JPH0228719B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a blower control device that adjusts the rotational speed of a blower in, for example, a heating and cooling system using a current limiting resistor of a motor that drives the blower. The present invention relates to an alarm device that warns when the situation occurs.

Conventionally, in this type of control device, it is known to use a semiconductor element such as barium titanate, which has a positive resistance-temperature characteristic in which the resistance value increases rapidly at a predetermined temperature, as a current-limiting resistor. −
22764).

In this conventional device, the semiconductor element is installed in the air blowing system path, and when the motor locks up, for example, no air is sent to the semiconductor element, so heat is no longer radiated, and although the semiconductor element is heated, once it reaches a predetermined temperature. The resistance value of a semiconductor element increases rapidly to prevent the semiconductor element from overheating.

However, although the resistance value of the semiconductor element rapidly increases and overheating of the semiconductor element is prevented, a current corresponding to the natural heat dissipation of the semiconductor element flows through the semiconductor element and also energizes the motor.

Therefore, the internal parts of the motor are likely to be damaged, resulting in a shortened service life and wasteful power consumption.

Further, there is a problem in that the current limiting resistor is not cooled well due to the influence of wind flow or the difference in the resistance value of the current limiting resistor, resulting in variations in the rotational speed of the motor.

In view of the above-mentioned points, the present invention provides an alarm device that satisfactorily adjusts the rotational speed of an electric motor and accurately and reliably warns of abnormalities such as locking of the electric motor by combining an alarm and a simple circuit. The purpose is to

The present invention will be explained below with reference to embodiments shown in the drawings. Figure 1 shows the case where the present invention is applied to an automotive air conditioning/heating blower circuit, where 1 is an axially mounted battery, 2 is a
is the ignition switch, 3 is the relay,
3a is a normally open contact. The excitation coil 3b is energized when the plate-shaped relay terminal 3c is grounded. 4
5 is a current limiting resistor section, and 6 is a semiconductor element made of barium titanate or the like and having a positive resistance temperature characteristic in which the resistance value rapidly increases at a predetermined temperature.

5' is a changeover switch part, 8 is a high speed contact,
9 is a medium speed contact, 10 is a low speed contact, 11 is an open contact, 12 is a plate-shaped ground contact, and 12' is a movable conductor piece for electrically switching each contact.
A diode 13 is used to protect the light emitting diode 14. In addition, diode 13
The light emitting diode 14 and the light emitting diode 14 may be placed on either the left or the right as long as they are connected in series. 15 and 16 are voltage dividing resistors for determining the potential of point A, which is the connection point between the two. The series circuit of the two voltage dividing resistors is connected in parallel to the series circuit of the semiconductor element 6 and the motor 4. The light emitting diode 14 is a semiconductor element 6
It is connected between point A, which is the connection point between the motor 4 and the electric motor 4, and the point B, and the cathode side is connected to A point and the anode side is connected to B point. Note that the diode 13 is also connected to point A on its cathode side and to point B on its anode side. The potential at point A is higher than the potential at point B when the electric motor 4 is operating normally and rotating the blower fan. On the other hand, when the motor 4 is locked, for example, and the fan stops rotating, the potential at point B becomes higher than the potential at point A, and the light emitting diode 14 lights up.

Next, the specific structure of the resistor section 5 will be explained with reference to FIGS. 3 to 5. The semiconductor element 6 has a honeycomb-like structure in which a large number of square-shaped through holes 18 are spaced apart from each other. A thin film electrode 19 having ohmic contact is provided on the entire surface of one end face (lattice-shaped portion) of the two end faces where the through hole 18 of the semiconductor element 6 is open. Further, on the other end surface of the semiconductor element 6, there are two thin film electrodes 20 in ohmic contact with different areas so as not to short-circuit each other at the finely shaded part as the border, as shown in FIG.
21 is provided. These electrodes 19, 20, 21
are provided by a method such as silver paste baking, and the electrodes 20 and 21 are provided by masking the semiconductor element 6 with a zigzag mask plate. 2
2 is a groove provided on the side surface of the semiconductor element 6. 2
3, 24, 25 are plate-shaped electrode plates made of conductive material such as brass, and one end of the electrode plates 23, 24 has claws 23a, 24a that fit into the grooves 22 of the semiconductor element 6.
and U-shaped support portions 23b, 24b, and mounting pieces 23c, 24c and a terminal 2 at the other end.
3d and 24d are provided. Moreover, the electrode plate 23,
24 are provided with contacts 23e and 24e that come into elastic contact with the electrodes 20 and 21 of the semiconductor element 6, respectively.
is provided.

On the other hand, the electrode plate 25 includes the electrode 1 of the semiconductor element 6.
9, a contactor 25a, a mounting piece 25b,
and a terminal 25c. 26 is a board made of heat-resistant resin, and this board 26 is integrally provided with a frame 26a for positioning the semiconductor element 6, and each mounting piece 23c, 24c, 25c of the electrode plates 23, 24, 25 is inserted therethrough. A hole 26b is integrally provided.

The electrode plates 23, 24, 25 are the holes 2 of the substrate 26.
Each mounting piece 23c, 24c, 25b inserted into 6b
The board 26 is folded toward the bottom of the board 26.
is fixed. In this fixed state, the semiconductor element 6 is positioned within the frame 26a of the substrate 26, the claws 23a, 24a of the electrode plates 23, 24 are fitted into the grooves 22 of the semiconductor element 6, and the contacts 23e, 2
4e are brought into contact with the electrodes 20 and 21 of the semiconductor element 6, respectively. Further, the contactor 25a of the electrode plate 25 is brought into contact with the electrode 19 of the semiconductor element 6. With this structure, the electrode 19 of the semiconductor element 6 is connected to the terminal 25c of the electrode plate 25, and the electrode 20 is connected to the terminal 25c of the electrode plate 23.
d, the electrodes 21 are electrically connected to the terminals 24d of the electrode plate 24, respectively.

The terminals 23d, 24d, and 25c are electrically connected to the low speed contact 10, the high speed contact 8, and the intermediate feed contact 9 shown in FIG. 1, respectively.

FIG. 6 shows an example of a specific installation location of the current limiting resistor section 5, in which 27 is a resin case of an automobile air conditioning system, and a blower 4a driven by an electric motor 4 is used for air conditioning and heating as shown by the arrow. Forms a ventilation path through which air is blown. Current limiting resistor section 5
is a blower 4 installed at an appropriate position inside the case 27.
It is configured to be forcedly cooled by the blown air of (a). 28 is a damper for switching between inside and outside air for intake air, 29 is an evaporator for cooling, 30 is a superheater for heating, 31 is a cold/hot air mixing damper for temperature adjustment, and 32 is an outlet for blowing into the vehicle interior. 33 is an outside air port, and 34 is an inside air port.

In the above configuration, the following operation will be explained. 1st
When the movable piece 12' of the blower rotation control switch 5' shown in the figure is connected to the low speed contact 10, the excitation coil 3b of the relay 3 is energized and the contact 3a is closed. The current then flows through the terminal 23d and the contact 23e of the electrode plate 23 to the electrode 20 of the semiconductor element 6, passes through this semiconductor element 6 to the electrode 19, and further passes through the semiconductor element 6 from the electrode 21 to the contact of the electrode plate 24. Child 24e
and flows to the electric motor 4 via the element 24d. Therefore, the rotational speed of the motor 4 becomes low due to the voltage drop across the semiconductor element 6.

Further, when the movable piece 12' is connected to the medium speed contact 9, the excitation coil 3b of the relay 3 is energized and the contact 3a is closed. The current then flows through the electrode plate 25 to the electrode 19 of the semiconductor element 6, through the semiconductor element 6 to the electrode 21, and through the electrode plate 24 to the motor 4. In this case, the substantial resistance value of the semiconductor element 6 is lower than in the above case, so the rotational speed of the electric motor 4 is medium.

Furthermore, when the movable piece 12' is connected to the high speed contact 8,
The current flows directly to the motor 4, and the speed of the motor 4 becomes high. Note that the movable piece 12' is connected to the open contact 11.
When connected to , the excitation coil 3b of the relay 3 is not energized, the contact 3a is opened, and the rotation of the motor 4 is stopped. In this way, using one semiconductor element 6,
By dividing the electrodes 20 and 21 on one end surface and connecting them selectively, the motor rotation speed can be freely changed.

By the way, the current flowing through the motor 4 flows through the semiconductor element 6 which has a positive resistance-temperature characteristic.
During normal operation, wind generated by the rotation of the blower 4a flows through the numerous through holes 1a of the semiconductor element 6, so that the semiconductor element 6 is cooled well and its temperature is maintained at a low temperature below the Curie point Tc in FIG. . Therefore, the resistance value of the semiconductor element 6 is sufficiently small. However, if there is some kind of malfunction, e.g.
Even if a current flows through the semiconductor element 6 due to a short circuit, a lock, a loosening of the rotating shaft of the blower, etc., if wind is not blown to this element 6, the semiconductor element 6 loses heat dissipation due to the wind, and the temperature of the semiconductor element 6 decreases. Since the temperature becomes higher than Tc in Figure 2, the resistance value increases rapidly and the potential at point B rises, becoming higher than the potential at point A. As a result, a current flows through the light emitting diode 14, the light emitting diode 14 lights up, and a warning can be given to the driver.

Note that since the resistance rapidly increases, the current flowing through the semiconductor element 6 becomes extremely small, and the increase in the amount of heat generated by the semiconductor element 6 stops.

Therefore, the temperature of the semiconductor element 6 rises only to a temperature slightly higher than the Tc shown in FIG.
If an element whose temperature is approximately 120° C. is used as the semiconductor element 6, the temperature of the semiconductor element 6 will not reach the point where the resin material of the case 27 ignites.

In addition, in the above embodiment, since the part dividing the two electrodes 20 and 21 of the semiconductor element 6 has a zigzag shape, there is a gap between the power supply 9 and the electrode 21 as in the connection of the medium speed contact 9 described above. Even when only the semiconductor element 6 is energized, the heat during energization is transferred to the electrode 20 portion of the semiconductor element 6, improving heat dissipation, so that the resistance value of the semiconductor element 6 when energized can be kept approximately constant, and the rotation of the motor 4 There is no change in speed.

Note that the present invention is not limited to the above embodiments, and similar effects can be obtained by the following method.

(1) The through hole 18 of the semiconductor element 6 may be triangular, hexagonal, or round.

(2) The present invention is not limited to automotive air conditioning systems;
It can also be applied to home air conditioning equipment.

As described in detail above, the present invention uses a semiconductor element as a current limiting resistor, which has a positive resistance temperature characteristic in which the resistance value rapidly increases at a predetermined temperature, and is formed in a honeycomb shape with a plurality of through holes. This semiconductor element has a plurality of thin film electrodes formed in a zigzag pattern with different areas as part of the end face of the semiconductor element, so that the rotational speed of the motor can be adjusted well. It prevents the current limiting resistor from overheating when the motor is locked, and the current flowing to the light emitting diode is controlled by varying the potential difference between both ends of the light emitting diode, so abnormalities can be detected without the need for any special sensors or circuits. This can be done easily, inexpensively, and reliably.

Furthermore, by protecting the light emitting diode with the protective diode, abnormalities in the electric motor can be reliably detected, so that the driving vehicle can be accurately notified of the abnormality in the electric motor.

[Brief explanation of drawings]

Fig. 1 is an electrical wiring diagram showing one embodiment of the device of the present invention, Fig. 2 is a characteristic diagram of a semiconductor element used in the device of the present invention, and Fig. 3 is a semiconductor element in the current limiting resistor section shown in Fig. 1. FIG. 4 is a perspective view of the current limiting resistor shown in FIG. 1, FIG. 5 is an exploded perspective view of FIG. 3, and FIG. 6 is an automobile illustrating the installation location of the current limiting resistor. FIG. 4...Electric motor, 4a...Blower, 6...Semiconductor element, 14...Light emitting diode, 15, 16...
Voltage dividing resistor, 27... case.

Claims (1)

[Claims] 1. A current limiting resistor is arranged in series in the current-carrying circuit of a motor that drives an air blower, and
In the blower control device that is arranged in a place where the air is blown by the blower and adjusts the rotation speed of the electric motor, the resistor is used as the resistor and has a positive resistance temperature characteristic in which the resistance value increases rapidly at a predetermined temperature. , a semiconductor element formed in a honeycomb shape with a plurality of through holes;
A plurality of thin film electrodes are formed as part of this semiconductor element, have different areas, and are intricately formed in a zigzag pattern. a changeover switch that short-circuits the semiconductor element at the time of speed and adjusts the voltage applied to the motor to adjust the rotation speed of the motor; and a switch that is connected in parallel to the series circuit of the semiconductor element and the motor. Two voltage dividing resistors are connected, and a cathode side is connected to a connection point between these two voltage dividing resistors, and an anode side is connected to a connection point between the semiconductor element and the motor, and an excessive current is applied to the current-carrying circuit of the motor. a light emitting diode that is energized by the potential difference between the two connection points when the current flows and emits light to issue an alarm, and is connected in series with the light emitting diode;
A cathode side is connected to a connection point between the two voltage dividing resistors, an anode side is connected to a connection point between the semiconductor element and the motor, and the semiconductor element has a withstand voltage higher than that of the light emitting diode. An alarm device for a blower control device, comprising: a protection diode that protects the light emitting diode when the motor is short-circuited and the rotational speed of the motor reaches a maximum.