JP2023091927A - Vehicle heat medium heating device - Google Patents

Abstract

To provide a vehicle heat medium heating device capable of surely stopping power supply to a heat without occurrence of malfunction even if flooding into a housing occurs.SOLUTION: A vehicle heat medium heating device 1 includes: a heater 3 which heats a heat medium in a housing; a control board 4 on which a heater control circuit 30 is mounted; and a pair of conductive pads 6a and 6b provided on the control board 4 while being spaced apart from each other and separately from the heater control circuit 30 and having conductivity. A breaker 4e is provided in a first power line 4a from a positive electrode of an external power source B. One conductive pad 6a is electrically connected to an intermediate line 4a1 in the first power line 4a, and the other conductive pad 6b is electrically connected to a second power line 4b from a negative electrode of the external power source B. In a state where the housing is fixed in a predetermined reference posture on a vehicle, the pair of conductive pads 6a and 6b is positioned lower than circuit elements of the heater control circuit 30.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a heat medium heating device for a vehicle that heats a heat medium.

2. Description of the Related Art As an example of a vehicle heat medium heating apparatus, a heat medium heating apparatus described in Patent Document 1 is known. The heat medium heating device described in Patent Document 1 includes a housing (case), a heater arranged in the housing to heat the heat medium, and a substrate arranged in the housing. A control circuit is provided for controlling the power supplied to the heater.

JP 2011-79344 A

In the heat medium heating device disclosed in Patent Literature 1, the circuit board arranged in the housing is provided with a control circuit for controlling power supplied to the heater. Therefore, even if water or the like enters the housing and flooding occurs, there is a problem that it is necessary to stop the power supply to the heater without malfunctioning.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a heat medium heating device for a vehicle that can reliably stop the power supply to the heater without malfunctioning even if water enters the interior of the housing.

According to one aspect of the present invention, a housing, a heater that generates heat by power supply from an external power supply to heat a heat medium in the housing, and a heater control circuit that controls power supply to the heater are mounted in the housing. and a control board housed in a vehicle heat medium heating device. This vehicular heat medium heating device includes a pair of electrically conductive pads which are separated from each other on the control board and provided separately from the heater control circuit. In the vehicle heat medium heating device, a first power supply line that electrically connects one pole of the external power supply and the heater control circuit cuts off power supply when a current exceeding a predetermined value flows. A circuit breaker is provided, and one of said pair of conductive pads is electrically connected to an intermediate line between said circuit breaker and said heater control circuit in said first power supply line, and said pair of conductive pads is electrically connected to said first power supply line. The other of the pads is electrically connected to a second power supply line that electrically connects the other pole of the external power supply and the heater control circuit, and the housing is fixed to the vehicle in a predetermined reference posture. In the folded state, the pair of conductive pads are located below the circuit elements forming the heater control circuit.

Advantageous Effects of Invention According to the present invention, it is possible to provide a heat medium heating device for a vehicle that can reliably stop power supply to the heater without malfunction even if water enters the housing.

1 is a diagram conceptually showing an in-vehicle heating device to which a heat medium heating device for a vehicle according to an embodiment is applied; FIG. FIG. 2 is a diagram showing a configuration example of a heater control circuit that controls power supply to a heater of the heat medium heating device for a vehicle according to the embodiment; 1 is a schematic top view of an example of a heat medium heating device for a vehicle according to an embodiment; FIG. FIG. 4 is a cross-sectional view taken along the line AA of FIG. 3; 4 is a cross-sectional view taken along the line BB of FIG. 3; FIG. 4 is a cross-sectional view taken along line CC of FIG. 3; FIG. FIG. 7 is a cross-sectional view taken along line DD of FIG. 6; It is a figure which shows the control board of the heat-medium heating apparatus for vehicles which concerns on embodiment. It is a figure which shows the modification of the said heater control circuit. 10 is a diagram showing an example of a control board on which the heater control circuit shown in FIG. 9 is mounted; FIG. It is a figure which shows another modification of the said heater control circuit.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 conceptually shows an in-vehicle heating device 10 to which a vehicle heat medium heating device 1 according to an embodiment of the present invention is applied. The vehicle-mounted heating device 10 shown in FIG. Water (including water mixed with antifreeze or the like) is usually used as the heat medium. Therefore, the vehicle heat medium heating device 1 is also called a water heating device.

The vehicle heat medium heating device 1 is provided at a first position of the heat medium circuit 11 . A heat medium heating device 1 for a vehicle includes a heater 3 that generates heat when energized, and is configured to heat a heat medium flowing through a heat medium circulation path 11 . Specifically, the vehicle heat medium heating device 1 heats a heat medium that has flowed in from an inflow portion (an inflow port 23, which will be described later) by the heater 3, and heats the heated heat medium through an outflow portion (an outflow port 24, which will be described later). configured to drain from Although not particularly limited, in the present embodiment, the heater 3 is composed of a pair of heaters (first heater 3A and second heater 3B) electrically connected in parallel. The vehicle heat medium heating device 1 will be described in detail later.

A heat exchanger 12 is provided at a second position of the heat medium circuit 11 . The heat exchanger 12 is arranged in a ventilation duct 13 for blowing out air for air conditioning into the vehicle interior, and generates air for heating the vehicle interior by heat exchange between the heat medium heated by the heat medium heating device 1 for the vehicle and the air. do. A bypass passage 14 bypassing the heat exchanger 12 is provided in the ventilation duct 13 , and an air mix damper 15 controls the flow of air in the ventilation duct 13 .

FIG. 2 is a diagram conceptually showing a configuration example of a heater control circuit 30 that controls power supply to the heaters 3 (the first heater 3A and the second heater 3B).

The vehicle heat medium heating device 1 has a control board 4 , and the heater control circuit 30 is mounted on the control board 4 . In this embodiment, the heater control circuit 30 is configured to supply electric power to the heater 3 from an external power supply B, which is a high voltage power supply mounted on the vehicle. That is, the heater 3 generates heat by power supply from the external power source B to heat the heat medium.

Referring to FIG. 2, in the heater control circuit 30, a first IGBT (insulated gate bipolar transistor) 31 as a switching element is provided on the positive electrode side (output side) of the external power source B rather than the heater 3. A second IGBT 32 is provided as a switching element on the negative electrode side (ground side) of the external power supply B. The first and second IGBTs 31 and 32 can be turned ON/OFF according to signals input to their gates. Two output terminals of an IGBT driver 33 are connected to the gates of the first and second IGBTs 31 and 32, respectively.

The IGBT driver 33 has two input terminals and two output terminals, and can individually turn on/off the first and second IGBTs 31 and 32 by output signals corresponding to the input signals. is. Two output terminals of a microcomputer (CPU) 34 are connected to two input terminals of the IGBT driver 33, respectively.

The microcomputer 34 generates a command signal for the IGBT driver 33 mainly based on the heating request. Specifically, the microcomputer 34 sets the ratio of the ON time of the heater 3 based on the heating request, generates a PWM signal corresponding to the set ON time, and outputs the PWM signal to the IGBT driver 33 . That is, the microcomputer 34 controls the ratio of the ON time of the first and second IGBT transistors 31 and 32 via the IGBT driver 33, thereby controlling the temperature of the heater 3 and the heat generated by the heater 3. Control the temperature of the medium.

Although not shown in FIG. 2, the heater control circuit 30 includes a first temperature detection unit for detecting the temperatures of the first and second IGBTs 31 and 32, a heater 3 (including the temperature of the heat medium heated by the heater 3), a voltage detection unit for detecting the voltage applied to the heater 3, the first and second IGBTs 31, 32, and A current detection unit for detecting the current flowing through the heater 3 is provided. The detection results of these detection units are input to, for example, the microcomputer 34 and can be used to determine the control signal to the IGBT driver 33 .

For example, the microcomputer 34 detects when the temperatures of the first and second IGBTs 31 and 32 exceed a predetermined value, when the temperature of the heater 3 exceeds a predetermined value, and when the voltage applied to the heater 3 exceeds a predetermined value. or when the current flowing through the first IGBT 31, the second IGBT 32, and the heater 3 exceeds a predetermined value, the control signal for forcibly turning off the first and second IGBTs 31, 32 is provided by the IGBT Output to driver 33 . As a result, the first and second IGBTs 31 and 32 are forcibly turned OFF, and power supply to the heater 3 is stopped. As a result, overheat protection and failure detection of the first and second IGBTs 31 and 32 and the heater 3 can be achieved.

Here, the heater control circuit 30 is connected to a first power supply line 4a and a second power supply line 4b that constitute power supply lines from the external power source B to the heater control circuit 30, respectively. Further, the heater control circuit 30 is connected to a first heater line 4 c and a second heater line 4 d that constitute power supply lines from the heater control circuit 30 to the heater 3 .

The first power line 4a electrically connects one pole of the external power source B and the heater control circuit 30 (control board 4), and the second power line 4b connects the other pole of the external power source B and the heater control circuit. 30 (control board 4) are electrically connected.

In this embodiment, the first power supply line 4a extends from the positive electrode side of the external power supply B, and the second power supply line 4b extends from the negative electrode side (ground side) of the external power supply B. As shown in FIG. On the control board 4, a positive power supply line connection part 35a, a negative power supply line connection part 35b, and a positive power supply line connection part 35b, which are all conductive and constitute a part of the circuit pattern of the heater control circuit 30, are provided. A heater line connection portion 35c and a negative heater line connection portion 35d are formed. Further, the positive power supply line connection portion 35a and the positive heater line connection portion 35c are connected via a positive wiring pattern 35e formed on the control board 4, and the negative power supply line connection portion 35b and the negative heater line are connected. The connecting portion 35d is connected via a negative wiring pattern 35f formed on the control board 4. As shown in FIG. Each of these connection portions (35a, 35b, 35c, 35d) and each pattern (35e, 35f) is a circuit pattern, and is part of the circuit elements constituting the heater control circuit 30. FIG.

Specifically, the first power supply line 4a electrically connects the positive electrode of the external power supply B and the positive power supply line connecting portion 35a, and the second power supply line 4b connects the negative electrode of the external power supply B to the negative power supply line. The first heater line 4c connects the positive electrode side heater line connection portion 35c and the positive electrode side terminal of the heater 3, and the second heater line 4d connects the negative electrode side heater line connection portion. 35d and the negative terminal of the heater 3 are connected. The second power supply line 4b is directly connected to the negative terminal of the external power supply B in this embodiment. However, it is not limited to this, and when the negative terminal of the external power supply B is connected to the vehicle body of the vehicle via an earth wire and grounded, the second power supply line 4b is connected to the vehicle body and grounded. It may be connected to the negative terminal of the external power supply B via a line.

Next, the vehicle heat medium heating device 1 will be described with reference to FIGS. 3 to 7. FIG. 3 is a schematic top view of an example of the vehicle heat medium heating device 1, FIG. 4 is a cross-sectional view along line AA in FIG. 3, and FIG. 5 is a schematic cross-sectional view along line BB in FIG. 6 is a sectional view taken along line CC of FIG. 3, and FIG. 7 is a sectional view taken along line DD of FIG.

A heat medium heating device 1 for a vehicle has a housing 2 . The housing 2 is constructed by integrally fastening a plurality of housing members (here, a first housing member 2A, a second housing member 2B, and a third housing portion 2C) with bolts (not shown) or the like.

The housing 2 has therein a heater accommodation chamber 21 that accommodates the heaters 3 (the first heater 3A and the second heater 3B) and a substrate accommodation chamber 22 that accommodates the control board 4 on which the heater control circuit 30 is mounted. In this embodiment, the heater accommodation chamber 21 is formed by fastening the first housing member 2A and the second housing member 2B together, and the substrate accommodation chamber 22 is formed by joining the first housing member 2A and the second housing member 2B. is formed by further fastening the third housing member 2C to the fastening body.

The heater accommodation chamber 21 includes a first accommodation portion 21A, a second accommodation portion 21B, and a communication portion 21C that communicates the first accommodation portion 21A and the second accommodation portion 21B. 21 A of 1st accommodating parts and the 2nd accommodating part 21B are provided in parallel, 21 C of communication parts connect these between 21 A of 1st accommodating parts, and the 2nd accommodating part 21B. The first heater 3A is accommodated in the first accommodation portion 21A, and the second heater 3B is accommodated in the second accommodation portion 21B.

In this embodiment, the first heater 3A and the second heater 3B have a substantially cylindrical outer shape. The first housing portion 21A and the second housing portion 21B are formed as substantially cylindrical spaces having a larger diameter than the first heater 3A and the second heater 3B. Therefore, a first annular space is formed between the inner surface of the first accommodating portion 21A and the outer surface of the first heater 3A, and a second annular space is formed between the inner surface of the second accommodating portion 21B and the outer surface of the second heater 3B. An annular space is formed. These first and second annular spaces communicate with each other through a communicating portion 21C.

Further, the housing 2 has an inlet 23 through which the heat medium flows into the heater housing chamber 21 and an outlet 24 through which the heat medium flows out of the heater housing chamber 21 . The inflow port 23 is formed to allow the heat medium to flow into one side of the heater housing chamber 21 (first housing portion 21A) in the longitudinal direction, and the outflow port 24 is formed in the heater housing chamber 21 (first housing portion 21A). It is formed so that the heat medium flows out from the other side in the longitudinal direction. In this embodiment, the inlet 23 and the outlet 24 are provided on the same side surface of the housing 2 . However, it is not limited to this, and the inflow port 23 and the outflow port 24 may be formed on different sides of the housing 2 .

The heater housing chamber 21 , the inlet 23 , and the outlet 24 constitute a heat medium flow path within the housing 2 , and this heat medium flow path constitutes a part of the heat medium circulation path 11 . That is, the heat medium flowing through the heat medium circulation path 11 flows into the heater housing chamber 21 through the inlet 23 , flows through the heater housing chamber 21 , and then flows out of the heater housing chamber 21 through the outlet 24 . It has become. When the heat medium flows through the heater housing chamber 21, more specifically, when it mainly flows through the first annular space and the second annular space, the heater 3 (the first heater 3A and the second heater 3B) heated.

The substrate storage chamber 22 is provided adjacent to the heater storage chamber 21 with the wall portion 25 interposed therebetween. Specifically, in the housing 2 , the board storage chamber 22 is separated from the heater storage chamber 21 by a wall portion 25 , and the heater storage chamber 21 is arranged on one side (lower side) of the wall portion 25 , and the wall A substrate receiving chamber 22 is arranged on the other side (upper side) of the portion 25 . A plurality of (here, four) board mounting portions 26 for mounting the control board 4 are provided in the board housing chamber 22 .

Although not shown in the drawings, seal members are provided between the first housing member 2A and the second housing member 2B, between the first housing member 2A and the third housing member 2C, and between the second housing member 2A and the second housing member 2C. They are provided between the member 2B and the third housing member 2C, respectively. Adjacent housing members are fastened together in an airtight and liquid-tight manner by these sealing members. Although not shown in the drawing, power supply lines (first power supply line 4a and second power supply line 4b) from the external power source B to the heater control circuit 30 and power supply lines (second power supply line 4b) from the heater control circuit 30 to the heater 3 are provided. A first heater line 4c and a second heater line 4d) extend through the wall of the housing 2 in gas-tight and liquid-tight manner respectively. In other words, the sealing member is also provided between the through-hole for the feeder line in the housing 2 and the feeder line portion. Therefore, the housing 2 has a structure capable of preventing water or the like from entering the substrate storage chamber 22 , that is, preventing water from entering the substrate storage chamber 22 .

As described above, the heat medium heating device 1 for a vehicle includes a housing 2, a heater 3 that heats the heat medium in the housing 2 by generating heat by power supply from the external power supply B, and a heater that controls power supply to the heater 3. It has a control board 4 on which a control circuit 30 is mounted and housed within the housing 2 .

Here, the control board 4 will be described in detail. FIG. 8 shows an example of the control board 4. As shown in FIG. As described above, the heater control circuit 30 is mounted on the control board 4. FIG. , the second IGBT 32, the IGBT driver 33, the microcomputer 34, the positive power line connection portion 35a, the negative power line connection portion 35b, the positive heater line connection portion 35c, and the negative heater line connection portion 35d. there is

A plurality of (that is, four) screw insertion holes 41 corresponding to the plurality of substrate mounting portions 26 are formed in the control substrate 4 . In this embodiment, the control board 4 is formed in a substantially rectangular shape in plan view, and screw insertion holes 41 are formed in the vicinity of each of its four corners. In the control board 4, the fixing screws 5 (see FIGS. 4 to 6) inserted through the plurality of screw insertion holes 41 are screwed into the corresponding screw holes formed on the upper surface of the board mounting portion 26. By fitting together, they are fixed (screwed) to the upper surfaces of the plurality of substrate mounting portions 26 .

By the way, the housing 2 has a structure capable of preventing water from entering the substrate accommodating chamber 22, but if the sealing member deteriorates due to aging, etc., the desired sealing performance cannot be obtained. , there is a risk that water will enter the substrate housing chamber 22 . When liquid such as water enters the substrate housing chamber 22, an unintended current path (large current path) may be formed in the heater control circuit 30 (control board 4) through the liquid. In this case, some of the electronic components that make up the heater control circuit 30 are located on the current path formed by the flooding, and an unintended high voltage is applied to the electronic components or a large current flows through the electronic components. put away. As a result, the original control of the heater control circuit 30, such as overheat protection and failure detection, is not properly executed, resulting in a malfunction state (in other words, an ambiguous state such as a state where the original control does not function satisfactorily/unstable state). state). Therefore, in this embodiment, by taking the following measures for the control board 4, the power supply to the heater 3 can be stopped without malfunction even if the housing 2 is flooded. It has become.

Referring to FIGS. 2 and 8, the vehicle heat medium heating device 1 includes a pair of electrically conductive conductive pads 6a and 6b provided separately from the heater control circuit 30 on the control board 4. . A first power supply line 4a extending from the external power supply B is provided with a circuit breaker 4e that cuts off power supply when a current exceeding a predetermined value flows. Although not particularly limited, in the present embodiment, the circuit breaker 4e is composed of a fuse that melts when a current exceeding a predetermined value flows.

One of the pair of conductive pads 6a and 6b (hereinafter referred to as the first conductive pad 6a) is connected to the intermediate line 4a1 between the circuit breaker 4e and the heater control circuit 30 in the first power supply line 4a and the first branch line. 4f are electrically connected. In this embodiment, the first conductive pad 6a is connected to the positive electrode of the external power supply B via the first branch line 4f and the first power supply line 4a. Therefore, the first conductive pad 6a is also called a high voltage positive electrode pad.

The other of the pair of conductive pads (hereinafter referred to as second conductive pad 6b) is electrically connected to second power supply line 4b via second branch line 4g. In this embodiment, the second conductive pad 6b is connected to the negative electrode of the external power supply B via the second branch line 4g and the second power supply line 4b. Therefore, the second conductive pad 6b is also called a high voltage negative electrode pad.

The first conductive pads 6 a and the second conductive pads 6 b may be conductive patterns formed on the control board 4 by etching or the like, for example, similar to the circuit pattern of the heater control circuit 30 . In this case, the first conductive pad 6 a and the second conductive pad 6 b may be made of the same material as the circuit pattern (for example, copper foil), but do not constitute the original electric circuit of the heater control circuit 30 . The first conductive pads 6a and the second conductive pads 6b are exposed on the control substrate 4 and separated from each other by a predetermined insulating distance.

Here, the vehicle heat medium heating device 1 is mounted in a required space in the vehicle, and the orientation of the housing 2 when mounted in the vehicle is often determined in advance according to the specifications of the vehicle. This predetermined orientation of the housing 2 is hereinafter referred to as a predetermined reference orientation. Then, the housing 2 can be fixed to the vehicle in the predetermined reference posture. Although not particularly limited, in this embodiment, when the housing 2 is fixed to the vehicle in the predetermined reference posture, the control board 4 stands up in the vertical direction (the direction of gravity) or tilts with respect to the vertical direction. It is designed to take a slanted posture. Therefore, when water enters the board storage chamber 22 and the water level gradually rises, the lower edge of the rectangular control board 4 is first immersed in the liquid.

The pair of conductive pads 6a and 6b are positioned below circuit elements including electronic components and circuit patterns that constitute the heater control circuit 30 when the housing 2 is fixed to the vehicle in the predetermined reference posture. . Therefore, in the control board 4, the circuit elements (the first IGBT 31, the second IGBT 31, the second 2 IGBT 32, IGBT driver 33, microcomputer 34, first temperature detector, second temperature detector, voltage detector, current detector, positive power line connection part 35a, negative power line connection part 35b , the positive electrode side heater line connection portion 35c, the negative electrode side heater line connection portion 35d, the positive electrode side wiring pattern 35e, the negative electrode side wiring pattern 35f, etc.) are not located. In other words, the circuit elements of the heater control circuit 30 are located above the pair of conductive pads 6a and 6b in the housing 2 in the predetermined reference posture.

In this embodiment, the pair of conductive pads 6 a and 6 b are provided near the edge of the control board 4 . As described above, for example, the control board 4 is formed in a substantially rectangular shape in plan view. For example, in the predetermined reference posture, the edge portions of the control board 4 corresponding to the pair of conductive pads 6a and 6b extend in a direction orthogonal to the vertical direction (that is, in the horizontal direction). Further, for example, the pair of conductive pads 6a and 6b are provided in the vicinity of the central portion in the longitudinal direction of the edge corresponding to the lower side of the four sides of the control board 4 in the predetermined reference posture. . In this embodiment, the pair of conductive pads 6a and 6b are separated from each other in the longitudinal direction (here, horizontal direction) of the edge corresponding to the lower side.

Next, the operation of the heat medium heating device 1 for a vehicle according to the present embodiment will be described by exemplifying a case where water enters the housing 2 (substrate storage chamber 22).

In the vehicle heat medium heating device 1, when liquid such as water gradually enters the substrate storage chamber 22, the water level in the substrate storage chamber 22 gradually rises. Then, the water level in the substrate housing chamber 22 exceeds the lower edge of the control substrate 4 housed in the substrate housing chamber 22, and then the position corresponding to the pair of conductive pads 6a and 6b (predetermined water level ) is reached. At this time, a short circuit is intentionally formed between the pair of conductive pads 6a and 6b by filling the gap (space) between the pair of conductive pads 6a and 6b with the liquid that has entered. As a result, a current exceeding a predetermined value flows through the circuit breaker 4e, and the power supply from the external power source B is interrupted by the circuit breaker 4e. In other words, it can be said that the pair of conductive pads 6a and 6b function as a water ingress detection sensor (or water leakage detection sensor).

Note that even if the water level rises to the portion of the circuit elements that make up the heater control circuit 30 after the power supply is cut off by the circuit breaker 4e, the power supply to the heater control circuit 30 has already been cut off. No short circuit is formed between the elements, thereby preventing high voltages or large currents from flowing between unintended circuit elements.

In the heat medium heating device 1 for a vehicle according to the present embodiment, the first conductive pad 6a and the second conductive pad 6b, which are provided separately from the heater control circuit 30 on the control board 4 and have conductivity, It is located below the circuit elements forming the heater control circuit 30 when the housing 2 is fixed to the vehicle in a predetermined reference posture. As a result, even if water enters the housing 2 (substrate housing chamber 22 ), the first conductive pad 6 a and the second conductive pad 6 b are separated before the liquid such as water reaches the circuit elements of the heater control circuit 30 . A short circuit may be intentionally formed between By causing a large current to flow through this intentionally formed short circuit, the power supply from the external power source B can be quickly interrupted by the circuit breaker 4e. Therefore, when water enters the housing 2, a short circuit is formed between the circuit elements of the heater control circuit 30, and a high voltage is applied or a large current flows between unintended circuit elements. is prevented. Therefore, when water enters the housing 2, the original control of the heater control circuit 30, such as overheat protection and failure detection, is not properly executed, and it is more likely that the control will continue in a malfunctioning state. definitely prevented. In this way, even if the housing 2 is flooded with water, the vehicle heat medium heating device 1 can reliably stop the power supply to the heater 3 without malfunction.

In this embodiment, the pair of conductive pads 6 a and 6 b are provided near the edge of the control board 4 . As a result, a large mounting area for the heater control circuit 30 on the control board 4 can be ensured, and the power supply to the heater 3 can be quickly stopped when water ingress occurs.

By the way, if the specifications of the vehicle are changed, the housing 2 fixed to the vehicle may take a different attitude from the predetermined reference attitude originally intended. In such a case, the pair of conductive pads 6a and 6b are not located below the circuit elements forming the heater control circuit 30 when the housing 2 is fixed to the vehicle in a posture different from the predetermined reference posture. A situation can occur. If such a situation is assumed to occur, the vehicle heat medium heating device 1 should be provided with a pair of conductive pads 6a and 6b separately from the pair of conductive pads 6a and 6b, as in a modification shown in FIGS. 9 and 10 below. A pair of preliminary conductive pads 7a, 7b may be provided.

FIG. 9 is a diagram showing a modification of the heater control circuit 30, and FIG. 10 is a diagram showing an example of the control board 4 on which the heater control circuit 30 shown in FIG. 9 is mounted. A heat medium heating device 1 for a vehicle according to a modification will be described below with respect to differences from the above-described embodiment.

9 and 10, the vehicle heat medium heating device 1 according to the modification includes a pair of spare conductive pads 7a and 7b separately from the pair of conductive pads 6a and 6b. The pair of preliminary conductive pads 7a and 7b are provided separately from the heater control circuit 30 and the pair of conductive pads 6a and 6b on the control board 4 and have conductivity. One of the pair of preliminary conductive pads 7a, 7b is electrically connected to the intermediate line 4a1 of the first power supply line 4a, and the other of the pair of preliminary conductive pads 7a, 7b is electrically connected to the second power supply line 4b. It is connected to the. In a state in which the housing 2 is fixed to the vehicle in a predetermined preliminary posture different from the predetermined reference posture, the pair of preliminary conductive pads 7a and 7b are positioned below the circuit elements forming the heater control circuit 30. ing.

Specifically, the pair of preliminary conductive pads 7a and 7b are conductive patterns formed on the control board 4 by etching or the like in the same manner as the pair of conductive pads 6a and 6b. Do not form an electrical circuit. A pair of preliminary conductive pads 7a and 7b are also exposed on the control board 4 and separated from each other by a predetermined insulating distance. Although not particularly limited, two of the four sides of the rectangular control board 4 extend in a direction perpendicular to the sides corresponding to the pair of conductive pads 6a and 6b. , constitutes the lower edge of the control board 4 in the predetermined preliminary posture. The pair of preliminary conductive pads 7a and 7b are provided in the vicinity of the edge forming the lower edge of the control board 4 in the predetermined preliminary posture, and are arranged in the direction along the edge (preliminary posture). are separated from each other horizontally).

Even when the housing 2 assumes a different attitude from the predetermined reference attitude that was initially planned, this different attitude can often be roughly assumed in advance. Therefore, the predetermined preliminary posture can be assumed in advance. When the housing 2 is fixed to the vehicle in the predetermined preliminary posture, the pair of preliminary conductive pads 7a and 7b prevents the vehicle heat medium heating device 1 from malfunctioning even if water enters the housing 2. Power supply to the heater 3 can be reliably stopped.

In some cases, a plurality of postures different from the predetermined reference posture can be assumed in advance. In this case, as shown in FIG. 11, the vehicle heat medium heating device 1 is provided with a pair of preliminary conductive pads 7a and 7b in a number (three patterns in FIG. 11) corresponding to the number of assumed postures. Just do it. Specifically, a pair of preliminary conductive pads 7a and 7b are provided near the respective edges of three sides of the four sides excluding the side corresponding to the pair of conductive pads 6a and 6b. That is, when a plurality of (three in FIG. 11) predetermined preliminary postures are determined, the pair of preliminary conductive pads 7a and 7b are provided near the edge of the control board 4 for each preliminary posture. As a result, the degree of freedom in fixing the posture of the housing 2 to the vehicle is improved.

Also, the pair of conductive pads 6a, 6b and the pair of preliminary conductive pads 7a, 7b are provided near the central portion in the longitudinal direction of the edge of the control board 4, but the present invention is not limited to this. It may be provided at the corner of the control board 4 included in the edge of the control board 4 . The first power supply line 4a provided with the circuit breaker 4e is connected to the positive electrode (output side) of the external power supply B, but is not limited to this. The first power supply line 4a provided with the circuit breaker 4e may be connected to the negative electrode of the external power supply B (ground side). That is, the circuit breaker 4e may be provided not only on the positive power supply line but also on the negative power supply line.

Although the embodiments and some modifications of the present invention have been described above, the present invention is not limited to the above-described embodiments and modifications, and further modifications and changes can be made based on the technical idea of the present invention. is of course possible.

DESCRIPTION OF SYMBOLS 1... Heat-medium heating apparatus for vehicles, 2... Housing, 3... Heater, 4... Control board, 4a... First power supply line, 4a1... Intermediate line, 4b... Second power supply line, 4e... Breaker, 6a, 6b... A pair of conductive pads 7a, 7b A pair of spare conductive pads 30 Heater control circuit 31 First IGBT (circuit element) 32 Second IGBT (circuit element) 33 IGBT driver (circuit element ), 34... microcomputer (circuit element), 35a... positive electrode side power supply line connection portion (circuit element), 35b... negative electrode side power supply line connection portion (circuit element), 35c... positive electrode side heater line connection portion (circuit element), 35d ... negative electrode side heater line connection portion (circuit element), 35e... positive electrode side wiring pattern (circuit element), 35f... negative electrode side wiring pattern (circuit element), B... external power supply

Claims (4)

a housing, a heater that generates heat by power supply from an external power source to heat a heat medium in the housing, and a control board that is housed in the housing and on which a heater control circuit that controls power supply to the heater is mounted. A heat medium heating device for a vehicle, comprising:
comprising a pair of conductive pads separated from each other on the control board and separate from the heater control circuit and having electrical conductivity;
A first power supply line that electrically connects one pole of the external power supply and the heater control circuit is provided with a circuit breaker that cuts off power supply when a current exceeding a predetermined value flows,
one of the pair of conductive pads is electrically connected to an intermediate line between the circuit breaker and the heater control circuit in the first power supply line;
the other of the pair of conductive pads is electrically connected to a second power supply line that electrically connects the other pole of the external power supply and the heater control circuit;
A heating medium heating device for a vehicle, wherein the pair of conductive pads are positioned below circuit elements forming the heater control circuit in a state in which the housing is fixed to the vehicle in a predetermined reference posture. 2. The heat medium heating device for a vehicle according to claim 1, wherein said pair of conductive pads are provided near edges of said control board. a pair of preliminary conductive pads having electrical conductivity and provided separately from the heater control circuit and the pair of conductive pads on the control substrate;
one of the pair of preliminary conductive pads electrically connected to the intermediate line of the first power supply line;
the other of the pair of preliminary conductive pads is electrically connected to the second power supply line;
3. The pair of preliminary conductive pads are located below the circuit element when the housing is fixed to the vehicle in a predetermined preliminary posture different from the predetermined reference posture. A heating medium heating device for a vehicle as described. A plurality of the predetermined preliminary postures are defined,
4. The heating medium heating device for a vehicle according to claim 3, wherein said pair of preliminary conductive pads are provided in the vicinity of the edge of said control board for each preliminary posture.

Images