JP2005278344A - Motor control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor control device that is suppressed in the delay of temperature transmission, reduced in the offset of a temperature detection value, and improved in the sureness of an overheat protection function. <P>SOLUTION: The motor control device 40 is constituted so as to operate the overheat protection function in accordance with the detected temperature of a temperature sensor 17 mounted to a circuit board 50. A wiring pattern 54 of a circuit including transistors T1, T2 also serves as heat conduction passages to the temperature sensor 17 from the transistors T1, T2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a motor control device that is suitably employed in, for example, an electric power steering device for a vehicle.

  2. Description of the Related Art An electric power steering device for a vehicle is configured to drive an assist motor with an H bridge circuit or a three-phase bridge circuit using a power element (switching element) such as an IGBT or a power MOSFET. The power element generates heat because a large current flows during steering of the steering wheel. An overheat protection function that detects the temperature at a specific position of the circuit board on which the power element is mounted with a temperature sensor such as a thermistor and operates according to the detection result in order to prevent the control system from failing due to excessive heat generation Is provided.

  On the circuit board, the temperature sensor and the power element often cannot be positioned close to each other due to the structure or arrangement, and because the positions are separated, a temperature transmission delay occurs. When the temperature transmission delay is large, when the temperature rise of the power element suddenly occurs, the operation of the overheat protection function may not be in time, and the occurrence of a thermal failure may not be prevented. Further, there is a difference (temperature detection value offset) between the actual temperature of the power element and the temperature detected by the temperature sensor. Therefore, it is necessary to perform overheat protection in consideration of such a temperature transmission delay and temperature detection value offset, but as a practical problem, it is difficult to accurately calculate the temperature transmission delay and temperature detection value offset. The error is transferred to the operating temperature of the overheat protection function as a margin, and overheat protection is performed early.

If this margin can be made as small as possible and the operation start temperature of the overheat protection function can be increased, the overheat protection function will be difficult to operate even if the steering wheel is operated frequently, and a high-performance electric motor that can always obtain sufficient assist power. A power steering device can be realized. For this purpose, it is important to reduce the temperature transmission delay and the temperature detection value offset between the power element and the temperature sensor. For example, Patent Document 1 below discloses a technique for reducing a temperature transmission delay and a temperature detection value offset between a power element and a temperature sensor by providing a circuit board with a conductor pattern that contacts both the power element and the temperature sensor. It is disclosed.
Japanese Patent Laid-Open No. 10-48057

  However, in the above technique, since it is necessary to provide a conductor pattern irrelevant to the circuit, a lot of space is wasted, and it goes against the trend of downsizing the motor control device. In addition, it is still insufficient in terms of versatility, such as whether it can be applied to a surface-mount type temperature sensor. Therefore, another technique capable of eliminating the temperature transmission delay and the temperature detection value offset is desired to be equal to or more than the above technique.

  In view of the above circumstances, an object of the present invention is to provide a motor control device that reduces the temperature transmission delay and the temperature detection value offset and improves the reliability of the overheat protection function.

Means for Solving the Problems and Effects of the Invention

  In order to solve the above problems, a first aspect of the present invention is that a power element that controls energization to a motor is mounted on a circuit board and is thermally coupled to the power element via the circuit board. In the motor control device configured to operate the overheat protection function according to the temperature detected by the temperature sensor, the circuit wiring pattern including the power element is provided as a board element of the circuit board. The main feature is that the wiring pattern is also used as a heat conduction path from the power element to the temperature sensor.

  The motor control device of the present invention has an overheat protection function for preventing the control system from being damaged due to heat. A wiring pattern with good thermal conductivity is used as a heat transfer path between the temperature sensor and the power element. Therefore, the temperature transmission delay and the temperature detection value offset can be reduced. Thereby, the margin of the operation start set temperature of the overheat protection function can be reduced, and as a result, the reliability of the overheat protection function can be improved. In addition, since the circuit wiring pattern itself is also used as a heat conduction path, it is advantageous in terms of circuit design compared to the case where a conductor pattern unrelated to the circuit is provided as a heat conduction path.

  Specifically, it is preferable that a wiring pattern that connects power elements that are transistors constituting the upper phase or the lower phase of the H-bridge circuit or the three-phase bridge circuit is also used as a heat conduction path. According to this, it is not necessary to provide a temperature sensor individually for each power element. For example, in the case of an H bridge circuit, it is sufficient to provide a temperature sensor in the upper phase or the lower phase, which is also preferable from the viewpoint of suppressing an increase in the number of parts.

  More preferably, a wiring pattern that connects the drain terminals that are likely to increase in temperature can be used as the heat conduction path. Moreover, you may provide a temperature sensor corresponding to an upper phase and a lower phase separately. In that case, temperature detection can be performed with higher accuracy.

  In one preferred embodiment, the circuit board described above has a structure in which dielectric layers and conductor layers are alternately stacked. The wiring pattern as the heat conduction path is provided as a board element constituting a conductor layer inside the board. Further, the circuit board is provided with a land on the conductor layer different from the one conductor layer on which the wiring pattern is provided in order to mount the temperature sensor so that the land overlaps the wiring pattern in the board thickness direction. . A dielectric layer is interposed between the wiring pattern as the heat conduction path and the land for mounting the temperature sensor. However, the thickness of one dielectric layer in a normal printed circuit board is not great (for example, about 300 μm). If so, considering the thermal coupling between the wiring pattern and the land, it is preferable that they overlap in the substrate thickness direction. Moreover, since the wiring pattern as the heat conduction path is provided in the inner layer of the substrate, it is less likely to be cooled than when exposed on the substrate surface. That is, positively using the wiring pattern on the inner layer of the substrate as a heat conduction path contributes to reducing the temperature detection value offset. Note that the conductor layer different from the one conductor layer is preferably conductor layers adjacent to each other via one dielectric layer. In such a case, the wiring pattern as the heat conduction path and the land for mounting the temperature sensor are brought closest to each other, and this is directly connected to improving the thermal coupling property.

  However, it is also possible to provide a wiring pattern as a heat conduction path on the same conductor layer as the land for mounting the temperature sensor. That is, the above-described circuit board can be provided with a land for mounting the temperature sensor so as to be surrounded by the wiring pattern in a cutout region formed by cutting out a part of the wiring pattern. If it does in this way, the effect | action which heat | fever conducts from multiple directions with respect to a land from a wiring pattern can be acquired, and the effect of making temperature transmission delay and a temperature detection value offset small can be heightened.

  Furthermore, the above embodiments can be combined. That is, in another preferred embodiment, the circuit board described above has a structure in which dielectric layers and conductor layers are alternately laminated, and the wiring pattern is provided as a board element constituting the conductor layer inside the board. The first wiring pattern and the second wiring pattern provided on the mounting surface of the temperature sensor, and the circuit board includes a land that is a board element for mounting the temperature sensor, The first wiring pattern overlaps in the substrate thickness direction, and is provided in a cutout region formed by cutting out a part of the second wiring pattern so as to be surrounded by the second wiring pattern. According to this configuration, (1) the effect of the configuration in which the temperature sensor mounting land and the wiring pattern as the heat transfer path overlap in the substrate thickness direction, and (2) the temperature sensor mounting land A synergistic effect with the effect of the configuration surrounded by the wiring pattern as the transmission path can be expected.

  As the temperature sensor, it is desirable to employ a surface mount type sensor. In this case, the temperature sensor mounting land (solder land) may be formed in a larger area than the terminal surface of the temperature sensor. And the wiring pattern for the signal extraction of a temperature sensor will be provided so that it may extend from a part of outer periphery of a land. In other words, the land for mounting the temperature sensor has an appropriately large heat capacity so that heat reception is promoted, and the wiring pattern connecting the land and the A / D conversion circuit is made thin to suppress heat dissipation. .

  In another aspect, in order to solve the problem, the second of the present invention is a circuit in which a power element that controls energization to a motor is mounted on a circuit board and thermally coupled to the power element through the circuit board. In a motor control device in which a temperature sensor is surface-mounted on a substrate and configured to activate an overheat protection function according to a temperature detected by the temperature sensor, a circuit pattern including a power element and a circuit including the temperature sensor This wiring pattern is provided as a board element of the circuit board, and both the wiring patterns are also used as a heat conduction path from the power element to the temperature sensor. A specific example of a wiring pattern of a circuit including a temperature sensor can indicate a land for surface mounting the temperature sensor. Other parts are the same as those of the above-described invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a configuration diagram of an electric power steering apparatus 1. A steering handle 10 is connected to the steering shaft 12a. Further, the lower end of the steering shaft 12 a is connected to the torque sensor 11, and the upper end of the pinion shaft 12 b is connected to the torque sensor 11. Further, a pinion (not shown) is provided at the lower end of the pinion shaft 12 b, and this pinion is meshed with the rack bar 18 in the steering gear box 16. Further, one end of a tie rod 20 is connected to each end of the rack bar 18, and a steered wheel 24 is connected to the other end of each tie rod 20 via a knuckle arm 22. An electric motor 15 is attached to the pinion shaft 12b via a gear (not shown) to constitute a so-called column type electric power steering apparatus.

  The mounting position of the electric motor 15 is a rack type that is coaxially attached to the rack bar 18 in addition to the configuration of FIG. 1 or a pinion type that is attached to the steering gear box 16 and rotates the steering shaft 12a. May be.

  The torque sensor 11 corresponds to a steering force detection means for detecting the movement of the steering handle 10 of the driver, and is composed of a known torque detection unit such as a torsion bar and a pair of resolvers that are spaced apart in the axial direction thereof. The When the handle shaft 12a rotates, torque corresponding to the torsion amount of the torsion bar is detected, and the detected information is sent to the steering control unit 30.

  A steering angle sensor 13 for detecting the steering angle of the steering handle 10 is attached to the steering shaft 12a. The steering angle sensor 13 corresponds to a steering angle detection means, and includes a known angle detection unit such as a rotary encoder or a resolver. The detected information is sent to the steering control unit 30.

  The steering control unit 30 includes a well-known CPU 31, RAM 32, ROM 33, I / O 34 as an input / output interface, and a bus line 35 for connecting these components. The CPU 31 controls the program and data stored in the ROM 33 and RAM 32. The ROM 33 has a program storage area 33a and a data storage area 33b. A steering control program 33p is stored in the program storage area 33a. The data storage area 33b stores data necessary for the operation of the steering control program 33p. The steering control program 33p includes a program that realizes an overheat protection function of the motor control device 40 described later.

  In the steering control unit 30, the CPU 31 executes a steering control program stored in the ROM 33, so that the electric motor 15 corresponding to the torque detected by the torque sensor 11 and the steering angle detected by the steering angle sensor 13 is driven. Torque is calculated, and a voltage for generating the calculated drive torque is applied to the electric motor 15 via the motor driver 14. The electric motor 15 may be of any type (DC motor, brushless motor, etc.) as long as it can be used in the electric power steering apparatus 1 of the present invention.

  Next, FIG. 2 is a control block diagram of the motor control device 40 provided in the electric power steering device 1 of FIG. The motor control device 40 includes the steering control unit 30, the temperature sensor 17, the PWM output device 14 (motor driver 14), and the current detector 8 described above. The current command value calculation unit 30a of the steering control unit 30 receives a steering torque signal obtained by converting the steering torque generated on the steering shaft 12a into an electric signal, and calculates a current command value from the steering torque signal. On the other hand, the actual motor current is detected by the current detector 8, and the detected value is fed back to the steering control unit 30. The voltage command value calculation unit 30 determines a voltage command value from the difference between the current detection value of the current detector 8 and the current command value of the current command value calculation unit 30a. The obtained voltage command value is applied to the motor 15 by the PWM output unit 14 as a motor applied voltage in the form of PWM drive.

  As shown in FIG. 3, the final stage of the PWM output unit 14 is configured by an H bridge circuit (may be a three-phase bridge circuit) including transistors T1, T2, T3, and T4. The transistors T1, T2, T3, and T4 are switched at a PWM (pulse width modulation) duty based on the voltage command value. Here, since the current supplied to the motor 15 is as large as several tens of amperes, the transistors T1, T2, T3, and T4 generate considerable heat. A heat sink 52 (see FIG. 4) is attached to each of the transistors T1, T2, T3, and T4. The heat sink 52 is set to be relatively small. This is because the transistors T1, T2, T3, and T4 do not generate heat when the steering wheel is not steered, and the realistic size of the entire control device is taken into consideration.

  However, in order to prevent thermal failure of the motor control device 40 when the steering of the steering wheel is concentrated in a short time and the transistors T1, T2, T3, T4 generate heat suddenly, the transistors T1, T2, T3 The temperature of the circuit board 50 on which T4 is mounted is detected, and the overheat protection function is activated according to the detection result. In the present embodiment, based on the temperature detected by the temperature sensor 17 and the operating rates of the transistors T1, T2, T3, and T4, control is performed to limit the current supplied to the motor 15 (limit assist force). Yes.

  FIG. 4 is a perspective view of the circuit board 50 on which the transistors T1, T2, T3, T4 and the temperature sensor 17 are mounted. Although not shown in the block diagram of FIG. 2, the circuit board 50 is a component constituting the motor control device 40, and includes the microcomputer as the steering control unit 30, the temperature sensor 17, and the transistors T <b> 1 and PWM 1 of the PWM output device 14. It is configured as a multilayer circuit board on which electronic components such as T2, T3, and T4 are mounted, and a wiring pattern for connecting the electronic components to each other is provided as a substrate element.

  A common heat sink 52 is attached to the transistors T1, T2, T3, and T4 mounted on the circuit board 50. Further, the temperature sensor 17 is surface-mounted so as to be connected to the wiring patterns 60 and 62 provided between the transistors T1 and T2. That is, the transistors T 1, T 2, T 3, T 4 (particularly T 1, T 2) and the temperature sensor 17 are thermally coupled via the circuit board 50. The output signal of the temperature sensor 17 is input to the A / D of the steering control unit 30 via the wiring patterns 60b and 62b. A known thermistor can be used for the temperature sensor 17.

  Next, FIG. 5 is a top view of the circuit board 50 of FIG. The broken line in FIG. 5 represents a portion that cannot be directly seen, and is useful for understanding the positional relationship in the substrate thickness direction. Reference numerals G, D, and S attached to the transistors T1 and T2 mean a gate, a drain, and a source, respectively. The drain terminals of the transistors T1 and T2 are connected to each other by an inner wiring pattern 54. The heat of the transistors T1 and T2 is transmitted to the temperature sensor 17 through the wiring pattern 54. That is, the wiring pattern 54 forming a part of the H-bridge circuit in FIG. 3 is also used as a heat conduction path from the transistors T1 and T2 to the temperature sensor 17.

  FIG. 6 shows a partial cross-sectional view of the circuit board 50 of FIG. As shown in FIG. 6, the circuit board 50 has a structure in which dielectric layers V1 and V2 and conductor layers M1 and M2 are alternately stacked. The wiring pattern 54 that is also used as a heat conduction path from the transistors T1 and T2 to the temperature sensor 17 is provided as a substrate element constituting the conductor layer M1 inside the substrate. Then, lands 60a and 62a (solder lands) for mounting the temperature sensor 17 are provided on the conductor layer M2 on the upper side of the dielectric layer V2. The lands 60a and 62a and the wiring pattern 54 are configured to overlap in the substrate thickness direction. That is, the arrangement is such that thermal coupling in the substrate thickness direction is likely to occur.

  With the above configuration, as shown in FIG. 7, a delay in temperature transmission from the transistors T1 and T2, which are heat generating units, to the temperature sensor 17 can be reduced as compared with the conventional case. In addition, since the dielectric layers V1 and V2 are arranged above and below, the temperature of the wiring pattern 54 is excellent, and the difference between the actual temperature of the transistors T1 and T2 and the detected temperature of the temperature sensor 17 (temperature detection value offset). ) Can be reduced. As a result, it is possible to design a margin based on the temperature transmission delay and the temperature detection value offset, and it is possible to optimize the timing at which the overheat protection function is to be activated. In FIG. 7, the horizontal axis indicates the passage of time, and the vertical axis indicates the temperature.

  Returning to FIG. In the present embodiment, the wiring pattern 54 as a heat transfer path is a wiring pattern 54 that connects the drain terminals of the transistors T1 and T2. This is because the drain terminal is one of the parts where the heat of the transistors T1 and T2 is most easily transmitted. In addition, the wiring pattern 54 that connects the drain terminals is originally formed thick, so that heat conduction is good. Therefore, it is suitable for use as a heat conduction path. In general MOSFETs, the lower surface of the chip is the drain electrode, and this electrode is directly soldered to the lead frame integrated with the drain terminal to the outside. It is easy to show accurately.

  In the present embodiment, the wiring pattern 54 that connects the terminals (drains) of the transistors T1 and T2 forming the upper phase of the H-bridge circuit is used as a heat transfer path. It is also possible to use a wiring pattern connecting the terminals (sources) of the transistors T3 and T4 forming the lower phase of the bridge circuit as a heat transfer path.

  As can be seen from FIGS. 5 and 6, the lands 60 a and 62 a for surface mounting the temperature sensor 17 have a larger area than the terminal surfaces 17 p and 17 q of the temperature sensor 17. By doing so, heat is received from the wiring pattern 54 directly below with high efficiency. Further, thin wiring patterns 60b and 62b extend from part of the outer periphery of the lands 60a and 62a. These wiring patterns 60b and 62b are narrower than the lands 60a and 62a in order to suppress heat dissipation.

  In addition, as shown in FIG. 5, the temperature sensor 17 and the lands 60 a and 62 a can all be located inside the outer peripheral edge of the wiring pattern 54 in the substrate thickness direction. In addition, with respect to the wiring patterns 60b and 62b for extracting sensor signals, only one end portion for connection to the lands 60a and 62a can overlap the wiring pattern 54. Thereby, the heat radiation from the wiring patterns 60b and 62b for sensor signal extraction can be effectively suppressed. Specifically, the heat capacities of the signal extraction wiring patterns 60b and 62b connected to the lands 60a and 62a are within the operating temperature range of the temperature sensor 17, and the heat capacities of the lands 60a and 62a and the heat capacities of the temperature sensor 17 are Adjust so that it is less than or equal to 1/2 of the sum. In this way, it is possible to reliably suppress a heat radiation error from the detection unit constituted by the temperature sensor 17 and the lands 60a and 62a. The size of the lands 60a and 62a and the lines of the signal extraction wiring patterns 60b and 62b are set so that the heat capacity of the signal extraction wiring patterns 60b and 62b is ½ or less of the heat capacity of the lands 60a and 62a. It is more preferable to adjust the width. The wiring patterns 60b and 62b are wirings leading to a mounting land such as a microcomputer (steering control unit) including an A / D conversion circuit.

(Second embodiment)
FIG. 8 shows another embodiment. In FIG. 8, only the parts different from the embodiment described so far (the parts corresponding to FIG. 5) are shown. This embodiment is common to the embodiments described so far in that the wiring pattern 58 of the circuit including the transistors T1 and T2 is also used as a heat conduction path to the temperature sensor 17. The difference is that the wiring pattern 58 of the H bridge circuit is arranged on the same conductor layer as the lands 60a and 62a for mounting the temperature sensor.

  Specifically, lands 60 a and 62 a for mounting the temperature sensor 17 are provided so as to be surrounded by the wiring pattern 58 in a cutout area KA formed by cutting out a part of the wiring pattern 58 in a concave shape. In the present embodiment, since the lands 60a and 62a are formed in a square shape including the above-described embodiments, the cutout area KA is also cut out in a square shape accordingly. According to such a configuration, since the distance between the wiring pattern 58 and the lands 60a and 62a can be made very close to each other, the thermal coupling property in the in-plane direction of the substrate is enhanced, and the same effect as the embodiment of FIG. 5 is achieved. Will be able to. Note that the embodiment of FIG. 8 has an advantage that it can be applied to a circuit board having only one conductor layer in some cases.

(Third embodiment)
FIG. 9 shows another embodiment. The embodiment of FIG. 9 is a combination of the embodiment of FIG. 5 and the embodiment of FIG. As the circuit board, a multilayer board is used. The wiring patterns used as the heat conduction path are a first wiring pattern 54 ′ provided on the inner layer of the substrate and a second wiring pattern 58 ′ provided on the mounting surface of the temperature sensor 17. The lands 60a and 62a for mounting the temperature sensor 17 overlap with the first wiring pattern 54 'in the substrate thickness direction, and are formed by cutting out a part of the second wiring pattern 58'. In KA, it is surrounded by the second wiring pattern 58 ′. According to such a configuration, the efficiency of heat transfer from the transistors T1, T2, T3, T4 to the temperature sensor 17 is further increased, and further improvement in temperature detection accuracy can be expected.

  There is no reason why both of these wiring patterns 54 'and 58' must belong to the upper phase of the bridge circuit. For example, it can be considered that the first wiring pattern 54 'forms the upper phase of the bridge circuit and the second wiring pattern 58' also forms the lower phase of the bridge circuit (and vice versa).

(Fourth embodiment)
In the embodiments so far, the motor control device 40 provided with only one temperature sensor 17 has been described, but two or more temperature sensors 17 may be provided depending on circumstances. The embodiment is shown in FIG. In the embodiment of FIG. 10, the arrangement of the transistors T1, T2, T3, and T4 is different from that of FIG. The transistors T1 and T2 can be the upper phase of the H bridge circuit, and the transistors T3 and T4 can be the lower phase of the H bridge circuit. That is, in the embodiment of FIG. 10, the temperature sensor 17 is individually provided for each of the upper-phase wiring pattern and the lower-phase wiring pattern of the H-bridge circuit.

  For example, in a three-phase bridge circuit, it is predicted that variations in temperature distribution will increase. In that case, it is possible to perform control such that a plurality of temperature sensors 17 detect the temperature of a plurality of locations on the circuit board 50 and determine whether the overheat protection function is activated or deactivated based on the highest detected temperature. become.

The block diagram which shows the whole structure of an electric power steering apparatus. The control block diagram of an electric power steering device. The H bridge circuit diagram which specified the part utilized as a heat conduction path | route. The perspective view of the circuit board which mounted the transistor and the temperature sensor. The top view of the circuit board of FIG. Sectional drawing of the circuit board of FIG. The figure explaining the effect of this invention. The schematic diagram explaining a 2nd Example. The schematic diagram explaining a 3rd Example. The perspective view of the circuit board which shows a 4th Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric power steering apparatus 14 PWM output device 15 Electric motor 17 Temperature sensor 40, 40 'Motor control apparatus 50 Circuit board
54, 58, 54 ', 58' Wiring pattern 60, 62 Wiring pattern (for sensor signal extraction)
60a, 62a Land T1, T2, T3, T4 Transistors V1, V2 Dielectric layers M1, M2 Conductor layers

Claims (8)

  A power element for controlling energization to the motor is mounted on the circuit board, and a temperature sensor is mounted on the circuit board so as to be thermally coupled to the power element via the circuit board. In the motor control device configured to operate the overheat protection function according to the detected temperature, a wiring pattern of a circuit including the power element is provided as a board element of the circuit board, and the wiring pattern is connected to the power element from the power element. A motor control device that is also used as a heat conduction path to a temperature sensor.   2. The power pattern that is also used as a heat conduction path connects the power elements that are transistors constituting at least one of an upper phase and a lower phase of an H-bridge circuit or a three-phase bridge circuit. Motor control device. The circuit board has a structure in which dielectric layers and conductor layers are alternately laminated, and the wiring pattern is provided as a board element constituting the conductor layer inside the board,
Further, the circuit board has a land overlapped with the wiring pattern in the board thickness direction for mounting the temperature sensor on the conductor layer different from the one conductor layer on which the wiring pattern is provided. The motor control device according to claim 1, wherein the motor control device is provided in an arrangement.   The motor control device according to claim 1 or 2, wherein a land for mounting the temperature sensor is provided so as to be surrounded by the wiring pattern in a cutout region formed by cutting out a part of the wiring pattern. The circuit board has a structure in which dielectric layers and conductor layers are alternately laminated,
The wiring pattern is configured to include a first wiring pattern provided as a substrate element constituting the conductor layer inside the substrate, and a second wiring pattern provided on a mounting surface of the temperature sensor,
Further, the circuit board has a land, which is a board element for mounting the temperature sensor, overlapping with the first wiring pattern in the board thickness direction, and cuts a part of the second wiring pattern. The motor control device according to claim 1 or 2, wherein the motor control device is provided in a cutout region formed by being cut out and arranged in a manner surrounded by the second wiring pattern.   The temperature sensor is a surface mounting type, and the land is formed in a larger area than the terminal surface of the temperature sensor, while the signal pattern of the temperature sensor is extended so as to extend from a part of the outer periphery of the land. The motor control device according to claim 1, wherein the motor control device is provided on the circuit board.   The motor control according to claim 6, wherein a heat capacity of the signal extraction wiring pattern connected to the land is adjusted to be not more than ½ of a sum of a heat capacity of the land and a heat capacity of the temperature sensor. apparatus.   A power element that controls energization of the motor is mounted on the circuit board, and a temperature sensor is surface-mounted on the circuit board so as to be thermally coupled to the power element via the circuit board, and the temperature sensor is detected. In a motor control device configured to operate an overheat protection function according to temperature, a wiring pattern of a circuit including the power element and a wiring pattern of a circuit including the temperature sensor are provided as substrate elements of the circuit board. And both the wiring patterns are also used as a heat conduction path from the power element to the temperature sensor.

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