JPH11339583A - Load control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a load control device that can be miniaturized and lightened and can reduce the cost by reducing the number of components. SOLUTION: For this load control device 1, a relay 2b to select a motor to which a driving current is carried from motors 9a, 9b of which rotating directions are changed forward or backward according to the direction in which the driving current is carried, and relays 2a and 2c to switch the direction of the driving current carried to the motor 9a or the motor 9b selected by the relay 2b are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load control device suitable for controlling the operation of a plurality of loads mounted on an automobile, and more particularly to a load control device having a reduced number of switching devices. .

[0002]

2. Description of the Related Art In some cases, multiplex communication is applied to control of driving of motors such as a remote control door mirror and a door lock of an automobile. By applying multiplex communication, the driving of the load is controlled by a switching device such as a relay or a power transistor. FIG. 4 is a schematic diagram showing a conventional load control device.

A load control circuit 25 is provided in the conventional load control device 21. The load control circuit 25 includes a power supply line 27a, a ground line 27b, and a multiplex communication line 28 which are drawn in from outside the load control device 21. It is connected to the. Power line 2
7a is connected to an external power supply (not shown) and supplied with a voltage of 12V, and the ground line 27b is grounded. The multiplex communication line 28 is connected to another load control circuit or the like.

The load control circuit 25 is further connected to a switch 26a for returning / retracting drive of the remote control door mirror and a switch 26b for locking / unlocking the door. The switches 26a and 26b are grounded. Further, the load control device 21 is provided with four relays 22 a to 22 d as current direction switching switches, and the negative terminals of the coils 23 a to 23 d of each relay are connected to the load control circuit 25. . On the other hand, the positive terminals of the coils 23a to 23d are connected to the power supply line 27a.

When the contact of the switch 26a is connected to the return side, the load control circuit 25
Is grounded, the negative terminal of the coil 23b is grounded when the contact of the switch 26a is connected to the storage side, and the negative terminal of the coil 23c is connected when the contact of the switch 26b is connected to the unlocked side. When the terminal is grounded and the contact of the switch 26b is connected to the locking side, the coil 23
A circuit for grounding the negative terminal of d is incorporated. Therefore, for example, when the contact of the switch 26a is connected to the return side, the coil 23a is excited.

The relays 22a to 22d are provided with switches 24a to 24d which are switched by turning on / off the excitation of the coils 23a to 23d. A motor 29a for returning / retracting the remote control door mirror is connected to the switches 24a and 24b, and the selection of the connection of the motor 29a to the power line 27a or the ground line 27b is controlled by the switches 24a and 24b. Similarly, a motor 29b for locking / unlocking the door is connected to the switches 24c and 24d, and the selection of the connection of the motor 29b to the power line 27a or the ground line 27b is controlled by the switches 24c and 24d. The motor 2
9a is connected in such a direction that the remote control door mirror is restored when a current flows from the relay 22a side, and the remote control door mirror is retracted when a current flows from the relay 22b side. The motor 29b is connected in such a direction that the door is unlocked when a current flows from the relay 22c side, and the door is locked when a current flows from the relay 22d side.

[0007] As shown in FIG.
And 26b are not connected anywhere, the contacts of switches 24a through 24d are all connected to ground line 27.
It is connected to the b side.

[0008] The storage operation of the remote control door mirror using the conventional load control device thus configured will be described. First, with the remote control door mirror opened, the contact of the switch 26a is connected to the storage side. This allows
The connection of the switch 26a to the storage side is detected by the load control circuit 25, and the negative terminal of the coil 23b is grounded. At this time, the positive terminal of the coil 23b is connected to the power supply line 27a.
3b is excited. The contact of the switch 24b is connected to the power supply line 27a. On the other hand, the contact point of the switch 24a remains connected to the ground line 27b. Therefore, a current flows to the motor 29a from the relay 22b side, and the remote control door mirror is retracted.

Next, the returning operation of the remote control door mirror will be described. First, with the remote control door mirror retracted, the contact of the switch 26a is connected to the return side. Thus, the load control circuit 25 detects that the contact of the switch 26a is connected to the return side, and the coil 23a
The negative terminal of is grounded. At this time, the coil 23
Since the positive terminal of a is connected to the power supply line 27a, the coil 23a is excited. And the switch 24
The contact a is connected to the power supply line 27a. On the other hand, the contact point of the switch 24b remains connected to the ground line 27b. As a result, a current flows to the motor 29a from the relay 22a side, so that the remote control door mirror is returned.

[0010] The unlocking operation and the locking operation of the door are performed in the same manner.

[0011]

However, in the conventional load control device, two relays are indispensable for each load (actuator) driven in two directions such as forward rotation / reverse rotation, and the load control device itself is required. However, there is a problem that it is large and it is difficult to secure an arrangement space. In addition, since there are many relays, a large number of electronic components such as transistors, resistance elements, capacitors, fly-hole diodes, and the like necessary for driving the load control circuit are provided. Therefore, there is also a problem that the cost of the load control device is high.

The present invention has been made in view of the above-mentioned problems, and provides a load control device which can be reduced in size and weight, and can reduce the number of electronic components to reduce the cost. The purpose is to do.

[0013]

According to the present invention, there is provided a load control device for controlling a drive current flowing through a plurality of loads that switch between normal rotation and reverse rotation depending on the direction in which the drive current flows. A load selecting switching device for selecting a load to which a driving current flows from the plurality of loads; and a current direction switching switching device for switching a direction of the driving current flowing to the load selected by the load selecting switching device. It is characterized by having.

In the present invention, the load to be driven is selected by the drive current flowing through the load selection switching device, and the direction of the drive current flowing through the load is switched by the current direction switching switching device. For this reason, since it is not necessary to provide two switching devices for each load, the size of the device itself can be reduced. Also, the number of electronic components used for controlling the switching devices is reduced by reducing the number of switching devices, so that the cost is reduced and the weight is reduced.

A load control circuit connected to the load selection switching device and the current direction switching switching device; and command input means connected to the load control circuit for inputting a load operation command. The load control circuit may include priority order determining means for determining an order of loads to be operated when operation instructions of two or more loads are input simultaneously from the instruction input means.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a load control device according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing a load control device according to a first embodiment of the present invention.

The load control device 1 according to the present embodiment is provided with a load control circuit 5, and the load control circuit 5 includes a power supply line 7 a and a ground line 7 drawn from outside the load control device 1.
b and the multiplex communication line 8. The power supply line 7a is connected to an external power supply (not shown) and supplied with a voltage of 12V, and the ground line 7b is grounded. The multiplex communication line 8 is connected to another load control circuit or the like.

Further, to the load control circuit 5, a switch 6a for returning / retracting operation of the remote control door mirror and a switch 6b for locking / unlocking the door are connected. The switches 6a and 6b are grounded. The load control device 1 is provided with two relays 2a and 2c as current-direction switching switching devices and a relay 2b as a load selection switching device.
The negative terminals of the coils 3 a to 3 c of each relay are connected to the load control circuit 5. On the other hand, coils 3a to 3
The positive terminal of c is connected to the power supply line 7a.

The load control circuit 5 includes a switch 6
When the contact b is connected to the unlocking side, the negative terminal of the coil 3c is grounded, and when the contact of the switch 6b is connected to the locking side, the negative terminal of the coil 3a is grounded,
When the contact of the switch 6a is connected to the return side, the negative terminals of the coils 3a and 3b are grounded, and the switch 6a
Coils 3b and 3c when the contacts of
A circuit for grounding the negative side terminal of is provided.
Therefore, for example, when the contact of the switch 6a is connected to the return side, only the coils 3a and 3b are excited,
When the contact b is connected to the locking side, only the coil 3a is excited.

Further, the circuit incorporated in the above-described load control circuit 5 has the grounding of the coils 3a to 3c such that the locking / unlocking operation of the door is performed with priority over the returning / retracting operation of the remote control door mirror. Is controlled.

The relays 2a to 2c are provided with switches 4a to 4c which are switched by turning on / off the excitation of the coils 3a to 3c. The switch 4a is
The switch 4b is connected between the power supply line 7a and the ground line 7b and the switch 4b, and controls the selection of the connection of the switch 4b to the power supply line 7a or the ground line 7b. The switch 4b is connected between the switch 4a and a motor 9a for returning / retracting operation of a remote control door mirror provided outside the load control device 1 and a motor 9b for locking / unlocking the door. The selection of the connection of the switch 4a to the motor 9a or the motor 9b is controlled. The switch 4c is connected to the motors 9a and 9b and the power line 7a.
And the switch 4c
Power supply line 7a or ground line 7b of motors 9a and 9b
The selection of the connection to is controlled.

When the coil 3a is not excited, the contact of the switch 4a is connected to the ground line 7b. When the coil 3b is not excited,
The contact of the switch 4b is connected to the locking / unlocking motor 9b. Furthermore, when the coil 3c is not excited, the contact of the switch 4c is connected to the ground line 7b.

Further, as shown in FIG. 1, the motor 9a and the motor 9b are connected in parallel between the switch 4b and the switch 4c. The motor 9a is connected in such a direction that the remote control door mirror is restored when a current flows from the relay 2b and the remote control door mirror is stored when a current flows from the relay 2c. On the other hand, the motor 9b is connected in such a direction that the door is locked when a current flows from the relay 2b and the door is unlocked when a current flows from the relay 2c.

The relays 2a to 2c, the load control circuit 5, and the switches 6a and 6b are arranged in the same unit.

Next, the operation of the load control device of the present embodiment configured as described above will be described. First, the door locking operation will be described. With the door unlocked, the contact of the switch 6b is connected to the locking side. As a result, the fact that the contact of the switch 6b is connected to the locking side is detected by the load control circuit 5, and the negative terminal of the coil 3a is grounded. At this time, since the positive terminal of the coil 3a is connected to the power line 7a, the coil 3a is excited. The contact of the switch 4a is connected to the power line 7a.
Connected to the side. On the other hand, since the coils 3b and 3c are not excited, the contact of the switch 4b is connected to the motor 9b, and the contact of the switch 4c is connected to the ground line 7b. For this reason, a current flows to the motor 9b from the relay 2b side, so that the door is locked.

Next, the unlocking operation of the door will be described.
With the door locked, the contact of the switch 6b is connected to the unlocked side. As a result, the fact that the contact of the switch 6b is connected to the unlocking side is detected by the load control circuit 5, and the negative terminal of the coil 3c is grounded. At this time, since the positive terminal of the coil 3c is connected to the power supply line 7a, the coil 3c is excited. The contact of the switch 4c is connected to the power line 7a. On the other hand, since the coils 3a and 3b are not excited, the contact of the switch 4a is connected to the ground line 7b, and the contact of the switch 4b is connected to the motor 9b. As a result, a current flows through the motor 9b from the relay 2c side, and the door is unlocked.

Next, the storing operation of the remote control door mirror will be described. With the remote control door mirror open,
The switch 6a is connected to the contact on the storage side. This allows
The connection of the switch 6a to the contact on the storage side is detected by the load control circuit 5, and the negative terminals of the coils 3b and 3c are grounded. At this time, the coils 3b and 3c
Is connected to the power supply line 7a side.
The coils 3b and 3c are excited. And switch 4
The contact b is connected to the motor 9a, and the contact of the switch 4c is connected to the power line 7a. On the other hand, since the coil 3a is not excited, the contact of the switch 4a is connected to the ground line 7b. Therefore, a current flows through the motor 9a from the relay 2c side, so that the remote control door mirror is retracted.

Next, the return operation of the remote control door mirror will be described. With the remote control door mirror retracted, the switch 6a is connected to the return-side contact. Thus, the load control circuit 5 detects that the switch 6a is connected to the contact on the return side, and the negative terminals of the coils 3a and 3b are grounded. At this time, since the positive terminals of the coils 3a and 3b are connected to the power line 7a, the coils 3a and 3b are excited. The contact of the switch 4a is connected to the power supply line 7a, and the switch 4b
Are connected to the motor 9a side. On the other hand, the coil 3c
Is not excited, the contact of the switch 4c is connected to the ground line 7b.
Connected to the side. Therefore, the relay 2 is connected to the motor 9a.
Since the current flows from the b side, the door mirror is returned.

The load control circuit 1 operates in this manner from the state where all the relays 2a to 2d are not excited.

Further, a case will be described in which one of the motors is operating and the other motor is to be operated. First, the case where the remote control door mirror is to be stored during the door locking operation will be described. As aforementioned,
During the door locking operation, only the coil 3a is excited, and the other coils 3b and 3c are not excited. In this state, when the contact of the remote control door mirror switch 6a is connected to the storage side, this is detected by the load control circuit 5. However, the grounding of the coils 3a to 3c is controlled by the load control circuit 5 so that the operation of locking / unlocking the door is performed with priority over the operation of returning / retracting the door mirror of the remote controller. Is connected to the storage side, the state of each of the relays 2a to 2c does not change, and the operation of the motor 9b, that is, the storage operation of the remote control door mirror is suspended. Then, the door locking operation is completed as described above.

Thereafter, the excitation of the coil 3a is turned off, and the coils 3b and 3c are excited. And, as mentioned above,
The motor 9a operates to store the remote control door mirror.

Since the door locking operation is completed in about several hundreds of milliseconds, the holding time of the storage operation of the remote control door mirror is extremely short. Therefore, the driver, who is the operator, hardly perceives the delay, so that no discomfort occurs and there is no practical problem.

Also, when the remote control door mirror is restored during the door locking operation and when the remote control door mirror is stored or restored during the door unlocking operation,
Similarly, the operation of the remote control door mirror is temporarily suspended, and the operation of the remote control door mirror is performed again after the door locking or unlocking operation is completed.

Next, a case where the door is locked during the storage operation of the remote control door mirror will be described. As aforementioned,
During the retracting operation of the remote control door mirror, the coils 3b and 3
Only c is excited, and the other coils 3a are not excited. When the contact of the door switch 6b is connected to the locking side in this state, this is detected by the load control circuit 5. At this time, the grounding of the coils 3a to 3c is controlled by the load control circuit 5 so that the locking / unlocking operation of the door is performed with higher priority than the returning / retracting operation of the remote control door mirror. The excitation of 3c is turned off, and the coil 3a is excited. And, as mentioned above,
The motor 9b operates to lock the door.

Thereafter, the excitation of the coil 3a is turned off, and the coils 3b and 3c are excited again. Then, as described above, the motor 9a operates to store the remote control door mirror.

In this case, since the door locking operation is completed in about several hundred ms, the holding time of the storage operation of the remote control door mirror is extremely short. Therefore, the driver, who is the operator, hardly perceives the delay, so that no discomfort occurs and there is no practical problem.

Similarly, when the door is unlocked during the storage operation of the remote control door mirror and when the door is locked or unlocked during the return operation of the remote control door mirror, the operation of the remote control door mirror is also temporarily suspended. After the door locking or unlocking operation is completed, the operation of the remote control door mirror is performed again.

As described above, in the load control device according to the present embodiment, the number of relays can be reduced as compared with the conventional one. Therefore, the load control device itself can be downsized, and the number of electronic components for driving the relay in the load control circuit 5 can be reduced. For this reason, it is possible to achieve weight reduction and cost reduction of the device.

The load controlled by the load control device is not limited to the door locking / unlocking motor and the door mirror storing / returning motor. For example, forward rotation of load such as power window, power seat and sunroof /
This is suitable for the case where the operation is changed by the reverse rotation and the effect is small even if the operation is temporarily suspended. Particularly, the motor for locking / unlocking the door used in the embodiment of the present invention is optimal because the operation time is extremely short, about 0.2 seconds.

The present invention is not limited to a load control device used for controlling two loads. For example,
When used to control three loads, four relays are used. FIG. 2 is a schematic diagram showing a load control device according to a second embodiment of the present invention.

A load control circuit 35 is provided in the load control device 31 according to the present embodiment, and the load control circuit 35 is connected to a power supply line 37 drawn from outside the load control device 31.
a, ground line 37b and multiplex communication line 38.

Further, the load control circuit 35 is connected to a switch 36a for returning / retracting the remote control door mirror, a switch 36b for locking / unlocking the door, and a switch 36c for opening / closing the sunroof. The switches 36a, 36b and 36c are grounded. The load control device 31 is provided with two relays 32a and 32d as switching devices for current direction switching and two relays 32b and 32c as switching devices for load selection. The negative terminals of 33a to 33d are load control circuits 3
5 is connected. On the other hand, the positive terminals of the coils 33a to 33d are connected to the power supply line 37a.

The load control circuit 35 includes, for example,
The operation of locking / unlocking the door is the return of the remote control door mirror /
Priority is given to storage operation, and remote control door mirror return /
A circuit for controlling the grounding of the coils 33a to 33d is incorporated so that the storing operation is performed prior to the opening / closing operation of the sunroof.

The relays 32a to 32d are provided with switches 34a to 34d which are switched by turning on / off the excitation of the coils 33a to 33d. The switch 34a is connected between the power line 37a and the ground line 37b and the switch 34b, and the selection of the connection of the switch 34b to the power line 37a or the ground line 37b is controlled by the switch 34a. The switch 34b is connected between the switch 34a, a door locking / unlocking operation motor 39b provided outside the load control device 31, and the switch 34c.
The selection of connection to the motor 39b or the switch 34c is controlled. The switch 34c is connected to the switch 34b.
And a motor 39a for returning / retracting the remote control door mirror and a motor 39c for opening / closing the sunroof provided outside the load control device 31, and the motor 39a or the motor of the switch 34b is operated by the switch 34c. The connection to 39c is selected. Switch 3
4d is connected between the motors 39a to 39c and the power supply line 37a and the ground line 37b, and the selection of connection of the motors 39a to 39c to the power supply line 37a or the ground line 37b is controlled by the switch 34d.

When the coil 33a is not excited, the contact of the switch 34a is connected to the ground line 37b. When the coil 33b is not excited, the contact of the switch 34b is connected to the locking / unlocking operation motor 39b. Furthermore, the coil 33c
Is not excited, the contact of the switch 34c is connected to the open / close operation motor 39c. When the coil 33d is not excited, the contact of the switch 34d is connected to the ground line 37b.

Further, as shown in FIG. 2, the motor 39a and the motor 39c are connected in parallel between the switch 34c and the switch 34d.
b is connected in parallel between the switch 34b and the switch 34d. Also, the motor 39a is connected in such a direction that the remote control door mirror is restored when a current flows from the relay 32c side, and the remote control door mirror is stored when a current flows from the relay 32d side. The motor 39b is connected in such a direction that the door is locked when a current flows from the relay 32b, and the door is unlocked when a current flows from the relay 32d. The motor 39c is connected in such a direction that the sunroof is closed when a current flows from the relay 32c side and the sunroof is opened when a current flows from the relay 32d side.

In the first embodiment, the relays 2a to 2c, the load control circuit 5, and the switches 6a and 6b are provided in the same unit. However, in the second embodiment, the load control circuit Only 35 are located in the unit. That is, the switches and relays connected to the load control circuit need not be provided in the same unit as the load control circuit.

In the load control device according to the second embodiment having the above-described configuration, when operation of two or more types of motors is commanded, a circuit incorporated in the load control circuit 35 determines the priority based on the priority. Until the operation of one motor is completed, the operation of the other motor is suspended, but there is no practical problem since the suspension time is short. And the first
Since the number of relays required for each additional load is only one, the effect of reducing the number of relays is extremely high as compared with the prior art. However, as the number of loads increases, the number of priority levels also increases.

Next, a third embodiment of the present invention will be described. This embodiment has a configuration in which two first embodiments are combined. FIG. 3 is a schematic diagram showing a load control device according to a third embodiment of the present invention.

A load control circuit 45 is provided in the load control device 41 according to the present embodiment, and the load control circuit 45 includes a power supply line 47 drawn from outside the load control device 41.
a, ground line 47b and multiplex communication line 48.

Further, the load control circuit 45 includes a switch 46a for returning / retracting the remote control door mirror, a switch 46b for locking / unlocking the door, and a raising / lowering operation of a power window provided on the right side of the rear seat. Switch 46c
And the power window provided on the left side of the rear seat
The switch 46d for the down operation is connected. The switches 46a, 46b, 46c and 46d are grounded. The load control device 41 has four relays 42a, 42 as current-direction switching switching devices.
c, 42d and 42f and two relays 42b and 42e as switching devices for load selection are arranged. The negative terminals of the coils 43a to 43f of each relay are connected to the load control circuit 45. on the other hand,
The positive terminals of the coils 43a to 43f are the power supply line 47a.
It is connected to the.

The load control circuit 45 includes, for example,
The operation of locking / unlocking the door has priority over the operation of raising / lowering the power window provided on the left side of the rear seat, and the operation of returning / retracting the remote control door mirror is raising / lowering the power window provided on the right side of the rear seat. A circuit for controlling the grounding of the coils 43a to 43f is incorporated so that the operation is performed in preference to the descending operation.

The relays 42a to 42f are provided with switches 44a to 44f which are switched by turning on / off the excitation of the coils 43a to 43f. The switch 44a is connected between the power line 47a and the ground line 47b and the switch 44b, and the selection of the connection of the switch 44b to the power line 47a or the ground line 47b is controlled by the switch 44a. The switch 44b includes a motor 49a for returning / retracting the remote control door mirror provided outside the switch 44a and the load control device 41, and a motor 49c for raising / lowering the power window on the right side of the rear seat.
The selection of the connection of the switch 44a to the motor 49a or the motor 49c is controlled by the switch 44b. The switch 44c is connected to the motor 49.
a and 49c are connected between the power supply line 47a and the ground line 47b, and the switch 44c controls selection of connection of the motors 49a and 49c to the power supply line 47a or the ground line 47b.

On the other hand, the switch 44d is connected between the power supply line 47a and the ground line 47b and the switch 44e.
a or the connection to the ground line 47b is controlled. The switch 44e is connected between the switch 44d and a motor 49b for locking / unlocking the door provided outside the load control device 41 and a motor 49d for raising / lowering the power window on the left side of the rear seat. The switch 44e controls the selection of the connection of the switch 44d to the motor 49b or the motor 49d. The switch 44f is connected to the motors 49b and 49d, the power line 47a and the ground line 47b.
The selection of connection of the motors 49b and 49d to the power supply line 47a or the ground line 47b is controlled by the switch 44f.

When the coil 43a is not excited, the contact of the switch 44a is connected to the ground line 47b. When the coil 43b is not excited, the contact of the switch 44b is connected to the motor 4
9c side. Further, when the coil 43c is not excited, the contact of the switch 44c is
7b.

On the other hand, when the coil 43d is not excited, the contact of the switch 44d is connected to the ground line 47b. When the coil 43e is not excited, the contact of the switch 44e is connected to the motor 4 for raising / lowering operation.
It is connected to the 9d side. Further, when the coil 43f is not excited, the contact of the switch 44f is connected to the ground wire 4f.
7b.

Further, as shown in FIG. 3, the motor 49a and the motor 49c are connected in parallel between the switch 44b and the switch 44c.
9d is connected in parallel between the switch 44e and the switch 44f. Further, the motor 49a is connected in such a direction that the remote control door mirror is restored when a current flows from the relay 42b side, and the remote control door mirror is stored when a current flows from the relay 42c side. Further, the motor 49c is connected in such a direction that the power window rises when a current flows from the relay 42b side and falls when the current flows from the relay 42c side. Furthermore, the relay 42
The motor 49b is connected in such a direction that the door is unlocked when a current flows from the e side and the door is locked when a current flows from the relay 42f side. The motor 49d is connected in such a manner that the power window rises when a current flows from the relay 42e, and falls when the current flows from the relay 42f.

In the third embodiment, only the load control circuit 45 is provided in the unit, and the switches 46a to 46d and the relays 42a to 42f are provided outside the unit.

In the load control device according to the third embodiment having the above-described configuration, when operation of two or more types of motors is commanded, depending on the combination, the circuit incorporated in the load control circuit 45 may be used. Until the operation of one motor is completed based on the priority order, the operation of the other motor is suspended, but there is no practical problem because the suspension time is short. Also, the configuration as in the present embodiment is applicable when an even number of loads are provided, and only three relays are required for every two additional loads from the first embodiment. The effect of reducing the number of relays is higher than that of the conventional one. Even when the number of loads increases, the priority order is always two stages.

[0060]

As described in detail above, according to the present invention,
The load to be driven is selected by the drive current flowing through the load selection switching device, and the direction of the drive current supplied to the load is switched by the current direction switching switching device. There is no need to provide a switching device, and the device itself can be downsized. Also, the number of electronic components used for control of the switching devices can be reduced by reducing the number of switching devices, so that the cost can be reduced and the weight can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a load control device according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating a load control device according to a second embodiment of the present invention.

FIG. 3 is a schematic diagram showing a load control device according to a third embodiment of the present invention.

FIG. 4 is a schematic diagram showing a conventional load control device.

[Explanation of symbols]

1, 21, 31, 41; load control devices 2a, 2b, 2c, 22a, 22b, 22c, 22d,
32a, 32b, 32c, 32d, 42a, 42b, 4
2c, 42d, 42e, 42f; relays 3a, 3b, 3c, 23a, 23b, 23c, 23d,
33a, 33b, 33c, 33d, 43a, 43b, 4
3c, 43d, 43e, 43f; coils 4a, 4b, 4c, 6a, 6b, 24a, 24b, 24
c, 24d, 26a, 26b, 34a, 34b, 34
c, 34d, 36a, 36b, 36c, 44a, 44
b, 44c, 44d, 44e, 44f, 46a, 46
b, 46c, 46d; switches 7a, 27a, 37a, 47a; power supply lines 7b, 27b, 37b, 47b; ground lines 8, 28, 38, 48; multiplex communication lines 9a, 9b, 29a, 29b, 39a, 39b, 39
c, 49a, 49b, 49c, 49d; motor

Claims (2)

[Claims] 1. A load control device for controlling a drive current flowing through a plurality of loads that switch between a normal rotation and a reverse rotation according to a direction in which the drive current flows. A load control device comprising: a switching device for selecting a load to be selected; and a switching device for switching a current direction that switches a direction of a drive current supplied to a load selected by the switching device for selecting a load. 2. A load control circuit connected to the load selection switching device and the current direction switching switching device, and command input means connected to the load control circuit and inputting a load operation command. 2. The load control circuit according to claim 1, wherein said load control circuit includes priority order determining means for determining an order of loads to be operated when operation instructions of two or more loads are simultaneously input from said instruction input means. The load control device as described in the above.