JPH0635989B2 - Indicator instrument - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an indicating instrument such as a cross coil type instrument or a moving coil type instrument used in a vehicle speedometer, and is particularly characterized by its driving portion. Is.

(Prior Art) In an electric speedometer using a cross coil type instrument or a moving coil type instrument, when an input signal proportional to the vehicle speed is received, the drive unit outputs an instruction drive current corresponding to the input signal. Then, as shown in Fig. 2 (a), the output signal proportional to the input signal, that is, the drive current necessary for the pointer to hold a predetermined angle, is generally displayed. Is being output. With these electric instruments, at low speeds, especially at the zero point, the pointer indication is not stable even though the vehicle is stopped, so it feels like the pointer is working,
It seems that the instrument is out of order. This is because in the moving coil type instrument, the drive current does not flow through the moving coil and the pointer is not held stably.In the cross coil type instrument, the drive current for supplying the zero point is supplied. This is because the holding force is generated, but the pointer rises above the stopper when the power is turned on or due to other subtle changes in the power supply voltage. As a means for solving this, in a moving coil type instrument, a stopper is provided at a position slightly moved to the deflection angle direction side from a normal zero point indication position, and the pointer operates only when a certain or more drive current flows with the stopper as a zero point. There is a so-called zero-raising technology. However, this zero-raising has a drawback that the low-speed area instruction is cut and only the scale display of the low-speed instruction portion does not become a proportional display. Therefore, a means for flowing a compensation current by the amount of zero rise is shown in Japanese Utility Model Publication No. 62-13012, and the pointer indicating characteristic by the input signal and the driving current is as shown in FIG.

(Problems to be Solved by the Invention) As described above, the mere zero-up means has a drawback that the display of the low speed portion is not suitable, and the means for supplying the zero-up compensation current has a compensation current which has nothing to do with the indicating function. Was adopted, which is useless in itself. That is, when the engine of the vehicle is operating, the compensating current flows through the timepiece, which is a waste of energy, and the driving current to the meter body also constantly flows by the compensating current, resulting in a large burden on the meter and durability of the meter. Must be raised. Further, the above-mentioned zero-raising means and zero-raising-compensating current supplying means cannot be applied to the cross coil type instrument.

(Means for Solving the Problems) In view of the above problems, the present invention proposes an indicating instrument having a driving unit that gives a clear zero point instruction without flowing a compensation current or zeroing. That is, the indicating instrument according to the present invention is an indicating instrument comprising a drive section that outputs a pointer drive current corresponding to an input signal from the object to be measured, and a stopper is provided at the zero point indicating position of the instrument display section. , At least with respect to the zero pointing input, a predetermined low pointing angle region has an output characteristic different from that of other pointing angle regions so that a driving current indicating a minus angle from the zero pointing position is output. It is characterized by having.

(Function) The indicator characteristic due to the drive current output in the low indicator angle area is different from the characteristic in other areas.Especially in the case of the zero point instruction, the pointer indicating angle by the instrument drive current becomes a negative angle from the zero point. , The pointer is pressed against the stopper and does not swing. In the high indication angle region, the indication angle by the drive current has a characteristic corresponding to the speed, and the entire characteristic is as shown in FIG.

(Example) Next, an example in which the present invention is applied to a cross-coil type vehicle speed meter will be described.

The entire configuration of the instrument comprises a conversion unit A, a drive unit B, and a display unit (instrument body) C. The conversion unit A receives a pulse input signal proportional to the vehicle speed and converts it into a voltage signal. 1 and an A-D converter 2 for converting the voltage signal into a digital signal, a drive unit B includes a ROM unit 3, a DA converter 4 and a drive output unit 5, and the ROM unit 3 includes the digital signal. Crossing coils X and Y of a display unit C described later corresponding to
Data for instructing the energization amount is stored in the memory and the memory data is digitally output. The characteristic of the present invention lies in a unique instruction characteristic determined by writing of this data. That is, in a predetermined low indication angle area (near the zero point), the pointer is driven to a negative indication angle than the zero indication angle at least in the case of zero indication input (vehicle speed zero) without making the vehicle speed and the indication angle proportional. Data for energizing the X and Y coils as much as possible, and data for energizing outputs of the sine value and cosine value with respect to the input amount to the X and Y coils so that the vehicle speed is proportional to the instructed angle in other indicated angle regions. Is stored in memory. The D-A conversion unit 4 converts each digital signal from the ROM unit 3 based on the memory into an analog amount, and the drive output unit 5 energizes the crossing coils X and Y corresponding to the analog amount. It is an eggplant. The display unit C is a so-called instrument body, in which a movable magnet is provided inside a bobbin formed by combining frames, and the cross coil X,
Y is wound, the movable magnet is provided with a pointer shaft, the pointer is mounted on the pointer shaft, and an appropriate pointer or a stopper for the pointer shaft is provided at the zero point indicating position.

Next, the operation of the above embodiment will be described.

The signal F-V converter 1 having a frequency proportional to the vehicle speed enters the F-V converter 1, which outputs a voltage signal proportional to the input frequency, and the voltage signal is divided by the A-D converter 2 according to the voltage level. It is converted into a predetermined digital signal and enters the ROM section 3. The ROM section 3 outputs an output digital signal to each coil corresponding to the input digital signal. The output digital signal is converted into an analog amount (voltage value or current value) by the D-A conversion section 4, It is for amplifying an analog amount and energizing the crossing coils X and Y.

Therefore, the indicator characteristic of the pointer is based on the data stored in the ROM section 3, and the cosine value or sine value of the input digital signal becomes the output digital signal except for the portion near the zero point, and it is converted into an analog quantity. The pointer deflection angle is proportional to the vehicle speed, and the pointer deflection angle near the zero point is not proportional to the vehicle speed.When the vehicle is stationary, the deflection angle is more negative than the zero point instruction position. Since the data of the ROM part 3 is determined so that the pointer is in a state of lightly pushing the stopper. Therefore, when the vehicle is in a stopped state, the pointer does not swing due to fluctuations in the power supply voltage, and a clear zero point instruction is given.

Although the above-mentioned embodiment has described the cross-coil type instrument,
The present invention is not necessarily limited to the cross coil type instrument, and the same can be applied to the moving coil type instrument. However, in the moving coil type instrument, the drive current of the zero point instruction is opposite to the normal display drive current. It must be flushed to.
Further, it goes without saying that the present invention is applied to instruments other than the vehicle speedometer.

(Effects of the Invention) As described above, the indicating instrument according to the present invention is provided with the stopper at the zero point indicating position, and at least when the zero point is indicated, the drive current indicates a minus deflection angle rather than the zero point indicating angle. It is equipped with an instrument drive unit that outputs a drive current that changes the indication characteristic in the low indication angle region, and it does not require compensation current and raises zero to cause unevenness of the low indication angle on the scale display. It is possible to suppress the swinging of the pointer indication at the zero point indication.

[Brief description of drawings]

FIG. 1 is a block diagram of an instrument according to an embodiment of the present invention, and FIG. 2 is a graph showing a relationship between an input signal of the present invention and a deflection angle due to a drive current. (A) and (b) are conventional. For example, (C) shows the invention. 1 is an FV conversion unit 2 is an A / D conversion unit 3 is a ROM unit 4 is a DA conversion unit 5 is a drive output unit A is a conversion unit B is a drive unit C is a display unit

Claims (1)

[Claims] 1. An indicator instrument comprising an instrument drive section for outputting a pointer drive current corresponding to an input signal from an object to be measured, wherein a stopper is provided at a zero point indication position of a display section of the instrument and at least a zero point is provided. In order to output a drive current that indicates a minus angle from the zero-point pointing position with respect to the pointing input, the predetermined low pointing angle area has a meter drive section with output characteristics different from those of other pointing angle areas. Characteristic indicating instrument.