JP2008114805A - Air conditioning control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioning control device for a vehicle preventing effects by electromagnetic wave noise generated by radio communication equipment etc. and having advanced measures against the electromagnetic wave noise. <P>SOLUTION: One end of a first electric circuit RT1 of a drive circuit part 22 is connected to a first input terminal a of a motor drive control part 25, and one end of a second electric circuit RT2 is connected to a second input terminal b of the motor drive control part 25 via a drive switching element Tr1. A logic circuit part 21 is directly connected to an electric circuit connection point 24 to which the other ends of the first electric circuit RT1 and second electric circuit RT2 are connected. By switch operation of an internal/external air changeover switch 5 or a defroster changeover switch 28, the voltage of the electric circuit connection point 24 is fluctuated and a motor 26 is switched and driven. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle air conditioning control device, and more particularly to a control circuit that controls the vehicle air conditioning control device and a countermeasure against electromagnetic wave noise on a printed circuit board.

  Conventionally, a vehicle air-conditioning control device is provided with functions for cooling, heating, dehumidification, and ventilation, and allows the user to adjust the air volume, wind direction, temperature, etc., for each mode of the wind direction. There is one that automatically switches between internal and external ventilation so that the passenger compartment is comfortable. It is not uncommon for recent vehicle air-conditioning control devices to perform electronic control as well as mechanical control. In such devices, a printed circuit board having a control circuit formed therein is accommodated.

Japanese Utility Model Publication No. 5-23152 Japanese Patent No. 3581971

  By the way, in recent years, there are increasing opportunities for mobile phones and wireless devices to be brought into the vehicle interior, but electromagnetic noise generated by such wireless communication devices propagates in the air and harnesses to control air conditioning for vehicles. There is a case where the vehicle air-conditioning control device enters into the device and malfunctions. In order to prevent malfunctions due to external electromagnetic noise as described above, countermeasures against electromagnetic noise have been conventionally taken.

  For example, there is known a device that performs a countermeasure against electromagnetic wave noise of an electronic device using a capacitor. In this prior art, when an electromagnetic wave is generated from a wireless communication device or the like in the vicinity of the electronic device, the electromagnetic wave is applied to the electronic device as high frequency noise via the connection harness in the air or inside the electronic device. However, by connecting the noise absorbing capacitor to a position as close as possible to the terminals of the electronic component in the electronic device, electromagnetic wave noise is prevented from entering between the terminals of the electronic component.

  In another prior art, if electromagnetic noise enters from a wireless communication device or the like, the electromagnetic noise that has entered is grounded through an EMI capacitor and then released to the vehicle body.

  However, just disposing a noise absorbing capacitor in the vicinity of a terminal of an electronic component as in the prior art cannot be said to be a sufficient countermeasure against malfunction, and may still malfunction. In particular, in recent years when electronic communication devices and the like brought into the passenger compartment are increasing, measures for preventing malfunction of the air conditioning control device for vehicles are an important issue. In addition, it is eagerly desired to achieve with a configuration as simple as possible.

  Therefore, an object of the present invention is to provide a vehicle air-conditioning control device that is not easily affected by electromagnetic noise generated by a wireless communication device or the like and that has a high countermeasure against electromagnetic noise.

  In order to achieve the above object, in the present invention, an inside / outside air changeover switch for switching between an outside air introduction mode for introducing outside air and an inside air circulation mode for circulating the inside air, and a defroster changeover switch for switching to a defroster mode for performing anti-fogging control, A motor drive control unit having at least a first input terminal, a second input terminal, and an output terminal, the output terminal being connected to a motor for switching between an outside air introduction mode and an inside air circulation mode, an inside / outside air changeover switch, and a defroster The drive circuit unit includes a logic circuit unit having a changeover switch connected in parallel, a first electric circuit, and a second electric circuit having a drive switching element. The first electric circuit of the drive circuit unit has one end One end of the second electric path is connected to the first input terminal of the motor drive control unit, and one end of the motor drive control unit is connected to the motor drive control unit via the drive switching element. The logic circuit unit is directly connected to an electric circuit connection point to which the other end of the first electric circuit and the second electric circuit of the drive circuit unit are connected, and connected to the two input terminals, the inside / outside air changeover switch, The motor is switched and driven by changing the voltage of the electric circuit connection point by operating any one of the defroster changeover switches.

  In addition, the logic circuit unit receives an abnormal state output signal from the vehicle-side control unit when the compressor of the vehicle is in an abnormal state, and an outside air introduction mode and an inside air circulation mode according to the voltage of the abnormal state output signal. A logic switching element for switching between the inside and outside air switch and the defroster switch, which are connected in parallel to any one of the inside / outside air switch, defroster switch, and logic switching element. The motor is switched and driven by changing the voltage of the electric circuit connection point by the switch operation.

  In addition, the vehicle control device accommodates a printed circuit board inside the operation panel. On both sides of the printed circuit board, a circuit conductor pattern that connects between electronic components mounted on the printed circuit board and a power source for the vehicle-mounted battery Forming a power supply conductor pattern to be connected to the ground side and a grounding conductor pattern to be connected to the ground side of the in-vehicle battery, and one surface of the printed circuit board supplies power to the remaining portion excluding the circuit conductor pattern and the ground conductor pattern Conductor pattern is formed, and on the other side of the printed circuit board, a ground conductor pattern is formed in the remaining portion excluding the circuit conductor pattern and the power supply conductor pattern, and at least the switching element of the electronic component is It is characterized in that it is mounted on the surface of the printed circuit board which is far from the operation panel.

  Further, the grounding conductor pattern is formed around the circuit conductor pattern connecting the inside / outside air changeover switch and the defroster changeover switch on one surface of the printed circuit board, and the circuit is formed on the other surface of the printed circuit board. A grounding conductor pattern is formed at a position facing the conductor pattern.

  The switching element is a transistor element, and includes at least a capacitor element and a resistance element as electronic components mounted on a printed circuit board, a base-side circuit conductor pattern to which the base of the transistor element is connected, and an emitter of the transistor element A parallel circuit composed of a capacitor element and a resistor element is connected between the emitter-side circuit conductor pattern to which the transistor is connected, and the transistor element and the capacitor element are arranged with a minimum distance so as not to be bridge-connected. A feature is that the width of the pattern is formed wider than the width of the emitter-side circuit conductor pattern and the collector-side circuit conductor pattern.

  As described above, the logic circuit unit is directly connected to the electric circuit connection point of the drive circuit unit, and the motor is switched and driven by changing the voltage at the electric circuit connection point, which causes malfunction due to the influence of electromagnetic noise. It is possible to simplify the control circuit of the vehicle air-conditioning control device that automatically switches between the outside air introduction mode and the inside air circulation mode according to the operation state of the inside / outside air changeover switch and the defroster changeover switch, without providing switching elements more than necessary. it can. Therefore, since a switching element is required as much as possible, a circuit configuration that is hardly affected by electromagnetic noise can be obtained.

  In addition to the inside / outside air changeover switch and the defroster changeover switch, the vehicle air conditioning control for automatically switching between the outside air introduction mode and the inside air circulation mode according to the compressor state signal input from the vehicle side control unit is provided in the logic circuit unit. The control circuit of the device can be achieved by adding only one switching element. Therefore, complicated automatic switching control can be achieved with a simple circuit configuration that is not easily affected by electromagnetic noise.

  On the other hand, among the printed circuit boards on which the control circuit is formed, the power supply conductor pattern occupies most of one surface and the ground conductor pattern occupies most of the other surface. Thus, the conductive pattern on the front surface and the conductive pattern on the back surface have a relationship of + and − like a capacitor, and a shield effect that absorbs external electromagnetic noise can be obtained by generating an electric field. And, by mounting the switching element on the back side of the printed circuit board (surface far from the operation panel), electromagnetic wave noise from the wireless communication device in the passenger compartment is absorbed, and electromagnetic wave noise reaching the switching element is reduced. Therefore, malfunction of the switching element can be prevented.

  Also, a grounding conductor pattern is formed around the circuit conductor pattern that connects between the inside / outside air changeover switch and the defroster changeover switch, and the grounding conductor pattern is also formed at the position of the back surface that faces this circuit conductor pattern. Has been. Thereby, the effect of absorbing extraneous electromagnetic noise between the circuit conductor pattern and the grounding conductor pattern can be obtained. Therefore, it is possible to prevent the switching element from malfunctioning due to propagation of external electromagnetic noise by a circuit conductor pattern having a long distance due to restrictions on vehicle specifications.

  Furthermore, a transistor is used as a switching element, and a capacitor is disposed in the immediate vicinity of the transistor, and at the same time, the width of the circuit conductor pattern on the base side (input side) of the transistor is wider than the width of the circuit conductor pattern on the emitter side and the collector side. Since the impedance of the current input to the transistor is reduced and unnecessary radiation can be reduced, the effect of preventing the transistor from malfunctioning due to electromagnetic wave noise can be further enhanced.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a control circuit of a vehicle air conditioning control device of the present invention will be described with reference to the drawings. FIG. 1 is a plan view of an operation panel of an automotive air conditioner employing the control circuit of the present invention, and FIG. 2 shows a control circuit of the vehicle air conditioning control apparatus according to the first embodiment of the present invention.

  The vehicle air-conditioning control device has functions of cooling, heating, dehumidification, and ventilation. As shown in FIG. 1, a temperature adjustment rotary switch 2 for adjusting a set temperature provided on the operation panel 1 and an air volume are switched. An air volume switching rotary switch 3, an air direction switching rotary switch 4 for switching an air outlet, an inside / outside air switching switch 5 for switching between inside and outside ventilation, an air conditioner switch 6 for driving a compressor, and a rear differential switch for operating a heat wire installed in a rear window 7 is operated to output an electric signal in accordance with the switch operation, and to drive a motor 26 (to be described later) that switches between internal and external ventilation according to this output, a compressor (not shown) that performs dehumidification, and the like. .

  When the wind direction switching rotary switch 4 of the operation panel 1 is operated and set to the vent position 8, the air passage is switched so as to blow near the passenger's face. "Bi-level mode" in which the air passage is switched so as to blow air from both the air blower outlet that blows air near the face and the air blower outlet that blows to the feet of the passenger. In addition, when matched with the heat position 10, a “heat mode” in which the air passage is switched so as to blow air to the feet of the occupant. Furthermore, when matched with the heat differential position 11, a “heat differential mode” is established in which the air passage is switched so that air is blown from both the air blower outlet that blows air to the feet of the occupant and the air blower outlet that blows air to the inner surface of the windshield. Further, when the position is adjusted to the differential position 12, the “differential mode” is selected in which the air passage is switched so as to blow air from the air blower outlet that blows air to the inner surface of the windshield.

  Each mode of the air outlet is configured to automatically switch between the inside and outside air so that the effect is optimal according to the purpose of each mode. In the differential mode, the mode is automatically switched to the outside air introduction mode. The operation of the inside / outside air changeover switch 5 is disabled and is fixed in the outside air introduction mode.

  Next, the control circuit 20 of the vehicle air conditioning control device will be described with reference to FIG. The control circuit 20 of the vehicle control device of the present invention is broadly divided into a logic circuit unit 21, a drive circuit unit 22 connected to the logic circuit unit 21, and an illumination circuit unit 23. The logic circuit unit 21 The drive circuit unit 22 and the illumination circuit unit 23 are connected to each other through an electric circuit connection point 24. The drive circuit unit 22 is connected to an IC 25 that is a motor drive control unit, and the IC 25 drives the motor 26 to switch between the outside air introduction mode and the inside air circulation mode.

  The battery terminals VB1 to VB4 of the control circuit 20 are connected to a 12V in-vehicle battery via a switch linked to an ignition key (not shown). If the ignition key is not on, power is supplied to the battery terminals VB1 to VB4. Is not supplied.

  One end of the logic circuit unit 21 is connected to the battery terminal VB 1, resistors R 1 and R 2 are connected in series, and the other end is connected to the electric circuit connection point 24. One end of a defroster switch 27 for detecting the differential position 12 of the wind direction switching rotary switch 4 is connected between the resistors R1 and R2, and the other end is grounded to the ground GND1. Further, a noise absorbing capacitor C1 is connected in parallel in the vicinity of the defroster switch 27.

  Further, between the resistors R1 and R2, one end of a push lock switch 28 for detecting a pressing operation of the inside / outside air switching switch 5 for switching between inside and outside ventilation is connected, and the other end is grounded to the ground GND2. . Here, the push lock switch 28 is grounded to the ground GND2 when switched to the terminal 28a (switch OFF), and is not connected to the ground GND2 when switched to the terminal 28b (switch ON). Further, a noise absorbing capacitor C2 is connected in parallel in the vicinity of the push lock switch 28. Furthermore, one end of the resistor R3 is connected between the resistor R2 and the electric circuit connection point 24, and the other end of the resistor R3 is grounded to the ground GND3.

  The drive circuit unit 22 is composed of two electric circuits. One end of the first electric circuit RT1 is connected to the electric circuit connection point 24, and the other end is connected to the first input terminal a of the IC 25, which is a motor drive control unit, via a resistor R4. On the other hand, one end of the second electric circuit RT2 is connected to the electric circuit connection point 24, the resistor R5 and the base of the NPN transistor Tr1 are connected in series, and the other end is connected to the second input terminal b of the IC 25. Yes. As will be described later, the transistor Tr1 plays a role of inverting the signal from the logic circuit section 21, and a resistor R6 and a noise absorbing capacitor C3 are connected between the base and emitter of the transistor Tr1, and the emitter is grounded. Grounded to GND4. The collector of the transistor Tr1 is connected to the battery terminal VB2 via the resistor R7.

  One end of a noise absorbing capacitor C4 and a constant voltage Zener diode ZD1 is connected between the resistor R4 of the first electric circuit RT1 and the first input terminal a of the IC 25, and the other ends are connected to the ground GND5. , GND6. Similarly, one end of a noise absorbing capacitor C5 and a constant voltage zener diode ZD2 is connected between the collector of the transistor Tr1 in the second electric circuit RT2 and the second input terminal b of the IC 25, and the other end. Are grounded to grounds GND7 and GND8, respectively.

  The lighting circuit unit 23 has one end connected to the electric circuit connection point 24, a resistor R8, a base of an NPN transistor Tr2, an LED as an illumination lamp for indicating that it is in the internal air circulation mode (REC), and a resistor R9 in series. The other end is connected to the battery terminal VB3. The transistor Tr2 plays a role of switching ON / OFF of the LED as will be described later. A resistor R10 and a noise absorbing capacitor C6 are connected between the base and emitter of the transistor Tr2, and the emitter is connected to the ground GND9. Grounded. In addition, a noise absorbing capacitor C7 is connected in parallel near the LED.

  In addition to the first input terminal a and the second input terminal b, the IC 25 which is a motor drive control unit has output terminals c and d, power terminals e and f, a signal ground terminal g, and a power ground terminal h. Yes. The output terminals c and d are connected to the motor 26, and the motor 26 is rotated forward or reverse by an output signal from the IC 25 to switch between the outside air introduction mode and the inside air circulation mode. The power terminals e and f are connected to the battery terminal VB4, a noise absorbing capacitor C8 and an electrolytic capacitor C9 for smoothing the voltage applied to the IC 26 are connected in parallel, and the other ends are grounded GND10 and GND11, respectively. Is grounded. The signal ground terminal g and the power supply ground terminal h are grounded to the grounds GND12 and GND13, respectively.

  Next, the operation of the control circuit 20 of the vehicle air conditioning control device according to the first embodiment will be described. The defroster switch 27 of the logic circuit section 21 is turned off (the wind direction switch rotary switch 4 is operated at the vent position 8, the bi-level position 9, the heat position 10 or the heat differential position 11), and the push lock switch 28 is turned on, that is, the terminal When switched to 28b (inside / outside air changeover switch 5 is in the inside air circulation mode (REC)), the voltage at the battery terminal VB1 passing through the resistors R1 and R2 is applied to the electric circuit connection point 24, and the voltage at the electric circuit connection point 24 is It becomes "HIGH" level.

  At this time, since the voltage that has passed through the resistor R4 of the first electric circuit RT1 of the drive circuit unit 22 is applied to the first input terminal a of the IC 25, the voltage of the first input terminal a becomes “HIGH” level. On the other hand, the voltage at the base of the transistor Tr1 in the second electric circuit RT2 of the drive circuit 22 becomes “HIGH” level that has passed through the resistor R5, the transistor Tr1 is turned ON, and the voltage at the second input terminal “b” becomes “LOW” level. . Accordingly, a drive current is supplied from the output terminal c of the IC 25 to the motor 26, and the motor 26 is driven to enter the inside air circulation mode (REC).

  In the lighting circuit unit 23, when the voltage at the electric circuit connection point 24 is at the “HIGH” level, the base voltage of the transistor Tr2 is at the “HIGH” level, so that the transistor Tr2 is turned on and the inside air circulation mode (REC) is set. The LED to display lights up.

  On the other hand, even if the defroster switch 27 of the logic circuit unit 21 is OFF (the wind direction switch rotary switch 4 is the vent position 8, the bi-level position 9, the heat position 10 or the heat differential position 11), the push lock switch 28 is OFF, When switched to the terminal 28a (inside / outside air changeover switch 5 is in the outside air introduction mode (FRE)), or the defroster changeover switch 27 of the logic circuit section 21 is turned on (the wind direction changeover rotary switch 4 is in the differential position 12). When the current is connected to the ground GND1 or the ground GND2 connected between the resistor R2 and the resistor R3, and the current from the battery terminal VB1 flows to the ground GND1 or the ground GND2, the voltage applied to the circuit connection point 24 becomes “LOW”. Level.

  At this time, since the voltage passing through the resistor R4 of the first electric circuit RT1 of the drive circuit unit 22 is applied to the first input terminal a of the IC 25, the voltage of the first input terminal a becomes the “LOW” level. On the other hand, since the voltage applied to the base of the transistor Tr1 in the second electric circuit RT2 of the drive circuit unit 22 is at the “LOW” level, the transistor Tr1 is not switched. Accordingly, since the voltage that has passed through the resistor R7 from the battery terminal VB2 is applied to the second input terminal b of the IC 25, the voltage of the second input terminal b is at the “HIGH” level. Therefore, a drive current is supplied from the output terminal d of the IC 25 to the motor 26, and the motor 26 is driven to enter the outside air introduction mode (FRE).

  In the illumination circuit unit 23, when the voltage at the electric circuit connection point 24 is at the “LOW” level, the base voltage of the transistor Tr2 is at the “LOW” level, and the transistor Tr2 is not switched. Therefore, the current from the battery terminal VB3 does not flow through the LED, and the LED is turned off.

  As described above, in the first embodiment of the present invention, the vehicle air conditioning control device that can automatically switch to the outside air introduction mode and disable the operation of the inside / outside air changeover switch 5 in the differential mode is achieved with a simple circuit configuration. can do. Therefore, since it is not necessary to provide a switching element such as a transistor that is affected by external electromagnetic noise from a wireless communication device such as a mobile phone more than necessary, the control circuit is less susceptible to malfunction and is resistant to noise.

  In addition, noise absorbing capacitors C1 to C8 are arranged as close to the terminals as possible for components that cause malfunctions, such as the defroster switch 27, push lock switch 28, transistors Tr1, Tr2, LED, and IC25. Therefore, countermeasures against electromagnetic interference are taken.

  Next, a second embodiment of the control circuit of the vehicle air conditioning control device of the present invention will be described with reference to FIG. FIG. 3 shows a control circuit of a vehicle air-conditioning control apparatus according to the second embodiment of the present invention. The control circuit 30 of the vehicle control apparatus according to the second embodiment is the same as that of the first embodiment except that the configuration of the logic circuit unit 31 and the logic circuit unit 31 are connected to a controller 32 installed in the vehicle. The same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The logic circuit unit 31 of the control circuit 30 according to the second embodiment of the present invention has one end connected to the controller 32, and a diode D, a resistor R11, a PNP transistor TR3, a resistor R12, and a resistor R2 connected in series. The other end side is connected to the electric circuit connection point 24. As will be described later, the transistor Tr3 serves to switch the IC 25, which is a motor drive control unit, by an abnormal signal of a compressor input from a controller 32 installed in the vehicle, and between the base and emitter of the transistor Tr3. The resistor R13 and the noise absorbing capacitor C10 are connected, and the emitter is connected to the battery terminal VB1.

  Next, the operation of the control circuit 30 of the vehicle air conditioning control device according to the second embodiment will be described. When the compressor is operating normally, a “LOW” level signal is output from the controller 32 and input to the logic circuit unit 31. Further, when there is an abnormality in the compressor, the controller 32 becomes “OPEN”.

  When the signal input from the controller 32 to the logic circuit unit 31 is at the “LOW” level (compressor is normal), and the defroster selector switch 27 is OFF (the wind direction selector rotary switch 4 is in the vent position 8, the bilevel position 9 or When it is operated to the heat position 10 or the heat differential position 11) and the push lock switch 28 is turned on, that is, switched to the terminal 28b (the inside / outside air changeover switch 5 is in the inside air circulation mode (REC)), the transistor Tr3 has a base. Is applied with a "LOW" level voltage that has passed through the resistor R12, the transistor Tr3 is switched, and the emitter-collector of the transistor Tr3 is conducted. Therefore, the voltage of the battery terminal VB1 that has passed through the resistors R12 and R2 is applied to the electric circuit connection point 24, and the voltage of the electric circuit connection point 24 becomes the “HIGH” level.

  At this time, as in the first embodiment, the voltage at the first input terminal “a” of the IC 25 is at the “HIGH” level. On the other hand, the voltage of the second input terminal b becomes “LOW” level. Accordingly, a drive current is supplied from the output terminal c of the IC 25 to the motor 26, and the motor 26 is driven to enter the inside air circulation mode (REC). In addition, an LED for displaying the inside air circulation mode (REC) is turned on.

  When the signal input from the controller 32 to the logic circuit unit 31 is “OPEN” (compressor is abnormal), since the “OPEN” signal is output to the base of the transistor Tr3, the transistor Tr3 is not switched. There is no conduction between the emitter and collector of the transistor Tr3. Therefore, the voltage applied to the electric circuit connection point 24 becomes the “LOW” level.

  At this time, the voltage applied to the first input terminal a of the IC 25 becomes the “LOW” level. On the other hand, the voltage applied to the second input terminal b of the IC 25 becomes “HIGH” level. Therefore, a drive current is supplied from the output terminal d of the IC 25 to the motor 26, and the motor 26 is driven to enter the outside air introduction mode (FRE). Further, the LED is turned off.

  Even when the signal input from the controller 32 to the logic circuit unit 31 is at the “LOW” level (compressor is normal), as described in the first embodiment, the defroster switch 27 of the logic circuit unit 31 is ON ( When the wind direction switching rotary switch 4 is operated to the differential position 12), or when the push lock switch 28 is turned off, that is, switched to the terminal 28a (inside / outside air switching switch 5 is in the outside air introduction mode (FRE)). The voltage applied to the electric circuit connection point 24 becomes the “LOW” level. Accordingly, the outside air introduction mode (FRE) is set, and the LED is turned off.

  As described above, in the second embodiment of the present invention, in the configuration of the first embodiment, a switching element (transistor) that switches the voltage at the circuit connection point 24 in accordance with the compressor state signal input from the vehicle-side controller 32. Tr3) is added. Therefore, more complicated control can be performed by adding only the minimum necessary switching elements, and the control circuit has few causes of malfunction and is resistant to noise.

  Similarly to the first embodiment, a noise absorbing capacitor C10 is disposed as close to the terminal as possible to a component that causes malfunction, such as the transistor Tr3, so that countermeasures against electromagnetic interference are taken. Has been.

  Next, the printed circuit board 40 of the vehicle air-conditioning control apparatus according to the first embodiment or the second embodiment of the present invention will be described with reference to FIGS. 4 and 5. FIG. 4 is a plan view showing a pattern configuration of a surface (hereinafter referred to as a front surface) of the printed circuit board 40 facing the operation panel 1, and FIG. 5 is a surface of the printed circuit board 40 far from the operation panel 1 (hereinafter referred to as a back surface). FIG. 6 is an enlarged plan view of a main part 5A of the printed board 40 shown in FIG.

  The vehicle air conditioning control apparatus accommodates a printed circuit board 40 inside the operation panel 1. Holes 41 to 43 are formed in the printed circuit board 40 so that the temperature adjustment rotary switch 2, the air volume switching rotary switch 3, and the air direction switching rotary switch 4 can pass therethrough, and are fixed to the base (not shown) with screws. Has been. The printed circuit board 40 is formed and fixed with a conductive pattern made of a conductive material on both surfaces of an electrically insulating material. As will be described later, the conductor pattern is connected to a circuit conductor pattern 44 that connects various electronic components, a power supply conductor pattern 45 that is connected to a power source side of an in-vehicle battery (not shown), and a ground side of the in-vehicle battery. It comprises a grounding conductor pattern 46 to be connected.

  The printed circuit board 40 includes switches such as the above-described defroster switch 27 and push lock switch 28, a connector CN that connects the in-vehicle battery and the printed circuit board 40, transistors Tr1 to Tr3, resistors R1 to R13, capacitors C1 to C10, Various electronic components such as Zener diodes ZD1 to ZD2, diode D, and LED are mounted. These electronic components are connected by a circuit conductor pattern 44, and the above-described logic circuit unit 21 or logic circuit unit 31, drive circuit unit 22, and illumination circuit unit 23 are formed.

  The front surface of the printed circuit board 40 is a surface facing the operation panel 1. Like the inside / outside air switching switch 5, a push lock switch 28 that detects a pressing operation of each push switch arranged on the operation panel 1, and a wind direction switching rotary A switch such as a defroster changeover switch 27 that detects a rotation operation of the switch 4 to the differential position 12 and electronic components such as an LED and a resistance element are mounted. Also, as shown in FIG. 4, a circuit conductor pattern 44 (a portion indicated by a solid black line in FIG. 4) and a power supply conductor pattern 45 (a portion indicated by dots in FIG. 4) mounted on the front surface of the printed circuit board 40. In the remaining portion excluding (), grounding conductor patterns 46 (portions shown by hatching in FIG. 4) are formed. That is, most of the space on the front surface of the printed circuit board 40 is occupied by the grounding conductor pattern 46.

  On the other hand, the back surface of the printed circuit board 40 is a surface far from the operation panel 1, and the transistors Tr1 to Tr3 are mounted on the back surface. As shown in FIG. 5, the circuit conductor pattern 44 (the portion indicated by the solid black line in FIG. 5) and the ground conductor pattern 46 (the portion indicated by the oblique line in FIG. 5) mounted on the back surface of the printed circuit board 40. A conductor pattern 45 for feeding (a portion indicated by a dot in FIG. 5) is formed in the remaining portion. That is, most of the space on the back surface of the printed circuit board 40 is occupied by the power supply conductor pattern 45.

  Therefore, the grounding conductor pattern 46 on one surface of the printed circuit board 40 and the feeding conductor pattern 45 on the other surface form a stray capacitance, and an electric field is generated between the front surface and the back surface across the insulator. Thus, the effect of absorbing external electromagnetic noise can be obtained. As described above, the transistors Tr1 to Tr3, which are switching elements that are easily affected by external electromagnetic noise generated from a wireless communication device or the like, are mounted on the back surface farther from the operation panel 1, and the operation panel 1 and the transistors Tr1 to Tr1 are mounted. Since the printed circuit board 40 having a noise absorbing effect is disposed between the printed circuit board 40 and the transistor Tr3, electromagnetic wave noise that affects the operation of the transistors Tr1 to Tr3 is absorbed by the printed circuit board 40, and the electromagnetic wave noise reaching the transistors Tr1 to Tr3 is reduced. Can be made. In this way, the printed circuit board 40 can prevent the switching element from malfunctioning due to external electromagnetic noise.

  In addition, the vehicle air-conditioning control device has various restrictions depending on specifications such as the design of the vehicle. For example, in the vehicle air-conditioning control apparatus of the present invention, the wind direction switching rotary switch 4 and the inside / outside air switching switch 5 are arranged separately as shown in FIG. In order to form the control circuit 20 of the first embodiment or the control circuit 30 of the second embodiment on the printed circuit board 40, as shown in FIG. 4, the rotation of the wind direction switching rotary switch 4 to the defroster position is detected. The distance at which the circuit conductor pattern 44 that connects the defroster switch 27 and the push lock switch 28 that detects the pressing operation of the inside / outside air switch 5 is inevitably increased. This is because the space of the printed circuit board 40 of the vehicle air-conditioning control device is limited, and the holes 41 to 43 and a large number of electronic components and conductor patterns are mounted, so the holes 41 to 43 and other electronic components are mounted. This is because it is inevitable that the conductor pattern is disposed around the conductor pattern.

  For the unavoidable reasons as described above, the circuit conductor pattern 44 that is disposed at a long distance propagates external electromagnetic noise, which causes malfunction of switching elements such as the transistors Tr1 to Tr3. In order to improve this, in the printed circuit board 40 of the vehicle air-conditioning control apparatus of the present invention, as shown in FIG. 4, the circuit board pattern 44 connecting the defroster switch 27 and the push lock switch 28 is provided around the circuit board pattern 44. A grounding conductor pattern 46 is provided. At the same time, a grounding conductor pattern 46 is also disposed at a corresponding position on the back side (back side) of the circuit conductor pattern 44 (see FIG. 5). Thereby, the effect of absorbing external electromagnetic noise can be obtained. Accordingly, it is possible to prevent the switching element from malfunctioning due to propagation of external electromagnetic noise by the circuit conductor pattern 44 formed with a long distance.

  Next, a pattern configuration around the transistor Tr1 will be described with reference to FIG. The transistor Tr1 has three terminals of a collector C, a base B, and an emitter E, which are connected to a collector side circuit conductor pattern 50, a base side circuit conductor pattern 51, and an emitter side circuit conductor pattern 52, respectively. It is fixed by soldering. Around the transistor Tr1, a capacitor C3, a resistor R6, and a resistor R5 are disposed in this order from the base B and the emitter E of the transistor Tr1, and the capacitor C3, the resistor R6, and the resistor R5 are disposed on the base side circuit conductor. The pattern 51 and the emitter-side circuit conductor pattern 52 are respectively connected in parallel and fixed to the printed circuit board 40 by soldering. Further, a resistor R7 is disposed in the vicinity of the collector C, is connected to the collector-side circuit conductor pattern 50, and is fixed to the printed circuit board 40 by soldering.

  Here, as shown in FIG. 6, the base B and emitter E of the transistor Tr1 and the capacitor C3 are disposed at a minimum distance L that does not form a solder bridge. In the present invention, the minimum distance between the pads is set to 0.5 mm. The base-side circuit conductor pattern 51 that is the input side is formed wider than the collector-side circuit conductor pattern 50 and the emitter-side circuit conductor pattern 52. In the present invention, the width of the base side circuit conductor pattern 51 is set to about twice the width of the collector side circuit conductor pattern 50 and the width of the emitter side circuit conductor pattern 52.

  With the above structure, since the impedance of the current flowing from the base B of the transistor Tr1 into the transistor Tr1 can be reduced and unnecessary radiation can be reduced, it is possible to prevent the transistor from malfunctioning due to electromagnetic noise. It gets even higher.

  In the above-described embodiment of the present invention, a transistor is used as a switching element. However, the present invention is not limited to this, and any switching element having an equivalent effect may be used. In addition, although the numerical value is limited and described, it is not limited to this numerical value.

The top view of the operation panel of the air conditioner for motor vehicles which employ | adopted the control circuit of this invention. The control circuit of the vehicle air-conditioning control apparatus which concerns on 1st Embodiment of this invention. The control circuit of the vehicle air-conditioning control apparatus which concerns on 2nd Embodiment of this invention. The top view which shows the pattern structure of the surface facing the operation panel 1 of the printed circuit board 40. FIG. The top view which shows the pattern structure of the surface far from the operation panel 1 of the printed circuit board 40. FIG. The top view which expanded the principal part 5A of the printed circuit board 40 shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Operation panel, 4 ... Wind direction changeover rotary switch, 5 ... Inside / outside air changeover switch, 20 ... Control circuit, 21 ... Logic circuit part, 22 ... Drive circuit part, 23 ... Proof circuit part, 24 ... Electric circuit connection point, 25 ... IC, 26 ... motor, 27 ... defroster changeover switch, 28 ... push lock switch, Tr1, Tr2, Tr3 ... transistor, 30 ... control circuit, 31 ... logic circuit section, 32 ... controller, 40 ... printed circuit board, 44 ... circuit conductor Pattern, 45 ... Power supply conductor pattern, 46 ... Grounding conductor pattern, RT1 ... First electric circuit, RT2 ... Second electric circuit.

Claims (5)

An inside / outside air changeover switch for switching between an outside air introduction mode for introducing outside air and an inside air circulation mode for circulating inside air;
A defroster selector switch for switching to a defroster mode for performing anti-fogging control,
A motor drive controller having at least a first input terminal, a second input terminal, and an output terminal, the output terminal being connected to a motor that switches between an outside air introduction mode and an inside air circulation mode;
A logic circuit unit in which an inside / outside air changeover switch and a defroster changeover switch are connected in parallel;
The driving circuit unit includes a first electric circuit and a second electric circuit having a driving switching element.
One end of the first electric circuit of the drive circuit unit is connected to the first input terminal of the motor drive control unit,
The second electric circuit has one end connected to the second input terminal of the motor drive control unit via the drive switching element,
The logic circuit unit is directly connected to an electric circuit connection point where the other end of the first electric circuit and the second electric circuit of the drive circuit unit are connected;
The vehicle control device, wherein the motor is switched and driven by changing the voltage at the electric circuit connection point by operating either the inside / outside air switching switch or the defroster switching switch. When the compressor of the vehicle is in an abnormal state, the logic circuit unit receives an abnormal state output signal from the vehicle-side control unit, and performs an outside air introduction mode and an inside air circulation mode according to the voltage of the abnormal state output signal. A logic switching element for switching,
An internal / external air changeover switch and a defroster changeover switch are connected in parallel to the logic switching element,
2. The vehicle according to claim 1, wherein the motor is switched and driven by changing a voltage at the electric circuit connection point by operating any one of the inside / outside air changeover switch, the defroster changeover switch, and the logic switching element. Control device. The vehicle control device houses a printed circuit board inside the operation panel,
On both sides of this printed circuit board, circuit conductor patterns that connect between electronic components mounted on the printed circuit board,
A power supply conductor pattern connected to the power supply side of the in-vehicle battery;
Form a grounding conductor pattern to be connected to the ground side of the vehicle battery,
On one side of the printed circuit board, a power supply conductor pattern is formed in the remaining portion excluding the circuit conductor pattern and the ground conductor pattern,
On the other surface of the printed circuit board, a grounding conductor pattern is formed in the remaining portion excluding the circuit conductor pattern and the power supply conductor pattern.
3. The vehicle control device according to claim 1, wherein at least the switching element of the electronic component is mounted on a surface farther from the operation panel among both surfaces of the printed circuit board. 4. On one surface of the printed circuit board, the grounding conductor pattern is formed around a circuit conductor pattern connecting the inside / outside air switching switch and the defroster switching switch,
4. The vehicle control device according to claim 3, wherein a grounding conductor pattern is formed on the other surface of the printed circuit board at a position facing the circuit conductor pattern. The switching element is a transistor element;
As an electronic component mounted on a printed circuit board, at least a capacitor element and a resistance element are provided,
A parallel circuit composed of a capacitor element and a resistance element is connected between a base side circuit conductor pattern to which the base of the transistor element is connected and an emitter side circuit conductor pattern to which the emitter of the transistor element is connected,
The transistor element and the capacitor element are arranged at a minimum distance that is not bridge-connected,
5. The vehicle-mounted control device according to claim 3, wherein the base-side circuit conductor pattern is formed wider than the emitter-side circuit conductor pattern and the collector-side circuit conductor pattern.

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