Title of Invention	"HORN DRIVING CIRCUIT FOR A VEHICLE"
Abstract	[Task] To ensure the sound making of an AC horn even when an engine is in a high rotation zone using a generated power of a multipolar AC generator to which an AC regulator which is served for applying a stable voltage to an electrical load isconnected. [Means for solving the Task] A horn energizing circuit 5 which includes an AC horn H is connected to a multipolar AC generator G independently from a circuit which is controlled by an ACregulator 2.[Selected Drawing]   Fig. 1

Title of Invention

"HORN DRIVING CIRCUIT FOR A VEHICLE"

Abstract

[Task] To ensure the sound making of an AC horn even when an engine is in a high rotation zone using a generated power of a multipolar AC generator to which an AC regulator which is served for applying a stable voltage to an electrical load isconnected. [Means for solving the Task] A horn energizing circuit 5 which includes an AC horn H is connected to a multipolar AC generator G independently from a circuit which is controlled by an ACregulator 2.[Selected Drawing]   Fig. 1

Full Text	[0001] [Technical Field to which the Invention Belongs] The present invention relates to an improvement of a horn driving circuit for a vehicle which is served for driving an AC horn by utilizing electric power generated by a multipolar AC generator which is driven by an engine. [0002] [Prior Art] As described in a patent literature 1, there has been known a horn driving circuit for a vehicle in which an AC horn is connected to one end of a power generating coil which a multipolar AC generator includes through a half-wave rectifying means. [0003] [Patent literature 1] Japanese Accepted Utility-Model Publication Sho63 (1988)-42025. [0004] [Problems to be solved by the Invention] In the conventional horn driving circuit, the natural oscillation frequency of an oscillation plate which the AC horn includes does not match with frequency of an AC current outputted from the multipolar AC generator. Accordingly, to prevent the horn from becoming incapable of making an alarming sound particularly in a high rotation zone of an engine, the AC current is subjected to a half-wave rectification and then is imparted to an exciting coil of the horn. [0005] On the other hand, to convert an AC voltage obtained by the multipolar AC generator into a stable AC voltage and, thereafter, to apply the stable AC voltage to an electrical load, a power source system in which the electrical load and the AC regulator are connected to the multipolar AC generator in parallel is generally mounted on a vehicle. Accordingly, from a viewpoint of the above-mentioned prior art, it is estimated that by further connecting the AC horn in parallel with the electrical load and an AC regulator in the power source system, the AC horn can surely make an alarming sound. [0006] Here, the AC horn makes an alarming sound by repeating the attraction of a diaphragm to an exciting coil side and the separation of the diaphragm from the exciting coil using an AC current. Accordingly, with the use of the constitution which connects the AC horn to the AC regulator in parallel as described above, when a rotational speed of the engine falls in a high rotation zone, due to an action of the AC regulator, a current which generates an electromagnetic force to attract the diaphragm becomes a pulsating current and continues flowing into the exciting coil of the AC horn whereby there exists a possibility that the AC horn cannot make an alarming sound. [0007] The present invention has been made in view of such circumstances and it is an object of the present invention to provide a horn driving circuit which can allow an AC horn to make an alarming sound even when a rotational speed of an engine falls in a high rotation zone in driving the AC horn using a generated power of a multipolar AC generator to which an AC regulator is connected to apply a stable voltage to an electrical load. [0008] [Means for Solving the Problem] To achieve the object, the invention described in claim 1 is characterized in that, in a horn driving circuit for a vehicle capable of driving an AC horn using a multipolar AC generator which has power generating coils to which an electrical load and an AC regulator are connected in parallel and is driven by an engine, the improvement is characterized in that a horn energizing circuit including the AC horn is connected to the multipolar AC generator independently from a circuit controlled by the AC regulator. [0009] According to the constitution of the present invention described in claim 1, when a rotational speed of the engine falls in a high rotation zone, even in a state that the AC regulator performs a function thereof, the horn energizing circuit is connected to the multipolar AC generator independently from a control of the AC regulator. Accordingly, it is possible to make an exciting current which flows into an exciting coil of the AC horn generate a zero cross and hence, it is possible to make a diaphragm surely oscillate thus ensuring the reliable sound making by the AC horn. [0010] Further, the invention described in claim 2 is, in addition to the constitution of the present invention described in the above-mentioned claim 1, characterized in that the multipolar AC generator which includes a plurality of power generating coils which are connected in series is provided with a horn dedicated coil which is wound around one of a plurality of poles which the multipolar AC generator includes and is connected to an intermediate tap of the respective power generating coils, and the horn energizing circuit is connected to the horn dedicated coil. Due to such a constitution, it is possible to prevent the multipolar AC generator from becoming large-sized and hence, the reduction of cost can be achieved. That is, since an electric power required by the AC horn is obtained by a portion of the plurality of power generating coils and the horn dedicated coil, the horn dedicated coil has a size corresponding to the minimum one pole and hence, it is possible to prevent the multipolar AC generator from becoming large-sized whereby the reduction of cost can be realized. Further, since the horn dedicated coil is connected to the intermediate tap of the plurality of power generating coils which are connected in series, it is possible to suppress the voltage fluctuation of an electrical load which is connected to th( power generating coils when the AC horn is operated. , [0011] [Mode for Carrying Out the Invention] The mode for carrying out the present invention is explained hereinafter in conjunction with one embodiment of the present invention shown in attached drawings. [Brief Description of the Drawings] [Fig. 1] An electric circuit diagram including an AC horn. [Fig.2] A-front view of a stator which a multi-polar AC generator includes. [Fig. 3] A longitudinal cross-sectional view of an AC horn. [Fig. 4] A view showing an electric current which is imparted to an exciting coil of the AC horn in a state that an AC regulator is stopped in a low rotation zone when an electrical load and the AC horn are connected in parallel. [Fig. 5] A view showing the electric current which is imparted to the exciting coil of the AC horn in a state that the AC regulator is operated in an intermediate rotation zone when the electrical load and the AC horn are connected in parallel. [Fig. 6] A view showing the electric current which is imparted to the exciting coil of the AC horn in a state that the AC regulator is operated in a high rotation zone when the electrical load and the AC horn are connected in parallel and when the AC horn is connected in accordance with the present invention. [0012] Fig. 1 is an electric circuit diagram including an AC horn, Fig. 2 is a front view of a stater which a multipolar AC generator includes. Fig. 3 is a longitudinal cross-sectional view of an AC horn. Fig. 4 is a view showing an electric current wiiich is imparted to an exciting coil of the AC horn in a state that an AC regulator is stopped in a low rotation zone when an electrical load and the AC horn are connected in parallel. Fig. 5 is a view showing the electric current which is imparted to the exciting coil of the AC horn in a state that the AC regulator is operated in an intermediate rotation zone when the electrical load and the AC horn are connected in parallel, and Fig. 6 is a view showing the electric current which is imparted to the exciting coil of the AC horn in a state that the AC regulator is operated in a high rotation zone when the electrical load and the AC horn are connected in parallel and when AC horn is connected in accordance with the present invention. [0013] First of all, in Fig. 1, an electrical load 1 such as a head lamp and an AC regulator 2 which stabilizes a voltage by short-circuiting a negative-side half wave out of an AC voltage and applies the voltage to the electrical load 1 are connected to a multipolar AC generator G driven by an engine in parallel. A horn energizing circuit 5 formed by connecting an exciting coil 3 which an AC horn H includes and a horn switch 4 in series is connected to the multipolar AC generator G. [0014] In Fig. 2, a stator 6 of the multipolar AC generator G includes a core 8 having a plurality of poles projecting outwardly at positions equidistantly spaced apart from each other in the circumferential direction, for example, 8-pole salient poles 7, 7 ... , a bobbin 9 which covers the core 8 at portions except for distal end portions of the respective salient poles 7, 7 ... and a center portion of the core 8, a pair of ignition coils 10, 10 which are wound around two salient poles 7, 7 out of the respective salient poles 7, 7 ... by way of the bobbin 9, power generating coils 11, 11 ... which are wound around a plurality of, for example, five salient poles 7, 7 out of the respective salient poles 7, 7 ... by way of the bobbin 9, and a horn dedicated coil 12 which is wound around one remaining salient pole 7 out of the respective salient poles 7, 7 ... by way of the bobbin 9. [0015] Returning to Fig. 1, a pair of ignition coils 10, 10 are connected in series and one ends of these ignition coils 10, 10 are connected to an ignition device 13. Further, five power generating coils 11, 11 ... are also connected in series and the electrical load 1 and the AC regulator 2 are connected to one ends of these power generating coils 11, 11 ... in parallel. Still further, one end of the horn dedicated coil 12 is connected to an intermediate tap 14 of five power generating coils 11, 11 ... , while the horn energizing circuit 5 is connected to the other end of the horn dedicated coil 12. That is, the horn energizing circuit 5 is connected to the multipolar AC generator G independently from a circuit which is controlled by the AC regulator 2. [0016] In Fig. 3, a casing 15 of the AC horn H is constituted of a bottomed cylindrical casing body 16 and a cover 17 which is connected to the casing body 16 while covering an open end of the casing body 16. A peripheral portipn of an oscillation plate 18 is clamped between the casing body 16 and the cover 17 and a movable core 19 is fixed to a center portion of the oscillation plate 18. [0017] On the other hand, in the inside of the casing body 16, a core 20 and the exciting coil 3 which is wound around the core 20 are arranged in a fixed state such that the core 20 and the exciting coil 3 face the movable core 19 in an opposed manner. The oscillation plate 18 is oscillated by repeating the attraction of the movable core 19 toward the exciting coil 3 side and the separation of the movable core 19 from the exciting coil 3 and hence, the AC horn H makes an alarming sound. [0018] Next, the manner of operation of this embodiment is explained in conjunction with Fig. 4 to Fig. 6. In these drawings. Fig. 4 to Fig. 6(a) are views which show a current which flows into the exciting coil 3 when the exciting coil 3 of the AC horn H and the electrical load 1 are connected in parallel in the conventional manner. [0019] Firstly, to consider a case in which the exciting coil 3 of the AC horn H is connected to the electrical load 1 in parallel in the conventional manner, when a rotational speed of the engine falls in a low rotation zone before starting the operation of the AC regulator 2, a current which is generated by the power generating coils 11, 11 ... and assumes a positive/negative symmetrical waveform is supplied to the exciting coil 3 of the AC horn H as shown in Fig. 4. Then, when the rotational speed of the engine falls in an intermediate rotation zone after starting the operation of the AC regulator 2, since the negative side of the AC horn H is short-circuited by the AC regulator 2, a current which is biased to the positive side is supplied to the exciting coil 3 of the AC horn H as shown in Fig. 5. [0020] In this manner, when the rotational speed of the engine falls in the low rotation zone and the intermediate rotation zone,as shown in Fig. 4 and Fig. 5, a zero cross is generated in the current which is supplied to the exciting coil 3 of the AC horn H. Accordingly, even when the exciting coil 3 of the AC horn H is connected to the electrical load 1 in parallel, it is possible to make the AC horn H make an alarming sound by repeating the attraction of the movable core 19 toward the exciting coil 3 side and the separation of the movable core 19 from the exciting coil 3 thus oscillating the oscillation plate 18. [0021] ^ To the contrary, when the rotational speed of the engine is increased and falls in the high rotation zone, as shown in Fig. 6{a), before the current which flows at the positive side extinguishes, a next positive-side waveform is applied and hence, the current having a pulsating waveform which is biased to the positive side with no zero cross is supplied to the exciting coil 3 of the AC horn H. Accordingly, when the exciting coil 3 of the AC horn H is connected to the electrical load 1 in parallel, the exciting coil 3 is kept attracted to the movable core 19 and hence, the oscillation plate 18 is not oscillated whereby the AC horn H does not make an alarming sound. [0022] However, since the horn energizing circuit 5 which includes the exciting coil 3 of the AC horn H is connected to the multipolar AC generator G independently from the circuit to be controlled by the AC regulator 2 , when the rotational speed of the engine falls in the high rotation zone, even when the AC regulator 2 performs a function thereof, as shown in Fig. 6(b), it is possible to make the energizing current which flows through the exciting coil 3 of the AC horn H generate the zero cross and hence, the oscillation plate 18 can be surely oscillated whereby the reliable sound making by the AC horn H can be ensured. [0023] Further, the multipolar AC generator G is provided with, besides the plurality of power generating coils 11, 11 ... which are connected to the electrical load (1) and AC regulator (2), the horn dedicated coil 12 which is wound around one of a plurality of poles which the multipolar AC generator G includes and is connected to the intermediate tap 14 of the power generating coils 11, 11 ... and the horn energizing circuit 5 is connected to the horn dedicated coil 12. Accordingly, it is possible to prevent the multipolar AC generator G from becoming large-sized and hence, the reduction of cost can be achieved. That is, since an electric power required by the AC horn H is obtained by a portion of the plurality of power generating coils 11, 11 ... and the horn dedicated coil 12, the horn dedicated coil 12 has a size corresponding to the minimum one pole and hence, it is possible to prevent the multipolar AC generator G from becoming large-sized whereby the reduction of cost can be realized. [0024] Further, since the horn dedicated coil 12 is connected to the intermediate tap 14 of the plurality of power generating coils 11, 11 ... which are connected in series, it is possible to suppress the voltage fluctuation of the electrical load 1 which is connected to the power generating coils 11, 11 ... when the AC horn H is operated. [0025] Although the embodiment of the present invention has been explained, the present invention is not limited to the above-mentioned embodiment and various design changes can be made without departing from the present invention described in Claims. [0026] [Advantageous effect of Invention] As has been explained heretofore, according to the invention described in claim 1, even when the rotational speed of.-the engine falls .in the high rotation zone, it is possible to make the excitation current which flows through the exciting coil of the AC horn generate the zero cross and hence, the reliable sound making by the AC horn is ensured. [0027] Further, according to the invention described in claim 2, it is possible to prevent the multipolar AC generator from becoming large-sized and hence, the reduction of cost can be achieved. Further, the voltage fluctuation of the electrical load when the AC horn is operated can be suppressed. [Explanation of Symbols] 1 ... electrical load 2 ... AC regulator 5 ... horn energizing circuit 11 ... power generating coil 12 ... horn dedicated coil 14 ... intermediate tap G ... multipolar AC generator . H ... AC horn [Claim 1] A horn driving circuit for a vehicle capable of driving .an AC horn (H) using a multipolar AC generator (G) which has power generating coils (11) to which an electrical load (1) and an AC regulator (2). are connected in parallel and is driven by an engine, the improvement being characterized in that a horn energizing circuit (5) including the AC horn (H) is connected to the multipolar AC generator (G) independently from a circuit controlled by the AC regulator (2). [Claim 2] A horn driving circuit for a vehicle according to claim 1, wherein the multipolar AC generator (G) which includes a plurality of power generating coils (11) which are connected in series is provided with a horn dedicated coil (12) which is wound around one of a plurality of poles which the multipolar AC generator (G) includes and is connected to an intermediate' tap (14) of the respective power generating coils (11), and the horn energizing circuit (5) is connected to the horn dedicated coil (12). 3. A horn driving circuit for a vehicle substantially as hereinbefore described with reference to the accompanying drawings.

Full Text

[0001] [Technical Field to which the Invention Belongs] The present invention relates to an improvement of a horn driving circuit for a vehicle which is served for driving an AC horn by utilizing electric power generated by a multipolar AC generator which is driven by an engine.
[0002]
[Prior Art]
As described in a patent literature 1, there has been known a horn driving circuit for a vehicle in which an AC horn is connected to one end of a power generating coil which a multipolar AC generator includes through a half-wave rectifying means.
[0003]
[Patent literature 1]
Japanese Accepted Utility-Model Publication Sho63 (1988)-42025.
[0004] [Problems to be solved by the Invention] In the conventional horn driving circuit, the natural oscillation frequency of an oscillation plate which the AC horn includes does not match with frequency of an AC current outputted from the multipolar AC generator. Accordingly, to prevent the horn from becoming incapable of making an alarming sound particularly in a high rotation zone of an engine, the AC current is subjected to a half-wave rectification and then
is imparted to an exciting coil of the horn.
[0005] On the other hand, to convert an AC voltage obtained by the multipolar AC generator into a stable AC voltage and, thereafter, to apply the stable AC voltage to an electrical load, a power source system in which the electrical load and the AC regulator are connected to the multipolar AC generator in parallel is generally mounted on a vehicle. Accordingly, from a viewpoint of the above-mentioned prior art, it is estimated that by further connecting the AC horn in parallel with the electrical load and an AC regulator in the power source system, the AC horn can surely make an alarming sound.
[0006] Here, the AC horn makes an alarming sound by repeating the attraction of a diaphragm to an exciting coil side and the separation of the diaphragm from the exciting coil using an AC current. Accordingly, with the use of the constitution which connects the AC horn to the AC regulator in parallel as described above, when a rotational speed of the engine falls in a high rotation zone, due to an action of the AC regulator, a current which generates an electromagnetic force to attract the diaphragm becomes a pulsating current and continues flowing into the exciting coil of the AC horn whereby there exists a possibility that the AC horn cannot make an alarming sound.
[0007]
The present invention has been made in view of such circumstances and it is an object of the present invention to provide a horn driving circuit which can allow an AC horn to make an alarming sound even when a rotational speed of an engine falls in a high rotation zone in driving the AC horn using a generated power of a multipolar AC generator to which an AC regulator is connected to apply a stable voltage to an electrical load.
[0008]
[Means for Solving the Problem]
To achieve the object, the invention described in claim 1 is characterized in that, in a horn driving circuit for a vehicle capable of driving an AC horn using a multipolar AC generator which has power generating coils to which an electrical load and an AC regulator are connected in parallel and is driven by an engine, the improvement is characterized in that a horn energizing circuit including the AC horn is connected to the multipolar AC generator independently from a circuit controlled by the AC regulator. [0009]
According to the constitution of the present invention described in claim 1, when a rotational speed of the engine falls in a high rotation zone, even in a state that the AC regulator performs a function thereof, the horn energizing circuit is connected to the multipolar AC generator independently from a
control of the AC regulator. Accordingly, it is possible to make an exciting current which flows into an exciting coil of the AC horn generate a zero cross and hence, it is possible to make a diaphragm surely oscillate thus ensuring the reliable sound making by the AC horn. [0010] Further, the invention described in claim 2 is, in addition to the constitution of the present invention described in the above-mentioned claim 1, characterized in that the multipolar AC generator which includes a plurality of power generating coils which are connected in series is provided with a horn dedicated coil which is wound around one of a plurality of poles which the multipolar AC generator includes and is connected to an intermediate tap of the respective power generating coils, and the horn energizing circuit is connected to the horn dedicated coil. Due to such a constitution, it is possible to prevent the multipolar AC generator from becoming large-sized and hence, the reduction of cost can be achieved. That is, since an electric power required by the AC horn is obtained by a portion of the plurality of power generating coils and the horn dedicated coil, the horn dedicated coil has a size corresponding to the minimum one pole and hence, it is possible to prevent the multipolar AC generator from becoming large-sized whereby the reduction of cost can be realized. Further, since the horn dedicated coil is connected to the intermediate
tap of the plurality of power generating coils which are connected in series, it is possible to suppress the voltage fluctuation of an electrical load which is connected to th( power generating coils when the AC horn is operated. , [0011]
[Mode for Carrying Out the Invention]
The mode for carrying out the present invention is explained hereinafter in conjunction with one embodiment of the present invention shown in attached drawings.
[Brief Description of the Drawings]
[Fig. 1]
An electric circuit diagram including an AC horn.
[Fig.2]
A-front view of a stator which a multi-polar AC generator includes.
[Fig. 3]
A longitudinal cross-sectional view of an AC horn.
[Fig. 4]
A view showing an electric current which is imparted to an exciting coil of the AC horn in a state that an AC regulator is stopped in a low rotation zone when an electrical load and the AC horn are connected in parallel.
[Fig. 5]
A view showing the electric current which is imparted to
the exciting coil of the AC horn in a state that the AC regulator is operated in an intermediate rotation zone when the electrical load and the AC horn are connected in parallel.
[Fig. 6] A view showing the electric current which is imparted to the exciting coil of the AC horn in a state that the AC regulator is operated in a high rotation zone when the electrical load and the AC horn are connected in parallel and when the AC horn is connected in accordance with the present invention.
[0012] Fig. 1 is an electric circuit diagram including an AC horn, Fig. 2 is a front view of a stater which a multipolar AC generator includes. Fig. 3 is a longitudinal cross-sectional view of an AC horn. Fig. 4 is a view showing an electric current wiiich is imparted to an exciting coil of the AC horn in a state that an AC regulator is stopped in a low rotation zone when an electrical load and the AC horn are connected in parallel. Fig. 5 is a view showing the electric current which is imparted to the exciting coil of the AC horn in a state that the AC regulator is operated in an intermediate rotation zone when the electrical load and the AC horn are connected in parallel, and Fig. 6 is a view showing the electric current which is imparted to the exciting coil of the AC horn in a state that the AC regulator is operated in a high rotation zone when the electrical load and the AC horn are connected in parallel and when AC horn is connected in
accordance with the present invention.
[0013] First of all, in Fig. 1, an electrical load 1 such as a head lamp and an AC regulator 2 which stabilizes a voltage by short-circuiting a negative-side half wave out of an AC voltage and applies the voltage to the electrical load 1 are connected to a multipolar AC generator G driven by an engine in parallel. A horn energizing circuit 5 formed by connecting an exciting coil 3 which an AC horn H includes and a horn switch 4 in series is connected to the multipolar AC generator G.
[0014] In Fig. 2, a stator 6 of the multipolar AC generator G includes a core 8 having a plurality of poles projecting outwardly at positions equidistantly spaced apart from each other in the circumferential direction, for example, 8-pole salient poles 7, 7 ... , a bobbin 9 which covers the core 8 at portions except for distal end portions of the respective salient poles 7, 7 ... and a center portion of the core 8, a pair of ignition coils 10, 10 which are wound around two salient poles 7, 7 out of the respective salient poles 7, 7 ... by way of the bobbin 9, power generating coils 11, 11 ... which are wound around a plurality of, for example, five salient poles 7, 7 out of the respective salient poles 7, 7 ... by way of the bobbin 9, and a horn dedicated coil 12 which is wound around one remaining salient pole 7 out of the respective salient poles 7, 7 ... by
way of the bobbin 9. [0015]
Returning to Fig. 1, a pair of ignition coils 10, 10 are connected in series and one ends of these ignition coils 10, 10 are connected to an ignition device 13. Further, five power generating coils 11, 11 ... are also connected in series and the electrical load 1 and the AC regulator 2 are connected to one ends of these power generating coils 11, 11 ... in parallel. Still further, one end of the horn dedicated coil 12 is connected to an intermediate tap 14 of five power generating coils 11, 11 ... , while the horn energizing circuit 5 is connected to the other end of the horn dedicated coil 12. That is, the horn energizing circuit 5 is connected to the multipolar AC generator G independently from a circuit which is controlled by the AC regulator 2.
[0016]
In Fig. 3, a casing 15 of the AC horn H is constituted of a bottomed cylindrical casing body 16 and a cover 17 which is connected to the casing body 16 while covering an open end of the casing body 16. A peripheral portipn of an oscillation plate 18 is clamped between the casing body 16 and the cover 17 and a movable core 19 is fixed to a center portion of the oscillation plate 18. [0017]
On the other hand, in the inside of the casing body 16,
a core 20 and the exciting coil 3 which is wound around the core 20 are arranged in a fixed state such that the core 20 and the exciting coil 3 face the movable core 19 in an opposed manner. The oscillation plate 18 is oscillated by repeating the attraction of the movable core 19 toward the exciting coil 3 side and the separation of the movable core 19 from the exciting coil 3 and hence, the AC horn H makes an alarming sound. [0018]
Next, the manner of operation of this embodiment is explained in conjunction with Fig. 4 to Fig. 6. In these drawings. Fig. 4 to Fig. 6(a) are views which show a current which flows into the exciting coil 3 when the exciting coil 3 of the AC horn H and the electrical load 1 are connected in parallel in the conventional manner. [0019]
Firstly, to consider a case in which the exciting coil 3 of the AC horn H is connected to the electrical load 1 in parallel in the conventional manner, when a rotational speed of the engine falls in a low rotation zone before starting the operation of the AC regulator 2, a current which is generated by the power generating coils 11, 11 ... and assumes a positive/negative symmetrical waveform is supplied to the exciting coil 3 of the AC horn H as shown in Fig. 4. Then, when the rotational speed of the engine falls in an intermediate rotation zone after starting the operation of the AC regulator
2, since the negative side of the AC horn H is short-circuited by the AC regulator 2, a current which is biased to the positive side is supplied to the exciting coil 3 of the AC horn H as shown in Fig. 5.
[0020] In this manner, when the rotational speed of the engine falls in the low rotation zone and the intermediate rotation zone,as shown in Fig. 4 and Fig. 5, a zero cross is generated in the current which is supplied to the exciting coil 3 of the AC horn H. Accordingly, even when the exciting coil 3 of the AC horn H is connected to the electrical load 1 in parallel, it is possible to make the AC horn H make an alarming sound by repeating the attraction of the movable core 19 toward the exciting coil 3 side and the separation of the movable core 19 from the exciting coil 3 thus oscillating the oscillation plate 18.
[0021] ^ To the contrary, when the rotational speed of the engine is increased and falls in the high rotation zone, as shown in Fig. 6{a), before the current which flows at the positive side extinguishes, a next positive-side waveform is applied and hence, the current having a pulsating waveform which is biased to the positive side with no zero cross is supplied to the exciting coil 3 of the AC horn H. Accordingly, when the exciting coil 3 of the AC horn H is connected to the electrical load 1
in parallel, the exciting coil 3 is kept attracted to the movable core 19 and hence, the oscillation plate 18 is not oscillated whereby the AC horn H does not make an alarming sound. [0022]
However, since the horn energizing circuit 5 which includes the exciting coil 3 of the AC horn H is connected to the multipolar AC generator G independently from the circuit to be controlled by the AC regulator 2 , when the rotational speed of the engine falls in the high rotation zone, even when the AC regulator 2 performs a function thereof, as shown in Fig. 6(b), it is possible to make the energizing current which flows through the exciting coil 3 of the AC horn H generate the zero cross and hence, the oscillation plate 18 can be surely oscillated whereby the reliable sound making by the AC horn H can be ensured.
[0023]
Further, the multipolar AC generator G is provided with, besides the plurality of power generating coils 11, 11 ... which are connected to the electrical load (1) and AC regulator (2), the horn dedicated coil 12 which is wound around one of a plurality of poles which the multipolar AC generator G includes and is connected to the intermediate tap 14 of the power generating coils 11, 11 ... and the horn energizing circuit 5 is connected to the horn dedicated coil 12. Accordingly, it is possible to prevent the multipolar AC generator G from
becoming large-sized and hence, the reduction of cost can be achieved. That is, since an electric power required by the AC horn H is obtained by a portion of the plurality of power generating coils 11, 11 ... and the horn dedicated coil 12, the horn dedicated coil 12 has a size corresponding to the minimum one pole and hence, it is possible to prevent the multipolar AC generator G from becoming large-sized whereby the reduction of cost can be realized.
[0024] Further, since the horn dedicated coil 12 is connected to the intermediate tap 14 of the plurality of power generating coils 11, 11 ... which are connected in series, it is possible to suppress the voltage fluctuation of the electrical load 1 which is connected to the power generating coils 11, 11 ... when the AC horn H is operated.
[0025] Although the embodiment of the present invention has been explained, the present invention is not limited to the above-mentioned embodiment and various design changes can be made without departing from the present invention described in Claims.
[0026] [Advantageous effect of Invention]
As has been explained heretofore, according to the invention described in claim 1, even when the rotational speed
of.-the engine falls .in the high rotation zone, it is possible to make the excitation current which flows through the exciting coil of the AC horn generate the zero cross and hence, the reliable sound making by the AC horn is ensured. [0027] Further, according to the invention described in claim 2, it is possible to prevent the multipolar AC generator from becoming large-sized and hence, the reduction of cost can be achieved. Further, the voltage fluctuation of the electrical load when the AC horn is operated can be suppressed.
[Explanation of Symbols]
1 ... electrical load
2 ... AC regulator
5 ... horn energizing circuit
11 ... power generating coil
12 ... horn dedicated coil 14 ... intermediate tap
G ... multipolar AC generator . H ... AC horn

[Claim 1]
A horn driving circuit for a vehicle capable of driving .an AC horn (H) using a multipolar AC generator (G) which has power generating coils (11) to which an electrical load (1) and an AC regulator (2). are connected in parallel and is driven by an engine, the improvement being characterized in that a horn energizing circuit (5) including the AC horn (H) is connected to the multipolar AC generator (G) independently from a circuit controlled by the AC regulator (2). [Claim 2]
A horn driving circuit for a vehicle according to claim 1, wherein the multipolar AC generator (G) which includes a plurality of power generating coils (11) which are connected in series is provided with a horn dedicated coil (12) which is wound around one of a plurality of poles which the multipolar AC generator (G) includes and is connected to an intermediate' tap (14) of the respective power generating coils (11), and the horn energizing circuit (5) is connected to the horn dedicated coil (12).
3. A horn driving circuit for a vehicle substantially as hereinbefore described with reference to the accompanying drawings.

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Patent Number

270292

Indian Patent Application Number

408/DEL/2004

PG Journal Number

50/2015

Publication Date

11-Dec-2015

Grant Date

09-Dec-2015

Date of Filing

10-Mar-2004

Name of Patentee

HONDA MOTOR CO., LTD.

Applicant Address

1-1, MINAMIAOYAMA 2-CHOME, MINATO-KU, TOKYO, JAPAN

Inventors:

#	Inventor's Name	Inventor's Address
1	HIROYUKI NAKAJIMA	C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, 4-1 CHUO 1-CHOME, WAKO-SHI, SAITAMA, JAPAN
2	MAKOTO ISHIZUKA	C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, 4-1 CHUO 1-CHOME, WAKO-SHI, SAITAMA, JAPAN
3	TAKESHI YANAGISAWA	C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, 4-1 CHUO 1-CHOME, WAKO-SHI, SAITAMA, JAPAN

PCT International Classification Number

B60 Q5/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2003-088156	2003-03-27	Japan