JP2019041055A - Electronic control device - Google Patents

Abstract

To provide an electronic control device capable of preventing erroneous detection of a fan abnormality.SOLUTION: An electronic control device comprises: a circuit board mounted with a control circuit unit; a housing for housing the circuit board inside; a blower unit including a fan whose driving is controlled by the control circuit unit and for air-cooling the housing from the outside; a first temperature detection unit which detects a physical quantity correlating with a temperature of the circuit board; and a second temperature detection unit which detects a physical quantity correlating with a temperature outside the housing and arranged in a position far from the fan in the first temperature detection unit. The control circuit unit determines whether the fan is abnormal on the basis of the physical quantity detected by the first temperature detection unit, and also determines whether the fan abnormality is true or false by comparing the physical quantity detected by the first temperature detection unit with the physical quantity detected by the second temperature detection unit.SELECTED DRAWING: Figure 2

Description

  The disclosure of this specification relates to a fan-cooled electronic control device.

  In a vehicle, for example, an electronic control device that controls driving of an engine has been reduced in size. With the downsizing of the electronic control device, the installation area of the heat dissipating fins is narrowed, and it has become difficult to ensure heat dissipation. Therefore, as disclosed in Patent Document 1, a cooling system for cooling the vehicle control device main body is known.

JP 2000-234518 A

  By the way, in the cooling system disclosed in Patent Document 1, the housing can be cooled by the rotation of the fan, but the rotation of the fan is accompanied by the consumption of electric power. For this reason, it is preferable from the viewpoint of power saving to rotate the fan in a timely manner without cooling the housing more than necessary. However, for example, if the blower unit is always on and the fan continues to rotate due to a failure or the like, excessive power consumption may occur. On the other hand, in the state where the rotation of the fan is always off and does not rotate, the original purpose of cooling cannot be achieved. For this reason, there is a request to detect the always-on or always-off state that the fan does not intend. That is, there is a demand for a diagnostic function related to the fan.

  As a method of diagnosing fan rotation, for example, a command for forcibly rotating the fan may be issued, and then a fan failure may be detected based on the degree of cooling thereafter. .

  However, when there is a temperature increase outside the housing that exceeds the cooling capacity of the fan, it is not possible to distinguish between a fan abnormality and a temperature increase due to an external factor. That is, it is impossible to determine whether the temperature rises due to an abnormal stop of the fan or an abnormal temperature rise outside the housing, and there is a possibility that a fan abnormality is erroneously detected.

  Therefore, an object of the disclosure of this specification is to provide an electronic control device that can prevent erroneous detection of fan abnormality.

  The disclosure of this specification employs the following technical means to achieve the above object. Note that the reference numerals in parentheses described in the claims and in this section indicate a corresponding relationship with specific means described in the embodiments described later as one aspect, and limit the technical scope of the invention. Not what you want.

  In order to achieve the above object, an electronic control device disclosed in this specification includes a circuit board (30) on which a control circuit unit (34) is mounted, and a housing (20) in which the circuit board is accommodated. And a fan unit (41) whose drive is controlled by the control circuit unit, and a blower unit (40) for air-cooling the casing from the outside, and a first temperature detection unit for detecting a physical quantity correlated with the temperature of the circuit board ( 35) and a physical quantity that correlates with the temperature outside the housing, and includes a second temperature detector (36) disposed at a location farther from the fan than the first temperature detector, and is controlled. The circuit unit determines an abnormality of the fan based on the physical quantity detected by the first temperature detection unit, and compares the physical quantity detected by the first temperature detection unit with the physical quantity detected by the second temperature detection unit. , Determine the true or false of the fan abnormality.

  According to this, the first temperature detection unit disposed at a position closer to the fan causes a temperature change accompanying the rotation of the fan, and the second temperature detection unit disposed at a position farther from the fan is less affected by the fan. Temperature change can be detected. In other words, the temperature of the portion that is not easily affected by the fan is the temperature of the portion that is easily affected by the temperature outside the housing. The disclosed electronic control device monitors the detection result of the second temperature detection unit that is greatly affected by the temperature outside the housing, so that the temperature detected by the first temperature detection unit is caused by the fan, or It can be judged whether it is influenced by the external temperature. That is, the authenticity of the fan abnormality determined by the physical quantity detected by the first temperature detection unit can be confirmed.

1 is a perspective view of an electronic control device according to a first embodiment. It is sectional drawing which follows the II-II line of FIG. It is a figure which shows an example of the circuit of an electronic controller. It is a figure which shows the temperature change in 2nd Embodiment. It is sectional drawing which shows the mounting position of the 2nd temperature detection part in 3rd Embodiment. It is sectional drawing which shows the mounting position of the 2nd temperature detection part in 4th Embodiment.

  Hereinafter, a plurality of modes for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, parts corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals, and redundant description may be omitted. When only a part of the configuration is described in each mode, the other modes described above can be applied to the other parts of the configuration. Not only combinations of parts that clearly indicate that combinations are possible in each form, but also forms may be partially combined even if they are not clearly specified, as long as there is no problem with the combination. Is possible.

  In the following, the thickness direction of the circuit board is indicated as the Z direction. Moreover, it is one direction orthogonal to the Z direction, and the longitudinal direction of the connector is indicated as the Y direction, and the direction orthogonal to both the Z direction and the Y direction is indicated as the X direction. Unless otherwise specified, the shape along the XY plane is a planar shape.

(First embodiment)
Initially, with reference to FIGS. 1-3, schematic structure of the electronic controller which concerns on this embodiment is demonstrated. In FIG. 2, the air flow accompanying the rotation of the fan is indicated by a one-dot chain line arrow.

  As shown in FIGS. 1 and 2, the electronic control device 10 includes a waterproof housing 20, a circuit board 30, and a blower unit 40. The electronic control device 10 is configured as an electronic control device (ECU) that controls an internal combustion engine of a vehicle.

  The waterproof housing 20 provides a waterproof space as an internal space 20 s that houses the circuit board 30. The waterproof housing 20 is divided into two members in the Z direction, which is the thickness direction of the circuit board 30, and one is a case 21 and the other is a cover 22. The waterproof housing 20 is configured by assembling a case 21 and a cover 22 with a seal member (not shown).

  The case 21 has a box shape with one side opened. In the present embodiment, the case 21 is formed using a metal material for heat dissipation. Specifically, the case 21 is formed by aluminum die casting.

  The bottom wall 210 of the case 21 has a substantially rectangular shape in plan view. One surface facing the outside of the bottom wall 210 of the case 21 is the outer surface 21a of the case, and in this embodiment, is a mounting surface on which the air blower unit 40 described later is mounted in the waterproof housing 20. One of the four side walls connected to the bottom wall 210 is provided with a notch (not shown). This notch is connected to the opening on one surface of the case 21.

  A plurality of through holes 211 are formed in the bottom wall 210. The through hole 211 is formed so as to penetrate from the outer surface 21a of the case 21 to the inner surface 21b. In the present embodiment, the case 21 includes a first housing portion 212 and a second housing portion 213 provided as a part of the bottom wall 210 so as to be recessed with respect to other portions of the bottom wall 210.

  The first accommodating portion 212 is provided on one end side in the X direction so as to accommodate the connector 33. The second accommodating portion 213 is provided to accommodate a high-profile component such as an aluminum electrolytic capacitor among the electronic components 32 constituting the circuit board 30. The second housing part 213 extends in the X direction, and one end is connected to the first housing part 212. The through hole 211 is formed in a portion of the bottom wall 210 excluding the first housing portion 212 and the second housing portion 213. The through hole 211 is formed in a substantially flat portion of the bottom wall 210.

  In addition, the code | symbol 214 shown in FIG. 1 is an attachment part for attaching the electronic control apparatus 10 to a vehicle, and the code | symbol 215 is a fixing hole for fixing the case 21 and the cover 22. As shown in FIG. A screw (not shown) is inserted into the fixing hole 215. The mounting portion 214 and the fixing hole 215 are provided integrally with the case 21.

  The cover 22 forms an internal space 20 s of the waterproof housing 20 together with the case 21. By assembling the case 21 and the cover 22, the opening on the one surface of the case 21 is closed by the cover 22. Moreover, the opening of one surface of the case 21 is closed by the cover 22, so that a notch formed in the side wall is partitioned and becomes an opening (not shown). Through this opening, a part of the connector 33 is exposed to the outside.

  In the present embodiment, the cover 22 is also formed using a metal material in order to improve heat dissipation. The cover 22 is also formed by aluminum die casting. The cover 22 has a box shape with a shallow bottom that opens on one side. The cover 22 has a plurality of heat radiation fins 220 on the outer surface side.

  The sealing member of the waterproof housing 20 has an internal space 20 s outside the waterproof housing 20 between the case 21 and the cover 22, between the case 21 and the connector 33, and between the cover 22 and the connector 33. It is provided to block communication with the space. The seal member is disposed on the peripheral edge of the case 21 and the cover 22 so as to surround the internal space 20s. The peripheral portions of the case 21 and the cover 22 are sealed in a watertight manner by the sealing member. As the seal member, for example, a liquid adhesive can be employed before curing.

  The circuit board 30 is fixed to the case 21. The circuit board 30 includes a printed board 31 and an electronic component 32 mounted on the printed board 31. The printed circuit board 31 has wirings arranged on a base material formed using an electrically insulating material such as a resin. A circuit is formed by the wiring and the electronic component 32. The printed circuit board 31 has a substantially rectangular plane shape. The electronic component 32 is mounted on at least one of the one surface 31 a that is the surface on the case 21 side and the back surface 31 b that is the surface on the cover 22 side in the printed circuit board 31. In the present embodiment, of the electronic component 32, a heating element such as a power MOSFET or a microcomputer is disposed on one surface 31a of the printed board 31 around the blower unit 40 in the XY plane as shown in FIG. Yes. The electronic component 32 includes a control circuit unit 34 that controls driving of the blower unit 40 described later. The control circuit unit 34 is mounted on the printed circuit board 31.

  The circuit board 30 includes a first temperature detection unit 35 and a second temperature detection unit 36 as electronic components 32. The 1st temperature detection part 35 and the 2nd temperature detection part 36 are temperature sensors using a PN junction diode, for example.

  The first temperature detector 35 is an element that is disposed in the vicinity of the heat generating element and in the vicinity of the blower unit 40 and detects the temperature of the circuit board 30 directly or indirectly. The physical quantity detected by the first temperature detection unit 35 is a physical quantity that correlates with the temperature of the circuit board 30. The physical quantity correlated with the temperature of the circuit board 30 is, for example, the direct temperature of the circuit board 30, the atmospheric temperature of the internal space 20s that conducts heat from the circuit board 30, and the temperature of the waterproof casing 20, and correspond to them. The voltage value and current value output from the first temperature detection unit 35 are also included. The first temperature detection unit 35 is disposed in the vicinity of the place where the blower unit 40 is installed, and is easily affected by cooling due to the drive of the blower unit 40.

  The second temperature detection unit 36 is an element that is disposed at a position farther than the first temperature detection unit 35 as viewed from the blower unit 40 and directly or indirectly detects the temperature outside the waterproof housing 20. The second temperature detection unit 36 in the present embodiment is disposed at the end on the outer edge of the printed circuit board 31 and is not easily affected by the heat from the heating element, and is not easily affected by the cooling due to the driving of the blower unit 40. Has been. In addition, the surface of the second temperature detection unit 36 opposite to the contact surface with the printed circuit board 31 is fixed to the inner surface 21 b of the case 21 via the heat radiating gel 37. That is, the second temperature detection unit 36 can detect the temperature of the waterproof casing 20 and, by extension, the outside of the waterproof casing 20 via the heat radiating gel 37. The heat dissipation gel 37 is an example of a heat dissipation member described in the claims. The heat dissipation member that mediates between the second temperature detection unit 36 and the waterproof housing 20 contributes to creating an environment in which the second temperature detection unit 36 can easily detect the temperature outside the waterproof housing 20, but is necessarily required. Rather, it is used as appropriate.

  A connector 33 is mounted on the circuit board 30. The connector 33 is mounted on one end side in the X direction on the circuit board 30. A part of the connector 33 is exposed to the outside through the opening of the waterproof casing 20, and the remaining part is accommodated in the internal space 20s. Although not shown, the connector 33 includes a housing formed using a resin material and a plurality of terminals formed using a conductive material and held in the housing.

  The blower unit 40 is attached to the bottom wall 210 of the case 21. Specifically, it is mounted on the outer surface 21 a of the bottom wall 210 facing the outside of the waterproof housing 20. The blower unit 40 is attached so as to cover the plurality of through holes 211 of the case 21. The blower unit 40 forms a flow of air by rotation, and thereby cools the case 21 and thus the circuit board 30. The blower unit 40 includes a fan 41, a housing 42, and terminals 43. The structure of the fan 41 is the same as the well-known structure in the axial fan. For this reason, in FIG. 2, the fan 41 is illustrated in a simplified manner.

  The fan 41 has a shaft portion 410 and a plurality of blades 411. The shaft portion 410 includes a rotating shaft 410a. The blade 411 rotates integrally with the rotation shaft 410a. Therefore, the rotation shaft 410 a becomes the rotation axis of the fan 41. The blower unit 40 is attached to the case 21 so that the axial direction of the rotation shaft 410a, that is, the direction of the rotation axis of the fan 41 coincides with the Z direction. That is, the blade 411 rotates in an XY plane parallel to the outer surface 21a. The flow of air generated along with the rotation of the fan 41 is mainly in the Z direction, and when the blade 411 rotates, an airflow directed to the outer surface 21a from the outside is generated.

  The shaft portion 410 has a boss 410b in addition to the rotating shaft 410a. The boss 410b has a bottomed cylindrical shape that opens to the circuit board 30 side in the Z direction and is closed to the other end side. A plurality of blades 411 are provided at equal intervals on the outer peripheral surface of the boss. The blade 411 is located above the outer surface 21a of the peripheral portion of the through hole 211 in the Z direction. The boss 410b and the blade 411 are integrally formed as a so-called impeller. The rotating shaft 410a is provided inside the boss 410b, and one end is fixed to the approximate center of the boss 410b. The metal rotating shaft 410a is insert-molded into a resin impeller and integrated with the impeller. A magnet 410c is attached to the inner peripheral surface of the boss 410b. As described above, the rotor includes the boss 410b, the blade 411, the rotating shaft 410a, and the magnet 410c.

  In addition to the above, the shaft portion 410 includes a bearing (not shown), a coil 410d, a bearing holder 410e, and the like. The bearing supports the rotating shaft 410a in a rotatable manner. The bearing holder 410e holds a bearing. The bearing holder 410 e protrudes from the bottom wall 420 of the housing 42 in the Z direction. In the present embodiment, the bearing holder 410 e is integrally provided using the same material as the housing 42. The bearing is disposed on the inner peripheral surface of the bearing holder 410e. The coil 410d is disposed on the outer peripheral surface of the bearing holder 410e. As described above, the stator includes the coil 410d, the bearing, and the bearing holder 410e. That is, the fan 41 has a motor.

  The housing 42 accommodates the fan 41 rotatably. The housing 42 is disposed so as to cover the through hole 211 while facing the peripheral portion of the through hole 211 on the outer surface 21a. A plurality of ventilation holes are formed in the housing 42. The plurality of vent holes are formed at different positions in the Z direction so that the air flow along the outer surface 21a of the bottom wall 210 is formed with the rotation of the fan 41 (blade 411).

  The housing 42 has a bottom wall 420 and a side wall 421. The housing 42 is formed using a resin material. The side wall 421 has a cylindrical shape with both ends opened in the Z direction. One opening of the cylinder is a first vent 423 described later. The bottom wall 420 closes the other opening, and the housing 42 has a bottomed cylindrical shape as a whole. Corners of adjacent side walls 421, that is, connecting portions have rounded round shapes.

  The housing 42 has a first vent 423 and a second vent 424. When the fan 41 rotates forward, the first vent 423 functions as an air inlet and the second vent 424 functions as an exhaust. The first vent 423 opens in the XY plane, and is formed at a position farther in the Z direction than the fan 41 when viewed from the case 21. That is, the blade 411 of the fan 41 can be visually recognized by looking into the first vent from the Z direction. The second vent 424 is a vent that opens in the side wall 421 of the housing 42. The side wall 421 has a substantially rectangular shape with rounded corners when viewed from the front in the Z direction, and the second vent 424 includes two openings that open in the X direction and two openings that open in the Y direction. Become. The second vent hole 424 opens between the blade 411 and the outer surface 21a in the Z direction. That is, all the vent holes 423 and 424 are located above the outer surface 21a around the opening of the through hole 211 in the Z direction.

  In the present embodiment, if the air flow accompanying the forward rotation of the fan 41 is a flow that uses the first vent 423 as a suction port as described above, the air flows from the first vent 423 in the Z direction. The air flow is changed in the direction along the XY plane after being sucked into the air, discharged from the second vent 424, and escapes outward along the outer surface 21a of the case 21. By the way, since the air tends to be warmed in the vicinity of the waterproof casing 20 that easily stores heat, air that is farther from the waterproof casing 20 due to the forward rotation is removed from the waterproof casing than the air circulation due to the reverse rotation. The cooling effect becomes higher as it flows into the 20 side.

  The bottom wall 420 is fixed to the outer surface 21a of the case 21 through a seal member (not shown). The bottom wall 420 is fixed in contact with the outer surface 21 a around the through hole 211 so as to cover the through hole 211. The seal member is interposed between the bottom wall 420 and the outer surface 21a so as to surround the through hole 211, and prevents water and dust from entering the through hole 211 from the outside.

  The terminal 43 protrudes from the housing 42 toward the internal space 20 s and is electrically connected to the circuit board 30. The terminal 43 passes through the bottom wall 420 of the housing 42. The terminal 43 protrudes into the internal space 20 s while being inserted through the through hole 211 in the case 21. One end of the terminal 43 is electrically connected to the fan board 44 disposed in the housing 42, and the other end is connected to the circuit board 30. Thus, the fan substrate 44, that is, the blower unit 40 and the circuit board 30 are electrically connected via the terminal 43. The metal terminal 43 is integrated with the resin housing 42 by insert molding.

  A drive circuit for rotating the fan 41 is formed on the fan substrate 44. The fan substrate 44 is electrically connected to a coil 410 d that constitutes the shaft portion 410. When the coil 410d is energized through the circuit board 30, the terminal 43, and the fan board 44, the rotor described above rotates. Then, an air pressure difference is generated in the housing 42 due to the predetermined shape of the blade 411, and the air sucked from the first vent 423 is discharged from the second vent 424 as shown in FIG. 2. When the rotor is rotated in the direction opposite to the forward direction, the air sucked from the second vent 424 is discharged from the first vent 423.

  The fan substrate 44 is disposed below the blades 411 in the housing 42. The fan substrate 44 is fixed to the housing 42. In the present embodiment, the fan substrate 44 is sealed by the potting body 45. The fan substrate 44 is fixed to the housing 42 by terminals 43 and a potting body 45. The potting body 45 is provided in the housing 42 at a depth that does not block the second vent hole 424 and does not hinder the movement of the rotor such as the boss and the blade 411. Note that the sealing of the fan substrate 44 is not limited to the potting body 45. For example, a configuration in which the fan substrate 44 on which the terminals 43 are mounted is insert-molded in the housing 42 and the fan substrate 44 is sealed by the bottom wall 420 may be employed.

  As described above, the circuit board 30 and the fan board 44 are electrically connected by the terminals 43, and the rotation of the fan 41 is controlled by the control circuit unit 34 mounted on the circuit board 30. Specifically, as shown in FIG. 3, the control circuit unit 34 controls energization to the coil 410 d via a switch SW formed on the circuit board 30. That is, the control circuit unit 34 transmits a control signal for opening and closing the switch SW. In FIG. 3, for simplicity of explanation, the coil 410 d is illustrated as being connected in series between the power source VB and the switch SW. However, in actuality, an inverter circuit in which the fan substrate 44 forms a three-phase alternating current is illustrated. Have. As described above, the circuit board 33 and the fan board 44 are connected to each other through the power supply line and the signal line. The power supply line may be separately wired from the outside.

  As described above, the circuit board 30 in the present embodiment includes the control circuit unit 34, the first temperature detection unit 35, and the second temperature detection unit 36. As described above, the control circuit unit 34 controls the opening / closing of the switch SW by outputting a control signal to the switch SW. When the switch SW is closed, the circuit is configured such that the coil 410d is interposed between the power source VB and the reference potential GND, and the fan 41 rotates. At this time, the control signal output from the control circuit 34 to the switch SW is referred to as an ON signal. On the other hand, when the switch SW is opened, no current flows through the coil 410d between the power source VB and the reference potential GND, and the fan 41 does not rotate or stops rotating. At this time, the control signal output from the control circuit 34 to the switch SW is referred to as an off signal. In other words, the control circuit unit 34 controls the rotation of the fan 41 by outputting an on signal or an off signal to the switch SW of the fan substrate 44. The control circuit unit 34 alternately outputs an on signal and an off signal when diagnosing the blower unit 40.

  Next, operational effects of the electronic control device 10 according to the present embodiment will be described together with an example of a method by which the control circuit unit 34 determines abnormality of the blower unit 40.

  After a predetermined time τ after the ON signal is issued, the control circuit unit 34 detects the physical quantity correlated with the temperature detected by the first temperature detection unit 35 (hereinafter simply referred to as temperature T1) and the second temperature detection. A physical quantity correlated with the temperature detected by the unit 36 (hereinafter simply referred to as temperature T2) is acquired. Since the first temperature detection unit 35 is in the vicinity of the heat generating element and is easily affected by cooling by driving the blower unit 40, the temperature T <b> 1 has a strong correlation with the temperature of the circuit board 30. On the other hand, the second temperature detection unit 36 is provided at the end of the printed circuit board 31 that is far from the heat generating element and the blower unit 40, and is in a position that is not easily affected by cooling due to the drive of the blower unit 40. In addition, since it is thermally connected to the case 21 via the heat radiating gel 37, the temperature T1 has a strong correlation with the temperature outside the waterproof casing 20.

  When the temperature T1 is not lower than the predetermined threshold value, the fan 41 of the blower unit 40 does not rotate sufficiently or at all even though the ON signal is issued from the control circuit unit 34, and the cooling capacity decreases. It is expected that That is, it is suggested that the blower unit 40 is abnormal, and the control circuit unit 34 sets a first flag that is an abnormal flag related to the blower unit 40 (logical value: H).

  On the other hand, the control circuit unit 34 also acquires the temperature T2. The control circuit unit 34 compares the temperature T1 and the temperature T2, and when T1> T2, sets a second flag that is an abnormality flag regarding the blower unit 40 (logical value: H).

  When the logical product (AND) of the first flag and the second flag is “H”, the control circuit unit 34 determines that an abnormality has occurred in the blower unit 40 and notifies the user to that effect. That is, the control circuit unit 34 generates an ON signal for rotating the fan 41 of the blower unit 40, and immediately after a predetermined time τ, even if the temperature T1 does not fall below the threshold value, the blower unit 40 immediately fails. Without judging that there is, it is confirmed whether the abnormality is true or not by comparing the temperature T1 and the temperature T2.

  Specifically, when the external temperature of the waterproof casing 20 is higher than the internal temperature (T1 <T2), the temperature of the environment in which the electronic control device 10 is placed increases the cooling capacity of the blower unit 40. It is assumed that the temperature is higher than that, and the blower unit 40 may be normal.

  As described above, by employing the electronic control device 10 according to the present embodiment, it is possible to prevent erroneous detection of abnormal rotation of the blower unit 40 and thus the fan 41.

(Second Embodiment)
In the first embodiment, when determining the abnormality of the blower unit 40, the absolute value of the physical quantity (temperature T1) correlated with the temperature detected by the first temperature detection unit 35 and the temperature detected by the second temperature detection unit 36 are correlated. Although the example of comparing the absolute value (temperature T2) of the physical quantity to be described has been described, the comparison target may be a temperature gradient.

  The control circuit unit 34 in the present embodiment continuously monitors the temperature T1 and the temperature T2. Assume that the behavior of temperature T1 and temperature T2 is as shown in FIG. That is, T1> T2 before the control circuit unit 34 issues an ON signal, and the temperature rises as time passes. After the ON signal is issued, the increase in temperature T1 is suppressed and the temperature T2 is Assume a situation in which the temperature rise before discharge is maintained. As shown in FIG. 4, the temperature gradient ΔT2 of the temperature T2 after the ON signal is issued is larger than the temperature gradient ΔT1 of the temperature T1.

  The control circuit unit 34 sets the first flag as in the first embodiment. That is, when the temperature T1 is not below the predetermined threshold value, the fan 41 of the blower unit 40 does not rotate sufficiently or at all even though the ON signal is issued from the control circuit unit 34, and the cooling capacity is low. Expected to decline. For this reason, it is suggested that the blower unit 40 is abnormal, and the control circuit unit 34 sets a first flag that is an abnormal flag related to the blower unit 40 (logical value: H).

  On the other hand, the control circuit unit 34 acquires the gradient ΔT1 of the temperature T1 detected by the first temperature detection unit 35 and the gradient ΔT2 of the temperature T2 detected by the second temperature detection unit 36. The control circuit unit 34 compares the temperature gradient ΔT1 and the temperature gradient ΔT2, and when ΔT1> ΔT2, sets a second flag that is an abnormality flag for the blower unit 40 (logical value: H).

  When the logical product (AND) of the first flag and the second flag is “H”, the control circuit unit 34 determines that an abnormality has occurred in the blower unit 40 and notifies the user to that effect. That is, the control circuit unit 34 generates an ON signal for rotating the fan 41 of the blower unit 40, and immediately after a predetermined time τ, even if the temperature T1 does not fall below the threshold value, the blower unit 40 immediately fails. Without judging that there is, the true / false of the abnormality is confirmed by comparing the temperature gradient ΔT1 with the temperature gradient ΔT2.

  Specifically, when the gradient ΔT2 of the temperature T2 is higher than the gradient ΔT1 of the temperature T1 (ΔT1 <ΔT2), the inflow of heat from the outside where the electronic control device 10 is placed to the inside of the prevention housing 20 is caused. It is assumed that it is in a high temperature environment that is large and exceeds the cooling capacity of the blower unit 40, and the blower unit 40 may have no abnormality. In particular, in the example shown in FIG. 4, the gradient ΔT1 of the temperature T1 is small after the ON signal is issued, and there is a high possibility that the fan 41 is rotating normally. That is, it is possible to prevent erroneous detection that an abnormality has occurred in the blower unit 40 because the temperature T1 does not fall below the threshold value after a predetermined time τ after the ON signal is issued.

  As described above, by employing the electronic control device 10 according to the present embodiment, it is possible to prevent erroneous detection of abnormal rotation of the blower unit 40 and thus the fan 41.

(Third embodiment)
In each of the above-described embodiments, it has been described that the second temperature detection unit 36 is disposed at the end of the outer edge of the printed circuit board 31, but is not limited to this example. The 2nd temperature detection part 36 should just be mounted in the position away from the 1st temperature detection part 35 mounted in the mounting position of the ventilation unit 40, and the ventilation unit 40 vicinity.

  In particular, the second temperature detector 36 is preferably mounted at a location where the temperature outside the waterproof casing 20 can be easily detected. As shown in FIG. 5, the second temperature detector 36 is attached to an earth land 38 formed on the printed circuit board 31. It should be implemented. The earth land 38 is a wiring on the circuit board 30 that comes into contact with the waterproof casing 20, and is used to fix the potential of the waterproof casing 20. The earth land 38 in the present embodiment corresponds to the housing contact wiring portion described in the claims.

  As shown in FIG. 5, the case 21 in the present embodiment has a protrusion 23 protruding from the inner surface 21 b. The protrusion 23 is provided with a screw hole, and the printed circuit board 31 is fixed to the case 21 so as to be held between the screw head of the screw 39 and the protrusion 23. The printed circuit board 31 has an earth land 38, and when the printed circuit board 31 and the protrusion 23 are sandwiched, the earth land 38 contacts the protrusion 23 and is electrically connected. That is, the case 21 and the earth land 38 have the same potential. The waterproof casing 20 is fixed at a potential for the purpose of preventing an antenna, preventing the formation of an unintended current path, and preventing charging. There are various connection destinations of the earth land 38 such as a vehicle body, a negative terminal of the battery, a ground inside the ECU, and the like, but the potential is fixed at any part. This may become the ground potential of the circuit board 30. Since the earth land 38 is electrically connected to the case 21, the thermal conductivity between the two is relatively high. That is, if the temperature of the earth land 38 is close to the temperature of the case 21 and is formed at a position far from the heating element mounted on the printed circuit board 31 or the air blowing unit 40 fixed to the case 21, the waterproof housing 20. It will be close to the outside temperature.

  The second temperature detection unit 36 in the present embodiment is mounted so as to contact the earth land 38. For this reason, the second temperature detection unit 36 can detect a temperature close to the temperature outside the waterproof housing 20.

(Fourth embodiment)
Since it is preferable that the second temperature detection unit 36 can easily detect the temperature outside the waterproof housing 20, the second temperature detection unit 36 may be directly fixed to the case 21 as shown in FIG. 6, for example. The second temperature detector 36 is fixed to the case 21 in the vicinity of the outer edge of the printed circuit board 31. The contact between the second temperature detection unit 36 and the case 31 may be fixed via an adhesive having thermal conductivity, or may be press-contacted by an elastic member or the like. The 2nd temperature detection part 36 and the printed circuit board 31 are connected so that communication is possible by the flexible substrate 36a, for example.

  Since the second temperature detection unit 36 is directly fixed to the case 21 and thus to the waterproof casing 20, the temperature outside the waterproof casing 20 can be detected more accurately.

(Other embodiments)
The preferred embodiment has been described above, but the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist disclosed in this specification.

  Although the example in which the electronic control device 10 is configured as a control device that controls the vehicle engine has been described, the present invention is not limited to this.

  Further, in each of the above-described embodiments, the example in which the second temperature detection unit 36 is mounted on the end of the outer edge of the printed circuit board 31 has been described. However, the second temperature detection unit 36 includes the mounting position of the blower unit 40 and the blower unit. It suffices to be mounted at a position away from the first temperature detection unit 35 mounted in the vicinity of 40, and it is not always necessary to mount at the end of the printed circuit board 31 or the vicinity of the printed circuit board 31 in the case 21.

DESCRIPTION OF SYMBOLS 10 ... Electronic control unit, 20 ... Waterproof housing, 20s ... Internal space, 21 ... Case, 21a ... Outer surface, 21b ... Inner surface, 210 ... Bottom wall, 211 ... Through-hole, 212 ... 1st accommodating part, 213 ... 2nd Accommodating portion, 214 ... mounting portion, 215 ... fixing hole, 22 ... cover, 220 ... heat radiation fin, 30 ... circuit board, 31 ... printed circuit board, 31a ... one side, 31b ... back side, 32 ... electronic component, 33 ... connector, 34 ... Control circuit part, 34a ... Temperature acquisition part, 34b ... Difference calculation part, 34c ... Counter, 35 ... First temperature detection part, 36 ... Second temperature detection part, 38 ... Earth land, 40 ... Blower unit, 41 ... Fan , 410 ... Shaft portion, 410 a ... Rotating shaft, 411 ... Blade, 42 ... Housing, 420 ... Bottom wall, 421 ... Side wall, 422 ... Flange, 423 ... First vent, 424 ... Second vent, 43 Terminal, 44 ... Fan substrate, 45 ... potting body 50 ... second housing, 523 ... third vent, 524 ... fourth vent

Claims (5)

A circuit board (30) on which a control circuit unit (34) is mounted;
A housing (20) in which the circuit board is housed;
A fan unit (40) whose drive is controlled by the control circuit unit, and a fan unit (40) for cooling the housing from the outside;
A first temperature detector (35) for detecting a physical quantity correlated with the temperature of the circuit board;
A physical quantity that correlates with the temperature outside the housing, and a second temperature detection unit (36) disposed at a location farther from the fan than the first temperature detection unit,
The control circuit unit determines an abnormality of the fan based on a physical quantity detected by the first temperature detection unit, a physical quantity detected by the first temperature detection unit, and a physical quantity detected by the second temperature detection unit. An electronic control unit that determines whether the fan is abnormal by comparing The first temperature detection unit and the second temperature detection unit are mounted on the circuit board,
The electronic control device according to claim 1, wherein the second temperature detection unit is disposed at an outer edge portion of the circuit board. The circuit board has a case contact wiring part (38) that contacts the case,
The electronic control device according to claim 1, wherein the second temperature detection unit is disposed on a wiring connected to the housing contact wiring unit.   The electronic control device according to claim 1, wherein the second temperature detection unit is fixed to the housing.   5. The electronic control device according to claim 1, wherein the second temperature detection unit is fixed to the inner surface (21 b) of the housing via a heat radiating member (37).

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