JP2531540B2 - Indicator instrument - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an indicating instrument for controlling driving by pulsewise modulation (PWM), among crossing coil type instruments and moving coil type instruments used for vehicle speedometers.

[Prior art]

For example, in a speedometer using a crossed coil type instrument or a moving coil type instrument, when a pulse input signal input signal proportional to the vehicle speed is received, the drive unit outputs a drive current corresponding to this as an output signal. The pointer is driven, and the pointing angle of the pointer indicates the state of the object to be measured. By the way, in the above-mentioned pointer driving, especially in the vicinity of the zero position, all of the predetermined input signals and below are output signals for indicating the zero position on the dial. This is because when an input signal from the object to be measured is received as a pulse signal, if the pulse interval (cycle) is long, it is difficult to measure within the specified measurement unit time, so the specified cycle (measurement lower limit) Anything longer than this is determined and output as "0". Further, if the pointer directs with this pointing characteristic as it is, the display in the vicinity of the zero position becomes unnatural, so generally, as shown in FIG. The position stopper that is moved to the plus side of the indicated angle a little more than the (output pointer indicated position) is provided, and the position of this stopper is set as the zero position on the dial, and the zero position is set until the input signal exceeds a certain level. A means called so-called get-up is adopted in which a drive current (an output signal, that is, an output of a drive unit) corresponding to an input signal starts to flow and a pointer operates in a predetermined manner.

[Problems to be Solved by the Invention]

However, in the getter raising means described above, when the pointer suddenly moves in the decreasing instruction direction, the pointer operation becomes unnatural. That is, as shown in FIG. 3 (a), even if the actual vehicle speed A decreases and the measurement lower limit of the drive unit is reached and the output signal B from the drive unit becomes zero, the indicator angle C of the pointer indicates the damper oil or other Since it is delayed due to mechanical friction, the zero position indicating output (the output signal or the output signal for indicating the zero position is zero) is actually output to the pointer before reaching the stopper position, and the pointer operation is There was a problem that the movement was faster than that until then (see "Unnatural part" in Fig. 3 (a)), giving the user a feeling of strangeness. Therefore, if the input signal from the object to be measured is less than or equal to the measurement lower limit of the drive unit, the drive unit outputs an output signal of a predetermined value. The difference from the pointed position corresponding to the signal is reduced, and the movement of the pointer becomes smooth. However, another problem occurs when the output signal of the drive unit is controlled by PWM. That is, when the pointer pointing position is near the zero position on the dial and contacts the stopper, the output signal of the moving coil type instrument becomes a prominent form when instructing with a low output signal (in PWM,
The output signal is a pulse signal, and the proposed output signal has a large cycle, and the pulse signal is generated in a slamming and protruding form.) When a collision between the pointer and the stopper occurs during this protruding output, the output signal The frequency and the vibration frequency of the pointer vibrating synchronously resonate with each other, so that the pointer finely strikes the stopper. This is likely to occur even when ripples are superimposed on the drive unit in order to increase the resolution of the input from the measurement target. Furthermore, in the cross-coil type instrument, the pointer is driven by the synthetic magnetic field generated by energizing the cross-coil, so in the case of adjusting the energization amount by the pulse width like PWM, If the energization timing is deviated, the pointer vibrates finely, and when the pointer comes into contact with the stopper as in the case of the movable coil type instrument, the stopper may be tapped finely. Therefore, the present invention proposes an indicator in which the above problems do not occur and the pointer operation is performed more smoothly.

[Means for Solving the Problems]

The indicating instrument according to the present invention measures the cycle of the pulse input signal generated according to the state of the object to be measured every predetermined unit time, and converts it into a predetermined measured value, and corresponds to the measured value. A drive unit for controlling an output signal, which is a drive current, by pulse-wise modulation and outputting it to a display unit, and the measured object at an indicated angle of a pointer that moves on the dial of the display unit according to the output signal. In the instrument for indicating the state of, the minimum value that can be measured within a predetermined unit time in the conversion unit is limited to measurement, and the pointing angle position of the pointer by the output signal based on this measurement lower limit is set on the dial. In the zero position, if the pulse input signal cannot be measured below the measurement lower limit, the pointer outputs a corresponding output signal indicating the zero position from the drive unit, and the pointer is placed on the negative side of the zero position. Guideline A stopper capable of abutting retaining is characterized in that provided in the dial.

[Action]

A position near the stopper on the plus side of the position of the stopper, for example, as shown in FIG. 2B, the pointer position by the output of the drive unit based on the lower limit of measurement of the conversion unit is set as the zero position on the character, and the input signal is set. When the vehicle speed A reaches the lower limit of measurement, the drive unit outputs an output signal of a predetermined zero position instruction that does not correspond to the input signal, so that the vehicle speed A decreases due to the decrease of the vehicle speed A as shown in FIG. The pointer pointing position (pointing angle of the pointer) when the speed is lower than the speed corresponding to the lower limit of measurement of the drive unit is constant at the zero position on the dial, and the zero position and the original zero position are set on this dial. The difference in the indicated angle is smaller than the difference between the gunshot and the zero position on the dial as shown in Fig. 3 (a), so the movement of the pointer changes sharply when the vehicle starts running from a stopped state. Without it, it will change smoothly. Further, even when the zero position is instructed by the predetermined output signal, the pointer and the stopper do not come into contact with each other, and the phenomenon that the pointer finely strikes the stopper does not occur.

【Example】

Next, an example in which the present invention is applied to a cross-coil type vehicle speedometer will be described. The overall configuration of the instrument consists of a conversion unit 1, a drive unit 2, and a display unit (instrument body) 3, and the conversion unit 1 receives a pulse input signal proportional to the vehicle speed, and a digital signal corresponding to the number of pulse inputs per unit time. It is converted into a numerical value. When the number of pulse inputs per unit time cannot be counted, it is determined that the measured value is lower than or equal to the measurement lower limit, and the same converted value as the measurement lower limit (minimum measurable value) is output. The drive unit 2 includes a ROM unit 21, a D / A converter 22 and a drive output unit 23.
The ROM section 21 stores the data indicating the energization amount in the crossing coils X and Y of the display section 3 which will be described later and corresponds to the digital numerical values, and outputs the memory data as digital numerical values. The feature is that the drive unit 2 stores data for outputting a predetermined output signal below the lower limit of measurement from the conversion unit 1. That is, if the period of the pulse signal becomes long due to the decrease of the vehicle speed and it becomes difficult to measure the pulse signal, the conversion unit 1 outputs a digital numerical value which is the lower limit value of the measurement.
Memorizes the data of the amount of electricity applied to the crossing coils X and Y where the pointer moves to the indicated angle based on the lower limit of the measurement on the plus side of the original zero position, and the indication corresponding to other measurable input signals. In the corner area, the energization output data of the sine value and the cosine value corresponding to the input amount signal to the crossing coils X and Y is stored in memory so that the vehicle speed and the indicated angle are proportional to each other.
The D / A conversion unit 22 is for converting the digital signal from the ROM unit 21 into an analog signal, and the drive output unit 23 outputs a current having a pulse width corresponding to the analog signal to the crossing coils X and Y as an output signal. It uses a so-called PWM that conducts electricity. The display unit 3 is a so-called instrument body, in which a movable magnet is provided inside a bobbin formed by combining a frame, crossing coils X and Y are wound on the outer surface of the frame, and a pointer shaft is projectingly provided on the movable magnet. The pointer is attached to the shaft, the dial is fixed to the upper part of the frame, and the pointer position by the output signal (driving current) based on the measurement lower limit of the drive unit 2 of the dial is displayed as zero, A stopper capable of abutting and holding the pointer is provided on the minus side. Next, the operation of this embodiment will be described. Normally, an input signal, which is a pulse signal having a frequency proportional to the vehicle speed, enters the conversion unit 1, and the conversion unit 1 outputs a digital numerical output signal in proportion to the frequency and inputs it to the ROM unit 21. The ROM section 21 outputs an output signal of the digital numerical value to the corresponding crossing coils X and Y corresponding to the input digital numerical value, and the D / A conversion section 22 converts this output signal into an analog numerical value (voltage value or current value). After conversion, a drive current having a pulse width corresponding to this analog numerical value is supplied to the crossing coils X and Y. Therefore, the pointer indicating characteristic is based on the data stored in the ROM unit 21, and the vehicle speed (state of the measured portion) is instructed at the pointer indicating angle proportional to the vehicle speed. Further, when receiving a digital value that is less than or equal to the measurement lower limit from the conversion unit 1, the ROM unit 21 of the drive unit 2 stores data based on a fixed measurement lower limit value, and therefore does not correspond to an input signal. , A predetermined drive current is output. The pointing position of the pointer at that time is the zero position on the dial. Therefore, when the vehicle speed suddenly decreases, even if there is a delay in the pointer indicating operation, for example, the pointer indicating operation below the measurement lower limit of the drive unit 2, the instruction corresponding to the input signal, and not the zero on the dial. In order to indicate the position, the pointer smoothly reaches the zero position, and when the vehicle speed A decreases below the speed corresponding to the lower limit of the measurement of the drive unit 2 due to the decrease of the vehicle speed A as shown in FIG. The pointer pointing position (pointing angle of the pointer) is constant at the zero position on the dial, and the pointing angle with the zero position on the dial is the same as on the conventional dial as shown in FIG. Since it is smaller than the difference with the zero point position at,
When the vehicle starts traveling from the stopped state, the movement of the pointer does not change suddenly but changes smoothly. Further, even when the zero position is designated by the predetermined output signal, the pointer does not come into contact with the stopper, and the phenomenon that the pointer finely strikes the stopper does not occur. By the way, according to the present invention, when the pointer indicates the zero position on the dial, the stopper does not come into contact with the pointer stopper. However, in actual use, when the ignition switch is turned off and the output signal from the drive unit 2 disappears, the pointer is returned so that the pointer comes into contact with the stopper by the magnetic field generated between the movable magnet and the small magnet for zero resetting ( It moves from the zero position on the dial to the zero position of the main body), and the pointer is held at that position. Therefore, in the present invention, the stopper is still provided. The output signal based on the lower limit of measurement is the drive current that moves the pointer to the pointer pointing angle that matches the value of the lower limit of measurement. It is intended to include (to the extent that the "unnatural portion" in FIG. 3 (a) does not occur). That is, by taking into account the manufacturing process of the indicating instrument, the variation in the parts accuracy, etc., and moving the pointer to the plus side from the pointer indicating position corresponding to the lower limit of measurement, the conventional problem can be solved more reliably. Of course, the pointer indication position by the pointer drive output signal in the case of being below the measurement lower limit shifted to the plus side is zero display on the dial. Further, it goes without saying that the above embodiment can be similarly applied to a moving coil type meter.

【The invention's effect】

INDUSTRIAL APPLICABILITY As described above, the present invention measures the input signal from the measured object, measures the input signal in the instrument that operates the pointer with the drive current corresponding to the measured value and indicates the state of the measured object. The minimum possible value is set as the lower limit of measurement, and if it is less than or equal to this lower limit of measurement, the pointer is driven by the output signal based on the lower limit of measurement, and the pointer indicating angle position at that time is set to the zero position on the dial. An indicator instrument provided with a stopper capable of abutting and holding the pointer on the minus side of the zero position, indicates the zero position of all dials below the lower limit of measurement. The difference between the zero position and the indicated angle is smaller than that of the conventional zero position (also the stopper formation position) on the dial and the original zero position, so the pointer movement is smoother than that of the previous instrument. It will be a natural movement, Since no path abuts, it is no reduction guidance finely tapping the stopper.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an instrument according to a first embodiment of the present invention, and FIG.
FIG. 3 is a graph showing the relationship between the input signal and the pointer pointing angle, and FIG. 3 is a graph showing abrupt pointer movement. Reference numeral 1 is a conversion unit, 2 is a drive unit, 21 is a ROM unit, 22 is a DA conversion unit, 23 is a drive output unit, and 3 is a display unit.

Claims (1)

(57) [Claims] 1. A converter for measuring a cycle of a pulse input signal generated according to a state of an object to be measured every predetermined unit time and converting the measured period into a predetermined measured value, and a drive current corresponding to the measured value. A drive unit for controlling a certain output signal by pulse-wise modulation and outputting the same to a display unit is provided, and the state of the object to be measured is indicated by a pointing angle of a pointer that moves on the dial of the display unit according to the output signal. In the indicating instrument, the minimum value that can be measured within the predetermined unit time in the conversion unit is the measurement lower limit, and the pointing angle position of the pointer by the output signal based on this measurement lower limit is the zero position on the dial. When the panel input signal is not measurable below the measurement lower limit, an output signal corresponding to the pointer indicating the zero position is output from the drive unit, and the pointer is placed on the minus side of the zero position. Contact hold Ur stopper indicating instrument, characterized in that provided in the dial.