JP2010112886A - Indicating instrument for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an indicating instrument for vehicles for reducing waste of consumption power. <P>SOLUTION: The indicating instrument 1 for vehicle includes a pointer 12 for indicating the remaining amount of fuel according to a rotary position; a step motor 13 for rotating and driving the pointer 12 by inputting an AC drive signal that corresponds to the electrical angle to field winding; and a meter control unit 20 for controlling each drive signal output to the field winding of the step motor 13. In the indicating instrument 1 for vehicle, the meter control unit 20 changes the electrical angle of each drive signal, by adjusting the output level of each drive signal to a prescribed normal level, when established determination of the change conditions for changing the rotary position of the pointer 12 is given, and holds the electrical angle of each drive signal, by adjusting the output level of each drive signal to a suppression level that is restrained, as compared with a normal level, when established determination of the holding conditions for holding the rotary position of the pointer 12 is given. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an indicating instrument for a vehicle.

  2. Description of the Related Art Conventionally, there is known a vehicular indicating instrument that is driven to rotate by a step motor with respect to a pointer that indicates a vehicle state value such as a remaining fuel amount or a vehicle speed according to a rotational position.

As a kind of such a vehicle indicating instrument, Patent Document 1 discloses that a rotational driving of a pointer is realized by inputting an AC driving signal corresponding to an electrical angle to a field winding of a step motor. . In the vehicle indicating instrument disclosed in Patent Document 1, the rotational position of the pointer can be changed to the indicated position by changing the electrical angle of the drive signal to the electrical angle corresponding to the indicated position of the vehicle state value. .
JP 2002-267501 A

  In the vehicle indicating instrument disclosed in Patent Document 1, in order to keep the rotation position of the pointer at the indicated position of the vehicle state value, the electrical angle of the drive signal is set so that the pointer does not rotate to the mechanical stable point. It is necessary to hold the electrical angle corresponding to the indicated position. Here, in particular, in the case of microstep drive that drives the step motor at a minute angle interval that further divides the unique step angle, the electrical angle of the drive signal is securely held in order to hold the rotational position of the pointer. It is important to do. However, in the vehicle indicating instrument disclosed in Patent Document 1, when the electrical angle of the changed drive signal is held, the output level of the drive signal is held at the level at the time of the change. There is a problem that power consumption is wasted despite the necessity of rotational driving.

  The present invention has been made in view of such problems, and an object thereof is to provide a vehicular indicating instrument that reduces waste of power consumption.

  According to the first aspect of the present invention, there is provided a step motor that rotationally drives the pointer by inputting a pointer indicating the vehicle state value according to the rotational position and an AC drive signal corresponding to the electrical angle to the field winding. And a control unit for controlling the drive signal output to the field winding of the step motor, wherein the control unit establishes a change condition for changing the rotational position of the pointer and rotates the pointer The condition determination means for determining whether the holding condition for holding the position is satisfied, and when the condition determination means determines whether the change condition is satisfied, the output angle of the drive signal is adjusted to a predetermined normal level. And a signal adjusting unit that holds the electrical angle of the drive signal by adjusting the output level of the drive signal to a suppression level that is lower than the normal level when the condition determination unit determines whether the holding condition is satisfied. Have And wherein the door.

  According to the present invention, when the changing condition for changing the rotational position of the pointer that indicates the vehicle state value is satisfied, the output level of the AC drive signal output to the field winding of the step motor to drive the pointer to rotate is normally set. The electrical angle of the drive signal changes while being adjusted to the level. Thereby, the pointer can be quickly driven to the rotational position corresponding to the electrical angle of the drive signal, and the vehicle state value can be accurately indicated. On the other hand, when the holding condition for holding the rotational position of the pointer that indicates the vehicle state value is established, the output level of the AC drive signal is adjusted to the suppression level that is suppressed from the normal level, and the electrical angle of the drive signal is Will be retained. As a result, when the rotational driving of the pointer is not required, the waste of power consumption can be reduced by suppressing the output level of the driving signal.

  According to the second aspect of the present invention, in the control unit that controls the drive signal by pulse width modulation, the signal adjustment unit reduces the duty ratio of the drive signal when the condition determination unit determines whether the holding condition is satisfied. As a result, the output level of the drive signal is adjusted to the suppression level. According to the present invention, when the holding condition for holding the rotational position of the pointer is satisfied, the duty ratio of the drive signal controlled by pulse width modulation is reduced, so that the output level of the drive signal can be reliably suppressed. Therefore, the wastefulness reduction effect of power consumption can be exhibited timely and accurately.

  According to a third aspect of the present invention, the signal adjustment means outputs the drive signal when the condition determination means makes a determination that the holding condition is satisfied when the rotational position of the pointer reaches the indicated position of the vehicle state value. Adjust the level to the suppression level. According to the present invention, the holding condition for holding the rotational position of the pointer is established after the probability that the rotational position of the pointer reaches the indicated position of the vehicle state value increases the possibility that the rotational driving of the pointer is unnecessary. Thus, the output level of the drive signal can be suppressed to the suppression level, and the wastefulness reduction effect of power consumption can be enhanced.

  According to the fourth aspect of the present invention, the signal adjustment means after adjusting the output level of the drive signal to the suppression level by the condition determination means determining whether the holding condition is satisfied determines whether the change condition is satisfied. The output level of the drive signal is held at the suppression level until the value is reduced. According to the present invention, the drive signal whose output level is suppressed to the suppression level due to the establishment of the holding condition for holding the rotation position of the pointer is set to the suppression level unless the change condition for changing the rotation position of the pointer is satisfied. Will be retained. Therefore, it is possible to continuously suppress the output level of the drive signal and enhance the power consumption waste effect.

  According to the fifth aspect of the present invention, the signal adjustment means after adjusting the output level of the drive signal to the suppression level by the condition determination means determining whether or not the holding condition is satisfied has a variation amount of the vehicle state value of the set amount. When the condition determination means maintains the determination that the holding condition is satisfied due to being less than the value, the driving signal output level is held at the suppression level and the electrical angle of the driving signal is changed, while the fluctuation amount of the vehicle state value is set. When the condition determination means makes a determination that the change condition is satisfied because it is greater than or equal to the amount, the output level of the drive signal is returned to the normal level to change the electrical angle of the drive signal. In this invention, when the vehicle state value fluctuates less than the set amount, the electrical angle of the drive signal changes while the output level of the drive signal is held at the suppression level by maintaining the holding condition for holding the rotational position of the pointer. Become. According to this, not only when the rotational driving of the pointer is unnecessary, but also when the necessary rotational driving of the pointer is slow, the output level of the drive signal is continuously suppressed to increase the power consumption waste effect. Is possible. On the other hand, when the vehicle state value fluctuates more than the set amount, the drive signal output level is returned from the suppression level to the normal level and the electrical angle of the drive signal changes due to the establishment of a change condition that changes the rotational position of the pointer. As a result, an accurate indication of the vehicle state value can be realized by rapidly rotating the pointer.

  According to the sixth aspect of the present invention, the signal adjustment means after adjusting the output level of the drive signal to the suppression level by the condition determination means determining whether the holding condition is satisfied is such that the ignition switch is turned off in the vehicle. When the condition determination means determines whether the change condition is satisfied, the output level is returned to the normal level for the drive signal that returns the pointer to the rotational position corresponding to the zero point of the electrical angle of the drive signal. Change to zero. In the present invention, when the ignition switch in the vehicle is turned off, the output level of the drive signal is returned from the suppression level to the normal level and the electrical angle of the drive signal is changed to the zero point by satisfying the change condition for changing the rotational position of the pointer. It will be. According to this, a zero return operation for returning the pointer to the rotational position corresponding to the zero point can be quickly performed.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

(Instrument configuration)
FIG. 1 shows a vehicle indicating instrument 1 according to a first embodiment of the present invention. The vehicle indicating instrument 1 includes a display unit 10, an instrument control unit 20, and the like, and is installed on an instrument panel in front of the driver's seat of the vehicle.

  The display unit 10 includes an instrument panel 11, a pointer 12 and a step motor 13. In the present embodiment, the instrument panel 11 as shown in FIG. 2 is formed with a fuel display portion 111 that displays the remaining amount of fuel in the fuel tank as a vehicle state value on the display surface 110 arranged toward the driver's seat. Yes. The fuel display unit 111 is a combination of a plurality of scales that engrave the remaining amount of fuel side by side on an arcuate curve, and characters that represent the remaining amount of fuel E and the full value F that are arranged near a predetermined scale. Become.

  The pointer 12 is rotatably supported along the display surface 110 of the instrument panel 11 by being pivotally supported at one end. The pointer 12 indicates a value corresponding to the rotational position in the fuel remaining amount indicated by the scale and characters of the fuel display unit 111.

  As shown in FIG. 3, the step motor 13 includes A and B two-phase stators 130 a and 130 b and a magnet rotor 131. Each stator 130a, 130b is formed by winding field windings 133a, 133b around yokes 132a, 132b made of a magnetic material. The magnet rotor 131 formed of a magnetic material and magnetized can be rotated together with the pointer 12 by being directly connected to the pointer 12 or indirectly via a speed reduction mechanism or the like.

  The step motor 13 excites the yokes 132a and 132b of each phase by inputting AC drive signals to the field windings 133a and 133b of each phase, and moves to a rotational position corresponding to the electrical angle of the drive signals. The magnet rotor 131 and the pointer 12 are driven. Here, as shown in FIG. 4, the drive signal input to the A-phase field winding 133a is a sine signal whose voltage level as an output level alternates in a sinusoidal manner with respect to the electrical angle. On the other hand, the drive signal input to the B-phase field winding 133a is a cosine signal in which the voltage as the output level alternates in a cosine function with respect to the electrical angle, as shown in FIG. As described above, in the present embodiment, with respect to the drive signals for the A-phase and B-phase field windings 133a and 133b, the voltage level becomes zero (0) and positive when the electrical angle becomes zero (0 degree). When the maximum level (V + max) is reached, the pointer 12 indicates an empty amount value E as an instruction value for the remaining amount of fuel.

  As shown in FIG. 1, the instrument control unit 20 includes a drive circuit 21 and a control circuit 22. As shown in FIG. 3, the drive circuit 21 is formed by combining A and B two-phase signal generators 210a and 210b. The A-phase signal generator 210 a includes a first complementary circuit 212 and a second complementary circuit 213. Each of the complementary circuits 212 and 213 is formed by complementarily connecting P-channel field effect transistors (Pch-FETs) 214 and 215 and N-channel field effect transistors (Nch-FETs) 216 and 217. In each of the complementary circuits 212 and 213, the midpoint between the FETs 214 and 216 and the midpoint between the FETs 215 and 217 are connected to the A-phase field winding 133a to form an H bridge. In contrast, the B-phase signal generator 210b generates an A-phase signal except that the midpoint between the FETs 214 and 216 and the midpoint between the FETs 215 and 217 are connected to the B-phase field winding 133b. Complementary circuits 212 and 213 having a configuration similar to that of the unit 210a are provided.

  In the drive circuit 21, the Pch-FET 214 of the first complementary circuit 212 and the Nch-FET 217 of the second complementary circuit 213 are turned on in each of the signal generation units 210a and 210b, whereby the voltage on the positive side (V + max side in FIG. 4). Is applied to the corresponding windings 133a and 133b. On the other hand, in the drive circuit 21, the Nch-FET 216 of the first complementary circuit 212 and the Pch-FET 215 of the second complementary circuit 213 are turned on in each signal generation unit 210a, 210b, thereby causing the negative side (V− in FIG. 4). voltage on the max side) is applied to the corresponding windings 133a and 133b. Therefore, on / off control of the FETs 214 to 217 for realizing the coil energization is controlled as will be described in detail later, so that the sine signal and the cosine signal are driven for the A-phase and B-phase field windings 133a and 133b, respectively. It is input as a signal.

  As shown in FIG. 1, the control circuit 22 is mainly composed of an interface circuit 220 and a microcomputer 221, an ignition switch 2 for turning on and off the engine in the vehicle, a fuel sender 3 for detecting the remaining amount of fuel, and a drive circuit 21. And connected to. The interface circuit 220 inputs the detection signal output from the fuel sender 3 to the microcomputer 221 through a digital filter that performs a smoothing process. The microcomputer 221 controls the FETs 214 to 217 (see FIG. 3) of the signal generators 210a and 210b of the drive circuit 21 to turn on and off, thereby sine the field windings 133a and 133b (see FIG. 3) of the step motor 13. A signal and a cosine signal are output and the detected fuel remaining amount of the fuel sender 3 is indicated by the pointer 12.

  Here, particularly in the present embodiment, on / off control of the FETs 214 to 217 of the signal generation units 210a and 210b in the drive circuit 21 is realized by pulse width modulation. Specifically, the ON times within one control cycle are controlled for the FETs 214 to 217 that are turned on by the signal generators 210a and 210b. With this control, on-duty ratios are set for the sine signals and cosine signals as drive signals input from the signal generators 210a and 210b to the field windings 133a and 133b, respectively, as shown in FIG. The output level is adjusted to a voltage according to the above. Therefore, as shown by the arrows in FIG. 4, when the on-duty ratio of the sine signal and cosine signal is decreased at the same rate, the output level of these signals can be suppressed without changing the electrical angle. is there.

(Instrument control processing)
Hereinafter, the instrument control process performed by the microcomputer 221 of the control circuit 22 executing the computer program will be described in detail with reference to FIG.

  When the ignition switch 2 is turned on in the vehicle, the control mode is set to the high torque mode by executing S10 of the instrument control process when the control circuit 22 is turned on.

  In this high torque mode, for the sine signal and cosine signal as drive signals, the on-duty ratio is increased to the maximum ratio defined for each control electrical angle obtained by dividing the step angle, as shown by the thin solid line in FIG. The needle 12 is driven at a high torque by adjusting the output level to the normal level. Therefore, in S11 following S10, the output levels of the sine signal and cosine signal are adjusted to the normal level, and the electrical angles of the sine signal and cosine signal correspond to the detected fuel remaining amount indication position of the fuel sender 3. To change.

  As a result, when the rotation position of the pointer 12 reaches the indicated position of the detected fuel remaining amount of the fuel sender 3, a determination is made in S12 that the holding condition for holding and stabilizing the rotation position is established, and the process proceeds to S13. Transition to set the control mode to the low torque mode.

  In this low torque mode, for the sine signal and cosine signal, as shown by the thick solid line in FIG. By adjusting the output level to the suppressed suppression level, the pointer 12 is driven with low torque. Here, the reduction ratio of the intermediate ratio with respect to the maximum ratio with respect to the on-duty ratio, that is, the suppression ratio of the suppression level with respect to the normal level with respect to the output level can be set as appropriate, but is set to, for example, 60% as shown in FIG. . As described above, in S14 subsequent to S13, the electrical angles of the sine signal and the cosine signal are adjusted to the suppression level, and the electrical angles of the sine signal and the cosine signal correspond to the indicated position of the detected fuel remaining amount of the fuel sender 3. Adjust to the corner.

  As a result, when the determination that the change condition for changing the rotational position of the pointer 12 is made in S15 due to the detected fuel remaining amount of the fuel sender 3 fluctuating by a predetermined amount or more, the process returns to S10. Therefore, if a change beyond the set amount of the remaining amount of fuel occurs due to fuel supply to the fuel tank or fuel decrease due to abnormality of the fuel tank, the control mode is set to the high torque mode by re-execution of S10. Thus, the electrical angle of the sine signal and cosine signal whose output level is returned to the normal level by re-execution of S11 changes. Note that the set amount for determining whether or not there is a change in the remaining amount of fuel in S15 is appropriately set in consideration of, for example, the smoothing effect of the remaining amount of fuel in the interface circuit 220 of the control circuit 22.

  Further, when the ignition switch 2 is turned off and the change condition for changing the rotational position of the pointer 12 is determined in S16, the process proceeds to S17. In S17, the control mode is set to the high torque mode as in S10. In the subsequent S18, the output levels of the sine signal and cosine signal are adjusted back to the normal levels, and the electrical angles of the sine signal and cosine signal are changed to the zero point corresponding to the remaining amount E of the remaining fuel amount. The pointer 12 is returned to zero. Then, after the pointer 12 returns to zero, the power source of the control circuit 22 is turned off, and the instrument control process is ended.

  On the other hand, when the change condition is not satisfied in both S15 and S16, that is, the fluctuation amount of the fuel remaining amount detected by the fuel sender 3 is less than the set amount, and the ignition switch 2 is in the ON state. In the case, the process returns to S13. According to the re-execution of S13, the electrical angles of the sine signal and the cosine signal are adjusted while the output levels of the sine signal and the cosine signal are suppressed to the suppression level. Here, the electrical angles of the sine signal and the cosine signal are held when the variation amount of the remaining fuel amount detected by the fuel sender 3 is substantially zero, and the set amount is within a range where the variation amount exceeds zero. If it is less than, it is changed.

  In the present embodiment described above, when various changing conditions of the pointer rotation position are satisfied, each drive signal (sine signal and cosine) input to the field windings 133a and 133b of the step motor 13 is set by setting the high torque mode. While the output level of the signal) is adjusted to the normal level, the electrical angle of these drive signals changes. At this time, the normal level is realized by setting the on-duty ratio of each drive signal to the maximum ratio for each control electrical angle, so the pointer 12 can be quickly moved to the rotational position corresponding to the electrical angle of each drive signal. By driving, the fuel remaining amount indicating operation or the zero return operation can be performed accurately.

  On the other hand, in the present embodiment, when the holding condition for the pointer rotation position is satisfied, the output angle of each drive signal is adjusted to the suppression level and the electrical angle of each drive signal is held by setting the low torque mode. It will be. At this time, since the on-duty ratio of each drive signal is set to an intermediate ratio for each control electrical angle, the suppression level is surely suppressed from the normal level, thereby reducing waste of power consumption. Can do. Moreover, in the present embodiment, the low torque mode is a period from when the rotational position of the pointer 12 reaches the fuel remaining amount indication position until various changing conditions of the pointer rotational position are satisfied, that is, the rotational driving of the pointer 12. Since the rotation is continued while unnecessary or necessary rotational drive is slow, the effect of reducing waste of power consumption can be enhanced.

  In the embodiments described so far, the instrument control unit 20 corresponds to the “control unit” recited in the claims, and the control circuit 22 for executing the instrument control processes S12, S15, and S16 in the instrument control unit 20 is provided. The control circuit 22 that executes the instrument control processes S10, S11, S13, S14, S17, and S18 in the instrument control unit 20 and the drive circuit 21 correspond to the “condition determination means” recited in the claims. Thus, the “signal adjusting means” described in the claims is configured.

(Other embodiments)
Although one embodiment of the present invention has been described above, the present invention is not construed as being limited to the embodiment described, and can be applied to various embodiments without departing from the scope of the invention.

  Specifically, the drive signal input to the step motor 13 is not limited to the above-described sine function or cosine function, as long as it is an AC signal that alternates according to the electrical angle. It may be a signal that alternates in a triangular wave shape or the like. Further, the vehicle state value indicated by the pointer 12 may be, for example, a vehicle speed, an engine speed, an engine coolant temperature, or the like other than the above-described remaining fuel amount as long as it is a value relating to various vehicle states.

It is a lineblock diagram showing the indication instrument for vehicles by one embodiment of the present invention. It is a front view which shows the indicator instrument for vehicles by one Embodiment of this invention. It is a block diagram which shows the detail of the step motor and drive circuit of FIG. It is a characteristic view for demonstrating the drive signal input into the step motor of FIG. It is a flowchart which shows the instrument control process implemented by the control circuit of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle indicating instrument, 2 Ignition switch, 3 Fuel sender, 10 Display unit, 11 Instrument panel, 110 Display surface, 111 Fuel display part, 12 Pointer, 13 Step motor, 20 Instrument control unit (control part), 21 Drive circuit (Signal adjustment means), 22 control circuit (condition determination means / signal adjustment means), 130a, 130b stator, 131 magnet rotor, 132a, 132b yoke, 133a, 133b field winding, 210a, 210b signal generator, 212, 213 Complementary circuit, 220 Interface circuit, 221 Microcomputer

Claims (6)

A pointer that indicates the vehicle state value according to the rotational position, a step motor that rotationally drives the pointer by inputting an AC drive signal according to the electrical angle to the field winding, and the field of the step motor A vehicle indicating instrument comprising a controller for controlling the drive signal output to the magnetic winding,
The controller is
Condition determining means for determining whether a change condition for changing the rotational position of the pointer and a holding condition for holding the rotational position of the pointer are satisfied;
When the condition determination means makes the change condition establishment determination, the drive signal output level is adjusted to a predetermined normal level to change the electrical angle of the drive signal, while the holding condition establishment determination is performed. And a signal adjustment unit that adjusts the output level of the drive signal to a suppression level that is lower than the normal level and holds the electrical angle of the drive signal when the condition determination unit lowers. Indicating instrument for vehicles.   In the control unit that controls the drive signal by pulse width modulation, the signal adjustment unit reduces the duty ratio of the drive signal when the condition determination unit determines whether the holding condition is satisfied. The vehicle indicating instrument according to claim 1, wherein an output level of a signal is adjusted to the suppression level.   The signal adjustment means suppresses the output level of the drive signal when the condition determination means makes a determination that the holding condition is satisfied when the rotational position of the pointer reaches the indicated position of the vehicle state value. The vehicle indicating instrument according to claim 1, wherein the indicator is adjusted to a level.   The signal adjusting means after adjusting the output level of the drive signal to the suppression level by making the holding condition satisfaction determination until the condition determining means makes the change condition establishment determination. The vehicular indicating instrument according to any one of claims 1 to 3, wherein the output level of the drive signal is held at the suppression level.   The signal adjustment means after adjusting the output level of the drive signal to the suppression level by making the determination of the holding condition established is that the fluctuation amount of the vehicle state value is less than a set amount. When the condition determination means maintains the determination that the holding condition is satisfied, the output level of the drive signal is held at the suppression level and the electrical angle of the drive signal is changed, while the amount of change in the vehicle state value When the condition determination means makes a determination that the change condition is satisfied when the change condition is equal to or greater than a set amount, the output level of the drive signal is returned to the normal level to change the electrical angle of the drive signal. The vehicle indicating instrument according to claim 4.   The signal adjusting means after adjusting the output level of the drive signal to the suppression level by making the holding condition satisfied is determined by the condition determining means when the ignition switch is turned off in the vehicle. For the drive signal that returns the pointer to the rotational position corresponding to the zero point of the electrical angle of the drive signal when the condition determination unit makes a determination of establishment, the output level is returned to the normal level and the electrical angle is set to the zero point. The vehicular indicating instrument according to claim 4 or 5, wherein

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