Title of Invention	IN-VEHICLE ELECTROMAGNETIC BUZZER CONTROL APPARATUS
Abstract	The invention relates to an in-vehicle electromagnetic buzzer control comprising; a main switch (SWI) for selectively setting an alarm mode for security and a normal mode in which the alarm mode is released; a sensor (7) for detecting tilt, vibration or shock of a vehicle; and a control circuit (6) for controlling the opening and closing of a current conducting path from power supply to an electromagnetic buzzer depending on the setting of the main switch (SWI). If the alarm mode is set, the control circuit (6) closes the current conducting path to and causes the electromagnetic buzzer (3) to emit a beep tone for alarm when the sensor (7) detects e.g. tilt of the vehicle, while if the normal mode is set, the control circuit closes the current conducting path to and causes the electromagnetic buzzer (3) to emit a beep tone for safety checking when a horn switch (SW2) is closed, controlling to provide the power supply so as to make the beep tone for alarm and the beep tone for safety checking different from each other. This differentiates a beep tone of the electromagnetic buzzer to be used for normal safety checking from a beep tone for alarm serving as a security apparatus, so as to be able to have a discriminability.

Title of Invention

IN-VEHICLE ELECTROMAGNETIC BUZZER CONTROL APPARATUS

Abstract

The invention relates to an in-vehicle electromagnetic buzzer control comprising; a main switch (SWI) for selectively setting an alarm mode for security and a normal mode in which the alarm mode is released; a sensor (7) for detecting tilt, vibration or shock of a vehicle; and a control circuit (6) for controlling the opening and closing of a current conducting path from power supply to an electromagnetic buzzer depending on the setting of the main switch (SWI). If the alarm mode is set, the control circuit (6) closes the current conducting path to and causes the electromagnetic buzzer (3) to emit a beep tone for alarm when the sensor (7) detects e.g. tilt of the vehicle, while if the normal mode is set, the control circuit closes the current conducting path to and causes the electromagnetic buzzer (3) to emit a beep tone for safety checking when a horn switch (SW2) is closed, controlling to provide the power supply so as to make the beep tone for alarm and the beep tone for safety checking different from each other. This differentiates a beep tone of the electromagnetic buzzer to be used for normal safety checking from a beep tone for alarm serving as a security apparatus, so as to be able to have a discriminability.

Full Text	DESCRIPTION TECHNICAL FIELD The present invention relates to an in-vehicle electromagnetic buzzer control apparatus for controlling beeping of an electromagnetic buzzer installed in a vehicle such as a car, a motorcycle or an engine-attached bicycle. BACKGROUND ART Conventionally, a security apparatus for anti-theft of e.g. a motorcycle is known which beeps a buzzer when detecting body (vehicle) tilt of the motorcycle (refer to e.g. Japanese Laid-open Patent Publication 2003-212095). DISCLOSURE OF INVENTION Now, an electromagnetic buzzer used to check safety in traveling is installed in a car, a motorcycle and an engine-attached bicycle. This electromagnetic buzzer is designed to be directly supplied with voltage from an in-vehicle power supply (battery) so as to beep and emit a beep tone specific to the electromagnetic buzzer, when a driver turns on a horn switch. This beep tone has a constant tone color based on the vibration frequency specific to a sound source of the electromagnetic buzzer. Accordingly, when the buzzer is used both for the safety checking in normal time as described above, and for alarm serving as a security apparatus, it has not been possible to use the tone color for discrimination. The present invention has been made in view of the above-described points, and it is an object of the present invention to provide an in-vehicle electromagnetic buzzer control apparatus which differentiates a beep tone of the electromagnetic buzzer to be used for normal safety checking from a beep tone for alarm serving as a security apparatus, so as to be able to have a discriminability. To achieve the above object, the present invention provides an in-vehicle electromagnetic buzzer control apparatus installed in a vehicle, comprising an electromagnetic buzzer, a power supply for driving this electromagnetic buzzer, and a horn switch for opening and closing a current conducting path from the driving power supply to the electromagnetic buzzer, and comprising: a mode switch for selectively setting an alarm mode for security and a normal mode in which the alarm mode is released; a sensor for detecting at least one of tilt, vibration or shock of the vehicle; and a control means for controlling the opening and closing of the current conducting path from the power supply to the electromagnetic buzzer depending on the setting of the mode switch. If the alarm mode is set, the control means closes the current conducting path to the electromagnetic buzzer to cause the electromagnetic buzzer to emit a beep tone for alarm when the sensor detects the tilt, vibration or shock of the vehicle, while if the normal mode is set, the control means closes the current conducting path to the electromagnetic buzzer to cause the electromagnetic buzzer to emit a beep tone for safety checking when a user operates to close the horn switch, controlling to provide the power supply so as to make the beep tone for alarm and the beep tone for safety checking different from each other. According to the present invention, if the alarm mode is set, it is possible to cause the electromagnetic buzzer to beep coupled to the detection of tilt, vibration or shock of the vehicle, so that it is possible to signal a theft alarm for the vehicle such as a motorcycle or an engine-attached bicycle. Further, because the beep tone for normal safety checking and the beep tone for alarm for security are different from each other, it is possible to obtain a discriminability. Further, it can be designed so that if the beep tone for alarm is to be emitted, the control means PWM-controls the voltage of the power supply, and applies this PWM-controlled voltage to the electromagnetic buzzer, while on the other hand, if the beep tone for safety checking is to be emitted, the control means continuously applies the voltage of the power supply to the electromagnetic buzzer. This increases the discriminability of the respective beep tones for safety checking and for alarm. Since the current flowing in the electromagnetic buzzer becomes intermittent when the beep tone for alarm is emitted, the power consumption can be reduced. Further, the electromagnetic buzzer, being one, can be used both for the alarm and for the safety checking. Furthermore, the electromagnetic buzzer can be one for the alarm and one for the safety checking which are separately provided. In addition, the apparatus can further comprise a threshold value setting means for changing sound pressure or frequency of the beep tone of (or motorcycle) 1 equipped with such control apparatus. The in-vehicle electromagnetic buzzer control apparatus 2 of the present Embodiment comprises: an electromagnetic buzzer 3 being installed for normal safety checking and serving as a horn; a power supply 4 using an in-vehicle battery for driving the electromagnetic buzzer 3; a main switch SW1; and a unit board 10 with a horn switch SW2 externally attached by a connector connection. The unit board 10 comprises: a control circuit (control means) 6 formed of a microcomputer for PWM-controlling the voltage of the power supply 4 by way of a drive circuit 5, and for applying this PWM-controlled voltage to the electromagnetic buzzer 3 as a drive voltage, so as to control beeping of the electromagnetic buzzer 3; a tilt sensor 7 for activating the control operation of the control circuit 6 using a detection signal; a power supply circuit 8 for converting the voltage of the power supply 4 to predetermined voltages, and for supplying them to the control circuit 6 and the tilt sensor 7 as operation voltages; a switching circuit 9 for switching the current conducting path of the electromagnetic buzzer 3, according to the operating position of the main switch SW1, between a current conducting path via the drive circuit 5 and a current conducting path to directly connect the power supply 4 to the electromagnetic buzzer 3; and the above-described drive circuit 5. The main switch SW1 is a mode switch operated by a user to selectively set a mode, and can switch to a contact a (LOCK) in a locking position, a neutral contact c (OFF) and a contact b (ON) in a lock-releasing position. The main switch is designed so as to be closed to the locking position (contact a) if alarm state is set, namely in alarm mode for security, and so as to be closed to the lock-releasing position (contact b) when traveling, namely in normal mode in which the alarm mode is released. The horn switch SW2 is operated by a user to beep the electromagnetic buzzer 3 in the normal mode for safety checking. The tilt sensor 7 (hereafter referred to simply as sensor) is designed to output a detection signal to an input port of the control circuit 6 when a vehicle tilts at a predetermined angle or more. The tilt sensor is formed of e.g. an acceleration sensor of an electrostatic capacitance type. This sensor 7 is not limited to one for detecting tilt, but can be a sensor for detecting vibration or shock of the vehicle. If the alarm mode is set, when the tilt sensor 7 detects tilt of the vehicle, the control circuit 6 PWM-controls the voltage of the power supply 4, and applies this PWM-controlled voltage to and causes the electromagnetic buzzer 3 to emit a beep tone for alarm. On the other hand, if the normal mode is set, the switching circuit 9 operates to form a current conducting path capable of continuously applying a power supply voltage to the electromagnetic buzzer 3, and causes it to emit a beep tone for safety checking when the horn switch SW2 is closed. Here, one electromagnetic buzzer 3 is used both for alarm for security and for safety checking, and the power supply is controlled to be provided so as to make the beep tone for alarm and the beep tone for safety checking different from each other. Because the beep tones are thus different from each other, it is possible to obtain a discriminability. Further, by setting the alarm mode, it is possible to emit an alarm beep tone coupled to the detection of the vehicle tilt so as to signal a theft alarm for the vehicle such as a motorcycle. The switching circuit 9 is formed of two DC relays Ry1, Ry2 and respective relay contacts r1, r2. Excitation windings CL1, CL2 of the relays Ry1, Ry2 are connected in parallel, and this parallel circuit is connected to the power supply 4 through the contact b, namely the lock-releasing position, of the main switch SW1. The relay contact rl has a common terminal connected to one end of the electromagnetic buzzer 3, an NO position connected to the contact b of the main switch SW1, and an NC position connected to the contact a, namely the locking position, of the main switch SW1. Further, the relay contact r2 has a common terminal connected to the other end of the electromagnetic buzzer 3, an NO position connected to the ground (negative polarity) of the power supply 4 through the horn switch SW2, and an NC position connected to a collector of a transistor of the drive circuit 5. The control circuit 6 operates using a voltage from the power supply circuit 8 as an operation voltage, and functions to output a PWM signal having a frequency of e.g. 10 kHz to the drive circuit 5 when a detection signal from the tilt sensor 7 is input thereto. Furthermore, the control circuit 6 is provided with switches d1, d2 as a threshold value setting means for changing the sound pressure or the frequency of the beep tone of the electromagnetic buzzer 3 according to the level of tilt, vibration or shock of the vehicle detected by the sensor 7. For example, when one switch dl is turned on, the threshold value increases to emit a beep tone with a large volume, while when the other switch d2 is turned on, the threshold value decreases to emit a beep tone with a small volume. Thus, when a beep tone is emitted with the switch dl on, it is understood that a pretty big shock has been applied to the vehicle. This prevents malfunction as well. Further, when a beep tone is emitted with the switch d2 on, it is understood that a slight shock has been applied thereto. Next, referring to the specific circuit configuration of FIG. 2, the power supply circuit 8 and the drive circuit 5 will be described. The power supply circuit 8 comprises: a surge absorbing element S connected between power supply input terminals I1, I2; a capacitor C1 connected in parallel to the surge absorbing element S via a reverse current blocking diode D1; a three-terminal regulator U for stabilizing the voltage across both terminals of this capacitor C1 to a constant voltage; and a capacitor C2 connected in parallel to an output terminal of this three-terminal regulator U. The power supply circuit is designed to provide a stabilized DC voltage, as an operation power supply, to the sensor 7 and the control circuit 6. The drive circuit 5 comprises: an NPN-type transistor Q1 having a collector and an emitter, the path between which is connected in parallel to the capacitor C1 via resistors R1, R2, and having a base to which a PWM signal from the control circuit 6 is input via a resistor R3; a PNP-type transistor Q2 having a base connected to the connection point of the resistors Rl, R2, and having an emitter and a collector, the path between which is connected in parallel to the capacitor C1 via resistors R4, R5; an NPN-type transistor Q3 having a base connected to the connection point of the resistors R4, R5, and having a collector and an emitter, the path between which is connected in parallel to the capacitor C1 via a series circuit formed by the NC position of the relay contact r1 of the relay Ry1 of the switching circuit 9, and by the electromagnetic buzzer 3, and further by the NC position of the relay contact r2 of the relay Ry2 as will be described later; and a counter-electromotive voltage absorbing diode D2 connected in parallel to the series circuit formed by the NC position of the relay contact rl of the relay Ry1, and by the electromagnetic buzzer 3, and further by the NC position of the relay contact r2 of the relay Ry2. Further, a capacitor C3 is connected in parallel to the electromagnetic buzzer 3. Next, the operation of the in-vehicle electromagnetic buzzer control apparatus 2 according to the present Embodiment will be described. First, when the main switch SW1 is closed to the position in the lock-releasing state (traveling state), namely to the contact b, from the neutral contact c shown in FIG. 1 or FIG. 2, a current conducting path is formed to allow an excitation current to flow from the power supply 4 through the excitation windings CL1, CL2 of the two relays Ry1, Ry2 which form the switching circuit 9. The respective relays Ry1, Ry2 switch the respective relay contacts r1, r2 from the NC position to the NO position. By this switching, a current conducting path is formed from the power supply 4 through the relay contact r1, the electromagnetic buzzer 3, the relay contact r2 and the horn switch SW2 back to the power supply 4. When, in this state, the horn switch SW2 is turned on, the voltage of the power supply 4 is continuously applied to the electromagnetic buzzer 3, causing emission of a beep tone at a predetermined sound pressure level determined by the power supply voltage. Namely, a beep tone for safely checking is emitted. Note that in this lock-releasing state, the power supply 4 is not connected to the power supply circuit 8, so that the power consumption of the electromagnetic buzzer control apparatus 2 is only power consumption for exciting the relays Ry1, Ry2. Next, when the main switch SW1 is closed to the contact a in order to set alarm state for anti-theft, i.e. alarm mode for security, in e.g. parking, the excitation current in the excitation windings CL1, CL2 of the relays Ry1, Ry2 is interrupted, thereby causing the relay contacts r1, r2 to be restored to the NC positions. On the other hand, the power supply 4 is connected to the power supply circuit 8, so that an operation power supply is provided to the tilt sensor 7 and the control circuit 6 from the three-terminal regulator U, going into an operation standby state. Then, when a body (vehicle) tilts at a predetermined amount or more, or receives vibration/shock, causing its detection signal to be output from the sensor 7, the control circuit 6 is activated to output a PWM signal, formed of a square wave voltage having a predetermined duty ratio, to the base of the transistor Q1 of the drive circuit 5. Note that here it is described using the specific circuit of FIG. 2. This causes that the transistor Q1 repeats an operation to turn on during the "H" period and turn off during the "L" period of the PWM signal, and that also the transistor Q2 repeats on/off in a pattern reversed from the on/off of the transistor Q1, and further that the transistor Q3 repeats on/off in a pattern reversed from the on/off of the transistor Q2. As a result, the voltage of the power supply 4, which is applied to the electromagnetic buzzer 3 via the path through the NC position of the contact r1 of the relay Ry1, the electromagnetic buzzer 3, the NC position of the relay contact r2 of the relay Ry2 and the transistor Q3, is PWM-controlled so as to cause the drive voltage applied to the electromagnetic buzzer 3 to be an average voltage determined by the duty ratio. This makes the sound pressure level lower than at the time of safety checking. In other words, the beep tone in the alarm mode becomes different from the beep tone at the time of safety checking, resulting in having a discriminability. Accordingly, a user recognizes this beep tone as an alarm signal tone, thus being able to immediately take an action for anti-theft. According to the present Embodiment, a PWM-controlled voltage is applied to the electromagnetic buzzer 3. Accordingly, the current flowing in the electromagnetic buzzer 3 becomes intermittent, reducing the power consumption of the electromagnetic buzzer 3 as compared with the case of applying a continuous voltage for driving. Further, in the state in which the main switch SW1 is closed to the neutral position, the power supply 4 does not provide an excitation current to the relays Ry1, Ry2 or power to the power supply circuit 8, so that the power consumption is reduced. Note that the main switch SW1 is preferably coupled to the key operation of the vehicle. More specifically, for example, it can be that a steering lock is set, and at the same time an alarm mode for security is set when a key is removed in the lock position (or the lock operation is performed by a remote control key), whereas the above alarm lock is released when the key is inserted into a key hole (or the lock is released by the remote control key), and is rotated to the engine start position. (Modified Example of Embodiment 1) FIG. 4 shows an in-vehicle electromagnetic buzzer control apparatus 2 according to a Modified Example of the above Embodiment. In this Modified Example, a unit board 10 does not have a switching circuit 9 formed of an electromagnetic relay as described above. Further, a diode D1, a horn switch SW2 and an electromagnetic buzzer 3 are connected in series and between a contact b of a main switch SW1 and ground. Furthermore, the electromagnetic buzzer 3, a diode D2 and a transistor Q driven by the unit board 10 are connected in series and between a contact a of the main switch SW1 and ground. The electromagnetic buzzer 3 is driven in a manner similar to the above that the beep tones are different from each other between when the electromagnetic buzzer 3 operates for safety checking and when it operates for alarm. In this Modified Example, if the unit board 10 should fail, it is still possible to use the electromagnetic buzzer 3 for normal safety checking. (Embodiment 2) FIG. 5 shows an in-vehicle electromagnetic buzzer control apparatus according to Embodiment 2. In the above Embodiment 1, one electromagnetic buzzer 3 is used both for safety checking and for alarm, whereas in Embodiment 2, an electromagnetic buzzer 3A for safety checking and an electromagnetic buzzer 3B for alarm are separately provided. The electromagnetic buzzer 3A and a horn switch SW2 are connected in series and between a contact b of a main switch SW1 and ground. The electromagnetic buzzer 3B and a transistor Q driven by a unit board 10 are connected in series and between a contact a of the main switch SW1 and ground. The electromagnetic buzzers 3A, 3B to be used can be the same one, or can have different functions and configurations. These electromagnetic buzzer 3A and electromagnetic buzzer 3B are operated to the electromagnetic buzzer according to level of the tilt, vibration or shock of the vehicle detected by the sensor. This makes it possible for a user to understand the level of the tilt, vibration or shock of the vehicle from the beep tone. BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS FIG. 1 is a circuit diagram of an in-vehicle electromagnetic buzzer control apparatus according to an Embodiment 1 of the present invention; FIG. 2 is a specific circuit configuration diagram of the above apparatus; FIG. 3 is a side view of a vehicle with the above apparatus being installed; FIG. 4 a circuit diagram of an apparatus according to a Modified Example of the above Embodiment 1; and FIG. 5 is a circuit diagram of an in-vehicle electromagnetic buzzer control apparatus according to Embodiment 2 of the present invention. BEST MODE FOR CARRAYING OUT THE INVENTION Hereinafter, in-vehicle electromagnetic buzzer control apparatus according to embodiments of the present invention will be described with reference to the drawings. (Embodiment 1) FIG 1 shows a circuit of an in-vehicle electromagnetic buzzer control apparatus 2 according to Embodiment 1, and FIG. 2 shows a specific circuit configuration thereof, while FIG. 3 shows an engine-attached bicycle have beep tones different from each other. Although this Embodiment 2 requires two electromagnetic buzzers, it has an advantage in that even if a constituent component for safety checking fails, or a constituent component for alarm fails, they do not affect the other because they are independent of each other. Note that although the present Embodiment shows the case where it is installed in a two-wheeled vehicle such as an engine-attached bicycle or a motorcycle, the present invention can be applied to a four-wheeled vehicle (car). It is to be noted that this application claims priority based on a patent application filed March 25, 2005. The entire content of such application is incorporated into this application by reference. We Claim 1. An in-vehicle electromagnetic buzzer control apparatus installed in a vehicle, comprising an electromagnetic buzzer, a power supply for driving this electromagnetic buzzer, and a horn switch for opening and closing a current conducting path from the driving power supply to the electromagnetic buzzer, comprising: a mode switch for selectively setting an alarm mode for security and a normal mode in which the alarm mode is released; a sensor for detecting at least one of tilt, vibration or shock of the vehicle; and a control means for controlling the opening and closing of the current conducting path from the power supply to the electromagnetic buzzer depending on the setting of the mode switch, wherein if the alarm mode is set, the control means Pulse-Width-Modulation- controls the voltage of the power supply, and applies this Pulse-Width-Modulation- controlled voltage to and causes the electromagnetic buzzer to emit the beep tone for alarm, and the control means closes the current conducting path to the electromagnetic buzzer to cause the electromagnetic buzzer to emit a beep tone for alarm when the sensor detects the tilt, vibration or shock of the vehicle, while if the normal mode is set, the control means forms the current conducting path to continuously apply the voltage of the power supply to and cause the electromagnetic buzzer to emit the beep tone for safety checking, and the control means closes the current conducting path to the electromagnetic buzzer to cause the electromagnetic buzzer to emit a beep tone for safety checking when a user operates to close the horn switch, controlling to provide the power supply so as to make the beep tone for alarm and the beep tone for safety checking different from each other. 2. The in-vehicle electromagnetic buzzer control apparatus as claimed in claim 1, wherein the electromagnetic buzzer, being one, is used both for the alarm and for the safety checking. 3. The in-vehicle electromagnetic buzzer control apparatus as claimed in claim 1, wherein the electromagnetic buzzer is one for the alarm and one for the safety checking which are separately provided. 4. The in-vehicle electromagnetic buzzer control apparatus as claimed in claim 1, wherein there is provided a threshold value setting means for changing sound pressure or frequency of the beep tone of the electromagnetic buzzer according to level of the tilt, vibration or shock of the vehicle detected by the sensor. ABSTRACT IN-VEHICLE ELECTROMAGNETIC BUZZER CONTROL APPARATUS The invention relates to an in-vehicle electromagnetic buzzer control comprising; a main switch (SWI) for selectively setting an alarm mode for security and a normal mode in which the alarm mode is released; a sensor (7) for detecting tilt, vibration or shock of a vehicle; and a control circuit (6) for controlling the opening and closing of a current conducting path from power supply to an electromagnetic buzzer depending on the setting of the main switch (SWI). If the alarm mode is set, the control circuit (6) closes the current conducting path to and causes the electromagnetic buzzer (3) to emit a beep tone for alarm when the sensor (7) detects e.g. tilt of the vehicle, while if the normal mode is set, the control circuit closes the current conducting path to and causes the electromagnetic buzzer (3) to emit a beep tone for safety checking when a horn switch (SW2) is closed, controlling to provide the power supply so as to make the beep tone for alarm and the beep tone for safety checking different from each other. This differentiates a beep tone of the electromagnetic buzzer to be used for normal safety checking from a beep tone for alarm serving as a security apparatus, so as to be able to have a discriminability.

Full Text

DESCRIPTION
TECHNICAL FIELD
The present invention relates to an in-vehicle electromagnetic buzzer
control apparatus for controlling beeping of an electromagnetic buzzer
installed in a vehicle such as a car, a motorcycle or an engine-attached
bicycle.
BACKGROUND ART
Conventionally, a security apparatus for anti-theft of e.g. a
motorcycle is known which beeps a buzzer when detecting body (vehicle)
tilt of the motorcycle (refer to e.g. Japanese Laid-open Patent Publication
2003-212095).
DISCLOSURE OF INVENTION
Now, an electromagnetic buzzer used to check safety in traveling is
installed in a car, a motorcycle and an engine-attached bicycle. This
electromagnetic buzzer is designed to be directly supplied with voltage from
an in-vehicle power supply (battery) so as to beep and emit a beep tone
specific to the electromagnetic buzzer, when a driver turns on a horn switch.
This beep tone has a constant tone color based on the vibration
frequency specific to a sound source of the electromagnetic buzzer.

Accordingly, when the buzzer is used both for the safety checking in normal
time as described above, and for alarm serving as a security apparatus, it has
not been possible to use the tone color for discrimination.
The present invention has been made in view of the above-described
points, and it is an object of the present invention to provide an in-vehicle
electromagnetic buzzer control apparatus which differentiates a beep tone of
the electromagnetic buzzer to be used for normal safety checking from a
beep tone for alarm serving as a security apparatus, so as to be able to have a
discriminability.
To achieve the above object, the present invention provides an
in-vehicle electromagnetic buzzer control apparatus installed in a vehicle,
comprising an electromagnetic buzzer, a power supply for driving this
electromagnetic buzzer, and a horn switch for opening and closing a current
conducting path from the driving power supply to the electromagnetic
buzzer, and comprising: a mode switch for selectively setting an alarm mode
for security and a normal mode in which the alarm mode is released; a
sensor for detecting at least one of tilt, vibration or shock of the vehicle; and
a control means for controlling the opening and closing of the current
conducting path from the power supply to the electromagnetic buzzer
depending on the setting of the mode switch. If the alarm mode is set, the
control means closes the current conducting path to the electromagnetic
buzzer to cause the electromagnetic buzzer to emit a beep tone for alarm
when the sensor detects the tilt, vibration or shock of the vehicle, while if the
normal mode is set, the control means closes the current conducting path to
the electromagnetic buzzer to cause the electromagnetic buzzer to emit a

beep tone for safety checking when a user operates to close the horn switch,
controlling to provide the power supply so as to make the beep tone for
alarm and the beep tone for safety checking different from each other.
According to the present invention, if the alarm mode is set, it is
possible to cause the electromagnetic buzzer to beep coupled to the detection
of tilt, vibration or shock of the vehicle, so that it is possible to signal a theft
alarm for the vehicle such as a motorcycle or an engine-attached bicycle.
Further, because the beep tone for normal safety checking and the beep tone
for alarm for security are different from each other, it is possible to obtain a
discriminability.
Further, it can be designed so that if the beep tone for alarm is to be
emitted, the control means PWM-controls the voltage of the power supply,
and applies this PWM-controlled voltage to the electromagnetic buzzer,
while on the other hand, if the beep tone for safety checking is to be emitted,
the control means continuously applies the voltage of the power supply to
the electromagnetic buzzer. This increases the discriminability of the
respective beep tones for safety checking and for alarm. Since the current
flowing in the electromagnetic buzzer becomes intermittent when the beep
tone for alarm is emitted, the power consumption can be reduced.
Further, the electromagnetic buzzer, being one, can be used both for
the alarm and for the safety checking.
Furthermore, the electromagnetic buzzer can be one for the alarm
and one for the safety checking which are separately provided.
In addition, the apparatus can further comprise a threshold value
setting means for changing sound pressure or frequency of the beep tone of

(or motorcycle) 1 equipped with such control apparatus. The in-vehicle
electromagnetic buzzer control apparatus 2 of the present Embodiment
comprises: an electromagnetic buzzer 3 being installed for normal safety
checking and serving as a horn; a power supply 4 using an in-vehicle battery
for driving the electromagnetic buzzer 3; a main switch SW1; and a unit
board 10 with a horn switch SW2 externally attached by a connector
connection.
The unit board 10 comprises: a control circuit (control means) 6
formed of a microcomputer for PWM-controlling the voltage of the power
supply 4 by way of a drive circuit 5, and for applying this PWM-controlled
voltage to the electromagnetic buzzer 3 as a drive voltage, so as to control
beeping of the electromagnetic buzzer 3; a tilt sensor 7 for activating the
control operation of the control circuit 6 using a detection signal; a power
supply circuit 8 for converting the voltage of the power supply 4 to
predetermined voltages, and for supplying them to the control circuit 6 and
the tilt sensor 7 as operation voltages; a switching circuit 9 for switching the
current conducting path of the electromagnetic buzzer 3, according to the
operating position of the main switch SW1, between a current conducting
path via the drive circuit 5 and a current conducting path to directly connect
the power supply 4 to the electromagnetic buzzer 3; and the above-described
drive circuit 5.
The main switch SW1 is a mode switch operated by a user to
selectively set a mode, and can switch to a contact a (LOCK) in a locking
position, a neutral contact c (OFF) and a contact b (ON) in a lock-releasing
position. The main switch is designed so as to be closed to the locking

position (contact a) if alarm state is set, namely in alarm mode for security,
and so as to be closed to the lock-releasing position (contact b) when
traveling, namely in normal mode in which the alarm mode is released.
The horn switch SW2 is operated by a user to beep the electromagnetic
buzzer 3 in the normal mode for safety checking.
The tilt sensor 7 (hereafter referred to simply as sensor) is designed
to output a detection signal to an input port of the control circuit 6 when a
vehicle tilts at a predetermined angle or more. The tilt sensor is formed of
e.g. an acceleration sensor of an electrostatic capacitance type. This sensor
7 is not limited to one for detecting tilt, but can be a sensor for detecting
vibration or shock of the vehicle.
If the alarm mode is set, when the tilt sensor 7 detects tilt of the
vehicle, the control circuit 6 PWM-controls the voltage of the power supply
4, and applies this PWM-controlled voltage to and causes the
electromagnetic buzzer 3 to emit a beep tone for alarm. On the other hand,
if the normal mode is set, the switching circuit 9 operates to form a current
conducting path capable of continuously applying a power supply voltage to
the electromagnetic buzzer 3, and causes it to emit a beep tone for safety
checking when the horn switch SW2 is closed.
Here, one electromagnetic buzzer 3 is used both for alarm for
security and for safety checking, and the power supply is controlled to be
provided so as to make the beep tone for alarm and the beep tone for safety
checking different from each other. Because the beep tones are thus
different from each other, it is possible to obtain a discriminability. Further,
by setting the alarm mode, it is possible to emit an alarm beep tone coupled

to the detection of the vehicle tilt so as to signal a theft alarm for the vehicle
such as a motorcycle.
The switching circuit 9 is formed of two DC relays Ry1, Ry2 and
respective relay contacts r1, r2. Excitation windings CL1, CL2 of the
relays Ry1, Ry2 are connected in parallel, and this parallel circuit is
connected to the power supply 4 through the contact b, namely the
lock-releasing position, of the main switch SW1. The relay contact rl has a
common terminal connected to one end of the electromagnetic buzzer 3, an
NO position connected to the contact b of the main switch SW1, and an NC
position connected to the contact a, namely the locking position, of the main
switch SW1. Further, the relay contact r2 has a common terminal
connected to the other end of the electromagnetic buzzer 3, an NO position
connected to the ground (negative polarity) of the power supply 4 through
the horn switch SW2, and an NC position connected to a collector of a
transistor of the drive circuit 5.
The control circuit 6 operates using a voltage from the power supply
circuit 8 as an operation voltage, and functions to output a PWM signal
having a frequency of e.g. 10 kHz to the drive circuit 5 when a detection
signal from the tilt sensor 7 is input thereto.
Furthermore, the control circuit 6 is provided with switches d1, d2 as
a threshold value setting means for changing the sound pressure or the
frequency of the beep tone of the electromagnetic buzzer 3 according to the
level of tilt, vibration or shock of the vehicle detected by the sensor 7. For
example, when one switch dl is turned on, the threshold value increases to
emit a beep tone with a large volume, while when the other switch d2 is

turned on, the threshold value decreases to emit a beep tone with a small
volume. Thus, when a beep tone is emitted with the switch dl on, it is
understood that a pretty big shock has been applied to the vehicle. This
prevents malfunction as well. Further, when a beep tone is emitted with the
switch d2 on, it is understood that a slight shock has been applied thereto.
Next, referring to the specific circuit configuration of FIG. 2, the
power supply circuit 8 and the drive circuit 5 will be described. The power
supply circuit 8 comprises: a surge absorbing element S connected between
power supply input terminals I1, I2; a capacitor C1 connected in parallel to
the surge absorbing element S via a reverse current blocking diode D1; a
three-terminal regulator U for stabilizing the voltage across both terminals of
this capacitor C1 to a constant voltage; and a capacitor C2 connected in
parallel to an output terminal of this three-terminal regulator U. The power
supply circuit is designed to provide a stabilized DC voltage, as an operation
power supply, to the sensor 7 and the control circuit 6.
The drive circuit 5 comprises: an NPN-type transistor Q1 having a
collector and an emitter, the path between which is connected in parallel to
the capacitor C1 via resistors R1, R2, and having a base to which a PWM
signal from the control circuit 6 is input via a resistor R3; a PNP-type
transistor Q2 having a base connected to the connection point of the resistors
Rl, R2, and having an emitter and a collector, the path between which is
connected in parallel to the capacitor C1 via resistors R4, R5; an NPN-type
transistor Q3 having a base connected to the connection point of the resistors
R4, R5, and having a collector and an emitter, the path between which is
connected in parallel to the capacitor C1 via a series circuit formed by the

NC position of the relay contact r1 of the relay Ry1 of the switching circuit 9,
and by the electromagnetic buzzer 3, and further by the NC position of the
relay contact r2 of the relay Ry2 as will be described later; and a
counter-electromotive voltage absorbing diode D2 connected in parallel to
the series circuit formed by the NC position of the relay contact rl of the
relay Ry1, and by the electromagnetic buzzer 3, and further by the NC
position of the relay contact r2 of the relay Ry2. Further, a capacitor C3 is
connected in parallel to the electromagnetic buzzer 3.
Next, the operation of the in-vehicle electromagnetic buzzer control
apparatus 2 according to the present Embodiment will be described. First,
when the main switch SW1 is closed to the position in the lock-releasing
state (traveling state), namely to the contact b, from the neutral contact c
shown in FIG. 1 or FIG. 2, a current conducting path is formed to allow an
excitation current to flow from the power supply 4 through the excitation
windings CL1, CL2 of the two relays Ry1, Ry2 which form the switching
circuit 9. The respective relays Ry1, Ry2 switch the respective relay
contacts r1, r2 from the NC position to the NO position. By this switching,
a current conducting path is formed from the power supply 4 through the
relay contact r1, the electromagnetic buzzer 3, the relay contact r2 and the
horn switch SW2 back to the power supply 4.
When, in this state, the horn switch SW2 is turned on, the voltage of
the power supply 4 is continuously applied to the electromagnetic buzzer 3,
causing emission of a beep tone at a predetermined sound pressure level
determined by the power supply voltage. Namely, a beep tone for safely
checking is emitted. Note that in this lock-releasing state, the power supply

4 is not connected to the power supply circuit 8, so that the power
consumption of the electromagnetic buzzer control apparatus 2 is only
power consumption for exciting the relays Ry1, Ry2.
Next, when the main switch SW1 is closed to the contact a in order
to set alarm state for anti-theft, i.e. alarm mode for security, in e.g. parking,
the excitation current in the excitation windings CL1, CL2 of the relays Ry1,
Ry2 is interrupted, thereby causing the relay contacts r1, r2 to be restored to
the NC positions. On the other hand, the power supply 4 is connected to
the power supply circuit 8, so that an operation power supply is provided to
the tilt sensor 7 and the control circuit 6 from the three-terminal regulator U,
going into an operation standby state.
Then, when a body (vehicle) tilts at a predetermined amount or more,
or receives vibration/shock, causing its detection signal to be output from the
sensor 7, the control circuit 6 is activated to output a PWM signal, formed of
a square wave voltage having a predetermined duty ratio, to the base of the
transistor Q1 of the drive circuit 5. Note that here it is described using the
specific circuit of FIG. 2. This causes that the transistor Q1 repeats an
operation to turn on during the "H" period and turn off during the "L" period
of the PWM signal, and that also the transistor Q2 repeats on/off in a pattern
reversed from the on/off of the transistor Q1, and further that the transistor
Q3 repeats on/off in a pattern reversed from the on/off of the transistor Q2.
As a result, the voltage of the power supply 4, which is applied to the
electromagnetic buzzer 3 via the path through the NC position of the contact
r1 of the relay Ry1, the electromagnetic buzzer 3, the NC position of the
relay contact r2 of the relay Ry2 and the transistor Q3, is PWM-controlled so

as to cause the drive voltage applied to the electromagnetic buzzer 3 to be an
average voltage determined by the duty ratio. This makes the sound
pressure level lower than at the time of safety checking. In other words, the
beep tone in the alarm mode becomes different from the beep tone at the
time of safety checking, resulting in having a discriminability. Accordingly,
a user recognizes this beep tone as an alarm signal tone, thus being able to
immediately take an action for anti-theft.
According to the present Embodiment, a PWM-controlled voltage is
applied to the electromagnetic buzzer 3. Accordingly, the current flowing
in the electromagnetic buzzer 3 becomes intermittent, reducing the power
consumption of the electromagnetic buzzer 3 as compared with the case of
applying a continuous voltage for driving. Further, in the state in which the
main switch SW1 is closed to the neutral position, the power supply 4 does
not provide an excitation current to the relays Ry1, Ry2 or power to the
power supply circuit 8, so that the power consumption is reduced.
Note that the main switch SW1 is preferably coupled to the key
operation of the vehicle. More specifically, for example, it can be that a
steering lock is set, and at the same time an alarm mode for security is set
when a key is removed in the lock position (or the lock operation is
performed by a remote control key), whereas the above alarm lock is
released when the key is inserted into a key hole (or the lock is released by
the remote control key), and is rotated to the engine start position.
(Modified Example of Embodiment 1)
FIG. 4 shows an in-vehicle electromagnetic buzzer control apparatus
2 according to a Modified Example of the above Embodiment. In this

Modified Example, a unit board 10 does not have a switching circuit 9
formed of an electromagnetic relay as described above. Further, a diode
D1, a horn switch SW2 and an electromagnetic buzzer 3 are connected in
series and between a contact b of a main switch SW1 and ground.
Furthermore, the electromagnetic buzzer 3, a diode D2 and a transistor Q
driven by the unit board 10 are connected in series and between a contact a
of the main switch SW1 and ground. The electromagnetic buzzer 3 is
driven in a manner similar to the above that the beep tones are different from
each other between when the electromagnetic buzzer 3 operates for safety
checking and when it operates for alarm. In this Modified Example, if the
unit board 10 should fail, it is still possible to use the electromagnetic buzzer
3 for normal safety checking.
(Embodiment 2)
FIG. 5 shows an in-vehicle electromagnetic buzzer control apparatus
according to Embodiment 2. In the above Embodiment 1, one
electromagnetic buzzer 3 is used both for safety checking and for alarm,
whereas in Embodiment 2, an electromagnetic buzzer 3A for safety checking
and an electromagnetic buzzer 3B for alarm are separately provided. The
electromagnetic buzzer 3A and a horn switch SW2 are connected in series
and between a contact b of a main switch SW1 and ground. The
electromagnetic buzzer 3B and a transistor Q driven by a unit board 10 are
connected in series and between a contact a of the main switch SW1 and
ground. The electromagnetic buzzers 3A, 3B to be used can be the same
one, or can have different functions and configurations. These
electromagnetic buzzer 3A and electromagnetic buzzer 3B are operated to

the electromagnetic buzzer according to level of the tilt, vibration or shock
of the vehicle detected by the sensor. This makes it possible for a user to
understand the level of the tilt, vibration or shock of the vehicle from the
beep tone.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
FIG. 1 is a circuit diagram of an in-vehicle electromagnetic buzzer
control apparatus according to an Embodiment 1 of the present invention;
FIG. 2 is a specific circuit configuration diagram of the above
apparatus;
FIG. 3 is a side view of a vehicle with the above apparatus being
installed;
FIG. 4 a circuit diagram of an apparatus according to a Modified
Example of the above Embodiment 1; and
FIG. 5 is a circuit diagram of an in-vehicle electromagnetic buzzer
control apparatus according to Embodiment 2 of the present invention.
BEST MODE FOR CARRAYING OUT THE INVENTION
Hereinafter, in-vehicle electromagnetic buzzer control apparatus
according to embodiments of the present invention will be described with
reference to the drawings.
(Embodiment 1)
FIG 1 shows a circuit of an in-vehicle electromagnetic buzzer
control apparatus 2 according to Embodiment 1, and FIG. 2 shows a specific
circuit configuration thereof, while FIG. 3 shows an engine-attached bicycle

have beep tones different from each other.
Although this Embodiment 2 requires two electromagnetic buzzers,
it has an advantage in that even if a constituent component for safety
checking fails, or a constituent component for alarm fails, they do not affect
the other because they are independent of each other.
Note that although the present Embodiment shows the case where it
is installed in a two-wheeled vehicle such as an engine-attached bicycle or a
motorcycle, the present invention can be applied to a four-wheeled vehicle
(car).
It is to be noted that this application claims priority based on a patent
application filed March 25, 2005. The entire content of such application is
incorporated into this application by reference.

We Claim
1. An in-vehicle electromagnetic buzzer control apparatus installed in a vehicle,
comprising an electromagnetic buzzer, a power supply for driving this electromagnetic
buzzer, and a horn switch for opening and closing a current conducting path from the
driving power supply to the electromagnetic buzzer, comprising:
a mode switch for selectively setting an alarm mode for security and a normal
mode in which the alarm mode is released;
a sensor for detecting at least one of tilt, vibration or shock of the vehicle; and
a control means for controlling the opening and closing of the current conducting
path from the power supply to the electromagnetic buzzer depending on the setting of the
mode switch,
wherein if the alarm mode is set, the control means Pulse-Width-Modulation-
controls the voltage of the power supply, and applies this Pulse-Width-Modulation-
controlled voltage to and causes the electromagnetic buzzer to emit the beep tone for
alarm, and the control means closes the current conducting path to the electromagnetic
buzzer to cause the electromagnetic buzzer to emit a beep tone for alarm when the sensor
detects the tilt, vibration or shock of the vehicle, while if the normal mode is set, the
control means forms the current conducting path to continuously apply the voltage of the
power supply to and cause the electromagnetic buzzer to emit the beep tone for safety
checking, and the control means closes the current conducting path to the electromagnetic
buzzer to cause the electromagnetic buzzer to emit a beep tone for safety checking when
a user operates to close the horn switch, controlling to provide the power supply so as to
make the beep tone for alarm and the beep tone for safety checking different from each
other.
2. The in-vehicle electromagnetic buzzer control apparatus as claimed in claim 1,
wherein the electromagnetic buzzer, being one, is used both for the alarm and for
the safety checking.
3. The in-vehicle electromagnetic buzzer control apparatus as claimed in claim 1,

wherein the electromagnetic buzzer is one for the alarm and one for the safety
checking which are separately provided.
4. The in-vehicle electromagnetic buzzer control apparatus as claimed in claim 1,
wherein there is provided a threshold value setting means for changing sound
pressure or frequency of the beep tone of the electromagnetic buzzer according to level of
the tilt, vibration or shock of the vehicle detected by the sensor.

ABSTRACT

IN-VEHICLE ELECTROMAGNETIC BUZZER CONTROL APPARATUS
The invention relates to an in-vehicle electromagnetic buzzer control comprising; a main
switch (SWI) for selectively setting an alarm mode for security and a normal mode in
which the alarm mode is released; a sensor (7) for detecting tilt, vibration or shock of a
vehicle; and a control circuit (6) for controlling the opening and closing of a current
conducting path from power supply to an electromagnetic buzzer depending on the
setting of the main switch (SWI). If the alarm mode is set, the control circuit (6) closes
the current conducting path to and causes the electromagnetic buzzer (3) to emit a beep
tone for alarm when the sensor (7) detects e.g. tilt of the vehicle, while if the normal
mode is set, the control circuit closes the current conducting path to and causes the
electromagnetic buzzer (3) to emit a beep tone for safety checking when a horn switch
(SW2) is closed, controlling to provide the power supply so as to make the beep tone for
alarm and the beep tone for safety checking different from each other. This differentiates
a beep tone of the electromagnetic buzzer to be used for normal safety checking from a
beep tone for alarm serving as a security apparatus, so as to be able to have a
discriminability.

IN-VEHICLE ELECTROMAGNETIC BUZZER CONTROL APPARATUS

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