a meter; and a compensation circuit that supplies a constant signal to the meter regardless of changes in the output signal and rotates the pointer in an increasing direction by the predetermined rotation range to compensate for the rotation characteristics of the meter. A meter drive device comprising: