JPH082287A - Motor drive circuit for display apparatus for vehicle - Google Patents

Abstract

PURPOSE:To set strength and resistance of a rib and a pair of stoppers to regulate rotation of a rotary mirror low. CONSTITUTION:In a head up display device for a vehicle, a rotary mirror 3 is driven by a step motor 7 through gears 5, 6. A rotation range of the rotary mirror 3 is set in a zone till a rib 5a is applied to a pair of stoppers 8, 8. In a drive circuit 9, a timer circuit 10 measures a continuity time of an operation switch 11, and when the continuity time becomes a specified time preliminarily determined or more, an oscillator 12 is stopped to stop the step motor 7. The specified time is set to be a total time of a moving time required for the rib 5a to move from one stopper 8 to the other stopper 8 to which an allowance time is added.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor drive circuit incorporated in a vehicle display device such as a vehicle head-up display device or a vehicle distance integrator.

[0002]

2. Description of the Related Art As shown in FIG. 5, a head-up display device for a vehicle has a rotating mirror (optical axis variable body) 3 arranged on the optical path of display light, and adjusts a rotation angle of the rotating mirror 3. By changing the optical axis, the half mirror 4
A virtual image can be formed within the range of the field of view of the observer (driver) via the.

The rotating mirror 3 is driven by a step motor 7 via gears 5 and 6. The gear 5 is provided with a rib (rotation restricting member) 5a, while the fixed side has a rib 5a.
A pair of stoppers (rotation regulating members) 8 and 8 so as to sandwich
Is provided, and the rib 5a has a pair of stoppers 8,8.
The turning range of the turning mirror 3 is restricted to the range where the turning mirror 3 abuts.

The drive circuit 9 of the step motor 7 is driven by a current switching circuit 13 in accordance with the forward rotation signal and the reverse rotation signal from the operation switch 11 arranged in the passenger compartment and in synchronization with the step signal from the oscillator 12. The polarity of the output current is switched, and the output current is amplified by the amplifier 14 and supplied to the excitation winding of the step motor 7 to generate a rotating magnetic field on the stator side.

[0005]

However, the motor drive circuit 9 of the above-described conventional vehicle head-up display device.
Even after the rib 5a comes into contact with the stopper 8 and the rotation of the rotating mirror 3 is restricted, the step motor 7 still continues to rotate as long as the operation switch 11 is operated in the conductive state. Because it has a configuration,
The stoppers 8 and 8 and the rib 5a are required to have strength and resistance enough to withstand the pressing force applied between the stoppers 8 and 8 and the rib 5a. Further, since the exciting current is continuously supplied to the step motor 7 even after the turning of the turning mirror 3 is restricted, the heat of the motor 7 is likely to be caused, the peripheral circuits are easily affected by heat, and the power consumption is increased. It also becomes.

It is a main object of the present invention to solve the above problems and provide a motor drive circuit for a display device for a vehicle which enables use of a rotation restricting member having low strength and durability.

Another object of the present invention is to prevent the heat generation of the motor, improve the thermal influence on the peripheral circuits, and reduce the power consumption.

Further, according to the present invention, in a vehicle distance integrating meter equipped with a step motor driven based on a vehicle speed signal, conventionally, power is supplied to the step motor even when the vehicle is stopped. In consideration of the fact that the motor heat is generated, the peripheral circuits are easily affected by heat, and the power consumption is also increased, this type of vehicle distance integrating meter prevents the step motor from generating heat and affects the peripheral circuits. The objective is to improve and reduce power consumption.

[0009]

According to a first aspect of the present invention, there is provided a head-up for a vehicle, wherein an optical axis variable body is arranged on an optical path of display light, and a rotational range of the optical axis variable body is regulated by a rotation regulating member. In the display device, the motor drive circuit of the display device for a vehicle is adopted, wherein the motor is stopped when the operation switch of the motor for driving the optical axis variable body is turned on for a predetermined period or longer.

According to a second aspect of the present invention, there is provided a head-up display device for a vehicle, wherein an optical axis variable body is arranged on an optical path of display light, and the rotation range of the optical axis variable body is regulated by a rotation regulating member. A motor drive circuit for a display device for a vehicle is adopted, which is configured to stop the power supply to the motor when the operation switch of the motor for driving the shaft variable body is cut off.

According to a third aspect of the present invention, the motor drive circuit of the vehicle display device according to the first or second aspect is employed, wherein the motor is a step motor.

According to a fourth aspect of the present invention, in a vehicle distance integrating meter equipped with a step motor driven based on a vehicle speed signal, power supply to the step motor is stopped when the vehicle is stopped. Uses a motor drive circuit for vehicle display devices.

[0013]

According to the motor drive circuit for a vehicle display device of the first aspect of the invention, the motor automatically stops after a predetermined period of time even if the operation switch continues to be conducted. The pressing force does not act on the member, and the strength and resistance of the rotation restricting member can be set low.

Further, according to the motor drive circuit of the vehicle display device of the second aspect, when the operation switch is cut off, the power supply to the motor is stopped, so that heat generation of the motor can be prevented and power consumption can be reduced. it can.

Further, according to the motor drive circuit for a vehicle display device according to the third aspect, in the vehicle display device using the step motor, the strength and resistance of the rotation restricting member can be set low, or the step motor It is possible to prevent heat generation and reduce power consumption.

According to the motor drive circuit of the vehicle display device of the fourth aspect, in the vehicle distance integrating meter using the step motor driven on the basis of the vehicle speed signal,
It is possible to prevent heat generation of the step motor and reduce power consumption when the vehicle is stopped.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

(1) First Embodiment (FIGS. 1 and 2) FIG. 1 shows the configuration of a motor drive circuit of a vehicle head-up display device when the present invention is applied to the device.

In the vehicle head-up display device shown in FIG. 1, the light from the light source 1 is transmitted or blocked based on the image pattern of the liquid crystal panel 2, and the transmitted light is converted by the rotating mirror (optical axis variable body) 3. It is refracted at an angle corresponding to the rotation angle, refracted by the half mirror 4 provided on the inner surface of the windshield glass (not shown), and is positioned in front of the windshield glass in the field of view of the observer (driver). A virtual image of the vehicle speed and the like corresponding to the image pattern is displayed.

The rotating mirror 3 is driven by a step motor 7 via gears 5 and 6. The gear 5 is provided with a rib (rotation restricting member) 5a, and a fixed side is provided with a pair of stoppers (rotation restricting members) 8 and 8 which can contact the rib 5a so as to sandwich the rib 5a. There is. The rotation of the rotating mirror 3 is restricted by the rib 5a coming into contact with the pair of stoppers 8 and 8. The rotating range of the rotating mirror 3 is until the rib 5a comes into contact with the pair of stoppers 8 and 8. It is set in the section.

The drive circuit 9 of the step motor 7 includes a timer circuit 10. The timer circuit 10 activates the oscillator 12 when the forward rotation signal and the reverse rotation signal are input from the operation switch 11 arranged in the vehicle compartment, and stops the oscillator 12 when the forward rotation signal and the reverse rotation signal are not input. To do. Further, the timer circuit 10 measures the duration of each of the forward rotation signal and the reverse rotation signal, in other words, the conduction time of the operation switch 11, and when the conduction time becomes a predetermined time or more,
The oscillator 12 is stopped. When operating, the oscillator 12 outputs a step signal to the current switching circuit 13 so that the current switching circuit 1
3 outputs the polarity of its output current to the amplifier 14 in accordance with the forward rotation signal and the reverse rotation signal from the operation switch 11 and in synchronization with the step signal from the oscillator 12. The amplifier 14 amplifies the output current of the current switching circuit 13 and supplies it to the excitation winding of the step motor 7 to generate a rotating magnetic field on the stator side.

The predetermined time preset in the timer circuit 10 is set to a total time obtained by adding a margin time to the moving time required for the rib 5a of the gear 5 to move from one stopper 8 to the other stopper 8. There is. For example, if the travel time is 5 seconds, 2 seconds is set as the margin time and 7 seconds is set as the predetermined time.

FIG. 2 is a flowchart showing the operation of the drive circuit 9 configured as described above. As shown in FIG. 2, the drive circuit 9 drives the step motor 7 (step 103) when the power is turned on (step 101) and the operation switch 11 is turned on (conduction) (step 102). Then, while the operation switch 11 is turned on, the count value N is incremented at 1 second intervals (steps 103 to 105), and the count value N is increased.
If the operation switch 11 is turned off before the predetermined value reaches "7", the step motor 7 is stopped (step 104,
107) and the procedure returns to step 101. Also, the count value N
If the operation switch 11 is turned on even after the predetermined value reaches "7", the step motor 7 is stopped when the count value N reaches the predetermined value "7" (step 106,
108), when the operation switch 11 is turned off, the process returns to step 101 (step 109).

When stopping the oscillator 12, the timer circuit 10 may have a configuration based on the number of steps, instead of the configuration based on the time as described above.

As described above, according to the first embodiment, the step motor 7 automatically stops after a predetermined period of time even if the operation switch 11 continues to be conducted, and thereafter the rib 5a, the stopper 8, The pressing force does not act between the ribs 8 and the strength and resistance of the rib 5a and the stoppers 8, 8 can be set low.

(2) Second Embodiment (FIG. 3) FIG. 3 shows the configuration of the motor drive circuit when the present invention is applied to the motor drive circuit of a vehicle head-up display device, as in the first embodiment. Since the step motor 7, the rotary mirror 3 and other components are the same as those in FIG. 1, the illustration thereof is omitted.

In FIG. 3, the drive circuit 9 of the step motor 7 includes a signal presence / absence detection circuit 15. The signal presence / absence detection circuit 15 detects the presence / absence of the normal rotation signal and the reverse rotation signal from the operation switch 11, and supplies the power to the amplifier 14 when there is the normal rotation signal and the reverse rotation signal, that is, when the operation switch 11 is in the conductive state. On the other hand, when there is no forward rotation signal and reverse rotation signal, that is, when the operation switch 11 is in the cutoff state, the power supply to the amplifier 14 is stopped. Oscillator 12
Outputs a step signal to the current switching circuit 13, and the current switching circuit 13 follows the forward rotation signal and the reverse rotation signal from the operation switch 11 and, in synchronization with the step signal from the oscillator 12, the polarity of its output current. Is output to the switching amplifier 14. When power is supplied, the amplifier 14 amplifies the output current of the current switching circuit 13 and supplies it to the excitation winding of the step motor 7 to generate a rotating magnetic field on the stator side to rotate the rotor. On the other hand, when the power supply is stopped, the exciting current is not supplied to the exciting winding and the rotor is stopped.

As described above, according to the second embodiment, when the operation switch 11 is cut off, the power supply to the step motor 7 is stopped, so that the step motor 7 can be prevented from generating heat and the power consumption can be reduced. .

(3) Third Embodiment (FIG. 4) FIG. 4 shows the configuration of the instrument when the present invention is applied to a motor drive circuit of a vehicle distance integrating meter.

In the vehicle distance integrator shown in FIG. 4, the counter 16 is driven by the step motor 7.

The drive circuit 9 of the step motor 7 includes a signal presence / absence detection circuit 15. The signal presence / absence detection circuit 15 detects the presence / absence of a vehicle speed signal from a vehicle speed sensor 17 arranged in the transmission 16, and when there is a vehicle speed signal, that is, when the vehicle is in a traveling state, supplies power to the amplifier 14, while When there is no vehicle speed signal, that is, when the vehicle is stopped, the power supply to the amplifier 14 is stopped. The frequency dividing circuit 18 frequency-divides the vehicle speed signal and outputs it to the current switching circuit 13, and the current switching circuit 13 outputs the polarity of the output current to the amplifier 14 in synchronization with the frequency dividing signal. When power is supplied, the amplifier 14 amplifies the output current of the current switching circuit 13 and supplies it to the excitation winding of the step motor 7 to generate a rotating magnetic field on the stator side to rotate the rotor. On the other hand, when the power supply is stopped, the exciting current is not supplied to the exciting winding and the rotor is stopped.

As described above, according to the third embodiment, when the vehicle stops, the power supply to the step motor 7 is stopped, so that the heat generation of the step motor 7 can be prevented and the power consumption can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a vehicle head-up display device in which a motor drive circuit according to a first embodiment is incorporated.

FIG. 2 is a flowchart for explaining the operation of the motor drive circuit.

FIG. 3 is a configuration diagram of a vehicle head-up display device incorporating a motor drive circuit according to a second embodiment.

FIG. 4 is a configuration diagram of a vehicle distance integrating meter in which a motor drive circuit according to a third embodiment is incorporated.

FIG. 5 is a configuration diagram of a vehicle head-up display device in which a conventional motor drive circuit is incorporated.

[Explanation of symbols]

 3 Rotation Mirror (Optical Axis Variable Body) 5a Rib (Rotation Restriction Member) 7 Step Motor (Motor) 8 Stopper (Rotation Restriction Member) 9 Motor Drive Circuit 11 Operation Switch

Claims (4)

[Claims] 1. A vehicle head-up display device in which an optical axis variable body is disposed on an optical path of display light, and a rotation range of the optical axis variable body is regulated by a rotation regulating member. A motor drive circuit for a vehicle display device, wherein the motor is stopped when an operation switch of the motor for driving the motor is turned on for a predetermined period or longer. 2. A vehicle head-up display device in which an optical axis variable body is disposed on an optical path of display light, and a rotation range of the optical axis variable body is regulated by a rotation regulating member. A motor drive circuit for a vehicle display device, characterized in that the power supply to the motor is stopped when an operation switch of the motor for driving the motor is cut off. 3. The motor drive circuit for a vehicle display device according to claim 1, wherein the motor is a step motor. 4. A vehicle distance integrating meter having a step motor driven on the basis of a vehicle speed signal, characterized in that the power supply to the step motor is stopped when the vehicle is stopped. Device motor drive circuit.