JPH0514206B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention uses automobile instruments, such as a speedometer or an engine tachometer, which tend to have a relatively pointer-type display, that is, an analog display, as an input, and a stepping motor and a digital signal such as the number of pulses/time. By using this, it is possible to provide a means for displaying an analog signal without converting it to an analog signal.

[Conventional technology]

A conventional display method of this kind is, for example, as shown in FIG.
The vehicle speed is determined by calculating SP in the microcomputer CPU, and this vehicle speed is output from the microcomputer CPU as, for example, a BCD output. This is displayed as a number that can be read by the driver on the seven segment display SS.

[Problem to be solved by the invention]

However, some users use the above-mentioned speedometers not only as a means of knowing the speed at that time, but also as a means of knowing the time it takes to reach that speed, that is, the acceleration. Similarly, in an engine tachometer, it is used as a means to determine engine speed, that is, the response of the engine.The digital display using the seven-segment display described above does not have a means for providing this point, so an analog display is used. On the other hand, it was considered that the display content was inferior and that this was an issue that needed to be resolved.

[Means to solve the problem]

The present invention is a specific means for solving the problems that occur in the conventional digitally driven automobile instruments described above, and is directed to an automobile instrument that is mounted on an automobile and is driven by a digital signal such as pulse number/time. Digital signals are counted continuously at predetermined time intervals, and the counting results are sequentially input into a storage means to calculate the difference from the previous count. By providing a display method for an automobile instrument characterized by driving an attached stepping motor, the above-mentioned acceleration or response can also be displayed, and the above-mentioned conventional problems can be solved.

【Example】

Next, the present invention will be explained in detail based on an embodiment shown in the drawings. FIG. 1 shows a method of displaying an automobile instrument according to the present invention in a block diagram. There is a microcomputer 2 connected to a speed pulse transmitter 51 that transmits a number of pulses and a tacho pulse transmitter 52 that transmits a number of pulses proportional to the rotation of the engine. A speedometer motor controller 3S corresponding to the speedometer and a tachometer motor controller 3T corresponding to the engine tachometer are respectively connected, and the outputs of these motor controllers 3S and 3T are connected to a speedometer motor drive motor. Circuit 4S and tachometer motor drive circuit 4
A speedometer stepping motor 5S and a tachometer stepping motor 5T, to which a speedometer pointer 6S and a tachometer pointer 6T are respectively attached, are connected to this output. .
In addition to the above-mentioned components, the microcomputer 2 is also equipped with an LCD driver 7 for driving, for example, a liquid crystal display element 8 that forms the background of the pointers, and further for confirming the positions of the pointers 6S and 6T. A speedometer photocoupler 9S and a tachometer photocoupler 9T are connected. Next, the operation of the control block 1 described above will be explained, but as it is clear from the above explanation, the speedometer section and the tachometer section have almost the same configuration, so the explanation here is unnecessary. To avoid complication, only one speedometer section will be explained. generated by the speed pulse transmitter 51,
The pulses, whose number is proportional to the speed of the vehicle in a fixed time period, are connected to the microcomputer 2 and are counted in the microcomputer 2 at fixed time intervals. At this time, if the speed of the car is specifically changing from 5 km/h to 7 km/h to 10 km/h, the first count will be "5".
is held in a storage means such as a memory or a register provided in the microcomputer 2, and is compared with the next numerical value "7", and this difference "2" is output, and the storage means “7” is replaced. Similarly, in the next time period, a comparison is made between "7" in the storage means and the count value "10", and the difference "8" is output and the numerical value in the storage means is also replaced with "10". The output signal as described above is processed by the speedometer motor controller 3S and the speedometer motor drive circuit 4S into a signal form suitable for driving the stepping motor, and then applied to the speedometer stepping motor 5S. Therefore, the speedometer step pig motor 5S performs normal rotation and reverse rotation according to the difference, and when there is no difference, it stops at that position. Therefore, the speedometer stepping motor 5S
The speedometer pointer 6S attached to the vehicle is at the position corresponding to the sum of the differences at that time (of course, negative values are also included), which is the speed of the vehicle at that time. Next, the action of the speedometer photocoupler 9S will be explained. This is mainly for regulating the position of the speedometer pointer 6S at the start of driving, and for example, the operation history of the previous driving, specifically, When the driver turns off the ignition even though the automobile is still coasting, the speedometer pointer 6S cannot return to the correct starting position, and this coasting speed remains as a history. Here, the position of the speedometer pointer 6S is detected before the start of the next run, that is, when the speed is 0, and when a positional deviation is detected, the microcomputer 2 issues a signal to correct it. This ensures accuracy by resetting to the 0 position, and by doing so, it is possible to implement the drive method of the present invention using an open loop.
This makes it possible to extremely simplify the circuit configuration. Incidentally, what is shown in FIG. 2 is a specific circuit diagram of the control block 1, and all the reference numerals in the figure correspond to the above description. What is shown in FIG. 3 is an example of a speedometer 10 driven by the control block 1 described above.
Speedometer pointer 6S via 0a, 10b, 10c
By decelerating and driving the speedometer pointer 6S in this way, it is possible to alleviate the intermittent movement peculiar to stepping motors and to reduce the sense of discomfort given to the viewer. It is possible. 4. Effects of the Invention As explained above, by driving the stepping motor based on the difference between successive measured values and the previous value, the display method of the automobile instrument of the present invention is driven by digital signals. Despite this, the display can display the current speed of the car at the same time as a conventional analog mechanical meter, and at the same time display the acceleration based on the moving speed of the pointer, causing the driver to lose information. This device has the outstanding effect of making it possible to display the display without any blemishes by using digital signals that are superior in accuracy and easy to process.In addition, a pointer position detection device is provided to reset the pointer to its initial position when the device is started. As a result, even in this type of simplified display system of open-loop control using digital signals, it is possible to eliminate accumulation of errors and improve accuracy.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the display method of an automobile instrument according to the present invention, FIG. 2 is a circuit diagram showing the block diagram of FIG. 1 with a specific circuit example, and FIG.
The figure is an explanatory diagram showing an example of the structure of an automobile instrument using a stepping motor, and FIG. 4 is a block diagram showing a conventional example. 1...Control block, 2...Microcomputer, 3S...Speedometer motor controller, 3
T...Motor controller for tachometer, 4S...Motor drive circuit for speedometer, 4T...Motor drive circuit for tachometer, 5S...Stepping motor for speedometer, 5T...Stepping motor for tachometer, 6S
...Speedometer pointer, 6T...Tachometer pointer, 9S
...Photocoupler for speedometer, 9T...Photocoupler for tachometer.

Claims (1)

[Claims] 1. In an automobile meter that is mounted on an automobile and driven by a digital signal such as pulse number/time, the digital signal for driving is continuously counted at a predetermined time interval. A display of an automobile instrument characterized in that the counting results are sequentially input to a storage means for holding the counting results, a difference from the previous counting is calculated, and this difference drives a stepping motor to which a pointer is attached. Method. 2. The method of displaying an automobile instrument according to claim 1, wherein the stepping motor is forcibly reset to a predetermined zero position when the automobile instrument starts driving.