JP2003130884A - Instrument for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the driving of a step motor to secure the rotation free from the sense of discomfort, of an indicator, even when a degree of change of the input analoque amount is large in an instrument for an automobile applying the step motor as a driving source of the indicator. SOLUTION: A speed of the rotation of the indicator is increased on the basis of the accelerating amount when the variation between a present target indication angle and the last target indication angle is more than the sum of the last driving amount of the stepping motor M and the predetermined acceleration amount during a time when the difference between the present target indication angle of the indicator and the present indication angle is larger than a deceleration start reference value, that is, when an increase degree or a decrease degree of a vehicle speed value is large, and the speed of the rotation of the indicator is decreased on the basis of the accelerating amount when the difference between the present target indication angle and the present indication angle is less than the deceleration start reference value, that is, when the increase degree or the decrease degree of the vehicle speed value becomes small, on the basis of the processing by a microcomputer 60.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle instrument.

[0002]

2. Description of the Related Art Conventionally, for example, in a passenger car instrument, when instructing the vehicle speed of the passenger car by rotating a pointer, the vehicle speed is calculated using a vehicle speed pulse signal generated at a frequency proportional to the vehicle speed of the passenger car. However, there is one in which a step motor is driven to swing a pointer according to the calculated vehicle speed.

[0003]

By the way, in the above instrument, the vehicle speed pulse signal changes in real time in a short time following the change of the actual vehicle speed of the passenger vehicle.
Therefore, even if the drive of the step motor is controlled in accordance with such a vehicle speed pulse signal, the degree of rotation of the pointer is too large or too small, and the occupant feels uncomfortable in the way of rotating the pointer. It causes the problem of giving.

Therefore, in order to deal with the above, the present invention does not make the pointer feel uncomfortable even in the case where the degree of change in the input analog amount is large in the automobile instrument which employs the step motor as the driving source of the pointer. The purpose is to control the drive of the step motor so as to ensure the rotation.

[0005]

In order to solve the above-mentioned problems, in the vehicle instrument according to the invention described in claim 1, a scale board (10) and a step motor (M) provided on the back side of this scale board are provided. ) Built-in internal unit body (30a),
A rotating internal unit having a pointer shaft (30b) operatively connected to a step motor in the internal unit main body and rotatably extending from the internal unit main body toward the through hole (11) of the dial. (3
0), a pointer (40) supported by the tip of the pointer shaft through the through hole of the dial so as to rotate along the surface of the dial, and a detection means (50) for detecting an analog amount.
And a required pointing angle calculation means (20) for calculating a required pointing angle with respect to the pointer based on the detected analog amount of the detecting means.
0, 210, 300 to 330) and a plurality of previous target pointing angles of the pointer to the required pointing angle, and a weighted average value of the addition results is calculated as the current target pointing angle (100). ), And a target pointing angle change amount calculating means (110) for calculating the amount of change between the current target pointing angle and the previous target pointing angle as the target pointing angle change amount.
And when the absolute value of the difference between the current target pointing angle and the current pointing angle of the pointer is larger than the predetermined value, the target pointing angle change amount is equal to or more than the sum of the previous drive amount of the step motor and the predetermined acceleration amount. If there is, the driving amount of the step motor is calculated to be increased by the acceleration amount, and if the absolute value of the difference is less than or equal to the predetermined value, the driving amount calculation means (120) is calculated to decrease the driving amount of the step motor by the acceleration amount. Is provided with control means (130, 70) for controlling the drive of the step motor according to the calculated drive amount of the drive amount calculation means so as to rotate from the current designated angle to the current target designated angle.

As described above, while the absolute value of the difference between the current target angle and the current target angle is larger than the predetermined value, that is, while the degree of increase or decrease of the analog amount is large, the target angle of change is changed. If the amount is equal to or greater than the sum of the previous drive amount of the step motor and the acceleration amount, the method of rotating the pointer is accelerated based on the acceleration amount, and the absolute value of the difference is equal to or less than the predetermined value, that is, When the degree of increase or decrease of the analog amount becomes small, the way of rotating the pointer is delayed based on the above acceleration amount, so that the pointer can be smoothly rotated while maintaining good responsiveness. Can be secured.

Further, in the vehicle instrument according to the invention as defined in claim 2, the scale board (10), the step motor (M) arranged on the back side of the scale board, and the scale board by the step motor. Pointer (4
0) and the target pointing angle determining means (100) for determining the target pointing angle of the pointer corresponding to the input analog amount (50).
Then, while the absolute value of the difference between the target designated angle and the current designated angle of the pointer is larger than the predetermined value, the drive amount of the step motor is calculated to be increased by a predetermined acceleration amount, and when the absolute value of the difference is equal to or smaller than the predetermined value, Drive amount calculation means (110, 120) for calculating the drive amount of the step motor smaller by the acceleration amount, and calculation of the drive amount calculation means for driving the step motor so that the pointer rotates from the current designated angle to the target designated angle. And a control unit (130, 70) for controlling according to the drive amount.

As described above, while the absolute value of the difference between the target designated angle and the current designated angle is larger than the predetermined value, that is, while the degree of increase or decrease of the analog amount is large, it is based on the acceleration amount. If the absolute value of the difference is less than or equal to the predetermined value, that is, the degree of increase or decrease of the analog amount becomes small, the method of rotating the pointer is slowed based on the acceleration amount. By doing so, it is possible to secure a smooth way of rotating the pointer while maintaining good responsiveness.

According to the invention of claim 3, in the invention of claim 1 or 2, the predetermined value is
It is a deceleration start reference value that specifies the position to switch the rotation of the pointer from the fast state to the slow state so that the pointer can be smoothly rotated to the target instruction angle this time while maintaining its good responsiveness. Characterize. Thereby, claim 1
Alternatively, the function and effect of the invention described in 2 can be further improved.

The reference numerals in parentheses of the above-mentioned means indicate the correspondence with the concrete means described in the embodiments described later.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of a passenger car instrument to which the present invention is applied. This instrument is provided as a vehicle speed meter on an instrument panel provided in a passenger compartment of the passenger car. The instrument includes a scale board 10, a wiring board 20, a rotating inner unit 30, and a pointer 40. The wiring board 20 is arranged along the scale board 10 on the back side thereof.

The rotating inner unit 30 includes an inner unit main body 30a and a pointer shaft 30b. The inner unit main body 30a is mounted on the wiring board 20 from the back side thereof at the upper end surface thereof.
The inner unit body 30a is a two-phase step motor M (see FIG.
(Refer to FIG. 3) and a reduction gear train (not shown). The inner machine main body 30a reduces the rotation of the step motor M by the reduction gear train and transmits it to the pointer shaft 30b.

The pointer shaft 30b is provided with a through hole portion 21 of the wiring board 20 and a through hole portion 11 of the scale board 10 from the inner machine body 30a.
It extends rotatably through. The reduction gear train is supported by its input stage gear coaxially with the shaft of the step motor M, and the output stage gear of the reduction gear train is
It is coaxially supported by the pointer shaft 30b. The pointer 40 is
The pivot base 41 is coaxially supported by the tip of the pointer shaft 30b and is rotatable along the surface of the scale 10.

Next, an electric circuit configuration for controlling the drive of the step motor M will be described with reference to FIG.
The vehicle speed sensor 50 detects the vehicle speed of the passenger vehicle and generates a vehicle speed pulse signal at a frequency proportional to the detected vehicle speed.
Here, the vehicle speed pulse sensor 50 is configured such that the vehicle speed pulse signal rises in a rectangular wave shape when the front half cycle elapses and falls in a rectangular wave shape when the rear half cycle elapses.

The microcomputer 60 executes the regular processing program according to the flowchart shown in FIG.
During this execution, the target pointing angle calculation process of the pointer 40, the target pointing angle change amount calculation process, the drive amount calculation process of the step motor M (see FIGS. 4 and 5), and the like are performed. The regular processing program is executed each time the timer for regular processing built in the microcomputer 60 finishes measuring time. The timer for periodical processing counts a predetermined time count time T at the start of the operation of the microcomputer 60, and counts the predetermined time count time T each time the time count ends. In this embodiment, the predetermined time count T is set to 2 ms, for example.

Further, the microcomputer 60 executes the pulse time calculation processing program according to the flowchart shown in FIG. 6, and during this execution, the vehicle speed sensor 50.
The calculation processing and the storage processing of the pulse time based on the vehicle speed pulse signal from are performed. The pulse time calculation processing program is used by the vehicle speed sensor 5 for the microcomputer 60.
Every time the vehicle speed pulse signal from 0 is input, the process is repeatedly executed at the rising timing or the falling timing.

Further, the microcomputer 60 executes the required instruction angle calculation processing program according to the flowchart shown in FIG. 7, and during this execution, the total pulse time calculation processing, the average pulse time calculation processing, and the vehicle speed value calculation. Processing and conversion processing to the requested designated angle for the pointer 40 are performed. The request instruction angle calculation processing program is executed every time the timer for request instruction angle calculation processing built in the microcomputer 60 finishes measuring. The request instruction angle calculation processing timer counts a predetermined time count T1 when the microcomputer 60 starts operating, and counts the predetermined time count T1 each time the time count ends. In this embodiment, the predetermined time count T1 is set to 20 ms, for example. The regular processing program (see the flowcharts of FIGS. 3 to 5), the pulse time calculation processing program (see the flowchart of FIG. 6), and the required instruction angle calculation processing program (see the flowchart of FIG. 7) described above are stored in the microcomputer 60. It is stored in advance in the ROM. Further, the microcomputer 60 uses the ignition switch IG of the passenger car to drive the battery B
It is powered by and operates.

The drive circuit 70 is a microcomputer 6
Under the control of 0, the stepper motor M is driven.

In the present embodiment configured as described above, when the ignition switch IG is turned on, the microcomputer 60 is powered by the battery B and operates. Along with this, the periodic processing timer repeats the measurement of the predetermined measurement time T, and the required instruction angle calculation processing timer repeats the measurement of the predetermined measurement time T1. Also,
The vehicle speed sensor 50 detects the vehicle speed of the passenger vehicle and sequentially generates vehicle speed pulse signals at a frequency proportional to this. The passenger vehicle is assumed to be in a traveling state when the ignition switch IG is turned on.

When vehicle speed pulse signals are sequentially generated from the vehicle speed sensor 50 in the running state of the passenger car as described above, the microcomputer 60 outputs the vehicle speed pulse signals each time the vehicle speed pulse signal is input from the vehicle speed sensor 50. At the fall timing or the rise timing, interrupt execution of the pulse time calculation processing program is repeated according to the flowchart of FIG.

Therefore, for example, in the pulse time calculation processing program which is interrupted and executed at the rising timing of the current vehicle speed pulse signal, in step 200, the rising edge of the current vehicle speed pulse signal and the falling edge of the previous vehicle speed pulse signal. The time corresponding to the pulse width between the edge and the edge is calculated as the pulse time, and in the pulse time storage processing routine 210, the pulse time is stored as data (hereinafter referred to as pulse time data) in the RAM of the microcomputer 60. Here, in the RAM,
If eight pieces of pulse time data have already been stored, the oldest pulse time data is erased. As a result, eight pieces of pulse time data including the current pulse time data are stored in the RAM.

Next, in the pulse time calculation processing program executed by interruption at the falling edge of the current vehicle speed pulse signal, in step 200, the pulse width between the falling edge and the rising edge of the current vehicle speed pulse signal is pulsed. It is calculated as time, and in the pulse time storage processing routine 210, the pulse time is stored in the RAM of the microcomputer 60 as pulse time data. Here, since the eight pulse time data are already stored in the RAM, the oldest pulse time data is erased. As a result, eight pieces of pulse time data including the current pulse time data are stored in the RAM.

At such a stage, when the timer for the required instruction angle calculation processing is finished, the microcomputer 60 starts the interrupt execution of the required instruction angle calculation processing program according to the flowchart of FIG. Accordingly, in step 300, the latest eight pulse times stored in the RAM are added and set as a total pulse time.

Then, in step 310, the average pulse time (total pulse time / 8) is calculated from the total pulse time, and in step 320, the product of the average pulse time and the vehicle speed conversion coefficient is calculated. Is set as the vehicle speed value. Next, at step 330, the vehicle speed value is converted into the required instruction angle for the pointer 40. This conversion process is performed by calculating the required instruction angle in accordance with the vehicle speed value set in step 320 based on a linear expression representing the relationship between the required instruction angle with respect to the pointer 40 and the vehicle speed value.

At this stage, when the timer for the periodical processing is finished, the microcomputer 6
0 starts interrupt execution of the regular processing program according to the flowchart of FIG.
Processing of 0 is performed. This target designated angle calculation routine 1
At 00, the current target instruction angle Af is calculated according to the target instruction angle Ap and the request instruction angle θr of the previous time, based on the equation (1).

[0026]

## EQU00001 ## Af = {Ap.times. (N-1) +. Theta.r} / n In the equation of Expression 1, n is a weighted average number, which is 32 in the present embodiment. The equation of the equation 1 is stored in advance in the ROM of the microcomputer 60.

After that, in the target designated angle change amount calculation routine 110, the target designated angle change amount ΔA is determined as the difference (Af-Ap) between the current target designated angle Af and the previous target designated angle Ap. It is calculated. Next, the processing of the drive amount calculation processing routine 120 (see FIG. 4) is performed as follows.

First, in step 121 of FIG. 4, it is determined whether or not the target designated angle Af this time is larger than the current designated angle Aa. When the pointer 40 swings in the direction of increasing the indicated angle due to the increase in the vehicle speed of the passenger vehicle, Af> Aa is satisfied, and thus the determination in step 121 is YES.

Then, at the next step 122, the difference (Af- between the current target designated angle Af and the current designated angle Aa).
Aa), that is, the required drive amount (Af-
It is determined whether Aa) is equal to or less than the self-startable amount ΔAo of the step motor M. In the present embodiment, the self-startable amount ΔAo represents the rotatable amount of the step motor M per unit time and corresponds to, for example, 15 degrees.

At the present stage, if the required drive amount (Af-Aa) ≤ self-startable amount ΔAo, the determination at step 122 is YES, and at step 122a, the drive amount ΔB per step of the step motor M is determined. Required drive amount (Af-
Aa) is set.

Then, since YES is determined in step 121, NO is determined in step 121a, and ΔB = (Af-Aa) is used as a drive signal in the drive signal output processing routine 130 (see FIG. 3). It is output to 70. Therefore, the step motor M is
Driven by the drive circuit 70 according to the drive signal,
It rotates so as to increase the pointing angle of the pointer 40 by the driving amount ΔB = (Af−Aa). Here, since (Af−Aa) ≦ self-startable amount ΔAo is satisfied as described above, the step motor M rotates in a self-startable state.
Therefore, the pointer 40 is swung so as to increase the pointing angle up to the current target pointing angle Af in the normal wobbling manner by repeating the processing passing through both steps 122 and 122a and the drive signal output processing routine 130.

On the other hand, when the drive amount calculation processing routine 120 proceeds to step 122 as described above, if the required drive amount (Af-Aa)> the self-startable amount ΔAo, the determination in step 122 is NO. , Step 1
At 23, it is determined whether the required drive amount (Af-Aa) is less than or equal to the deceleration start reference value Rth.

Here, the deceleration start reference value Rth is set as follows. At the time of acceleration of the passenger car, the pointer 40 swings so as to increase its indicated angle, following the increase in vehicle speed. However, if the vehicle speed increases significantly, the responsiveness of the manner of turning the pointer 40 is too good, which gives an occupant a feeling of strangeness. Therefore, in the present embodiment, while the difference between the current designated angle of the pointer 40 and the target designated angle is large, the way of rotating the pointer 40 is speeded up, and the difference between the current designated angle of the pointer 40 and the target designated angle is reduced. After reaching a certain small value, the pointer 40
Focusing on the fact that the discomfort can be eliminated while maintaining good responsiveness by slowing down the method of rotation, the deceleration start reference value Rth is set from this viewpoint. That is, the deceleration start reference value Rth represents a predetermined position for switching from the above-described fast rotation method of the pointer 40 to the slow rotation method.

At the present stage, the required drive amount (Af-Aa)>
With the deceleration start reference value Rth, when rotating the pointer 40 from the current designated angle toward the target designated angle, it is necessary to accelerate and then slow the manner of rotation of the pointer 40.
Therefore, it is determined to be NO in step 123, and thereafter, in step 124, the target designated angle change amount Δ
A (= Af-Ap) is the drive amount ΔCp of the step motor M per previous drive (ΔCf in step 125a).
Is greater than or equal to the predetermined acceleration amount ΔAc.
Here, if ΔA ≧ ΔCp + ΔAc is satisfied, YES is determined in step 124.

As described above, the judgment in step 124 is Y.
At ES, in the next step 125, the sum of the previous drive amount ΔCp and the acceleration amount ΔAc is the maximum drive amount ΔCm.
It is determined whether or not it is ax or less. Here, the maximum drive amount ΔC
max corresponds to the maximum amount of rotation that the step motor M can rotate without step-out.

At the present stage, (ΔCp + ΔAc) ≦ Δ
If Cmax is established, YES in step 125.
Then, in step 125a, the sum of the previous drive amount ΔCp and the acceleration amount ΔAc is set as the current drive amount ΔCf of the step motor M.

When the current drive amount ΔCf is set in step 125a as described above, the current drive amount ΔCf is set in the drive signal output processing routine 130 (see FIG. 3).
Cf is output to the drive circuit 70 as a drive signal. For this reason, the step motor M is driven by the drive circuit 70 in accordance with the drive signal, and the pointer 4 is moved by the drive amount ΔCf.
Rotate to increase the indicated angle of zero. Here, since ΔCf = (ΔCp + ΔAc) as described above, the step motor M rotates in the accelerated state according to the acceleration amount ΔAc. Therefore, each step 124, 125, 12
By repeating the processing through 5a and the drive signal output processing routine 130, the pointer 40 rotates so as to increase the instructed angle toward the current target instructed angle Af in a swinging manner faster than the normal swinging manner. .

After that, the determination in step 124 is N.
When it becomes O, ΔCf = ΔCp is set at step 124a, and this ΔCf is the drive signal output processing routine 1
30 (see FIG. 3), the drive circuit 7 is used as a drive signal.
It is output to 0. Therefore, the step motor M is driven by the drive circuit 70 according to the drive signal, and rotates by the drive amount ΔCf so as to increase the pointing angle of the pointer 40 at the same speed as the previous time.

After that, when the drive amount calculation processing routine 120 proceeds to step 123, (Af-Aa) ≤Rth
If is satisfied, YES is determined in step 123. In this determination, the pointer 40 indicates that the target designated angle A
This means that in the process of rotating so as to increase the indicated angle toward f, the switch position from the fast rotating manner to the slow rotating manner is reached.

With the determination of YES in step 123, in step 123a, the difference between the previous drive amount ΔCp and the acceleration amount ΔAc is the current drive amount ΔCf (=
ΔCp-ΔAc). Along with this, the drive amount ΔCf (= ΔCp−ΔAc) is output to the drive circuit 70 as a drive signal in the drive signal output processing routine 130 (see FIG. 3). Therefore, the step motor M is driven by the drive circuit 70 according to the drive signal, and the pointer 40 is moved by ΔCf (= ΔCp−ΔAc).
Rotate to increase the indicated angle of. Here, since ΔCf = (ΔCp−ΔAc) as described above,
The step motor M rotates in a decelerated state according to the acceleration amount ΔAc. Therefore, the pointer 40 has steps 123, 12
3A and the process of passing through the drive signal output processing routine 130 are repeated, the swinging manner is swung so as to increase the designated angle toward the target designated angle Af in a slower rotating manner than usual.

On the other hand, when the regular processing program proceeds to step 121 as described above, if the determination in step 121 is NO, in step 121a of FIG. 5, the current target instruction angle Af is the current instruction. It is determined whether the angle is smaller than the angle Aa. When the pointer 40 rotates in the direction of decreasing the indicated angle because the vehicle speed of the passenger vehicle decreases, Af <Aa, and therefore, step 1
The determination in 21a is YES.

Then, in the next step 126, the difference between the current designated angle Aa and the current target designated angle Af (Aa-
Af), that is, the required drive amount of the step motor M (Aa-
It is determined whether Af) is less than or equal to the self-startable amount ΔAo of the step motor M.

At the present stage, if the required drive amount (Aa-Af) ≤ self-startable amount ΔAo, the determination at step 126 is YES, and at step 126a, the drive amount ΔB per step of the step motor M is determined. Required drive amount (Aa-
Af) is set. Then, in the drive signal output processing routine 130 (see FIG. 3), ΔB = (Aa−A
f) is output to the drive circuit 70 as a drive signal. Therefore, the step motor M is driven by the drive circuit 70 according to the drive signal, and the drive amount ΔB = (Aa−A
Only f) rotates so as to decrease the pointing angle of the pointer 40. Here, since (Aa-Af) ≤ self-startable amount ΔAo is established as described above, the step motor M rotates in a self-startable state. Therefore, both steps 12
6, 126a and the process of passing through the drive signal output processing routine 130, the pointer 40 rotates so as to decrease the designated angle to the current target designated angle Af in the normal manner of rotation.

On the other hand, when the drive amount calculation processing routine 120 proceeds to step 126 as described above, if the required drive amount (Aa-Af)> the self-startable amount ΔAo, the determination at step 126 becomes NO. , Step 1
At 27, it is determined whether the required drive amount (Aa-Af) is less than or equal to the deceleration start reference value Rth.

At the time of deceleration of the passenger car, the pointer 40 rotates so as to decrease the indicated angle in accordance with the decrease in vehicle speed. When the vehicle speed is greatly reduced, the responsiveness of the way of rotating the pointer 40 is too good, which gives the occupant a feeling of strangeness. Therefore, the deceleration start reference value Rth described above is also used as the determination reference in step 127.

At the present stage, the required drive amount (Aa-Af)>
With the deceleration start reference value Rth, in order to swing the pointer 40 from the current designated angle toward the target designated angle, it is necessary to speed up and slow down the manner of rotation of the pointer 40.
Therefore, it is determined to be NO in step 127, and thereafter, in step 128, the target designated angle change amount Δ
A is the drive amount Δ of the step motor M per previous drive
Cp (Cf in step 129a) and predetermined acceleration amount ΔA
It is determined whether the sum is greater than or equal to c. Where ΔA ≧ ΔC
If p + ΔAc is satisfied, then in step 128 YE
It is determined to be S.

As described above, the determination at step 128 is Y.
At ES, in the next step 129, the sum of the previous drive amount ΔCp and the acceleration amount ΔAc is the maximum drive amount ΔCm.
It is determined whether or not it is ax or less. At this stage, (ΔC
If p + ΔAc) ≦ ΔCmax holds, step 12
It is determined to be YES in 9 and in step 129a, the sum of the previous drive amount ΔCp and the acceleration amount ΔAc is set as the current drive amount ΔCf.

When the current drive amount ΔCf is set in step 129a as described above, the current drive amount ΔCf is set in the drive signal output processing routine 130 (see FIG. 3).
Cf is output to the drive circuit 70 as a drive signal. For this reason, the step motor M is driven by the drive circuit 70 in accordance with the drive signal, and the pointer 4 is moved by the drive amount ΔCf.
Rotate to decrease the indicated angle of zero. Here, since ΔCf = (ΔCp + ΔAc) as described above, the step motor M rotates in the accelerated state. Therefore,
By repeating the processing through each of the steps 128, 129, 129a and the drive signal output processing routine 130, the pointer 40 is turned toward the target instruction angle Af of this time in a rotating manner faster than the normal rotating manner. Rotate to decrease the pointing angle.

Thereafter, the determination at step 128 is N
When it becomes O, ΔCf = ΔCp is set in step 128a, and this ΔCf is the drive signal output processing routine 1
30 (see FIG. 3), the drive circuit 7 is used as a drive signal.
It is output to 0. Therefore, the step motor M is driven by the drive circuit 70 according to the drive signal and rotates by the drive amount ΔCf so as to decrease the indicated angle of the pointer 40 at the same speed as the previous time.

After that, when the drive amount calculation processing routine 120 proceeds to step 127, (Aa-Af) ≤Rth
When is satisfied, YES is determined in the step 127. In this determination, the pointer 40 indicates that the target designated angle A
This means that in the process of rotating toward the f so as to decrease the indicated angle, the switch position from the fast rotating manner to the slow rotating manner is reached.

With the determination of YES in step 127, in step 127a, the difference between the previous drive amount ΔCp and the acceleration amount ΔAc is the current drive amount ΔCf (=
ΔCp-ΔAc). Along with this, the drive amount ΔCf (= ΔCp−ΔAc) is output to the drive circuit 70 as a drive signal in the drive signal output processing routine 130 (see FIG. 3). Therefore, the step motor M is driven by the drive circuit 70 according to the drive signal, and the pointer 40 is moved by ΔCf (= ΔCp−ΔAc).
Rotate to decrease the indicated angle of. Here, since ΔCf = (ΔCp−ΔAc) as described above,
The step motor M rotates in a decelerated state according to the acceleration amount ΔAc. Therefore, the pointer 40 uses the steps 127, 12
7a and the process of passing through the drive signal output processing routine 130, the rotation angle is rotated in a manner slower than usual so as to decrease the designated angle toward the target designated angle Af.

As described above, in the acceleration state of the passenger vehicle, the difference (Af-Aa) between the current target indication angle Af and the current indication angle Aa of the pointer 40, that is, the required drive amount (Af) of the step motor M. -Aa) is the deceleration start reference value Rt
While larger than h, the target designated angle change amount Δ, which is the difference between the target designated angle Af of this time and the target designated angle Ap of the previous time.
Until A becomes smaller than the sum of the previous drive amount ΔCp and the acceleration amount ΔAc, the previous drive amount ΔCp and the acceleration amount ΔAc
By driving the step motor M with the current driving amount Cf which is the sum of the above, the pointer 40 is increased by ΔCp so as to increase the pointing angle of the pointer 40 toward the target pointing angle Af.
The rotation is performed in a manner faster than the normal rotation depending on the minute. After that, when the required drive amount (Af-Aa) becomes equal to or less than the deceleration start reference value Rth, the step motor M is driven by the current drive amount Cf which is the difference between the previous drive amount ΔCp and the acceleration amount ΔAc. As a result, the pointer 40 is increased so that the pointing angle of the pointer 40 increases toward the target pointing angle Af.
Is rotated in a slower rotation manner than the normal rotation manner by ΔCp.

On the other hand, in the decelerated state of the passenger vehicle, the difference (Aa-Af) between the current designated angle Aa of the pointer 40 and the current target designated angle Af, that is, the required drive amount (Aa-Af) of the step motor M is determined. While it is larger than the deceleration start reference value Rth, the target instruction angle change amount ΔA, which is the difference between the current target instruction angle Af and the previous target instruction angle Ap, is equal to the previous drive amount ΔCp and the acceleration amount ΔAc. Until it becomes smaller than the sum of the drive amount ΔCp and the acceleration amount ΔAc, the step motor M is driven by the drive amount Cf of this time, which is the sum of the previous drive amount ΔCp and the acceleration amount ΔAc. The pointer 40 is rotated in a rotation manner faster than the normal rotation manner by ΔCp so as to decrease toward. After that, the required drive amount (Af-Aa) is equal to the deceleration start reference value Rth.
In the following cases, by driving the step motor M with the current drive amount Cf which is the difference between the previous drive amount ΔCp and the acceleration amount ΔAc, the indication angle of the pointer 40 is changed to the target indication angle A.
The pointer 40 is rotated in a manner slower than the normal manner of turning by ΔCp so as to decrease toward f.

In this way, the deceleration start reference value Rth is introduced so that the required drive amount (Af-Aa) is equal to the deceleration start reference value Rth.
When the required drive amount (Af-Aa) becomes less than or equal to the deceleration start reference value Rth, the pointer 40 is swung quickly based on the acceleration amount ΔAc while the vehicle speed increases or decreases significantly. That is, when the degree of increase or decrease of the vehicle speed becomes small, the indicator 40 is slowly swung based on the acceleration amount ΔAc, so that the indicator 4
It is possible to maintain a smooth response of the pointer 40 while maintaining a good responsiveness of 0.

In implementing the present invention, the number of pulse widths stored in the RAM of the microcomputer 60 is not limited to eight and may be changed as appropriate.

In implementing the present invention, the interrupt timing of the regular processing program is not limited to 20 ms.
You may change suitably as needed.

Further, in carrying out the present invention, the target pointing angle Af this time is not limited to the formula 1 and may be an arithmetic mean value of the previous target pointing angle Ap and the required pointing angle in step 330. Alternatively, it may be the required instruction angle in step 330.

Further, in carrying out the present invention, the instrument is not limited to the vehicle speed gauge, but may be, for example, an engine tachometer, a fuel gauge, or a water temperature gauge. That is, not only the vehicle speed of the passenger car, but an instrument for indicating an analog amount such as the engine speed of the passenger car, the amount of fuel in the fuel tank of the passenger car, or the water temperature of the engine cooling system of the passenger car (step motor Even when the present invention is applied to the driving source of the pointer), the same operational effect as that of the above embodiment can be achieved.

Further, the measuring instrument is not limited to the one for a passenger car, but may be a measuring instrument for a vehicle such as an automobile in general.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view showing an embodiment of a passenger car measuring instrument according to the present invention.

FIG. 2 is a block diagram showing an electric circuit configuration of the instrument.

FIG. 3 is a flowchart of a regular processing program executed by the microcomputer of FIG.

FIG. 4 is a front part of a flowchart showing in detail the drive amount calculation routine of FIG.

5 is a latter part of a flow chart showing the drive amount calculation routine of FIG. 3 in detail.

FIG. 6 is a flowchart of a pulse time calculation processing program executed by the microcomputer of FIG.

FIG. 7 is a flowchart of a request indication angle calculation processing program executed by the microcomputer of FIG.

[Explanation of symbols]

10 ... Scale plate, 11 ... Through hole portion, 30 ... Rotating inner unit, 30
a ... Inner unit body, 30b ... Pointer shaft, 40 ... Pointer, 50 ... Vehicle speed sensor, 60 ... Microcomputer, 70 ... Drive circuit, M ... Step motor.

Claims (3)

[Claims] 1. A scale plate (10), and a step motor (M) provided on the back side of the scale plate.
And an internal unit main body (30a) having a built-in internal unit, and rotatably extended from the internal unit main body to the through hole portion (11) of the dial by being operatively connected to the step motor in the internal unit main body. Rotating internal unit (30) having a protruding pointer shaft (30b)
A pointer (40) supported by the tip of the pointer shaft through a through hole of the dial so as to rotate along the surface of the dial, and a detection means (50) for detecting an analog amount. A required pointing angle calculating means (20) for calculating a required pointing angle with respect to the pointer based on the detected analog amount of the detecting means.
0, 210, 300 to 330), and a target pointing angle calculation means for adding a plurality of previous target pointing angles of the pointer to the required pointing angle and calculating a weighted average value of the addition results as the current target pointing angle. (100)
And a target pointing angle change amount calculation means (110) for calculating a change amount between the current target pointing angle and the previous target pointing angle as a target pointing angle change amount, and the current target pointing angle. When the absolute value of the difference from the current indication angle of the pointer is larger than a predetermined value, if the target indication angle change amount is equal to or more than the sum of the previous drive amount of the step motor and a predetermined acceleration amount, the step motor Driving amount calculation means (120) for calculating the driving amount of the step motor larger by the acceleration amount and reducing the driving amount of the step motor by the acceleration amount when the absolute value of the difference is less than or equal to the predetermined value; For a vehicle provided with control means (130, 70) for controlling the drive of the step motor according to the drive amount calculated by the drive amount calculation means so as to rotate from the current instructed angle to the target instructed angle this time. Vessel. 2. A scale plate (10) and a step motor (M) arranged on the back side of the scale plate.
A pointer (40) rotated along the surface of the dial by the step motor, and a target pointing angle determining means (100) for determining a target pointing angle of the pointer corresponding to an input analog amount (50). ), While the absolute value of the difference between the target designated angle and the current designated angle of the pointer is larger than a predetermined value, the drive amount of the step motor is calculated to be increased by a predetermined acceleration amount, and the absolute value of the difference is Below a predetermined value, the drive amount calculation means (110, 12) calculates the drive amount of the step motor smaller by the acceleration amount.
0), and a control means (13) for controlling the drive of the step motor according to the calculated drive amount of the drive amount calculation means so that the pointer rotates from the current designated angle to the target designated angle.
0, 70) and an automotive instrument. 3. The predetermined value is changed from a fast state to a slow state by rotating the pointer so as to smoothly rotate the pointer up to the target designated angle of this time while maintaining its good responsiveness. The vehicle instrument according to claim 1 or 2, which is a deceleration start reference value that specifies a switching position.